Adding debian version 5.10.209-2.debian/5.10.209-2debian

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

324 files changed, 43253 insertions, 0 deletions

diff --git a/debian/patches-rt/0001-z3fold-remove-preempt-disabled-sections-for-RT.patch b/debian/patches-rt/0001-z3fold-remove-preempt-disabled-sections-for-RT.patch
new file mode 100644
index 000000000..c161007b7
--- /dev/null
+++ b/debian/patches-rt/0001-z3fold-remove-preempt-disabled-sections-for-RT.patch
@@ -0,0 +1,86 @@
+From 373cc1c1427a46b4bf77f0d782d8bd8b2d00bc54 Mon Sep 17 00:00:00 2001
+From: Vitaly Wool <vitaly.wool@konsulko.com>
+Date: Mon, 14 Dec 2020 19:12:36 -0800
+Subject: [PATCH 001/323] z3fold: remove preempt disabled sections for RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Replace get_cpu_ptr() with migrate_disable()+this_cpu_ptr() so RT can take
+spinlocks that become sleeping locks.
+
+Signed-off-by Mike Galbraith <efault@gmx.de>
+
+Link: https://lkml.kernel.org/r/20201209145151.18994-3-vitaly.wool@konsulko.com
+Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.com>
+Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/z3fold.c | 17 ++++++++++-------
+ 1 file changed, 10 insertions(+), 7 deletions(-)
+
+diff --git a/mm/z3fold.c b/mm/z3fold.c
+index 912ac9a64a15..f3d875fcaeb7 100644
+--- a/mm/z3fold.c
++++ b/mm/z3fold.c
+@@ -623,14 +623,16 @@ static inline void add_to_unbuddied(struct z3fold_pool *pool,
+ {
+ 	if (zhdr->first_chunks == 0 || zhdr->last_chunks == 0 ||
+ 			zhdr->middle_chunks == 0) {
+-		struct list_head *unbuddied = get_cpu_ptr(pool->unbuddied);
+-
++		struct list_head *unbuddied;
+ 		int freechunks = num_free_chunks(zhdr);
++
++		migrate_disable();
++		unbuddied = this_cpu_ptr(pool->unbuddied);
+ 		spin_lock(&pool->lock);
+ 		list_add(&zhdr->buddy, &unbuddied[freechunks]);
+ 		spin_unlock(&pool->lock);
+ 		zhdr->cpu = smp_processor_id();
+-		put_cpu_ptr(pool->unbuddied);
++		migrate_enable();
+ 	}
+ }
+ 
+@@ -880,8 +882,9 @@ static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool,
+ 	int chunks = size_to_chunks(size), i;
+ 
+ lookup:
++	migrate_disable();
+ 	/* First, try to find an unbuddied z3fold page. */
+-	unbuddied = get_cpu_ptr(pool->unbuddied);
++	unbuddied = this_cpu_ptr(pool->unbuddied);
+ 	for_each_unbuddied_list(i, chunks) {
+ 		struct list_head *l = &unbuddied[i];
+ 
+@@ -899,7 +902,7 @@ static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool,
+ 		    !z3fold_page_trylock(zhdr)) {
+ 			spin_unlock(&pool->lock);
+ 			zhdr = NULL;
+-			put_cpu_ptr(pool->unbuddied);
++			migrate_enable();
+ 			if (can_sleep)
+ 				cond_resched();
+ 			goto lookup;
+@@ -913,7 +916,7 @@ static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool,
+ 		    test_bit(PAGE_CLAIMED, &page->private)) {
+ 			z3fold_page_unlock(zhdr);
+ 			zhdr = NULL;
+-			put_cpu_ptr(pool->unbuddied);
++			migrate_enable();
+ 			if (can_sleep)
+ 				cond_resched();
+ 			goto lookup;
+@@ -928,7 +931,7 @@ static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool,
+ 		kref_get(&zhdr->refcount);
+ 		break;
+ 	}
+-	put_cpu_ptr(pool->unbuddied);
++	migrate_enable();
+ 
+ 	if (!zhdr) {
+ 		int cpu;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0002-stop_machine-Add-function-and-caller-debug-info.patch b/debian/patches-rt/0002-stop_machine-Add-function-and-caller-debug-info.patch
new file mode 100644
index 000000000..f68789cd5
--- /dev/null
+++ b/debian/patches-rt/0002-stop_machine-Add-function-and-caller-debug-info.patch
@@ -0,0 +1,135 @@
+From 863bc087d69814dc4113ca9ec91ce1895b53480e Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:11:59 +0200
+Subject: [PATCH 002/323] stop_machine: Add function and caller debug info
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Crashes in stop-machine are hard to connect to the calling code, add a
+little something to help with that.
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/stop_machine.h |  5 +++++
+ kernel/stop_machine.c        | 23 ++++++++++++++++++++---
+ lib/dump_stack.c             |  2 ++
+ 3 files changed, 27 insertions(+), 3 deletions(-)
+
+--- a/include/linux/stop_machine.h
++++ b/include/linux/stop_machine.h
+@@ -24,6 +24,7 @@
+ struct cpu_stop_work {
+ 	struct list_head	list;		/* cpu_stopper->works */
+ 	cpu_stop_fn_t		fn;
++	unsigned long		caller;
+ 	void			*arg;
+ 	struct cpu_stop_done	*done;
+ };
+@@ -36,6 +37,8 @@
+ void stop_machine_unpark(int cpu);
+ void stop_machine_yield(const struct cpumask *cpumask);
+ 
++extern void print_stop_info(const char *log_lvl, struct task_struct *task);
++
+ #else	/* CONFIG_SMP */
+ 
+ #include <linux/workqueue.h>
+@@ -80,6 +83,8 @@
+ 	return false;
+ }
+ 
++static inline void print_stop_info(const char *log_lvl, struct task_struct *task) { }
++
+ #endif	/* CONFIG_SMP */
+ 
+ /*
+--- a/kernel/stop_machine.c
++++ b/kernel/stop_machine.c
+@@ -42,11 +42,23 @@
+ 	struct list_head	works;		/* list of pending works */
+ 
+ 	struct cpu_stop_work	stop_work;	/* for stop_cpus */
++	unsigned long		caller;
++	cpu_stop_fn_t		fn;
+ };
+ 
+ static DEFINE_PER_CPU(struct cpu_stopper, cpu_stopper);
+ static bool stop_machine_initialized = false;
+ 
++void print_stop_info(const char *log_lvl, struct task_struct *task)
++{
++	struct cpu_stopper *stopper = this_cpu_ptr(&cpu_stopper);
++
++	if (task != stopper->thread)
++		return;
++
++	printk("%sStopper: %pS <- %pS\n", log_lvl, stopper->fn, (void *)stopper->caller);
++}
++
+ /* static data for stop_cpus */
+ static DEFINE_MUTEX(stop_cpus_mutex);
+ static bool stop_cpus_in_progress;
+@@ -123,7 +135,7 @@
+ int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg)
+ {
+ 	struct cpu_stop_done done;
+-	struct cpu_stop_work work = { .fn = fn, .arg = arg, .done = &done };
++	struct cpu_stop_work work = { .fn = fn, .arg = arg, .done = &done, .caller = _RET_IP_ };
+ 
+ 	cpu_stop_init_done(&done, 1);
+ 	if (!cpu_stop_queue_work(cpu, &work))
+@@ -331,7 +343,8 @@
+ 	work1 = work2 = (struct cpu_stop_work){
+ 		.fn = multi_cpu_stop,
+ 		.arg = &msdata,
+-		.done = &done
++		.done = &done,
++		.caller = _RET_IP_,
+ 	};
+ 
+ 	cpu_stop_init_done(&done, 2);
+@@ -367,7 +380,7 @@
+ bool stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,
+ 			struct cpu_stop_work *work_buf)
+ {
+-	*work_buf = (struct cpu_stop_work){ .fn = fn, .arg = arg, };
++	*work_buf = (struct cpu_stop_work){ .fn = fn, .arg = arg, .caller = _RET_IP_, };
+ 	return cpu_stop_queue_work(cpu, work_buf);
+ }
+ 
+@@ -487,6 +500,8 @@
+ 		int ret;
+ 
+ 		/* cpu stop callbacks must not sleep, make in_atomic() == T */
++		stopper->caller = work->caller;
++		stopper->fn = fn;
+ 		preempt_count_inc();
+ 		ret = fn(arg);
+ 		if (done) {
+@@ -495,6 +510,8 @@
+ 			cpu_stop_signal_done(done);
+ 		}
+ 		preempt_count_dec();
++		stopper->fn = NULL;
++		stopper->caller = 0;
+ 		WARN_ONCE(preempt_count(),
+ 			  "cpu_stop: %ps(%p) leaked preempt count\n", fn, arg);
+ 		goto repeat;
+--- a/lib/dump_stack.c
++++ b/lib/dump_stack.c
+@@ -12,6 +12,7 @@
+ #include <linux/atomic.h>
+ #include <linux/kexec.h>
+ #include <linux/utsname.h>
++#include <linux/stop_machine.h>
+ #include <generated/package.h>
+ 
+ static char dump_stack_arch_desc_str[128];
+@@ -59,6 +60,7 @@
+ 		       log_lvl, dump_stack_arch_desc_str);
+ 
+ 	print_worker_info(log_lvl, current);
++	print_stop_info(log_lvl, current);
+ }
+ 
+ /**
diff --git a/debian/patches-rt/0003-sched-Fix-balance_callback.patch b/debian/patches-rt/0003-sched-Fix-balance_callback.patch
new file mode 100644
index 000000000..265608440
--- /dev/null
+++ b/debian/patches-rt/0003-sched-Fix-balance_callback.patch
@@ -0,0 +1,235 @@
+From db31f287a66b122733214b4a2bac9d59a564b77d Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:00 +0200
+Subject: [PATCH 003/323] sched: Fix balance_callback()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The intent of balance_callback() has always been to delay executing
+balancing operations until the end of the current rq->lock section.
+This is because balance operations must often drop rq->lock, and that
+isn't safe in general.
+
+However, as noted by Scott, there were a few holes in that scheme;
+balance_callback() was called after rq->lock was dropped, which means
+another CPU can interleave and touch the callback list.
+
+Rework code to call the balance callbacks before dropping rq->lock
+where possible, and otherwise splice the balance list onto a local
+stack.
+
+This guarantees that the balance list must be empty when we take
+rq->lock. IOW, we'll only ever run our own balance callbacks.
+
+Reported-by: Scott Wood <swood@redhat.com>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/core.c  | 119 +++++++++++++++++++++++++++----------------
+ kernel/sched/sched.h |   3 ++
+ 2 files changed, 78 insertions(+), 44 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 40f40f359c5d..ab8b7fd46334 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -3511,6 +3511,69 @@ static inline void finish_task(struct task_struct *prev)
+ #endif
+ }
+ 
++#ifdef CONFIG_SMP
++
++static void do_balance_callbacks(struct rq *rq, struct callback_head *head)
++{
++	void (*func)(struct rq *rq);
++	struct callback_head *next;
++
++	lockdep_assert_held(&rq->lock);
++
++	while (head) {
++		func = (void (*)(struct rq *))head->func;
++		next = head->next;
++		head->next = NULL;
++		head = next;
++
++		func(rq);
++	}
++}
++
++static inline struct callback_head *splice_balance_callbacks(struct rq *rq)
++{
++	struct callback_head *head = rq->balance_callback;
++
++	lockdep_assert_held(&rq->lock);
++	if (head)
++		rq->balance_callback = NULL;
++
++	return head;
++}
++
++static void __balance_callbacks(struct rq *rq)
++{
++	do_balance_callbacks(rq, splice_balance_callbacks(rq));
++}
++
++static inline void balance_callbacks(struct rq *rq, struct callback_head *head)
++{
++	unsigned long flags;
++
++	if (unlikely(head)) {
++		raw_spin_lock_irqsave(&rq->lock, flags);
++		do_balance_callbacks(rq, head);
++		raw_spin_unlock_irqrestore(&rq->lock, flags);
++	}
++}
++
++#else
++
++static inline void __balance_callbacks(struct rq *rq)
++{
++}
++
++static inline struct callback_head *splice_balance_callbacks(struct rq *rq)
++{
++	return NULL;
++}
++
++static inline void balance_callbacks(struct rq *rq, struct callback_head *head)
++{
++}
++
++#endif
++
+ static inline void
+ prepare_lock_switch(struct rq *rq, struct task_struct *next, struct rq_flags *rf)
+ {
+@@ -3536,6 +3599,7 @@ static inline void finish_lock_switch(struct rq *rq)
+ 	 * prev into current:
+ 	 */
+ 	spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
++	__balance_callbacks(rq);
+ 	raw_spin_unlock_irq(&rq->lock);
+ }
+ 
+@@ -3677,43 +3741,6 @@ static struct rq *finish_task_switch(struct task_struct *prev)
+ 	return rq;
+ }
+ 
+-#ifdef CONFIG_SMP
+-
+-/* rq->lock is NOT held, but preemption is disabled */
+-static void __balance_callback(struct rq *rq)
+-{
+-	struct callback_head *head, *next;
+-	void (*func)(struct rq *rq);
+-	unsigned long flags;
+-
+-	raw_spin_lock_irqsave(&rq->lock, flags);
+-	head = rq->balance_callback;
+-	rq->balance_callback = NULL;
+-	while (head) {
+-		func = (void (*)(struct rq *))head->func;
+-		next = head->next;
+-		head->next = NULL;
+-		head = next;
+-
+-		func(rq);
+-	}
+-	raw_spin_unlock_irqrestore(&rq->lock, flags);
+-}
+-
+-static inline void balance_callback(struct rq *rq)
+-{
+-	if (unlikely(rq->balance_callback))
+-		__balance_callback(rq);
+-}
+-
+-#else
+-
+-static inline void balance_callback(struct rq *rq)
+-{
+-}
+-
+-#endif
+-
+ /**
+  * schedule_tail - first thing a freshly forked thread must call.
+  * @prev: the thread we just switched away from.
+@@ -3733,7 +3760,6 @@ asmlinkage __visible void schedule_tail(struct task_struct *prev)
+ 	 */
+ 
+ 	rq = finish_task_switch(prev);
+-	balance_callback(rq);
+ 	preempt_enable();
+ 
+ 	if (current->set_child_tid)
+@@ -4548,10 +4574,11 @@ static void __sched notrace __schedule(bool preempt)
+ 		rq = context_switch(rq, prev, next, &rf);
+ 	} else {
+ 		rq->clock_update_flags &= ~(RQCF_ACT_SKIP|RQCF_REQ_SKIP);
+-		rq_unlock_irq(rq, &rf);
+-	}
+ 
+-	balance_callback(rq);
++		rq_unpin_lock(rq, &rf);
++		__balance_callbacks(rq);
++		raw_spin_unlock_irq(&rq->lock);
++	}
+ }
+ 
+ void __noreturn do_task_dead(void)
+@@ -4972,9 +4999,11 @@ void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task)
+ out_unlock:
+ 	/* Avoid rq from going away on us: */
+ 	preempt_disable();
+-	__task_rq_unlock(rq, &rf);
+ 
+-	balance_callback(rq);
++	rq_unpin_lock(rq, &rf);
++	__balance_callbacks(rq);
++	raw_spin_unlock(&rq->lock);
++
+ 	preempt_enable();
+ }
+ #else
+@@ -5217,6 +5246,7 @@ static int __sched_setscheduler(struct task_struct *p,
+ 	int oldpolicy = -1, policy = attr->sched_policy;
+ 	int retval, oldprio, newprio, queued, running;
+ 	const struct sched_class *prev_class;
++	struct callback_head *head;
+ 	struct rq_flags rf;
+ 	int reset_on_fork;
+ 	int queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK;
+@@ -5466,6 +5496,7 @@ static int __sched_setscheduler(struct task_struct *p,
+ 
+ 	/* Avoid rq from going away on us: */
+ 	preempt_disable();
++	head = splice_balance_callbacks(rq);
+ 	task_rq_unlock(rq, p, &rf);
+ 
+ 	if (pi) {
+@@ -5475,7 +5506,7 @@ static int __sched_setscheduler(struct task_struct *p,
+ 	}
+ 
+ 	/* Run balance callbacks after we've adjusted the PI chain: */
+-	balance_callback(rq);
++	balance_callbacks(rq, head);
+ 	preempt_enable();
+ 
+ 	return 0;
+diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
+index 8de07aba8bdd..fd71da3a4f0f 100644
+--- a/kernel/sched/sched.h
++++ b/kernel/sched/sched.h
+@@ -1225,6 +1225,9 @@ static inline void rq_pin_lock(struct rq *rq, struct rq_flags *rf)
+ 	rq->clock_update_flags &= (RQCF_REQ_SKIP|RQCF_ACT_SKIP);
+ 	rf->clock_update_flags = 0;
+ #endif
++#ifdef CONFIG_SMP
++	SCHED_WARN_ON(rq->balance_callback);
++#endif
+ }
+ 
+ static inline void rq_unpin_lock(struct rq *rq, struct rq_flags *rf)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0004-sched-hotplug-Ensure-only-per-cpu-kthreads-run-durin.patch b/debian/patches-rt/0004-sched-hotplug-Ensure-only-per-cpu-kthreads-run-durin.patch
new file mode 100644
index 000000000..6cb47e482
--- /dev/null
+++ b/debian/patches-rt/0004-sched-hotplug-Ensure-only-per-cpu-kthreads-run-durin.patch
@@ -0,0 +1,244 @@
+From bc9c6ea411da55a929b5bc3663c0a89449613d47 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:01 +0200
+Subject: [PATCH 004/323] sched/hotplug: Ensure only per-cpu kthreads run
+ during hotplug
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+In preparation for migrate_disable(), make sure only per-cpu kthreads
+are allowed to run on !active CPUs.
+
+This is ran (as one of the very first steps) from the cpu-hotplug
+task which is a per-cpu kthread and completion of the hotplug
+operation only requires such tasks.
+
+This constraint enables the migrate_disable() implementation to wait
+for completion of all migrate_disable regions on this CPU at hotplug
+time without fear of any new ones starting.
+
+This replaces the unlikely(rq->balance_callbacks) test at the tail of
+context_switch with an unlikely(rq->balance_work), the fast path is
+not affected.
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/core.c  | 114 ++++++++++++++++++++++++++++++++++++++++++-
+ kernel/sched/sched.h |   7 ++-
+ 2 files changed, 118 insertions(+), 3 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index ab8b7fd46334..32c3acef5781 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -3535,8 +3535,10 @@ static inline struct callback_head *splice_balance_callbacks(struct rq *rq)
+ 	struct callback_head *head = rq->balance_callback;
+ 
+ 	lockdep_assert_held(&rq->lock);
+-	if (head)
++	if (head) {
+ 		rq->balance_callback = NULL;
++		rq->balance_flags &= ~BALANCE_WORK;
++	}
+ 
+ 	return head;
+ }
+@@ -3557,6 +3559,21 @@ static inline void balance_callbacks(struct rq *rq, struct callback_head *head)
+ 	}
+ }
+ 
++static void balance_push(struct rq *rq);
++
++static inline void balance_switch(struct rq *rq)
++{
++	if (likely(!rq->balance_flags))
++		return;
++
++	if (rq->balance_flags & BALANCE_PUSH) {
++		balance_push(rq);
++		return;
++	}
++
++	__balance_callbacks(rq);
++}
++
+ #else
+ 
+ static inline void __balance_callbacks(struct rq *rq)
+@@ -3572,6 +3589,10 @@ static inline void balance_callbacks(struct rq *rq, struct callback_head *head)
+ {
+ }
+ 
++static inline void balance_switch(struct rq *rq)
++{
++}
++
+ #endif
+ 
+ static inline void
+@@ -3599,7 +3620,7 @@ static inline void finish_lock_switch(struct rq *rq)
+ 	 * prev into current:
+ 	 */
+ 	spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
+-	__balance_callbacks(rq);
++	balance_switch(rq);
+ 	raw_spin_unlock_irq(&rq->lock);
+ }
+ 
+@@ -6833,6 +6854,90 @@ static void migrate_tasks(struct rq *dead_rq, struct rq_flags *rf)
+ 
+ 	rq->stop = stop;
+ }
++
++static int __balance_push_cpu_stop(void *arg)
++{
++	struct task_struct *p = arg;
++	struct rq *rq = this_rq();
++	struct rq_flags rf;
++	int cpu;
++
++	raw_spin_lock_irq(&p->pi_lock);
++	rq_lock(rq, &rf);
++
++	update_rq_clock(rq);
++
++	if (task_rq(p) == rq && task_on_rq_queued(p)) {
++		cpu = select_fallback_rq(rq->cpu, p);
++		rq = __migrate_task(rq, &rf, p, cpu);
++	}
++
++	rq_unlock(rq, &rf);
++	raw_spin_unlock_irq(&p->pi_lock);
++
++	put_task_struct(p);
++
++	return 0;
++}
++
++static DEFINE_PER_CPU(struct cpu_stop_work, push_work);
++
++/*
++ * Ensure we only run per-cpu kthreads once the CPU goes !active.
++ */
++static void balance_push(struct rq *rq)
++{
++	struct task_struct *push_task = rq->curr;
++
++	lockdep_assert_held(&rq->lock);
++	SCHED_WARN_ON(rq->cpu != smp_processor_id());
++
++	/*
++	 * Both the cpu-hotplug and stop task are in this case and are
++	 * required to complete the hotplug process.
++	 */
++	if (is_per_cpu_kthread(push_task))
++		return;
++
++	get_task_struct(push_task);
++	/*
++	 * Temporarily drop rq->lock such that we can wake-up the stop task.
++	 * Both preemption and IRQs are still disabled.
++	 */
++	raw_spin_unlock(&rq->lock);
++	stop_one_cpu_nowait(rq->cpu, __balance_push_cpu_stop, push_task,
++			    this_cpu_ptr(&push_work));
++	/*
++	 * At this point need_resched() is true and we'll take the loop in
++	 * schedule(). The next pick is obviously going to be the stop task
++	 * which is_per_cpu_kthread() and will push this task away.
++	 */
++	raw_spin_lock(&rq->lock);
++}
++
++static void balance_push_set(int cpu, bool on)
++{
++	struct rq *rq = cpu_rq(cpu);
++	struct rq_flags rf;
++
++	rq_lock_irqsave(rq, &rf);
++	if (on)
++		rq->balance_flags |= BALANCE_PUSH;
++	else
++		rq->balance_flags &= ~BALANCE_PUSH;
++	rq_unlock_irqrestore(rq, &rf);
++}
++
++#else
++
++static inline void balance_push(struct rq *rq)
++{
++}
++
++static inline void balance_push_set(int cpu, bool on)
++{
++}
++
+ #endif /* CONFIG_HOTPLUG_CPU */
+ 
+ void set_rq_online(struct rq *rq)
+@@ -6920,6 +7025,8 @@ int sched_cpu_activate(unsigned int cpu)
+ 	struct rq *rq = cpu_rq(cpu);
+ 	struct rq_flags rf;
+ 
++	balance_push_set(cpu, false);
++
+ #ifdef CONFIG_SCHED_SMT
+ 	/*
+ 	 * When going up, increment the number of cores with SMT present.
+@@ -6967,6 +7074,8 @@ int sched_cpu_deactivate(unsigned int cpu)
+ 	 */
+ 	synchronize_rcu();
+ 
++	balance_push_set(cpu, true);
++
+ #ifdef CONFIG_SCHED_SMT
+ 	/*
+ 	 * When going down, decrement the number of cores with SMT present.
+@@ -6980,6 +7089,7 @@ int sched_cpu_deactivate(unsigned int cpu)
+ 
+ 	ret = cpuset_cpu_inactive(cpu);
+ 	if (ret) {
++		balance_push_set(cpu, false);
+ 		set_cpu_active(cpu, true);
+ 		return ret;
+ 	}
+diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
+index fd71da3a4f0f..81dc4212423a 100644
+--- a/kernel/sched/sched.h
++++ b/kernel/sched/sched.h
+@@ -976,6 +976,7 @@ struct rq {
+ 	unsigned long		cpu_capacity_inverted;
+ 
+ 	struct callback_head	*balance_callback;
++	unsigned char		balance_flags;
+ 
+ 	unsigned char		nohz_idle_balance;
+ 	unsigned char		idle_balance;
+@@ -1389,6 +1390,9 @@ init_numa_balancing(unsigned long clone_flags, struct task_struct *p)
+ 
+ #ifdef CONFIG_SMP
+ 
++#define BALANCE_WORK	0x01
++#define BALANCE_PUSH	0x02
++
+ static inline void
+ queue_balance_callback(struct rq *rq,
+ 		       struct callback_head *head,
+@@ -1396,12 +1400,13 @@ queue_balance_callback(struct rq *rq,
+ {
+ 	lockdep_assert_held(&rq->lock);
+ 
+-	if (unlikely(head->next))
++	if (unlikely(head->next || (rq->balance_flags & BALANCE_PUSH)))
+ 		return;
+ 
+ 	head->func = (void (*)(struct callback_head *))func;
+ 	head->next = rq->balance_callback;
+ 	rq->balance_callback = head;
++	rq->balance_flags |= BALANCE_WORK;
+ }
+ 
+ #define rcu_dereference_check_sched_domain(p) \
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0005-sched-core-Wait-for-tasks-being-pushed-away-on-hotpl.patch b/debian/patches-rt/0005-sched-core-Wait-for-tasks-being-pushed-away-on-hotpl.patch
new file mode 100644
index 000000000..abd6b3875
--- /dev/null
+++ b/debian/patches-rt/0005-sched-core-Wait-for-tasks-being-pushed-away-on-hotpl.patch
@@ -0,0 +1,124 @@
+From 94b59ab31222fc252603987e1ee316264426a015 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 23 Oct 2020 12:12:02 +0200
+Subject: [PATCH 005/323] sched/core: Wait for tasks being pushed away on
+ hotplug
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+RT kernels need to ensure that all tasks which are not per CPU kthreads
+have left the outgoing CPU to guarantee that no tasks are force migrated
+within a migrate disabled section.
+
+There is also some desire to (ab)use fine grained CPU hotplug control to
+clear a CPU from active state to force migrate tasks which are not per CPU
+kthreads away for power control purposes.
+
+Add a mechanism which waits until all tasks which should leave the CPU
+after the CPU active flag is cleared have moved to a different online CPU.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/core.c  | 40 +++++++++++++++++++++++++++++++++++++++-
+ kernel/sched/sched.h |  4 ++++
+ 2 files changed, 43 insertions(+), 1 deletion(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 32c3acef5781..b902755615d7 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -6896,8 +6896,21 @@ static void balance_push(struct rq *rq)
+ 	 * Both the cpu-hotplug and stop task are in this case and are
+ 	 * required to complete the hotplug process.
+ 	 */
+-	if (is_per_cpu_kthread(push_task))
++	if (is_per_cpu_kthread(push_task)) {
++		/*
++		 * If this is the idle task on the outgoing CPU try to wake
++		 * up the hotplug control thread which might wait for the
++		 * last task to vanish. The rcuwait_active() check is
++		 * accurate here because the waiter is pinned on this CPU
++		 * and can't obviously be running in parallel.
++		 */
++		if (!rq->nr_running && rcuwait_active(&rq->hotplug_wait)) {
++			raw_spin_unlock(&rq->lock);
++			rcuwait_wake_up(&rq->hotplug_wait);
++			raw_spin_lock(&rq->lock);
++		}
+ 		return;
++	}
+ 
+ 	get_task_struct(push_task);
+ 	/*
+@@ -6928,6 +6941,20 @@ static void balance_push_set(int cpu, bool on)
+ 	rq_unlock_irqrestore(rq, &rf);
+ }
+ 
++/*
++ * Invoked from a CPUs hotplug control thread after the CPU has been marked
++ * inactive. All tasks which are not per CPU kernel threads are either
++ * pushed off this CPU now via balance_push() or placed on a different CPU
++ * during wakeup. Wait until the CPU is quiescent.
++ */
++static void balance_hotplug_wait(void)
++{
++	struct rq *rq = this_rq();
++
++	rcuwait_wait_event(&rq->hotplug_wait, rq->nr_running == 1,
++			   TASK_UNINTERRUPTIBLE);
++}
++
+ #else
+ 
+ static inline void balance_push(struct rq *rq)
+@@ -6938,6 +6965,10 @@ static inline void balance_push_set(int cpu, bool on)
+ {
+ }
+ 
++static inline void balance_hotplug_wait(void)
++{
++}
++
+ #endif /* CONFIG_HOTPLUG_CPU */
+ 
+ void set_rq_online(struct rq *rq)
+@@ -7094,6 +7125,10 @@ int sched_cpu_deactivate(unsigned int cpu)
+ 		return ret;
+ 	}
+ 	sched_domains_numa_masks_clear(cpu);
++
++	/* Wait for all non per CPU kernel threads to vanish. */
++	balance_hotplug_wait();
++
+ 	return 0;
+ }
+ 
+@@ -7334,6 +7369,9 @@ void __init sched_init(void)
+ 
+ 		rq_csd_init(rq, &rq->nohz_csd, nohz_csd_func);
+ #endif
++#ifdef CONFIG_HOTPLUG_CPU
++		rcuwait_init(&rq->hotplug_wait);
++#endif
+ #endif /* CONFIG_SMP */
+ 		hrtick_rq_init(rq);
+ 		atomic_set(&rq->nr_iowait, 0);
+diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
+index 81dc4212423a..a72464d370cd 100644
+--- a/kernel/sched/sched.h
++++ b/kernel/sched/sched.h
+@@ -1007,6 +1007,10 @@ struct rq {
+ 
+ 	/* This is used to determine avg_idle's max value */
+ 	u64			max_idle_balance_cost;
++
++#ifdef CONFIG_HOTPLUG_CPU
++	struct rcuwait		hotplug_wait;
++#endif
+ #endif /* CONFIG_SMP */
+ 
+ #ifdef CONFIG_IRQ_TIME_ACCOUNTING
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0006-workqueue-Manually-break-affinity-on-hotplug.patch b/debian/patches-rt/0006-workqueue-Manually-break-affinity-on-hotplug.patch
new file mode 100644
index 000000000..7eb185ce2
--- /dev/null
+++ b/debian/patches-rt/0006-workqueue-Manually-break-affinity-on-hotplug.patch
@@ -0,0 +1,34 @@
+From e3372f0d43a35f1070d1689e6aa1f84d6cd9784b Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:03 +0200
+Subject: [PATCH 006/323] workqueue: Manually break affinity on hotplug
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Don't rely on the scheduler to force break affinity for us -- it will
+stop doing that for per-cpu-kthreads.
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Acked-by: Tejun Heo <tj@kernel.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/workqueue.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/kernel/workqueue.c b/kernel/workqueue.c
+index 63140e4dd5df..7c14773dc4c4 100644
+--- a/kernel/workqueue.c
++++ b/kernel/workqueue.c
+@@ -4941,6 +4941,10 @@ static void unbind_workers(int cpu)
+ 		pool->flags |= POOL_DISASSOCIATED;
+ 
+ 		raw_spin_unlock_irq(&pool->lock);
++
++		for_each_pool_worker(worker, pool)
++			WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, cpu_active_mask) < 0);
++
+ 		mutex_unlock(&wq_pool_attach_mutex);
+ 
+ 		/*
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0007-sched-hotplug-Consolidate-task-migration-on-CPU-unpl.patch b/debian/patches-rt/0007-sched-hotplug-Consolidate-task-migration-on-CPU-unpl.patch
new file mode 100644
index 000000000..606e32fa1
--- /dev/null
+++ b/debian/patches-rt/0007-sched-hotplug-Consolidate-task-migration-on-CPU-unpl.patch
@@ -0,0 +1,283 @@
+From 61ebefbbf2500f6ade2182806061526bbde76a28 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 23 Oct 2020 12:12:04 +0200
+Subject: [PATCH 007/323] sched/hotplug: Consolidate task migration on CPU
+ unplug
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+With the new mechanism which kicks tasks off the outgoing CPU at the end of
+schedule() the situation on an outgoing CPU right before the stopper thread
+brings it down completely is:
+
+ - All user tasks and all unbound kernel threads have either been migrated
+   away or are not running and the next wakeup will move them to a online CPU.
+
+ - All per CPU kernel threads, except cpu hotplug thread and the stopper
+   thread have either been unbound or parked by the responsible CPU hotplug
+   callback.
+
+That means that at the last step before the stopper thread is invoked the
+cpu hotplug thread is the last legitimate running task on the outgoing
+CPU.
+
+Add a final wait step right before the stopper thread is kicked which
+ensures that any still running tasks on the way to park or on the way to
+kick themself of the CPU are either sleeping or gone.
+
+This allows to remove the migrate_tasks() crutch in sched_cpu_dying(). If
+sched_cpu_dying() detects that there is still another running task aside of
+the stopper thread then it will explode with the appropriate fireworks.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/cpuhotplug.h    |   1 +
+ include/linux/sched/hotplug.h |   2 +
+ kernel/cpu.c                  |   9 +-
+ kernel/sched/core.c           | 154 ++++++++--------------------------
+ 4 files changed, 46 insertions(+), 120 deletions(-)
+
+diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
+index f5a5df3a8cfd..daf39c04a552 100644
+--- a/include/linux/cpuhotplug.h
++++ b/include/linux/cpuhotplug.h
+@@ -155,6 +155,7 @@ enum cpuhp_state {
+ 	CPUHP_AP_ONLINE,
+ 	CPUHP_TEARDOWN_CPU,
+ 	CPUHP_AP_ONLINE_IDLE,
++	CPUHP_AP_SCHED_WAIT_EMPTY,
+ 	CPUHP_AP_SMPBOOT_THREADS,
+ 	CPUHP_AP_X86_VDSO_VMA_ONLINE,
+ 	CPUHP_AP_IRQ_AFFINITY_ONLINE,
+diff --git a/include/linux/sched/hotplug.h b/include/linux/sched/hotplug.h
+index 9a62ffdd296f..412cdaba33eb 100644
+--- a/include/linux/sched/hotplug.h
++++ b/include/linux/sched/hotplug.h
+@@ -11,8 +11,10 @@ extern int sched_cpu_activate(unsigned int cpu);
+ extern int sched_cpu_deactivate(unsigned int cpu);
+ 
+ #ifdef CONFIG_HOTPLUG_CPU
++extern int sched_cpu_wait_empty(unsigned int cpu);
+ extern int sched_cpu_dying(unsigned int cpu);
+ #else
++# define sched_cpu_wait_empty	NULL
+ # define sched_cpu_dying	NULL
+ #endif
+ 
+diff --git a/kernel/cpu.c b/kernel/cpu.c
+index abf717c4f57c..f8280edb679f 100644
+--- a/kernel/cpu.c
++++ b/kernel/cpu.c
+@@ -1674,7 +1674,7 @@ static struct cpuhp_step cpuhp_hp_states[] = {
+ 		.name			= "ap:online",
+ 	},
+ 	/*
+-	 * Handled on controll processor until the plugged processor manages
++	 * Handled on control processor until the plugged processor manages
+ 	 * this itself.
+ 	 */
+ 	[CPUHP_TEARDOWN_CPU] = {
+@@ -1683,6 +1683,13 @@ static struct cpuhp_step cpuhp_hp_states[] = {
+ 		.teardown.single	= takedown_cpu,
+ 		.cant_stop		= true,
+ 	},
++
++	[CPUHP_AP_SCHED_WAIT_EMPTY] = {
++		.name			= "sched:waitempty",
++		.startup.single		= NULL,
++		.teardown.single	= sched_cpu_wait_empty,
++	},
++
+ 	/* Handle smpboot threads park/unpark */
+ 	[CPUHP_AP_SMPBOOT_THREADS] = {
+ 		.name			= "smpboot/threads:online",
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index b902755615d7..a26a82c3e939 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -6741,120 +6741,6 @@ void idle_task_exit(void)
+ 	/* finish_cpu(), as ran on the BP, will clean up the active_mm state */
+ }
+ 
+-/*
+- * Since this CPU is going 'away' for a while, fold any nr_active delta
+- * we might have. Assumes we're called after migrate_tasks() so that the
+- * nr_active count is stable. We need to take the teardown thread which
+- * is calling this into account, so we hand in adjust = 1 to the load
+- * calculation.
+- *
+- * Also see the comment "Global load-average calculations".
+- */
+-static void calc_load_migrate(struct rq *rq)
+-{
+-	long delta = calc_load_fold_active(rq, 1);
+-	if (delta)
+-		atomic_long_add(delta, &calc_load_tasks);
+-}
+-
+-static struct task_struct *__pick_migrate_task(struct rq *rq)
+-{
+-	const struct sched_class *class;
+-	struct task_struct *next;
+-
+-	for_each_class(class) {
+-		next = class->pick_next_task(rq);
+-		if (next) {
+-			next->sched_class->put_prev_task(rq, next);
+-			return next;
+-		}
+-	}
+-
+-	/* The idle class should always have a runnable task */
+-	BUG();
+-}
+-
+-/*
+- * Migrate all tasks from the rq, sleeping tasks will be migrated by
+- * try_to_wake_up()->select_task_rq().
+- *
+- * Called with rq->lock held even though we'er in stop_machine() and
+- * there's no concurrency possible, we hold the required locks anyway
+- * because of lock validation efforts.
+- */
+-static void migrate_tasks(struct rq *dead_rq, struct rq_flags *rf)
+-{
+-	struct rq *rq = dead_rq;
+-	struct task_struct *next, *stop = rq->stop;
+-	struct rq_flags orf = *rf;
+-	int dest_cpu;
+-
+-	/*
+-	 * Fudge the rq selection such that the below task selection loop
+-	 * doesn't get stuck on the currently eligible stop task.
+-	 *
+-	 * We're currently inside stop_machine() and the rq is either stuck
+-	 * in the stop_machine_cpu_stop() loop, or we're executing this code,
+-	 * either way we should never end up calling schedule() until we're
+-	 * done here.
+-	 */
+-	rq->stop = NULL;
+-
+-	/*
+-	 * put_prev_task() and pick_next_task() sched
+-	 * class method both need to have an up-to-date
+-	 * value of rq->clock[_task]
+-	 */
+-	update_rq_clock(rq);
+-
+-	for (;;) {
+-		/*
+-		 * There's this thread running, bail when that's the only
+-		 * remaining thread:
+-		 */
+-		if (rq->nr_running == 1)
+-			break;
+-
+-		next = __pick_migrate_task(rq);
+-
+-		/*
+-		 * Rules for changing task_struct::cpus_mask are holding
+-		 * both pi_lock and rq->lock, such that holding either
+-		 * stabilizes the mask.
+-		 *
+-		 * Drop rq->lock is not quite as disastrous as it usually is
+-		 * because !cpu_active at this point, which means load-balance
+-		 * will not interfere. Also, stop-machine.
+-		 */
+-		rq_unlock(rq, rf);
+-		raw_spin_lock(&next->pi_lock);
+-		rq_relock(rq, rf);
+-
+-		/*
+-		 * Since we're inside stop-machine, _nothing_ should have
+-		 * changed the task, WARN if weird stuff happened, because in
+-		 * that case the above rq->lock drop is a fail too.
+-		 */
+-		if (WARN_ON(task_rq(next) != rq || !task_on_rq_queued(next))) {
+-			raw_spin_unlock(&next->pi_lock);
+-			continue;
+-		}
+-
+-		/* Find suitable destination for @next, with force if needed. */
+-		dest_cpu = select_fallback_rq(dead_rq->cpu, next);
+-		rq = __migrate_task(rq, rf, next, dest_cpu);
+-		if (rq != dead_rq) {
+-			rq_unlock(rq, rf);
+-			rq = dead_rq;
+-			*rf = orf;
+-			rq_relock(rq, rf);
+-		}
+-		raw_spin_unlock(&next->pi_lock);
+-	}
+-
+-	rq->stop = stop;
+-}
+-
+ static int __balance_push_cpu_stop(void *arg)
+ {
+ 	struct task_struct *p = arg;
+@@ -7125,10 +7011,6 @@ int sched_cpu_deactivate(unsigned int cpu)
+ 		return ret;
+ 	}
+ 	sched_domains_numa_masks_clear(cpu);
+-
+-	/* Wait for all non per CPU kernel threads to vanish. */
+-	balance_hotplug_wait();
+-
+ 	return 0;
+ }
+ 
+@@ -7148,6 +7030,41 @@ int sched_cpu_starting(unsigned int cpu)
+ }
+ 
+ #ifdef CONFIG_HOTPLUG_CPU
++
++/*
++ * Invoked immediately before the stopper thread is invoked to bring the
++ * CPU down completely. At this point all per CPU kthreads except the
++ * hotplug thread (current) and the stopper thread (inactive) have been
++ * either parked or have been unbound from the outgoing CPU. Ensure that
++ * any of those which might be on the way out are gone.
++ *
++ * If after this point a bound task is being woken on this CPU then the
++ * responsible hotplug callback has failed to do it's job.
++ * sched_cpu_dying() will catch it with the appropriate fireworks.
++ */
++int sched_cpu_wait_empty(unsigned int cpu)
++{
++	balance_hotplug_wait();
++	return 0;
++}
++
++/*
++ * Since this CPU is going 'away' for a while, fold any nr_active delta we
++ * might have. Called from the CPU stopper task after ensuring that the
++ * stopper is the last running task on the CPU, so nr_active count is
++ * stable. We need to take the teardown thread which is calling this into
++ * account, so we hand in adjust = 1 to the load calculation.
++ *
++ * Also see the comment "Global load-average calculations".
++ */
++static void calc_load_migrate(struct rq *rq)
++{
++	long delta = calc_load_fold_active(rq, 1);
++
++	if (delta)
++		atomic_long_add(delta, &calc_load_tasks);
++}
++
+ int sched_cpu_dying(unsigned int cpu)
+ {
+ 	struct rq *rq = cpu_rq(cpu);
+@@ -7161,7 +7078,6 @@ int sched_cpu_dying(unsigned int cpu)
+ 		BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
+ 		set_rq_offline(rq);
+ 	}
+-	migrate_tasks(rq, &rf);
+ 	BUG_ON(rq->nr_running != 1);
+ 	rq_unlock_irqrestore(rq, &rf);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0008-sched-Fix-hotplug-vs-CPU-bandwidth-control.patch b/debian/patches-rt/0008-sched-Fix-hotplug-vs-CPU-bandwidth-control.patch
new file mode 100644
index 000000000..6c09cbe86
--- /dev/null
+++ b/debian/patches-rt/0008-sched-Fix-hotplug-vs-CPU-bandwidth-control.patch
@@ -0,0 +1,94 @@
+From 36d2d778f786cb7fd55c549911a6055d6b6f40ef Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:05 +0200
+Subject: [PATCH 008/323] sched: Fix hotplug vs CPU bandwidth control
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Since we now migrate tasks away before DYING, we should also move
+bandwidth unthrottle, otherwise we can gain tasks from unthrottle
+after we expect all tasks to be gone already.
+
+Also; it looks like the RT balancers don't respect cpu_active() and
+instead rely on rq->online in part, complete this. This too requires
+we do set_rq_offline() earlier to match the cpu_active() semantics.
+(The bigger patch is to convert RT to cpu_active() entirely)
+
+Since set_rq_online() is called from sched_cpu_activate(), place
+set_rq_offline() in sched_cpu_deactivate().
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/core.c     | 14 ++++++++++----
+ kernel/sched/deadline.c |  2 +-
+ kernel/sched/rt.c       |  2 +-
+ 3 files changed, 12 insertions(+), 6 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index a26a82c3e939..c5d5576c67fb 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -6979,6 +6979,8 @@ int sched_cpu_activate(unsigned int cpu)
+ 
+ int sched_cpu_deactivate(unsigned int cpu)
+ {
++	struct rq *rq = cpu_rq(cpu);
++	struct rq_flags rf;
+ 	int ret;
+ 
+ 	set_cpu_active(cpu, false);
+@@ -6993,6 +6995,14 @@ int sched_cpu_deactivate(unsigned int cpu)
+ 
+ 	balance_push_set(cpu, true);
+ 
++	rq_lock_irqsave(rq, &rf);
++	if (rq->rd) {
++		update_rq_clock(rq);
++		BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
++		set_rq_offline(rq);
++	}
++	rq_unlock_irqrestore(rq, &rf);
++
+ #ifdef CONFIG_SCHED_SMT
+ 	/*
+ 	 * When going down, decrement the number of cores with SMT present.
+@@ -7074,10 +7084,6 @@ int sched_cpu_dying(unsigned int cpu)
+ 	sched_tick_stop(cpu);
+ 
+ 	rq_lock_irqsave(rq, &rf);
+-	if (rq->rd) {
+-		BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
+-		set_rq_offline(rq);
+-	}
+ 	BUG_ON(rq->nr_running != 1);
+ 	rq_unlock_irqrestore(rq, &rf);
+ 
+diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
+index d91295d3059f..af8569dbdc9c 100644
+--- a/kernel/sched/deadline.c
++++ b/kernel/sched/deadline.c
+@@ -566,7 +566,7 @@ static int push_dl_task(struct rq *rq);
+ 
+ static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev)
+ {
+-	return dl_task(prev);
++	return rq->online && dl_task(prev);
+ }
+ 
+ static DEFINE_PER_CPU(struct callback_head, dl_push_head);
+diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
+index f690f901b6cc..fdcce04913db 100644
+--- a/kernel/sched/rt.c
++++ b/kernel/sched/rt.c
+@@ -270,7 +270,7 @@ static void pull_rt_task(struct rq *this_rq);
+ static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev)
+ {
+ 	/* Try to pull RT tasks here if we lower this rq's prio */
+-	return rq->rt.highest_prio.curr > prev->prio;
++	return rq->online && rq->rt.highest_prio.curr > prev->prio;
+ }
+ 
+ static inline int rt_overloaded(struct rq *rq)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0009-sched-Massage-set_cpus_allowed.patch b/debian/patches-rt/0009-sched-Massage-set_cpus_allowed.patch
new file mode 100644
index 000000000..24fc3200e
--- /dev/null
+++ b/debian/patches-rt/0009-sched-Massage-set_cpus_allowed.patch
@@ -0,0 +1,175 @@
+From 1125b34b63aa303af592b0ea5be730dc92ce6d53 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:06 +0200
+Subject: [PATCH 009/323] sched: Massage set_cpus_allowed()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Thread a u32 flags word through the *set_cpus_allowed*() callchain.
+This will allow adding behavioural tweaks for future users.
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/core.c     | 28 ++++++++++++++++++----------
+ kernel/sched/deadline.c |  5 +++--
+ kernel/sched/sched.h    |  7 +++++--
+ 3 files changed, 26 insertions(+), 14 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index c5d5576c67fb..569cc5e48e68 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1838,13 +1838,14 @@ static int migration_cpu_stop(void *data)
+  * sched_class::set_cpus_allowed must do the below, but is not required to
+  * actually call this function.
+  */
+-void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask)
++void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask, u32 flags)
+ {
+ 	cpumask_copy(&p->cpus_mask, new_mask);
+ 	p->nr_cpus_allowed = cpumask_weight(new_mask);
+ }
+ 
+-void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
++static void
++__do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask, u32 flags)
+ {
+ 	struct rq *rq = task_rq(p);
+ 	bool queued, running;
+@@ -1865,7 +1866,7 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
+ 	if (running)
+ 		put_prev_task(rq, p);
+ 
+-	p->sched_class->set_cpus_allowed(p, new_mask);
++	p->sched_class->set_cpus_allowed(p, new_mask, flags);
+ 
+ 	if (queued)
+ 		enqueue_task(rq, p, ENQUEUE_RESTORE | ENQUEUE_NOCLOCK);
+@@ -1873,6 +1874,11 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
+ 		set_next_task(rq, p);
+ }
+ 
++void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
++{
++	__do_set_cpus_allowed(p, new_mask, 0);
++}
++
+ /*
+  * Change a given task's CPU affinity. Migrate the thread to a
+  * proper CPU and schedule it away if the CPU it's executing on
+@@ -1883,7 +1889,8 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
+  * call is not atomic; no spinlocks may be held.
+  */
+ static int __set_cpus_allowed_ptr(struct task_struct *p,
+-				  const struct cpumask *new_mask, bool check)
++				  const struct cpumask *new_mask,
++				  u32 flags)
+ {
+ 	const struct cpumask *cpu_valid_mask = cpu_active_mask;
+ 	unsigned int dest_cpu;
+@@ -1905,7 +1912,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
+ 	 * Must re-check here, to close a race against __kthread_bind(),
+ 	 * sched_setaffinity() is not guaranteed to observe the flag.
+ 	 */
+-	if (check && (p->flags & PF_NO_SETAFFINITY)) {
++	if ((flags & SCA_CHECK) && (p->flags & PF_NO_SETAFFINITY)) {
+ 		ret = -EINVAL;
+ 		goto out;
+ 	}
+@@ -1924,7 +1931,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
+ 		goto out;
+ 	}
+ 
+-	do_set_cpus_allowed(p, new_mask);
++	__do_set_cpus_allowed(p, new_mask, flags);
+ 
+ 	if (p->flags & PF_KTHREAD) {
+ 		/*
+@@ -1961,7 +1968,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
+ 
+ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
+ {
+-	return __set_cpus_allowed_ptr(p, new_mask, false);
++	return __set_cpus_allowed_ptr(p, new_mask, 0);
+ }
+ EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
+ 
+@@ -2420,7 +2427,8 @@ void sched_set_stop_task(int cpu, struct task_struct *stop)
+ #else
+ 
+ static inline int __set_cpus_allowed_ptr(struct task_struct *p,
+-					 const struct cpumask *new_mask, bool check)
++					 const struct cpumask *new_mask,
++					 u32 flags)
+ {
+ 	return set_cpus_allowed_ptr(p, new_mask);
+ }
+@@ -6022,7 +6030,7 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
+ 	}
+ #endif
+ again:
+-	retval = __set_cpus_allowed_ptr(p, new_mask, true);
++	retval = __set_cpus_allowed_ptr(p, new_mask, SCA_CHECK);
+ 
+ 	if (!retval) {
+ 		cpuset_cpus_allowed(p, cpus_allowed);
+@@ -6598,7 +6606,7 @@ void __init init_idle(struct task_struct *idle, int cpu)
+ 	 *
+ 	 * And since this is boot we can forgo the serialization.
+ 	 */
+-	set_cpus_allowed_common(idle, cpumask_of(cpu));
++	set_cpus_allowed_common(idle, cpumask_of(cpu), 0);
+ #endif
+ 	/*
+ 	 * We're having a chicken and egg problem, even though we are
+diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
+index af8569dbdc9c..5566f157640b 100644
+--- a/kernel/sched/deadline.c
++++ b/kernel/sched/deadline.c
+@@ -2311,7 +2311,8 @@ static void task_woken_dl(struct rq *rq, struct task_struct *p)
+ }
+ 
+ static void set_cpus_allowed_dl(struct task_struct *p,
+-				const struct cpumask *new_mask)
++				const struct cpumask *new_mask,
++				u32 flags)
+ {
+ 	struct root_domain *src_rd;
+ 	struct rq *rq;
+@@ -2340,7 +2341,7 @@ static void set_cpus_allowed_dl(struct task_struct *p,
+ 		raw_spin_unlock(&src_dl_b->lock);
+ 	}
+ 
+-	set_cpus_allowed_common(p, new_mask);
++	set_cpus_allowed_common(p, new_mask, flags);
+ }
+ 
+ /* Assumes rq->lock is held */
+diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
+index a72464d370cd..f0f396cc1bee 100644
+--- a/kernel/sched/sched.h
++++ b/kernel/sched/sched.h
+@@ -1818,7 +1818,8 @@ struct sched_class {
+ 	void (*task_woken)(struct rq *this_rq, struct task_struct *task);
+ 
+ 	void (*set_cpus_allowed)(struct task_struct *p,
+-				 const struct cpumask *newmask);
++				 const struct cpumask *newmask,
++				 u32 flags);
+ 
+ 	void (*rq_online)(struct rq *rq);
+ 	void (*rq_offline)(struct rq *rq);
+@@ -1911,7 +1912,9 @@ extern void update_group_capacity(struct sched_domain *sd, int cpu);
+ 
+ extern void trigger_load_balance(struct rq *rq);
+ 
+-extern void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask);
++#define SCA_CHECK		0x01
++
++extern void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask, u32 flags);
+ 
+ #endif
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0010-sched-Add-migrate_disable.patch b/debian/patches-rt/0010-sched-Add-migrate_disable.patch
new file mode 100644
index 000000000..d0ea31279
--- /dev/null
+++ b/debian/patches-rt/0010-sched-Add-migrate_disable.patch
@@ -0,0 +1,356 @@
+From e9f7c2225ee3e1ce9317762393618c1c81a8febe Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:07 +0200
+Subject: [PATCH 010/323] sched: Add migrate_disable()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Add the base migrate_disable() support (under protest).
+
+While migrate_disable() is (currently) required for PREEMPT_RT, it is
+also one of the biggest flaws in the system.
+
+Notably this is just the base implementation, it is broken vs
+sched_setaffinity() and hotplug, both solved in additional patches for
+ease of review.
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/preempt.h |  65 +++++++++++++++++++++++
+ include/linux/sched.h   |   3 ++
+ kernel/sched/core.c     | 112 +++++++++++++++++++++++++++++++++++++---
+ kernel/sched/sched.h    |   6 ++-
+ lib/smp_processor_id.c  |   5 ++
+ 5 files changed, 183 insertions(+), 8 deletions(-)
+
+diff --git a/include/linux/preempt.h b/include/linux/preempt.h
+index 7d9c1c0e149c..97ba7c920653 100644
+--- a/include/linux/preempt.h
++++ b/include/linux/preempt.h
+@@ -322,6 +322,69 @@ static inline void preempt_notifier_init(struct preempt_notifier *notifier,
+ 
+ #endif
+ 
++#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
++
++/*
++ * Migrate-Disable and why it is (strongly) undesired.
++ *
++ * The premise of the Real-Time schedulers we have on Linux
++ * (SCHED_FIFO/SCHED_DEADLINE) is that M CPUs can/will run M tasks
++ * concurrently, provided there are sufficient runnable tasks, also known as
++ * work-conserving. For instance SCHED_DEADLINE tries to schedule the M
++ * earliest deadline threads, and SCHED_FIFO the M highest priority threads.
++ *
++ * The correctness of various scheduling models depends on this, but is it
++ * broken by migrate_disable() that doesn't imply preempt_disable(). Where
++ * preempt_disable() implies an immediate priority ceiling, preemptible
++ * migrate_disable() allows nesting.
++ *
++ * The worst case is that all tasks preempt one another in a migrate_disable()
++ * region and stack on a single CPU. This then reduces the available bandwidth
++ * to a single CPU. And since Real-Time schedulability theory considers the
++ * Worst-Case only, all Real-Time analysis shall revert to single-CPU
++ * (instantly solving the SMP analysis problem).
++ *
++ *
++ * The reason we have it anyway.
++ *
++ * PREEMPT_RT breaks a number of assumptions traditionally held. By forcing a
++ * number of primitives into becoming preemptible, they would also allow
++ * migration. This turns out to break a bunch of per-cpu usage. To this end,
++ * all these primitives employ migirate_disable() to restore this implicit
++ * assumption.
++ *
++ * This is a 'temporary' work-around at best. The correct solution is getting
++ * rid of the above assumptions and reworking the code to employ explicit
++ * per-cpu locking or short preempt-disable regions.
++ *
++ * The end goal must be to get rid of migrate_disable(), alternatively we need
++ * a schedulability theory that does not depend on abritrary migration.
++ *
++ *
++ * Notes on the implementation.
++ *
++ * The implementation is particularly tricky since existing code patterns
++ * dictate neither migrate_disable() nor migrate_enable() is allowed to block.
++ * This means that it cannot use cpus_read_lock() to serialize against hotplug,
++ * nor can it easily migrate itself into a pending affinity mask change on
++ * migrate_enable().
++ *
++ *
++ * Note: even non-work-conserving schedulers like semi-partitioned depends on
++ *       migration, so migrate_disable() is not only a problem for
++ *       work-conserving schedulers.
++ *
++ */
++extern void migrate_disable(void);
++extern void migrate_enable(void);
++
++#elif defined(CONFIG_PREEMPT_RT)
++
++static inline void migrate_disable(void) { }
++static inline void migrate_enable(void) { }
++
++#else /* !CONFIG_PREEMPT_RT */
++
+ /**
+  * migrate_disable - Prevent migration of the current task
+  *
+@@ -352,4 +415,6 @@ static __always_inline void migrate_enable(void)
+ 	preempt_enable();
+ }
+ 
++#endif /* CONFIG_SMP && CONFIG_PREEMPT_RT */
++
+ #endif /* __LINUX_PREEMPT_H */
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index aa015416c569..76907e9876d5 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -726,6 +726,9 @@ struct task_struct {
+ 	int				nr_cpus_allowed;
+ 	const cpumask_t			*cpus_ptr;
+ 	cpumask_t			cpus_mask;
++#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
++	int				migration_disabled;
++#endif
+ 
+ #ifdef CONFIG_PREEMPT_RCU
+ 	int				rcu_read_lock_nesting;
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 569cc5e48e68..5c9db4b2b6ec 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1710,6 +1710,61 @@ void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
+ 
+ #ifdef CONFIG_SMP
+ 
++#ifdef CONFIG_PREEMPT_RT
++
++static void
++__do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask, u32 flags);
++
++static int __set_cpus_allowed_ptr(struct task_struct *p,
++				  const struct cpumask *new_mask,
++				  u32 flags);
++
++static void migrate_disable_switch(struct rq *rq, struct task_struct *p)
++{
++	if (likely(!p->migration_disabled))
++		return;
++
++	if (p->cpus_ptr != &p->cpus_mask)
++		return;
++
++	/*
++	 * Violates locking rules! see comment in __do_set_cpus_allowed().
++	 */
++	__do_set_cpus_allowed(p, cpumask_of(rq->cpu), SCA_MIGRATE_DISABLE);
++}
++
++void migrate_disable(void)
++{
++	if (current->migration_disabled++)
++		return;
++
++	barrier();
++}
++EXPORT_SYMBOL_GPL(migrate_disable);
++
++void migrate_enable(void)
++{
++	struct task_struct *p = current;
++
++	if (--p->migration_disabled)
++		return;
++
++	barrier();
++
++	if (p->cpus_ptr == &p->cpus_mask)
++		return;
++
++	__set_cpus_allowed_ptr(p, &p->cpus_mask, SCA_MIGRATE_ENABLE);
++}
++EXPORT_SYMBOL_GPL(migrate_enable);
++
++static inline bool is_migration_disabled(struct task_struct *p)
++{
++	return p->migration_disabled;
++}
++
++#endif
++
+ /*
+  * Per-CPU kthreads are allowed to run on !active && online CPUs, see
+  * __set_cpus_allowed_ptr() and select_fallback_rq().
+@@ -1719,7 +1774,7 @@ static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
+ 	if (!cpumask_test_cpu(cpu, p->cpus_ptr))
+ 		return false;
+ 
+-	if (is_per_cpu_kthread(p))
++	if (is_per_cpu_kthread(p) || is_migration_disabled(p))
+ 		return cpu_online(cpu);
+ 
+ 	return cpu_active(cpu);
+@@ -1840,6 +1895,11 @@ static int migration_cpu_stop(void *data)
+  */
+ void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask, u32 flags)
+ {
++	if (flags & (SCA_MIGRATE_ENABLE | SCA_MIGRATE_DISABLE)) {
++		p->cpus_ptr = new_mask;
++		return;
++	}
++
+ 	cpumask_copy(&p->cpus_mask, new_mask);
+ 	p->nr_cpus_allowed = cpumask_weight(new_mask);
+ }
+@@ -1850,7 +1910,22 @@ __do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask, u32
+ 	struct rq *rq = task_rq(p);
+ 	bool queued, running;
+ 
+-	lockdep_assert_held(&p->pi_lock);
++	/*
++	 * This here violates the locking rules for affinity, since we're only
++	 * supposed to change these variables while holding both rq->lock and
++	 * p->pi_lock.
++	 *
++	 * HOWEVER, it magically works, because ttwu() is the only code that
++	 * accesses these variables under p->pi_lock and only does so after
++	 * smp_cond_load_acquire(&p->on_cpu, !VAL), and we're in __schedule()
++	 * before finish_task().
++	 *
++	 * XXX do further audits, this smells like something putrid.
++	 */
++	if (flags & SCA_MIGRATE_DISABLE)
++		SCHED_WARN_ON(!p->on_cpu);
++	else
++		lockdep_assert_held(&p->pi_lock);
+ 
+ 	queued = task_on_rq_queued(p);
+ 	running = task_current(rq, p);
+@@ -1901,9 +1976,14 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
+ 	rq = task_rq_lock(p, &rf);
+ 	update_rq_clock(rq);
+ 
+-	if (p->flags & PF_KTHREAD) {
++	if (p->flags & PF_KTHREAD || is_migration_disabled(p)) {
+ 		/*
+-		 * Kernel threads are allowed on online && !active CPUs
++		 * Kernel threads are allowed on online && !active CPUs.
++		 *
++		 * Specifically, migration_disabled() tasks must not fail the
++		 * cpumask_any_and_distribute() pick below, esp. so on
++		 * SCA_MIGRATE_ENABLE, otherwise we'll not call
++		 * set_cpus_allowed_common() and actually reset p->cpus_ptr.
+ 		 */
+ 		cpu_valid_mask = cpu_online_mask;
+ 	}
+@@ -1917,7 +1997,7 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
+ 		goto out;
+ 	}
+ 
+-	if (cpumask_equal(&p->cpus_mask, new_mask))
++	if (!(flags & SCA_MIGRATE_ENABLE) && cpumask_equal(&p->cpus_mask, new_mask))
+ 		goto out;
+ 
+ 	/*
+@@ -2009,6 +2089,8 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
+ 	 * Clearly, migrating tasks to offline CPUs is a fairly daft thing.
+ 	 */
+ 	WARN_ON_ONCE(!cpu_online(new_cpu));
++
++	WARN_ON_ONCE(is_migration_disabled(p));
+ #endif
+ 
+ 	trace_sched_migrate_task(p, new_cpu);
+@@ -2339,6 +2421,12 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
+ 			}
+ 			fallthrough;
+ 		case possible:
++			/*
++			 * XXX When called from select_task_rq() we only
++			 * hold p->pi_lock and again violate locking order.
++			 *
++			 * More yuck to audit.
++			 */
+ 			do_set_cpus_allowed(p, cpu_possible_mask);
+ 			state = fail;
+ 			break;
+@@ -2373,7 +2461,7 @@ int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags)
+ {
+ 	lockdep_assert_held(&p->pi_lock);
+ 
+-	if (p->nr_cpus_allowed > 1)
++	if (p->nr_cpus_allowed > 1 && !is_migration_disabled(p))
+ 		cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags);
+ 	else
+ 		cpu = cpumask_any(p->cpus_ptr);
+@@ -2435,6 +2523,17 @@ static inline int __set_cpus_allowed_ptr(struct task_struct *p,
+ 
+ #endif /* CONFIG_SMP */
+ 
++#if !defined(CONFIG_SMP) || !defined(CONFIG_PREEMPT_RT)
++
++static inline void migrate_disable_switch(struct rq *rq, struct task_struct *p) { }
++
++static inline bool is_migration_disabled(struct task_struct *p)
++{
++	return false;
++}
++
++#endif
++
+ static void
+ ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
+ {
+@@ -4595,6 +4694,7 @@ static void __sched notrace __schedule(bool preempt)
+ 		 */
+ 		++*switch_count;
+ 
++		migrate_disable_switch(rq, prev);
+ 		psi_sched_switch(prev, next, !task_on_rq_queued(prev));
+ 
+ 		trace_sched_switch(preempt, prev, next);
+diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
+index f0f396cc1bee..f3109adda484 100644
+--- a/kernel/sched/sched.h
++++ b/kernel/sched/sched.h
+@@ -1906,14 +1906,16 @@ static inline bool sched_fair_runnable(struct rq *rq)
+ extern struct task_struct *pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf);
+ extern struct task_struct *pick_next_task_idle(struct rq *rq);
+ 
++#define SCA_CHECK		0x01
++#define SCA_MIGRATE_DISABLE	0x02
++#define SCA_MIGRATE_ENABLE	0x04
++
+ #ifdef CONFIG_SMP
+ 
+ extern void update_group_capacity(struct sched_domain *sd, int cpu);
+ 
+ extern void trigger_load_balance(struct rq *rq);
+ 
+-#define SCA_CHECK		0x01
+-
+ extern void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask, u32 flags);
+ 
+ #endif
+diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
+index 2916606a9333..dbb96ebf661f 100644
+--- a/lib/smp_processor_id.c
++++ b/lib/smp_processor_id.c
+@@ -26,6 +26,11 @@ unsigned int check_preemption_disabled(const char *what1, const char *what2)
+ 	if (current->nr_cpus_allowed == 1)
+ 		goto out;
+ 
++#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
++	if (current->migration_disabled)
++		goto out;
++#endif
++
+ 	/*
+ 	 * It is valid to assume CPU-locality during early bootup:
+ 	 */
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0011-sched-Fix-migrate_disable-vs-set_cpus_allowed_ptr.patch b/debian/patches-rt/0011-sched-Fix-migrate_disable-vs-set_cpus_allowed_ptr.patch
new file mode 100644
index 000000000..d89f86138
--- /dev/null
+++ b/debian/patches-rt/0011-sched-Fix-migrate_disable-vs-set_cpus_allowed_ptr.patch
@@ -0,0 +1,370 @@
+From f6fcadc60ec427b9eeb4b734b77b7b110c050b83 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:08 +0200
+Subject: [PATCH 011/323] sched: Fix migrate_disable() vs
+ set_cpus_allowed_ptr()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Concurrent migrate_disable() and set_cpus_allowed_ptr() has
+interesting features. We rely on set_cpus_allowed_ptr() to not return
+until the task runs inside the provided mask. This expectation is
+exported to userspace.
+
+This means that any set_cpus_allowed_ptr() caller must wait until
+migrate_enable() allows migrations.
+
+At the same time, we don't want migrate_enable() to schedule, due to
+patterns like:
+
+	preempt_disable();
+	migrate_disable();
+	...
+	migrate_enable();
+	preempt_enable();
+
+And:
+
+	raw_spin_lock(&B);
+	spin_unlock(&A);
+
+this means that when migrate_enable() must restore the affinity
+mask, it cannot wait for completion thereof. Luck will have it that
+that is exactly the case where there is a pending
+set_cpus_allowed_ptr(), so let that provide storage for the async stop
+machine.
+
+Much thanks to Valentin who used TLA+ most effective and found lots of
+'interesting' cases.
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/sched.h |   1 +
+ kernel/sched/core.c   | 234 ++++++++++++++++++++++++++++++++++++------
+ 2 files changed, 205 insertions(+), 30 deletions(-)
+
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index 76907e9876d5..5b5c194f5a62 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -726,6 +726,7 @@ struct task_struct {
+ 	int				nr_cpus_allowed;
+ 	const cpumask_t			*cpus_ptr;
+ 	cpumask_t			cpus_mask;
++	void				*migration_pending;
+ #if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+ 	int				migration_disabled;
+ #endif
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 5c9db4b2b6ec..3af7c42896c9 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1746,15 +1746,26 @@ void migrate_enable(void)
+ {
+ 	struct task_struct *p = current;
+ 
+-	if (--p->migration_disabled)
++	if (p->migration_disabled > 1) {
++		p->migration_disabled--;
+ 		return;
++	}
+ 
++	/*
++	 * Ensure stop_task runs either before or after this, and that
++	 * __set_cpus_allowed_ptr(SCA_MIGRATE_ENABLE) doesn't schedule().
++	 */
++	preempt_disable();
++	if (p->cpus_ptr != &p->cpus_mask)
++		__set_cpus_allowed_ptr(p, &p->cpus_mask, SCA_MIGRATE_ENABLE);
++	/*
++	 * Mustn't clear migration_disabled() until cpus_ptr points back at the
++	 * regular cpus_mask, otherwise things that race (eg.
++	 * select_fallback_rq) get confused.
++	 */
+ 	barrier();
+-
+-	if (p->cpus_ptr == &p->cpus_mask)
+-		return;
+-
+-	__set_cpus_allowed_ptr(p, &p->cpus_mask, SCA_MIGRATE_ENABLE);
++	p->migration_disabled = 0;
++	preempt_enable();
+ }
+ EXPORT_SYMBOL_GPL(migrate_enable);
+ 
+@@ -1819,8 +1830,16 @@ static struct rq *move_queued_task(struct rq *rq, struct rq_flags *rf,
+ }
+ 
+ struct migration_arg {
+-	struct task_struct *task;
+-	int dest_cpu;
++	struct task_struct		*task;
++	int				dest_cpu;
++	struct set_affinity_pending	*pending;
++};
++
++struct set_affinity_pending {
++	refcount_t		refs;
++	struct completion	done;
++	struct cpu_stop_work	stop_work;
++	struct migration_arg	arg;
+ };
+ 
+ /*
+@@ -1852,16 +1871,19 @@ static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf,
+  */
+ static int migration_cpu_stop(void *data)
+ {
++	struct set_affinity_pending *pending;
+ 	struct migration_arg *arg = data;
+ 	struct task_struct *p = arg->task;
++	int dest_cpu = arg->dest_cpu;
+ 	struct rq *rq = this_rq();
++	bool complete = false;
+ 	struct rq_flags rf;
+ 
+ 	/*
+ 	 * The original target CPU might have gone down and we might
+ 	 * be on another CPU but it doesn't matter.
+ 	 */
+-	local_irq_disable();
++	local_irq_save(rf.flags);
+ 	/*
+ 	 * We need to explicitly wake pending tasks before running
+ 	 * __migrate_task() such that we will not miss enforcing cpus_ptr
+@@ -1871,21 +1893,83 @@ static int migration_cpu_stop(void *data)
+ 
+ 	raw_spin_lock(&p->pi_lock);
+ 	rq_lock(rq, &rf);
++
++	pending = p->migration_pending;
+ 	/*
+ 	 * If task_rq(p) != rq, it cannot be migrated here, because we're
+ 	 * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
+ 	 * we're holding p->pi_lock.
+ 	 */
+ 	if (task_rq(p) == rq) {
++		if (is_migration_disabled(p))
++			goto out;
++
++		if (pending) {
++			p->migration_pending = NULL;
++			complete = true;
++		}
++
++		/* migrate_enable() --  we must not race against SCA */
++		if (dest_cpu < 0) {
++			/*
++			 * When this was migrate_enable() but we no longer
++			 * have a @pending, a concurrent SCA 'fixed' things
++			 * and we should be valid again. Nothing to do.
++			 */
++			if (!pending) {
++				WARN_ON_ONCE(!is_cpu_allowed(p, cpu_of(rq)));
++				goto out;
++			}
++
++			dest_cpu = cpumask_any_distribute(&p->cpus_mask);
++		}
++
+ 		if (task_on_rq_queued(p))
+-			rq = __migrate_task(rq, &rf, p, arg->dest_cpu);
++			rq = __migrate_task(rq, &rf, p, dest_cpu);
+ 		else
+-			p->wake_cpu = arg->dest_cpu;
++			p->wake_cpu = dest_cpu;
++
++	} else if (dest_cpu < 0) {
++		/*
++		 * This happens when we get migrated between migrate_enable()'s
++		 * preempt_enable() and scheduling the stopper task. At that
++		 * point we're a regular task again and not current anymore.
++		 *
++		 * A !PREEMPT kernel has a giant hole here, which makes it far
++		 * more likely.
++		 */
++
++		/*
++		 * When this was migrate_enable() but we no longer have an
++		 * @pending, a concurrent SCA 'fixed' things and we should be
++		 * valid again. Nothing to do.
++		 */
++		if (!pending) {
++			WARN_ON_ONCE(!is_cpu_allowed(p, cpu_of(rq)));
++			goto out;
++		}
++
++		/*
++		 * When migrate_enable() hits a rq mis-match we can't reliably
++		 * determine is_migration_disabled() and so have to chase after
++		 * it.
++		 */
++		task_rq_unlock(rq, p, &rf);
++		stop_one_cpu_nowait(task_cpu(p), migration_cpu_stop,
++				    &pending->arg, &pending->stop_work);
++		return 0;
+ 	}
+-	rq_unlock(rq, &rf);
+-	raw_spin_unlock(&p->pi_lock);
++out:
++	task_rq_unlock(rq, p, &rf);
++
++	if (complete)
++		complete_all(&pending->done);
++
++	/* For pending->{arg,stop_work} */
++	pending = arg->pending;
++	if (pending && refcount_dec_and_test(&pending->refs))
++		wake_up_var(&pending->refs);
+ 
+-	local_irq_enable();
+ 	return 0;
+ }
+ 
+@@ -1954,6 +2038,110 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
+ 	__do_set_cpus_allowed(p, new_mask, 0);
+ }
+ 
++/*
++ * This function is wildly self concurrent, consider at least 3 times.
++ */
++static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flags *rf,
++			    int dest_cpu, unsigned int flags)
++{
++	struct set_affinity_pending my_pending = { }, *pending = NULL;
++	struct migration_arg arg = {
++		.task = p,
++		.dest_cpu = dest_cpu,
++	};
++	bool complete = false;
++
++	/* Can the task run on the task's current CPU? If so, we're done */
++	if (cpumask_test_cpu(task_cpu(p), &p->cpus_mask)) {
++		pending = p->migration_pending;
++		if (pending) {
++			refcount_inc(&pending->refs);
++			p->migration_pending = NULL;
++			complete = true;
++		}
++		task_rq_unlock(rq, p, rf);
++
++		if (complete)
++			goto do_complete;
++
++		return 0;
++	}
++
++	if (!(flags & SCA_MIGRATE_ENABLE)) {
++		/* serialized by p->pi_lock */
++		if (!p->migration_pending) {
++			refcount_set(&my_pending.refs, 1);
++			init_completion(&my_pending.done);
++			p->migration_pending = &my_pending;
++		} else {
++			pending = p->migration_pending;
++			refcount_inc(&pending->refs);
++		}
++	}
++	pending = p->migration_pending;
++	/*
++	 * - !MIGRATE_ENABLE:
++	 *   we'll have installed a pending if there wasn't one already.
++	 *
++	 * - MIGRATE_ENABLE:
++	 *   we're here because the current CPU isn't matching anymore,
++	 *   the only way that can happen is because of a concurrent
++	 *   set_cpus_allowed_ptr() call, which should then still be
++	 *   pending completion.
++	 *
++	 * Either way, we really should have a @pending here.
++	 */
++	if (WARN_ON_ONCE(!pending))
++		return -EINVAL;
++
++	if (flags & SCA_MIGRATE_ENABLE) {
++
++		refcount_inc(&pending->refs); /* pending->{arg,stop_work} */
++		task_rq_unlock(rq, p, rf);
++
++		pending->arg = (struct migration_arg) {
++			.task = p,
++			.dest_cpu = -1,
++			.pending = pending,
++		};
++
++		stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
++				    &pending->arg, &pending->stop_work);
++
++		return 0;
++	}
++
++	if (task_running(rq, p) || p->state == TASK_WAKING) {
++
++		task_rq_unlock(rq, p, rf);
++		stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
++
++	} else {
++
++		if (!is_migration_disabled(p)) {
++			if (task_on_rq_queued(p))
++				rq = move_queued_task(rq, rf, p, dest_cpu);
++
++			p->migration_pending = NULL;
++			complete = true;
++		}
++		task_rq_unlock(rq, p, rf);
++
++do_complete:
++		if (complete)
++			complete_all(&pending->done);
++	}
++
++	wait_for_completion(&pending->done);
++
++	if (refcount_dec_and_test(&pending->refs))
++		wake_up_var(&pending->refs);
++
++	wait_var_event(&my_pending.refs, !refcount_read(&my_pending.refs));
++
++	return 0;
++}
++
+ /*
+  * Change a given task's CPU affinity. Migrate the thread to a
+  * proper CPU and schedule it away if the CPU it's executing on
+@@ -2023,23 +2211,8 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
+ 			p->nr_cpus_allowed != 1);
+ 	}
+ 
+-	/* Can the task run on the task's current CPU? If so, we're done */
+-	if (cpumask_test_cpu(task_cpu(p), new_mask))
+-		goto out;
++	return affine_move_task(rq, p, &rf, dest_cpu, flags);
+ 
+-	if (task_running(rq, p) || p->state == TASK_WAKING) {
+-		struct migration_arg arg = { p, dest_cpu };
+-		/* Need help from migration thread: drop lock and wait. */
+-		task_rq_unlock(rq, p, &rf);
+-		stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
+-		return 0;
+-	} else if (task_on_rq_queued(p)) {
+-		/*
+-		 * OK, since we're going to drop the lock immediately
+-		 * afterwards anyway.
+-		 */
+-		rq = move_queued_task(rq, &rf, p, dest_cpu);
+-	}
+ out:
+ 	task_rq_unlock(rq, p, &rf);
+ 
+@@ -3230,6 +3403,7 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
+ 	init_numa_balancing(clone_flags, p);
+ #ifdef CONFIG_SMP
+ 	p->wake_entry.u_flags = CSD_TYPE_TTWU;
++	p->migration_pending = NULL;
+ #endif
+ }
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0012-sched-core-Make-migrate-disable-and-CPU-hotplug-coop.patch b/debian/patches-rt/0012-sched-core-Make-migrate-disable-and-CPU-hotplug-coop.patch
new file mode 100644
index 000000000..e89668431
--- /dev/null
+++ b/debian/patches-rt/0012-sched-core-Make-migrate-disable-and-CPU-hotplug-coop.patch
@@ -0,0 +1,137 @@
+From 02829fffd43c5fe3e617d07e0a94d5164324449b Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 23 Oct 2020 12:12:09 +0200
+Subject: [PATCH 012/323] sched/core: Make migrate disable and CPU hotplug
+ cooperative
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+On CPU unplug tasks which are in a migrate disabled region cannot be pushed
+to a different CPU until they returned to migrateable state.
+
+Account the number of tasks on a runqueue which are in a migrate disabled
+section and make the hotplug wait mechanism respect that.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/core.c  | 36 ++++++++++++++++++++++++++++++------
+ kernel/sched/sched.h |  4 ++++
+ 2 files changed, 34 insertions(+), 6 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 3af7c42896c9..2517a003295b 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1735,10 +1735,17 @@ static void migrate_disable_switch(struct rq *rq, struct task_struct *p)
+ 
+ void migrate_disable(void)
+ {
+-	if (current->migration_disabled++)
++	struct task_struct *p = current;
++
++	if (p->migration_disabled) {
++		p->migration_disabled++;
+ 		return;
++	}
+ 
+-	barrier();
++	preempt_disable();
++	this_rq()->nr_pinned++;
++	p->migration_disabled = 1;
++	preempt_enable();
+ }
+ EXPORT_SYMBOL_GPL(migrate_disable);
+ 
+@@ -1765,6 +1772,7 @@ void migrate_enable(void)
+ 	 */
+ 	barrier();
+ 	p->migration_disabled = 0;
++	this_rq()->nr_pinned--;
+ 	preempt_enable();
+ }
+ EXPORT_SYMBOL_GPL(migrate_enable);
+@@ -1774,6 +1782,11 @@ static inline bool is_migration_disabled(struct task_struct *p)
+ 	return p->migration_disabled;
+ }
+ 
++static inline bool rq_has_pinned_tasks(struct rq *rq)
++{
++	return rq->nr_pinned;
++}
++
+ #endif
+ 
+ /*
+@@ -2705,6 +2718,11 @@ static inline bool is_migration_disabled(struct task_struct *p)
+ 	return false;
+ }
+ 
++static inline bool rq_has_pinned_tasks(struct rq *rq)
++{
++	return false;
++}
++
+ #endif
+ 
+ static void
+@@ -7064,15 +7082,20 @@ static void balance_push(struct rq *rq)
+ 	 * Both the cpu-hotplug and stop task are in this case and are
+ 	 * required to complete the hotplug process.
+ 	 */
+-	if (is_per_cpu_kthread(push_task)) {
++	if (is_per_cpu_kthread(push_task) || is_migration_disabled(push_task)) {
+ 		/*
+ 		 * If this is the idle task on the outgoing CPU try to wake
+ 		 * up the hotplug control thread which might wait for the
+ 		 * last task to vanish. The rcuwait_active() check is
+ 		 * accurate here because the waiter is pinned on this CPU
+ 		 * and can't obviously be running in parallel.
++		 *
++		 * On RT kernels this also has to check whether there are
++		 * pinned and scheduled out tasks on the runqueue. They
++		 * need to leave the migrate disabled section first.
+ 		 */
+-		if (!rq->nr_running && rcuwait_active(&rq->hotplug_wait)) {
++		if (!rq->nr_running && !rq_has_pinned_tasks(rq) &&
++		    rcuwait_active(&rq->hotplug_wait)) {
+ 			raw_spin_unlock(&rq->lock);
+ 			rcuwait_wake_up(&rq->hotplug_wait);
+ 			raw_spin_lock(&rq->lock);
+@@ -7119,7 +7142,8 @@ static void balance_hotplug_wait(void)
+ {
+ 	struct rq *rq = this_rq();
+ 
+-	rcuwait_wait_event(&rq->hotplug_wait, rq->nr_running == 1,
++	rcuwait_wait_event(&rq->hotplug_wait,
++			   rq->nr_running == 1 && !rq_has_pinned_tasks(rq),
+ 			   TASK_UNINTERRUPTIBLE);
+ }
+ 
+@@ -7366,7 +7390,7 @@ int sched_cpu_dying(unsigned int cpu)
+ 	sched_tick_stop(cpu);
+ 
+ 	rq_lock_irqsave(rq, &rf);
+-	BUG_ON(rq->nr_running != 1);
++	BUG_ON(rq->nr_running != 1 || rq_has_pinned_tasks(rq));
+ 	rq_unlock_irqrestore(rq, &rf);
+ 
+ 	calc_load_migrate(rq);
+diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
+index f3109adda484..8237c9ab2bb8 100644
+--- a/kernel/sched/sched.h
++++ b/kernel/sched/sched.h
+@@ -1057,6 +1057,10 @@ struct rq {
+ 	/* Must be inspected within a rcu lock section */
+ 	struct cpuidle_state	*idle_state;
+ #endif
++
++#if defined(CONFIG_PREEMPT_RT) && defined(CONFIG_SMP)
++	unsigned int		nr_pinned;
++#endif
+ };
+ 
+ #ifdef CONFIG_FAIR_GROUP_SCHED
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0013-sched-rt-Use-cpumask_any-_distribute.patch b/debian/patches-rt/0013-sched-rt-Use-cpumask_any-_distribute.patch
new file mode 100644
index 000000000..b190e58d4
--- /dev/null
+++ b/debian/patches-rt/0013-sched-rt-Use-cpumask_any-_distribute.patch
@@ -0,0 +1,121 @@
+From 0d3b4a8d9391d1eb1efb998bfcaff013a01466bf Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:10 +0200
+Subject: [PATCH 013/323] sched,rt: Use cpumask_any*_distribute()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Replace a bunch of cpumask_any*() instances with
+cpumask_any*_distribute(), by injecting this little bit of random in
+cpu selection, we reduce the chance two competing balance operations
+working off the same lowest_mask pick the same CPU.
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/cpumask.h |  6 ++++++
+ kernel/sched/deadline.c |  6 +++---
+ kernel/sched/rt.c       |  6 +++---
+ lib/cpumask.c           | 18 ++++++++++++++++++
+ 4 files changed, 30 insertions(+), 6 deletions(-)
+
+diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
+index f0d895d6ac39..383684e30f12 100644
+--- a/include/linux/cpumask.h
++++ b/include/linux/cpumask.h
+@@ -199,6 +199,11 @@ static inline int cpumask_any_and_distribute(const struct cpumask *src1p,
+ 	return cpumask_next_and(-1, src1p, src2p);
+ }
+ 
++static inline int cpumask_any_distribute(const struct cpumask *srcp)
++{
++	return cpumask_first(srcp);
++}
++
+ #define for_each_cpu(cpu, mask)			\
+ 	for ((cpu) = 0; (cpu) < 1; (cpu)++, (void)mask)
+ #define for_each_cpu_not(cpu, mask)		\
+@@ -252,6 +257,7 @@ int cpumask_any_but(const struct cpumask *mask, unsigned int cpu);
+ unsigned int cpumask_local_spread(unsigned int i, int node);
+ int cpumask_any_and_distribute(const struct cpumask *src1p,
+ 			       const struct cpumask *src2p);
++int cpumask_any_distribute(const struct cpumask *srcp);
+ 
+ /**
+  * for_each_cpu - iterate over every cpu in a mask
+diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
+index 5566f157640b..e64d378e4e87 100644
+--- a/kernel/sched/deadline.c
++++ b/kernel/sched/deadline.c
+@@ -2012,8 +2012,8 @@ static int find_later_rq(struct task_struct *task)
+ 				return this_cpu;
+ 			}
+ 
+-			best_cpu = cpumask_first_and(later_mask,
+-							sched_domain_span(sd));
++			best_cpu = cpumask_any_and_distribute(later_mask,
++							      sched_domain_span(sd));
+ 			/*
+ 			 * Last chance: if a CPU being in both later_mask
+ 			 * and current sd span is valid, that becomes our
+@@ -2035,7 +2035,7 @@ static int find_later_rq(struct task_struct *task)
+ 	if (this_cpu != -1)
+ 		return this_cpu;
+ 
+-	cpu = cpumask_any(later_mask);
++	cpu = cpumask_any_distribute(later_mask);
+ 	if (cpu < nr_cpu_ids)
+ 		return cpu;
+ 
+diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
+index fdcce04913db..695526a54a89 100644
+--- a/kernel/sched/rt.c
++++ b/kernel/sched/rt.c
+@@ -1766,8 +1766,8 @@ static int find_lowest_rq(struct task_struct *task)
+ 				return this_cpu;
+ 			}
+ 
+-			best_cpu = cpumask_first_and(lowest_mask,
+-						     sched_domain_span(sd));
++			best_cpu = cpumask_any_and_distribute(lowest_mask,
++							      sched_domain_span(sd));
+ 			if (best_cpu < nr_cpu_ids) {
+ 				rcu_read_unlock();
+ 				return best_cpu;
+@@ -1784,7 +1784,7 @@ static int find_lowest_rq(struct task_struct *task)
+ 	if (this_cpu != -1)
+ 		return this_cpu;
+ 
+-	cpu = cpumask_any(lowest_mask);
++	cpu = cpumask_any_distribute(lowest_mask);
+ 	if (cpu < nr_cpu_ids)
+ 		return cpu;
+ 
+diff --git a/lib/cpumask.c b/lib/cpumask.c
+index fb22fb266f93..c3c76b833384 100644
+--- a/lib/cpumask.c
++++ b/lib/cpumask.c
+@@ -261,3 +261,21 @@ int cpumask_any_and_distribute(const struct cpumask *src1p,
+ 	return next;
+ }
+ EXPORT_SYMBOL(cpumask_any_and_distribute);
++
++int cpumask_any_distribute(const struct cpumask *srcp)
++{
++	int next, prev;
++
++	/* NOTE: our first selection will skip 0. */
++	prev = __this_cpu_read(distribute_cpu_mask_prev);
++
++	next = cpumask_next(prev, srcp);
++	if (next >= nr_cpu_ids)
++		next = cpumask_first(srcp);
++
++	if (next < nr_cpu_ids)
++		__this_cpu_write(distribute_cpu_mask_prev, next);
++
++	return next;
++}
++EXPORT_SYMBOL(cpumask_any_distribute);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0014-sched-rt-Use-the-full-cpumask-for-balancing.patch b/debian/patches-rt/0014-sched-rt-Use-the-full-cpumask-for-balancing.patch
new file mode 100644
index 000000000..c2817a0b7
--- /dev/null
+++ b/debian/patches-rt/0014-sched-rt-Use-the-full-cpumask-for-balancing.patch
@@ -0,0 +1,105 @@
+From 75c028b5537f7205cfe5aecf8cf6bb61ef1428f6 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:11 +0200
+Subject: [PATCH 014/323] sched,rt: Use the full cpumask for balancing
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+We want migrate_disable() tasks to get PULLs in order for them to PUSH
+away the higher priority task.
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/cpudeadline.c | 4 ++--
+ kernel/sched/cpupri.c      | 4 ++--
+ kernel/sched/deadline.c    | 4 ++--
+ kernel/sched/rt.c          | 4 ++--
+ 4 files changed, 8 insertions(+), 8 deletions(-)
+
+diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
+index 8cb06c8c7eb1..ceb03d76c0cc 100644
+--- a/kernel/sched/cpudeadline.c
++++ b/kernel/sched/cpudeadline.c
+@@ -120,7 +120,7 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
+ 	const struct sched_dl_entity *dl_se = &p->dl;
+ 
+ 	if (later_mask &&
+-	    cpumask_and(later_mask, cp->free_cpus, p->cpus_ptr)) {
++	    cpumask_and(later_mask, cp->free_cpus, &p->cpus_mask)) {
+ 		unsigned long cap, max_cap = 0;
+ 		int cpu, max_cpu = -1;
+ 
+@@ -151,7 +151,7 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
+ 
+ 		WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
+ 
+-		if (cpumask_test_cpu(best_cpu, p->cpus_ptr) &&
++		if (cpumask_test_cpu(best_cpu, &p->cpus_mask) &&
+ 		    dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
+ 			if (later_mask)
+ 				cpumask_set_cpu(best_cpu, later_mask);
+diff --git a/kernel/sched/cpupri.c b/kernel/sched/cpupri.c
+index 0033731a0797..11c4df2010de 100644
+--- a/kernel/sched/cpupri.c
++++ b/kernel/sched/cpupri.c
+@@ -73,11 +73,11 @@ static inline int __cpupri_find(struct cpupri *cp, struct task_struct *p,
+ 	if (skip)
+ 		return 0;
+ 
+-	if (cpumask_any_and(p->cpus_ptr, vec->mask) >= nr_cpu_ids)
++	if (cpumask_any_and(&p->cpus_mask, vec->mask) >= nr_cpu_ids)
+ 		return 0;
+ 
+ 	if (lowest_mask) {
+-		cpumask_and(lowest_mask, p->cpus_ptr, vec->mask);
++		cpumask_and(lowest_mask, &p->cpus_mask, vec->mask);
+ 
+ 		/*
+ 		 * We have to ensure that we have at least one bit
+diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
+index e64d378e4e87..94977a6ced8b 100644
+--- a/kernel/sched/deadline.c
++++ b/kernel/sched/deadline.c
+@@ -1922,7 +1922,7 @@ static void task_fork_dl(struct task_struct *p)
+ static int pick_dl_task(struct rq *rq, struct task_struct *p, int cpu)
+ {
+ 	if (!task_running(rq, p) &&
+-	    cpumask_test_cpu(cpu, p->cpus_ptr))
++	    cpumask_test_cpu(cpu, &p->cpus_mask))
+ 		return 1;
+ 	return 0;
+ }
+@@ -2072,7 +2072,7 @@ static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq)
+ 		/* Retry if something changed. */
+ 		if (double_lock_balance(rq, later_rq)) {
+ 			if (unlikely(task_rq(task) != rq ||
+-				     !cpumask_test_cpu(later_rq->cpu, task->cpus_ptr) ||
++				     !cpumask_test_cpu(later_rq->cpu, &task->cpus_mask) ||
+ 				     task_running(rq, task) ||
+ 				     !dl_task(task) ||
+ 				     !task_on_rq_queued(task))) {
+diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
+index 695526a54a89..f91339c0dee8 100644
+--- a/kernel/sched/rt.c
++++ b/kernel/sched/rt.c
+@@ -1672,7 +1672,7 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
+ static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
+ {
+ 	if (!task_running(rq, p) &&
+-	    cpumask_test_cpu(cpu, p->cpus_ptr))
++	    cpumask_test_cpu(cpu, &p->cpus_mask))
+ 		return 1;
+ 
+ 	return 0;
+@@ -1825,7 +1825,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
+ 			 * Also make sure that it wasn't scheduled on its rq.
+ 			 */
+ 			if (unlikely(task_rq(task) != rq ||
+-				     !cpumask_test_cpu(lowest_rq->cpu, task->cpus_ptr) ||
++				     !cpumask_test_cpu(lowest_rq->cpu, &task->cpus_mask) ||
+ 				     task_running(rq, task) ||
+ 				     !rt_task(task) ||
+ 				     !task_on_rq_queued(task))) {
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0015-sched-lockdep-Annotate-pi_lock-recursion.patch b/debian/patches-rt/0015-sched-lockdep-Annotate-pi_lock-recursion.patch
new file mode 100644
index 000000000..05030516b
--- /dev/null
+++ b/debian/patches-rt/0015-sched-lockdep-Annotate-pi_lock-recursion.patch
@@ -0,0 +1,52 @@
+From c0e34a5ef4e854220a216e934ab90f04d4432bdd Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:12 +0200
+Subject: [PATCH 015/323] sched, lockdep: Annotate ->pi_lock recursion
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+There's a valid ->pi_lock recursion issue where the actual PI code
+tries to wake up the stop task. Make lockdep aware so it doesn't
+complain about this.
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/core.c | 15 +++++++++++++++
+ 1 file changed, 15 insertions(+)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 2517a003295b..abbf01f77a76 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -2670,6 +2670,7 @@ int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags)
+ 
+ void sched_set_stop_task(int cpu, struct task_struct *stop)
+ {
++	static struct lock_class_key stop_pi_lock;
+ 	struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
+ 	struct task_struct *old_stop = cpu_rq(cpu)->stop;
+ 
+@@ -2685,6 +2686,20 @@ void sched_set_stop_task(int cpu, struct task_struct *stop)
+ 		sched_setscheduler_nocheck(stop, SCHED_FIFO, &param);
+ 
+ 		stop->sched_class = &stop_sched_class;
++
++		/*
++		 * The PI code calls rt_mutex_setprio() with ->pi_lock held to
++		 * adjust the effective priority of a task. As a result,
++		 * rt_mutex_setprio() can trigger (RT) balancing operations,
++		 * which can then trigger wakeups of the stop thread to push
++		 * around the current task.
++		 *
++		 * The stop task itself will never be part of the PI-chain, it
++		 * never blocks, therefore that ->pi_lock recursion is safe.
++		 * Tell lockdep about this by placing the stop->pi_lock in its
++		 * own class.
++		 */
++		lockdep_set_class(&stop->pi_lock, &stop_pi_lock);
+ 	}
+ 
+ 	cpu_rq(cpu)->stop = stop;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0016-sched-Fix-migrate_disable-vs-rt-dl-balancing.patch b/debian/patches-rt/0016-sched-Fix-migrate_disable-vs-rt-dl-balancing.patch
new file mode 100644
index 000000000..b665e6d22
--- /dev/null
+++ b/debian/patches-rt/0016-sched-Fix-migrate_disable-vs-rt-dl-balancing.patch
@@ -0,0 +1,495 @@
+From 8121011ded919f172bbbc7f5c095ca29d83a5aed Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:13 +0200
+Subject: [PATCH 016/323] sched: Fix migrate_disable() vs rt/dl balancing
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+In order to minimize the interference of migrate_disable() on lower
+priority tasks, which can be deprived of runtime due to being stuck
+below a higher priority task. Teach the RT/DL balancers to push away
+these higher priority tasks when a lower priority task gets selected
+to run on a freshly demoted CPU (pull).
+
+This adds migration interference to the higher priority task, but
+restores bandwidth to system that would otherwise be irrevocably lost.
+Without this it would be possible to have all tasks on the system
+stuck on a single CPU, each task preempted in a migrate_disable()
+section with a single high priority task running.
+
+This way we can still approximate running the M highest priority tasks
+on the system.
+
+Migrating the top task away is (ofcourse) still subject to
+migrate_disable() too, which means the lower task is subject to an
+interference equivalent to the worst case migrate_disable() section.
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/preempt.h | 40 +++++++++++++-----------
+ include/linux/sched.h   |  3 +-
+ kernel/sched/core.c     | 67 +++++++++++++++++++++++++++++++++++------
+ kernel/sched/deadline.c | 29 +++++++++++++-----
+ kernel/sched/rt.c       | 63 ++++++++++++++++++++++++++++++--------
+ kernel/sched/sched.h    | 32 ++++++++++++++++++++
+ 6 files changed, 186 insertions(+), 48 deletions(-)
+
+diff --git a/include/linux/preempt.h b/include/linux/preempt.h
+index 97ba7c920653..8b43922e65df 100644
+--- a/include/linux/preempt.h
++++ b/include/linux/preempt.h
+@@ -325,24 +325,28 @@ static inline void preempt_notifier_init(struct preempt_notifier *notifier,
+ #if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+ 
+ /*
+- * Migrate-Disable and why it is (strongly) undesired.
+- *
+- * The premise of the Real-Time schedulers we have on Linux
+- * (SCHED_FIFO/SCHED_DEADLINE) is that M CPUs can/will run M tasks
+- * concurrently, provided there are sufficient runnable tasks, also known as
+- * work-conserving. For instance SCHED_DEADLINE tries to schedule the M
+- * earliest deadline threads, and SCHED_FIFO the M highest priority threads.
+- *
+- * The correctness of various scheduling models depends on this, but is it
+- * broken by migrate_disable() that doesn't imply preempt_disable(). Where
+- * preempt_disable() implies an immediate priority ceiling, preemptible
+- * migrate_disable() allows nesting.
+- *
+- * The worst case is that all tasks preempt one another in a migrate_disable()
+- * region and stack on a single CPU. This then reduces the available bandwidth
+- * to a single CPU. And since Real-Time schedulability theory considers the
+- * Worst-Case only, all Real-Time analysis shall revert to single-CPU
+- * (instantly solving the SMP analysis problem).
++ * Migrate-Disable and why it is undesired.
++ *
++ * When a preempted task becomes elegible to run under the ideal model (IOW it
++ * becomes one of the M highest priority tasks), it might still have to wait
++ * for the preemptee's migrate_disable() section to complete. Thereby suffering
++ * a reduction in bandwidth in the exact duration of the migrate_disable()
++ * section.
++ *
++ * Per this argument, the change from preempt_disable() to migrate_disable()
++ * gets us:
++ *
++ * - a higher priority tasks gains reduced wake-up latency; with preempt_disable()
++ *   it would have had to wait for the lower priority task.
++ *
++ * - a lower priority tasks; which under preempt_disable() could've instantly
++ *   migrated away when another CPU becomes available, is now constrained
++ *   by the ability to push the higher priority task away, which might itself be
++ *   in a migrate_disable() section, reducing it's available bandwidth.
++ *
++ * IOW it trades latency / moves the interference term, but it stays in the
++ * system, and as long as it remains unbounded, the system is not fully
++ * deterministic.
+  *
+  *
+  * The reason we have it anyway.
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index 5b5c194f5a62..7ca1f3e740dd 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -728,8 +728,9 @@ struct task_struct {
+ 	cpumask_t			cpus_mask;
+ 	void				*migration_pending;
+ #if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+-	int				migration_disabled;
++	unsigned short			migration_disabled;
+ #endif
++	unsigned short			migration_flags;
+ 
+ #ifdef CONFIG_PREEMPT_RCU
+ 	int				rcu_read_lock_nesting;
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index abbf01f77a76..452fc1dfb143 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1777,11 +1777,6 @@ void migrate_enable(void)
+ }
+ EXPORT_SYMBOL_GPL(migrate_enable);
+ 
+-static inline bool is_migration_disabled(struct task_struct *p)
+-{
+-	return p->migration_disabled;
+-}
+-
+ static inline bool rq_has_pinned_tasks(struct rq *rq)
+ {
+ 	return rq->nr_pinned;
+@@ -1986,6 +1981,49 @@ static int migration_cpu_stop(void *data)
+ 	return 0;
+ }
+ 
++int push_cpu_stop(void *arg)
++{
++	struct rq *lowest_rq = NULL, *rq = this_rq();
++	struct task_struct *p = arg;
++
++	raw_spin_lock_irq(&p->pi_lock);
++	raw_spin_lock(&rq->lock);
++
++	if (task_rq(p) != rq)
++		goto out_unlock;
++
++	if (is_migration_disabled(p)) {
++		p->migration_flags |= MDF_PUSH;
++		goto out_unlock;
++	}
++
++	p->migration_flags &= ~MDF_PUSH;
++
++	if (p->sched_class->find_lock_rq)
++		lowest_rq = p->sched_class->find_lock_rq(p, rq);
++
++	if (!lowest_rq)
++		goto out_unlock;
++
++	// XXX validate p is still the highest prio task
++	if (task_rq(p) == rq) {
++		deactivate_task(rq, p, 0);
++		set_task_cpu(p, lowest_rq->cpu);
++		activate_task(lowest_rq, p, 0);
++		resched_curr(lowest_rq);
++	}
++
++	double_unlock_balance(rq, lowest_rq);
++
++out_unlock:
++	rq->push_busy = false;
++	raw_spin_unlock(&rq->lock);
++	raw_spin_unlock_irq(&p->pi_lock);
++
++	put_task_struct(p);
++	return 0;
++}
++
+ /*
+  * sched_class::set_cpus_allowed must do the below, but is not required to
+  * actually call this function.
+@@ -2066,6 +2104,14 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 
+ 	/* Can the task run on the task's current CPU? If so, we're done */
+ 	if (cpumask_test_cpu(task_cpu(p), &p->cpus_mask)) {
++		struct task_struct *push_task = NULL;
++
++		if ((flags & SCA_MIGRATE_ENABLE) &&
++		    (p->migration_flags & MDF_PUSH) && !rq->push_busy) {
++			rq->push_busy = true;
++			push_task = get_task_struct(p);
++		}
++
+ 		pending = p->migration_pending;
+ 		if (pending) {
+ 			refcount_inc(&pending->refs);
+@@ -2074,6 +2120,11 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 		}
+ 		task_rq_unlock(rq, p, rf);
+ 
++		if (push_task) {
++			stop_one_cpu_nowait(rq->cpu, push_cpu_stop,
++					    p, &rq->push_work);
++		}
++
+ 		if (complete)
+ 			goto do_complete;
+ 
+@@ -2110,6 +2161,7 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 	if (flags & SCA_MIGRATE_ENABLE) {
+ 
+ 		refcount_inc(&pending->refs); /* pending->{arg,stop_work} */
++		p->migration_flags &= ~MDF_PUSH;
+ 		task_rq_unlock(rq, p, rf);
+ 
+ 		pending->arg = (struct migration_arg) {
+@@ -2728,11 +2780,6 @@ static inline int __set_cpus_allowed_ptr(struct task_struct *p,
+ 
+ static inline void migrate_disable_switch(struct rq *rq, struct task_struct *p) { }
+ 
+-static inline bool is_migration_disabled(struct task_struct *p)
+-{
+-	return false;
+-}
+-
+ static inline bool rq_has_pinned_tasks(struct rq *rq)
+ {
+ 	return false;
+diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
+index 94977a6ced8b..7cf3248894a9 100644
+--- a/kernel/sched/deadline.c
++++ b/kernel/sched/deadline.c
+@@ -2139,6 +2139,9 @@ static int push_dl_task(struct rq *rq)
+ 		return 0;
+ 
+ retry:
++	if (is_migration_disabled(next_task))
++		return 0;
++
+ 	if (WARN_ON(next_task == rq->curr))
+ 		return 0;
+ 
+@@ -2216,7 +2219,7 @@ static void push_dl_tasks(struct rq *rq)
+ static void pull_dl_task(struct rq *this_rq)
+ {
+ 	int this_cpu = this_rq->cpu, cpu;
+-	struct task_struct *p;
++	struct task_struct *p, *push_task;
+ 	bool resched = false;
+ 	struct rq *src_rq;
+ 	u64 dmin = LONG_MAX;
+@@ -2246,6 +2249,7 @@ static void pull_dl_task(struct rq *this_rq)
+ 			continue;
+ 
+ 		/* Might drop this_rq->lock */
++		push_task = NULL;
+ 		double_lock_balance(this_rq, src_rq);
+ 
+ 		/*
+@@ -2277,17 +2281,27 @@ static void pull_dl_task(struct rq *this_rq)
+ 					   src_rq->curr->dl.deadline))
+ 				goto skip;
+ 
+-			resched = true;
+-
+-			deactivate_task(src_rq, p, 0);
+-			set_task_cpu(p, this_cpu);
+-			activate_task(this_rq, p, 0);
+-			dmin = p->dl.deadline;
++			if (is_migration_disabled(p)) {
++				push_task = get_push_task(src_rq);
++			} else {
++				deactivate_task(src_rq, p, 0);
++				set_task_cpu(p, this_cpu);
++				activate_task(this_rq, p, 0);
++				dmin = p->dl.deadline;
++				resched = true;
++			}
+ 
+ 			/* Is there any other task even earlier? */
+ 		}
+ skip:
+ 		double_unlock_balance(this_rq, src_rq);
++
++		if (push_task) {
++			raw_spin_unlock(&this_rq->lock);
++			stop_one_cpu_nowait(src_rq->cpu, push_cpu_stop,
++					    push_task, &src_rq->push_work);
++			raw_spin_lock(&this_rq->lock);
++		}
+ 	}
+ 
+ 	if (resched)
+@@ -2548,6 +2562,7 @@ const struct sched_class dl_sched_class
+ 	.rq_online              = rq_online_dl,
+ 	.rq_offline             = rq_offline_dl,
+ 	.task_woken		= task_woken_dl,
++	.find_lock_rq		= find_lock_later_rq,
+ #endif
+ 
+ 	.task_tick		= task_tick_dl,
+diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
+index f91339c0dee8..c25e35f41555 100644
+--- a/kernel/sched/rt.c
++++ b/kernel/sched/rt.c
+@@ -1873,7 +1873,7 @@ static struct task_struct *pick_next_pushable_task(struct rq *rq)
+  * running task can migrate over to a CPU that is running a task
+  * of lesser priority.
+  */
+-static int push_rt_task(struct rq *rq)
++static int push_rt_task(struct rq *rq, bool pull)
+ {
+ 	struct task_struct *next_task;
+ 	struct rq *lowest_rq;
+@@ -1887,6 +1887,34 @@ static int push_rt_task(struct rq *rq)
+ 		return 0;
+ 
+ retry:
++	if (is_migration_disabled(next_task)) {
++		struct task_struct *push_task = NULL;
++		int cpu;
++
++		if (!pull || rq->push_busy)
++			return 0;
++
++		cpu = find_lowest_rq(rq->curr);
++		if (cpu == -1 || cpu == rq->cpu)
++			return 0;
++
++		/*
++		 * Given we found a CPU with lower priority than @next_task,
++		 * therefore it should be running. However we cannot migrate it
++		 * to this other CPU, instead attempt to push the current
++		 * running task on this CPU away.
++		 */
++		push_task = get_push_task(rq);
++		if (push_task) {
++			raw_spin_unlock(&rq->lock);
++			stop_one_cpu_nowait(rq->cpu, push_cpu_stop,
++					    push_task, &rq->push_work);
++			raw_spin_lock(&rq->lock);
++		}
++
++		return 0;
++	}
++
+ 	if (WARN_ON(next_task == rq->curr))
+ 		return 0;
+ 
+@@ -1941,12 +1969,10 @@ static int push_rt_task(struct rq *rq)
+ 	deactivate_task(rq, next_task, 0);
+ 	set_task_cpu(next_task, lowest_rq->cpu);
+ 	activate_task(lowest_rq, next_task, 0);
+-	ret = 1;
+-
+ 	resched_curr(lowest_rq);
++	ret = 1;
+ 
+ 	double_unlock_balance(rq, lowest_rq);
+-
+ out:
+ 	put_task_struct(next_task);
+ 
+@@ -1956,7 +1982,7 @@ static int push_rt_task(struct rq *rq)
+ static void push_rt_tasks(struct rq *rq)
+ {
+ 	/* push_rt_task will return true if it moved an RT */
+-	while (push_rt_task(rq))
++	while (push_rt_task(rq, false))
+ 		;
+ }
+ 
+@@ -2109,7 +2135,8 @@ void rto_push_irq_work_func(struct irq_work *work)
+ 	 */
+ 	if (has_pushable_tasks(rq)) {
+ 		raw_spin_lock(&rq->lock);
+-		push_rt_tasks(rq);
++		while (push_rt_task(rq, true))
++			;
+ 		raw_spin_unlock(&rq->lock);
+ 	}
+ 
+@@ -2134,7 +2161,7 @@ static void pull_rt_task(struct rq *this_rq)
+ {
+ 	int this_cpu = this_rq->cpu, cpu;
+ 	bool resched = false;
+-	struct task_struct *p;
++	struct task_struct *p, *push_task;
+ 	struct rq *src_rq;
+ 	int rt_overload_count = rt_overloaded(this_rq);
+ 
+@@ -2181,6 +2208,7 @@ static void pull_rt_task(struct rq *this_rq)
+ 		 * double_lock_balance, and another CPU could
+ 		 * alter this_rq
+ 		 */
++		push_task = NULL;
+ 		double_lock_balance(this_rq, src_rq);
+ 
+ 		/*
+@@ -2208,11 +2236,14 @@ static void pull_rt_task(struct rq *this_rq)
+ 			if (p->prio < src_rq->curr->prio)
+ 				goto skip;
+ 
+-			resched = true;
+-
+-			deactivate_task(src_rq, p, 0);
+-			set_task_cpu(p, this_cpu);
+-			activate_task(this_rq, p, 0);
++			if (is_migration_disabled(p)) {
++				push_task = get_push_task(src_rq);
++			} else {
++				deactivate_task(src_rq, p, 0);
++				set_task_cpu(p, this_cpu);
++				activate_task(this_rq, p, 0);
++				resched = true;
++			}
+ 			/*
+ 			 * We continue with the search, just in
+ 			 * case there's an even higher prio task
+@@ -2222,6 +2253,13 @@ static void pull_rt_task(struct rq *this_rq)
+ 		}
+ skip:
+ 		double_unlock_balance(this_rq, src_rq);
++
++		if (push_task) {
++			raw_spin_unlock(&this_rq->lock);
++			stop_one_cpu_nowait(src_rq->cpu, push_cpu_stop,
++					    push_task, &src_rq->push_work);
++			raw_spin_lock(&this_rq->lock);
++		}
+ 	}
+ 
+ 	if (resched)
+@@ -2470,6 +2508,7 @@ const struct sched_class rt_sched_class
+ 	.rq_offline             = rq_offline_rt,
+ 	.task_woken		= task_woken_rt,
+ 	.switched_from		= switched_from_rt,
++	.find_lock_rq		= find_lock_lowest_rq,
+ #endif
+ 
+ 	.task_tick		= task_tick_rt,
+diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
+index 8237c9ab2bb8..69ef7cac3d29 100644
+--- a/kernel/sched/sched.h
++++ b/kernel/sched/sched.h
+@@ -1061,6 +1061,8 @@ struct rq {
+ #if defined(CONFIG_PREEMPT_RT) && defined(CONFIG_SMP)
+ 	unsigned int		nr_pinned;
+ #endif
++	unsigned int		push_busy;
++	struct cpu_stop_work	push_work;
+ };
+ 
+ #ifdef CONFIG_FAIR_GROUP_SCHED
+@@ -1088,6 +1090,16 @@ static inline int cpu_of(struct rq *rq)
+ #endif
+ }
+ 
++#define MDF_PUSH	0x01
++
++static inline bool is_migration_disabled(struct task_struct *p)
++{
++#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
++	return p->migration_disabled;
++#else
++	return false;
++#endif
++}
+ 
+ #ifdef CONFIG_SCHED_SMT
+ extern void __update_idle_core(struct rq *rq);
+@@ -1827,6 +1839,8 @@ struct sched_class {
+ 
+ 	void (*rq_online)(struct rq *rq);
+ 	void (*rq_offline)(struct rq *rq);
++
++	struct rq *(*find_lock_rq)(struct task_struct *p, struct rq *rq);
+ #endif
+ 
+ 	void (*task_tick)(struct rq *rq, struct task_struct *p, int queued);
+@@ -1922,6 +1936,24 @@ extern void trigger_load_balance(struct rq *rq);
+ 
+ extern void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask, u32 flags);
+ 
++static inline struct task_struct *get_push_task(struct rq *rq)
++{
++	struct task_struct *p = rq->curr;
++
++	lockdep_assert_held(&rq->lock);
++
++	if (rq->push_busy)
++		return NULL;
++
++	if (p->nr_cpus_allowed == 1)
++		return NULL;
++
++	rq->push_busy = true;
++	return get_task_struct(p);
++}
++
++extern int push_cpu_stop(void *arg);
++
+ #endif
+ 
+ #ifdef CONFIG_CPU_IDLE
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0017-sched-proc-Print-accurate-cpumask-vs-migrate_disable.patch b/debian/patches-rt/0017-sched-proc-Print-accurate-cpumask-vs-migrate_disable.patch
new file mode 100644
index 000000000..44d87463d
--- /dev/null
+++ b/debian/patches-rt/0017-sched-proc-Print-accurate-cpumask-vs-migrate_disable.patch
@@ -0,0 +1,35 @@
+From e8ed7f739c2f8113927b0b3489bc357c36e27040 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:14 +0200
+Subject: [PATCH 017/323] sched/proc: Print accurate cpumask vs
+ migrate_disable()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Ensure /proc/*/status doesn't print 'random' cpumasks due to
+migrate_disable().
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ fs/proc/array.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/fs/proc/array.c b/fs/proc/array.c
+index 18a4588c35be..decaa7768044 100644
+--- a/fs/proc/array.c
++++ b/fs/proc/array.c
+@@ -384,9 +384,9 @@ static inline void task_context_switch_counts(struct seq_file *m,
+ static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
+ {
+ 	seq_printf(m, "Cpus_allowed:\t%*pb\n",
+-		   cpumask_pr_args(task->cpus_ptr));
++		   cpumask_pr_args(&task->cpus_mask));
+ 	seq_printf(m, "Cpus_allowed_list:\t%*pbl\n",
+-		   cpumask_pr_args(task->cpus_ptr));
++		   cpumask_pr_args(&task->cpus_mask));
+ }
+ 
+ static inline void task_core_dumping(struct seq_file *m, struct mm_struct *mm)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0018-sched-Add-migrate_disable-tracepoints.patch b/debian/patches-rt/0018-sched-Add-migrate_disable-tracepoints.patch
new file mode 100644
index 000000000..0f315ce9d
--- /dev/null
+++ b/debian/patches-rt/0018-sched-Add-migrate_disable-tracepoints.patch
@@ -0,0 +1,110 @@
+From 8b4906578ce683b9bce7df984b4179519152345f Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Fri, 23 Oct 2020 12:12:15 +0200
+Subject: [PATCH 018/323] sched: Add migrate_disable() tracepoints
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+XXX write a tracer:
+
+ - 'migirate_disable() -> migrate_enable()' time in task_sched_runtime()
+ - 'migrate_pull -> sched-in' time in task_sched_runtime()
+
+The first will give worst case for the second, which is the actual
+interference experienced by the task to due migration constraints of
+migrate_disable().
+
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/trace/events/sched.h | 12 ++++++++++++
+ kernel/sched/core.c          |  4 ++++
+ kernel/sched/deadline.c      |  1 +
+ kernel/sched/rt.c            |  8 +++++++-
+ 4 files changed, 24 insertions(+), 1 deletion(-)
+
+diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
+index c96a4337afe6..e48f584abf5f 100644
+--- a/include/trace/events/sched.h
++++ b/include/trace/events/sched.h
+@@ -650,6 +650,18 @@ DECLARE_TRACE(sched_update_nr_running_tp,
+ 	TP_PROTO(struct rq *rq, int change),
+ 	TP_ARGS(rq, change));
+ 
++DECLARE_TRACE(sched_migrate_disable_tp,
++	      TP_PROTO(struct task_struct *p),
++	      TP_ARGS(p));
++
++DECLARE_TRACE(sched_migrate_enable_tp,
++	      TP_PROTO(struct task_struct *p),
++	      TP_ARGS(p));
++
++DECLARE_TRACE(sched_migrate_pull_tp,
++	      TP_PROTO(struct task_struct *p),
++	      TP_ARGS(p));
++
+ #endif /* _TRACE_SCHED_H */
+ 
+ /* This part must be outside protection */
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 452fc1dfb143..b5f35b512577 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1742,6 +1742,8 @@ void migrate_disable(void)
+ 		return;
+ 	}
+ 
++	trace_sched_migrate_disable_tp(p);
++
+ 	preempt_disable();
+ 	this_rq()->nr_pinned++;
+ 	p->migration_disabled = 1;
+@@ -1774,6 +1776,8 @@ void migrate_enable(void)
+ 	p->migration_disabled = 0;
+ 	this_rq()->nr_pinned--;
+ 	preempt_enable();
++
++	trace_sched_migrate_enable_tp(p);
+ }
+ EXPORT_SYMBOL_GPL(migrate_enable);
+ 
+diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
+index 7cf3248894a9..fcf546cd2eac 100644
+--- a/kernel/sched/deadline.c
++++ b/kernel/sched/deadline.c
+@@ -2282,6 +2282,7 @@ static void pull_dl_task(struct rq *this_rq)
+ 				goto skip;
+ 
+ 			if (is_migration_disabled(p)) {
++				trace_sched_migrate_pull_tp(p);
+ 				push_task = get_push_task(src_rq);
+ 			} else {
+ 				deactivate_task(src_rq, p, 0);
+diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
+index c25e35f41555..c5038d680c2c 100644
+--- a/kernel/sched/rt.c
++++ b/kernel/sched/rt.c
+@@ -1891,7 +1891,12 @@ static int push_rt_task(struct rq *rq, bool pull)
+ 		struct task_struct *push_task = NULL;
+ 		int cpu;
+ 
+-		if (!pull || rq->push_busy)
++		if (!pull)
++			return 0;
++
++		trace_sched_migrate_pull_tp(next_task);
++
++		if (rq->push_busy)
+ 			return 0;
+ 
+ 		cpu = find_lowest_rq(rq->curr);
+@@ -2237,6 +2242,7 @@ static void pull_rt_task(struct rq *this_rq)
+ 				goto skip;
+ 
+ 			if (is_migration_disabled(p)) {
++				trace_sched_migrate_pull_tp(p);
+ 				push_task = get_push_task(src_rq);
+ 			} else {
+ 				deactivate_task(src_rq, p, 0);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0019-sched-Deny-self-issued-__set_cpus_allowed_ptr-when-m.patch b/debian/patches-rt/0019-sched-Deny-self-issued-__set_cpus_allowed_ptr-when-m.patch
new file mode 100644
index 000000000..ca7d5923b
--- /dev/null
+++ b/debian/patches-rt/0019-sched-Deny-self-issued-__set_cpus_allowed_ptr-when-m.patch
@@ -0,0 +1,46 @@
+From 5857482efa6b272402feb4b063c4273e70dd67fb Mon Sep 17 00:00:00 2001
+From: Valentin Schneider <valentin.schneider@arm.com>
+Date: Fri, 23 Oct 2020 12:12:16 +0200
+Subject: [PATCH 019/323] sched: Deny self-issued __set_cpus_allowed_ptr() when
+ migrate_disable()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+  migrate_disable();
+  set_cpus_allowed_ptr(current, {something excluding task_cpu(current)});
+  affine_move_task(); <-- never returns
+
+Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Link: https://lkml.kernel.org/r/20201013140116.26651-1-valentin.schneider@arm.com
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/core.c | 13 +++++++++++--
+ 1 file changed, 11 insertions(+), 2 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index b5f35b512577..3b7bb01eecc0 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -2254,8 +2254,17 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
+ 		goto out;
+ 	}
+ 
+-	if (!(flags & SCA_MIGRATE_ENABLE) && cpumask_equal(&p->cpus_mask, new_mask))
+-		goto out;
++	if (!(flags & SCA_MIGRATE_ENABLE)) {
++		if (cpumask_equal(&p->cpus_mask, new_mask))
++			goto out;
++
++		if (WARN_ON_ONCE(p == current &&
++				 is_migration_disabled(p) &&
++				 !cpumask_test_cpu(task_cpu(p), new_mask))) {
++			ret = -EBUSY;
++			goto out;
++		}
++	}
+ 
+ 	/*
+ 	 * Picking a ~random cpu helps in cases where we are changing affinity
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0020-sched-Comment-affine_move_task.patch b/debian/patches-rt/0020-sched-Comment-affine_move_task.patch
new file mode 100644
index 000000000..ce16fe3bc
--- /dev/null
+++ b/debian/patches-rt/0020-sched-Comment-affine_move_task.patch
@@ -0,0 +1,130 @@
+From ef79ed54f47d3ce342809e4914f4d9cf400f1ae0 Mon Sep 17 00:00:00 2001
+From: Valentin Schneider <valentin.schneider@arm.com>
+Date: Fri, 23 Oct 2020 12:12:17 +0200
+Subject: [PATCH 020/323] sched: Comment affine_move_task()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Link: https://lkml.kernel.org/r/20201013140116.26651-2-valentin.schneider@arm.com
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/core.c | 81 +++++++++++++++++++++++++++++++++++++++++++--
+ 1 file changed, 79 insertions(+), 2 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 3b7bb01eecc0..565d8011c832 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -2094,7 +2094,75 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
+ }
+ 
+ /*
+- * This function is wildly self concurrent, consider at least 3 times.
++ * This function is wildly self concurrent; here be dragons.
++ *
++ *
++ * When given a valid mask, __set_cpus_allowed_ptr() must block until the
++ * designated task is enqueued on an allowed CPU. If that task is currently
++ * running, we have to kick it out using the CPU stopper.
++ *
++ * Migrate-Disable comes along and tramples all over our nice sandcastle.
++ * Consider:
++ *
++ *     Initial conditions: P0->cpus_mask = [0, 1]
++ *
++ *     P0@CPU0                  P1
++ *
++ *     migrate_disable();
++ *     <preempted>
++ *                              set_cpus_allowed_ptr(P0, [1]);
++ *
++ * P1 *cannot* return from this set_cpus_allowed_ptr() call until P0 executes
++ * its outermost migrate_enable() (i.e. it exits its Migrate-Disable region).
++ * This means we need the following scheme:
++ *
++ *     P0@CPU0                  P1
++ *
++ *     migrate_disable();
++ *     <preempted>
++ *                              set_cpus_allowed_ptr(P0, [1]);
++ *                                <blocks>
++ *     <resumes>
++ *     migrate_enable();
++ *       __set_cpus_allowed_ptr();
++ *       <wakes local stopper>
++ *                         `--> <woken on migration completion>
++ *
++ * Now the fun stuff: there may be several P1-like tasks, i.e. multiple
++ * concurrent set_cpus_allowed_ptr(P0, [*]) calls. CPU affinity changes of any
++ * task p are serialized by p->pi_lock, which we can leverage: the one that
++ * should come into effect at the end of the Migrate-Disable region is the last
++ * one. This means we only need to track a single cpumask (i.e. p->cpus_mask),
++ * but we still need to properly signal those waiting tasks at the appropriate
++ * moment.
++ *
++ * This is implemented using struct set_affinity_pending. The first
++ * __set_cpus_allowed_ptr() caller within a given Migrate-Disable region will
++ * setup an instance of that struct and install it on the targeted task_struct.
++ * Any and all further callers will reuse that instance. Those then wait for
++ * a completion signaled at the tail of the CPU stopper callback (1), triggered
++ * on the end of the Migrate-Disable region (i.e. outermost migrate_enable()).
++ *
++ *
++ * (1) In the cases covered above. There is one more where the completion is
++ * signaled within affine_move_task() itself: when a subsequent affinity request
++ * cancels the need for an active migration. Consider:
++ *
++ *     Initial conditions: P0->cpus_mask = [0, 1]
++ *
++ *     P0@CPU0            P1                             P2
++ *
++ *     migrate_disable();
++ *     <preempted>
++ *                        set_cpus_allowed_ptr(P0, [1]);
++ *                          <blocks>
++ *                                                       set_cpus_allowed_ptr(P0, [0, 1]);
++ *                                                         <signal completion>
++ *                          <awakes>
++ *
++ * Note that the above is safe vs a concurrent migrate_enable(), as any
++ * pending affinity completion is preceded an uninstallion of
++ * p->migration_pending done with p->pi_lock held.
+  */
+ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flags *rf,
+ 			    int dest_cpu, unsigned int flags)
+@@ -2138,6 +2206,7 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 	if (!(flags & SCA_MIGRATE_ENABLE)) {
+ 		/* serialized by p->pi_lock */
+ 		if (!p->migration_pending) {
++			/* Install the request */
+ 			refcount_set(&my_pending.refs, 1);
+ 			init_completion(&my_pending.done);
+ 			p->migration_pending = &my_pending;
+@@ -2181,7 +2250,11 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 	}
+ 
+ 	if (task_running(rq, p) || p->state == TASK_WAKING) {
+-
++		/*
++		 * Lessen races (and headaches) by delegating
++		 * is_migration_disabled(p) checks to the stopper, which will
++		 * run on the same CPU as said p.
++		 */
+ 		task_rq_unlock(rq, p, rf);
+ 		stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
+ 
+@@ -2206,6 +2279,10 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 	if (refcount_dec_and_test(&pending->refs))
+ 		wake_up_var(&pending->refs);
+ 
++	/*
++	 * Block the original owner of &pending until all subsequent callers
++	 * have seen the completion and decremented the refcount
++	 */
+ 	wait_var_event(&my_pending.refs, !refcount_read(&my_pending.refs));
+ 
+ 	return 0;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0021-sched-Unlock-the-rq-in-affine_move_task-error-path.patch b/debian/patches-rt/0021-sched-Unlock-the-rq-in-affine_move_task-error-path.patch
new file mode 100644
index 000000000..bc78d7729
--- /dev/null
+++ b/debian/patches-rt/0021-sched-Unlock-the-rq-in-affine_move_task-error-path.patch
@@ -0,0 +1,34 @@
+From 9a34ae4ec3b4af5cc98c8405ea590096a1380af9 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 9 Nov 2020 15:54:03 +0100
+Subject: [PATCH 021/323] sched: Unlock the rq in affine_move_task() error path
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Unlock the rq if returned early in the error path.
+
+Reported-by: Joe Korty <joe.korty@concurrent-rt.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Link: https://lkml.kernel.org/r/20201106203921.GA48461@zipoli.concurrent-rt.com
+---
+ kernel/sched/core.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 565d8011c832..d12d91510789 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -2228,8 +2228,10 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 	 *
+ 	 * Either way, we really should have a @pending here.
+ 	 */
+-	if (WARN_ON_ONCE(!pending))
++	if (WARN_ON_ONCE(!pending)) {
++		task_rq_unlock(rq, p, rf);
+ 		return -EINVAL;
++	}
+ 
+ 	if (flags & SCA_MIGRATE_ENABLE) {
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0022-sched-Fix-migration_cpu_stop-WARN.patch b/debian/patches-rt/0022-sched-Fix-migration_cpu_stop-WARN.patch
new file mode 100644
index 000000000..6f1a0cb21
--- /dev/null
+++ b/debian/patches-rt/0022-sched-Fix-migration_cpu_stop-WARN.patch
@@ -0,0 +1,47 @@
+From 09d09da2b8c97fd09f50deb278f9d4a25b99ad55 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Tue, 17 Nov 2020 12:14:51 +0100
+Subject: [PATCH 022/323] sched: Fix migration_cpu_stop() WARN
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Oleksandr reported hitting the WARN in the 'task_rq(p) != rq' branch
+of migration_cpu_stop(). Valentin noted that using cpu_of(rq) in that
+case is just plain wrong to begin with, since per the earlier branch
+that isn't the actual CPU of the task.
+
+Replace both instances of is_cpu_allowed() by a direct p->cpus_mask
+test using task_cpu().
+
+Reported-by: Oleksandr Natalenko <oleksandr@natalenko.name>
+Debugged-by: Valentin Schneider <valentin.schneider@arm.com>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/core.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index d12d91510789..7d67a0e03f9a 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1929,7 +1929,7 @@ static int migration_cpu_stop(void *data)
+ 			 * and we should be valid again. Nothing to do.
+ 			 */
+ 			if (!pending) {
+-				WARN_ON_ONCE(!is_cpu_allowed(p, cpu_of(rq)));
++				WARN_ON_ONCE(!cpumask_test_cpu(task_cpu(p), &p->cpus_mask));
+ 				goto out;
+ 			}
+ 
+@@ -1957,7 +1957,7 @@ static int migration_cpu_stop(void *data)
+ 		 * valid again. Nothing to do.
+ 		 */
+ 		if (!pending) {
+-			WARN_ON_ONCE(!is_cpu_allowed(p, cpu_of(rq)));
++			WARN_ON_ONCE(!cpumask_test_cpu(task_cpu(p), &p->cpus_mask));
+ 			goto out;
+ 		}
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0023-sched-core-Add-missing-completion-for-affine_move_ta.patch b/debian/patches-rt/0023-sched-core-Add-missing-completion-for-affine_move_ta.patch
new file mode 100644
index 000000000..19fcddc66
--- /dev/null
+++ b/debian/patches-rt/0023-sched-core-Add-missing-completion-for-affine_move_ta.patch
@@ -0,0 +1,79 @@
+From 5188e4c01f37c8c179cf88261297d546f5d2502e Mon Sep 17 00:00:00 2001
+From: Valentin Schneider <valentin.schneider@arm.com>
+Date: Fri, 13 Nov 2020 11:24:14 +0000
+Subject: [PATCH 023/323] sched/core: Add missing completion for
+ affine_move_task() waiters
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Qian reported that some fuzzer issuing sched_setaffinity() ends up stuck on
+a wait_for_completion(). The problematic pattern seems to be:
+
+  affine_move_task()
+      // task_running() case
+      stop_one_cpu();
+      wait_for_completion(&pending->done);
+
+Combined with, on the stopper side:
+
+  migration_cpu_stop()
+    // Task moved between unlocks and scheduling the stopper
+    task_rq(p) != rq &&
+    // task_running() case
+    dest_cpu >= 0
+
+    => no complete_all()
+
+This can happen with both PREEMPT and !PREEMPT, although !PREEMPT should
+be more likely to see this given the targeted task has a much bigger window
+to block and be woken up elsewhere before the stopper runs.
+
+Make migration_cpu_stop() always look at pending affinity requests; signal
+their completion if the stopper hits a rq mismatch but the task is
+still within its allowed mask. When Migrate-Disable isn't involved, this
+matches the previous set_cpus_allowed_ptr() vs migration_cpu_stop()
+behaviour.
+
+Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()")
+Reported-by: Qian Cai <cai@redhat.com>
+Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Link: https://lore.kernel.org/lkml/8b62fd1ad1b18def27f18e2ee2df3ff5b36d0762.camel@redhat.com
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/core.c | 13 ++++++++++++-
+ 1 file changed, 12 insertions(+), 1 deletion(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 7d67a0e03f9a..c1e52319669d 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1941,7 +1941,7 @@ static int migration_cpu_stop(void *data)
+ 		else
+ 			p->wake_cpu = dest_cpu;
+ 
+-	} else if (dest_cpu < 0) {
++	} else if (dest_cpu < 0 || pending) {
+ 		/*
+ 		 * This happens when we get migrated between migrate_enable()'s
+ 		 * preempt_enable() and scheduling the stopper task. At that
+@@ -1951,6 +1951,17 @@ static int migration_cpu_stop(void *data)
+ 		 * more likely.
+ 		 */
+ 
++		/*
++		 * The task moved before the stopper got to run. We're holding
++		 * ->pi_lock, so the allowed mask is stable - if it got
++		 * somewhere allowed, we're done.
++		 */
++		if (pending && cpumask_test_cpu(task_cpu(p), p->cpus_ptr)) {
++			p->migration_pending = NULL;
++			complete = true;
++			goto out;
++		}
++
+ 		/*
+ 		 * When this was migrate_enable() but we no longer have an
+ 		 * @pending, a concurrent SCA 'fixed' things and we should be
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0024-mm-highmem-Un-EXPORT-__kmap_atomic_idx.patch b/debian/patches-rt/0024-mm-highmem-Un-EXPORT-__kmap_atomic_idx.patch
new file mode 100644
index 000000000..ba252d03e
--- /dev/null
+++ b/debian/patches-rt/0024-mm-highmem-Un-EXPORT-__kmap_atomic_idx.patch
@@ -0,0 +1,33 @@
+From 44027cc10df8025d820ea864076dae75fb26626d Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:13 +0100
+Subject: [PATCH 024/323] mm/highmem: Un-EXPORT __kmap_atomic_idx()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Nothing in modules can use that.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Christoph Hellwig <hch@lst.de>
+Cc: Andrew Morton <akpm@linux-foundation.org>
+Cc: linux-mm@kvack.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/highmem.c | 2 --
+ 1 file changed, 2 deletions(-)
+
+diff --git a/mm/highmem.c b/mm/highmem.c
+index 1352a27951e3..6abfd762eee7 100644
+--- a/mm/highmem.c
++++ b/mm/highmem.c
+@@ -108,8 +108,6 @@ static inline wait_queue_head_t *get_pkmap_wait_queue_head(unsigned int color)
+ atomic_long_t _totalhigh_pages __read_mostly;
+ EXPORT_SYMBOL(_totalhigh_pages);
+ 
+-EXPORT_PER_CPU_SYMBOL(__kmap_atomic_idx);
+-
+ unsigned int nr_free_highpages (void)
+ {
+ 	struct zone *zone;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0025-highmem-Remove-unused-functions.patch b/debian/patches-rt/0025-highmem-Remove-unused-functions.patch
new file mode 100644
index 000000000..55deed269
--- /dev/null
+++ b/debian/patches-rt/0025-highmem-Remove-unused-functions.patch
@@ -0,0 +1,43 @@
+From 2060c9ea726ebd649d8d2e596fa2acebef644cd8 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:14 +0100
+Subject: [PATCH 025/323] highmem: Remove unused functions
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Nothing uses totalhigh_pages_dec() and totalhigh_pages_set().
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/highmem.h | 10 ----------
+ 1 file changed, 10 deletions(-)
+
+diff --git a/include/linux/highmem.h b/include/linux/highmem.h
+index b25df1f8d48d..3297bfca78ed 100644
+--- a/include/linux/highmem.h
++++ b/include/linux/highmem.h
+@@ -104,21 +104,11 @@ static inline void totalhigh_pages_inc(void)
+ 	atomic_long_inc(&_totalhigh_pages);
+ }
+ 
+-static inline void totalhigh_pages_dec(void)
+-{
+-	atomic_long_dec(&_totalhigh_pages);
+-}
+-
+ static inline void totalhigh_pages_add(long count)
+ {
+ 	atomic_long_add(count, &_totalhigh_pages);
+ }
+ 
+-static inline void totalhigh_pages_set(long val)
+-{
+-	atomic_long_set(&_totalhigh_pages, val);
+-}
+-
+ void kmap_flush_unused(void);
+ 
+ struct page *kmap_to_page(void *addr);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0026-fs-Remove-asm-kmap_types.h-includes.patch b/debian/patches-rt/0026-fs-Remove-asm-kmap_types.h-includes.patch
new file mode 100644
index 000000000..3cbd4847e
--- /dev/null
+++ b/debian/patches-rt/0026-fs-Remove-asm-kmap_types.h-includes.patch
@@ -0,0 +1,50 @@
+From 280d9322736bea3870ae507592e1d2880bff8bd9 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:15 +0100
+Subject: [PATCH 026/323] fs: Remove asm/kmap_types.h includes
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Historical leftovers from the time where kmap() had fixed slots.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Alexander Viro <viro@zeniv.linux.org.uk>
+Cc: Benjamin LaHaise <bcrl@kvack.org>
+Cc: linux-fsdevel@vger.kernel.org
+Cc: linux-aio@kvack.org
+Cc: Chris Mason <clm@fb.com>
+Cc: Josef Bacik <josef@toxicpanda.com>
+Cc: David Sterba <dsterba@suse.com>
+Cc: linux-btrfs@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ fs/aio.c         | 1 -
+ fs/btrfs/ctree.h | 1 -
+ 2 files changed, 2 deletions(-)
+
+diff --git a/fs/aio.c b/fs/aio.c
+index 5934ea84b499..c90e045a37bc 100644
+--- a/fs/aio.c
++++ b/fs/aio.c
+@@ -43,7 +43,6 @@
+ #include <linux/mount.h>
+ #include <linux/pseudo_fs.h>
+ 
+-#include <asm/kmap_types.h>
+ #include <linux/uaccess.h>
+ #include <linux/nospec.h>
+ 
+diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
+index 67831868ef0d..17c920aa6bc2 100644
+--- a/fs/btrfs/ctree.h
++++ b/fs/btrfs/ctree.h
+@@ -17,7 +17,6 @@
+ #include <linux/wait.h>
+ #include <linux/slab.h>
+ #include <trace/events/btrfs.h>
+-#include <asm/kmap_types.h>
+ #include <asm/unaligned.h>
+ #include <linux/pagemap.h>
+ #include <linux/btrfs.h>
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0027-sh-highmem-Remove-all-traces-of-unused-cruft.patch b/debian/patches-rt/0027-sh-highmem-Remove-all-traces-of-unused-cruft.patch
new file mode 100644
index 000000000..bcf3a9b1f
--- /dev/null
+++ b/debian/patches-rt/0027-sh-highmem-Remove-all-traces-of-unused-cruft.patch
@@ -0,0 +1,94 @@
+From 61e1ac8c3bd29dec41ae2f631bb142e26b790de2 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:16 +0100
+Subject: [PATCH 027/323] sh/highmem: Remove all traces of unused cruft
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+For whatever reasons SH has highmem bits all over the place but does
+not enable it via Kconfig. Remove the bitrot.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/sh/include/asm/fixmap.h     |  8 --------
+ arch/sh/include/asm/kmap_types.h | 15 ---------------
+ arch/sh/mm/init.c                |  8 --------
+ 3 files changed, 31 deletions(-)
+ delete mode 100644 arch/sh/include/asm/kmap_types.h
+
+diff --git a/arch/sh/include/asm/fixmap.h b/arch/sh/include/asm/fixmap.h
+index f38adc189b83..b07fbc7f7bc6 100644
+--- a/arch/sh/include/asm/fixmap.h
++++ b/arch/sh/include/asm/fixmap.h
+@@ -13,9 +13,6 @@
+ #include <linux/kernel.h>
+ #include <linux/threads.h>
+ #include <asm/page.h>
+-#ifdef CONFIG_HIGHMEM
+-#include <asm/kmap_types.h>
+-#endif
+ 
+ /*
+  * Here we define all the compile-time 'special' virtual
+@@ -53,11 +50,6 @@ enum fixed_addresses {
+ 	FIX_CMAP_BEGIN,
+ 	FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS) - 1,
+ 
+-#ifdef CONFIG_HIGHMEM
+-	FIX_KMAP_BEGIN,	/* reserved pte's for temporary kernel mappings */
+-	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1,
+-#endif
+-
+ #ifdef CONFIG_IOREMAP_FIXED
+ 	/*
+ 	 * FIX_IOREMAP entries are useful for mapping physical address
+diff --git a/arch/sh/include/asm/kmap_types.h b/arch/sh/include/asm/kmap_types.h
+deleted file mode 100644
+index b78107f923dd..000000000000
+--- a/arch/sh/include/asm/kmap_types.h
++++ /dev/null
+@@ -1,15 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-#ifndef __SH_KMAP_TYPES_H
+-#define __SH_KMAP_TYPES_H
+-
+-/* Dummy header just to define km_type. */
+-
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-#define  __WITH_KM_FENCE
+-#endif
+-
+-#include <asm-generic/kmap_types.h>
+-
+-#undef __WITH_KM_FENCE
+-
+-#endif
+diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
+index 3348e0c4d769..0db6919af8d3 100644
+--- a/arch/sh/mm/init.c
++++ b/arch/sh/mm/init.c
+@@ -362,9 +362,6 @@ void __init mem_init(void)
+ 	mem_init_print_info(NULL);
+ 	pr_info("virtual kernel memory layout:\n"
+ 		"    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
+-#ifdef CONFIG_HIGHMEM
+-		"    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
+-#endif
+ 		"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
+ 		"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB) (cached)\n"
+ #ifdef CONFIG_UNCACHED_MAPPING
+@@ -376,11 +373,6 @@ void __init mem_init(void)
+ 		FIXADDR_START, FIXADDR_TOP,
+ 		(FIXADDR_TOP - FIXADDR_START) >> 10,
+ 
+-#ifdef CONFIG_HIGHMEM
+-		PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
+-		(LAST_PKMAP*PAGE_SIZE) >> 10,
+-#endif
+-
+ 		(unsigned long)VMALLOC_START, VMALLOC_END,
+ 		(VMALLOC_END - VMALLOC_START) >> 20,
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0028-asm-generic-Provide-kmap_size.h.patch b/debian/patches-rt/0028-asm-generic-Provide-kmap_size.h.patch
new file mode 100644
index 000000000..bb5d5f717
--- /dev/null
+++ b/debian/patches-rt/0028-asm-generic-Provide-kmap_size.h.patch
@@ -0,0 +1,70 @@
+From 5ed7d8c8905e639e711f1a21e5f978fc21585f8c Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:17 +0100
+Subject: [PATCH 028/323] asm-generic: Provide kmap_size.h
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+kmap_types.h is a misnomer because the old atomic MAP based array does not
+exist anymore and the whole indirection of architectures including
+kmap_types.h is inconinstent and does not allow to provide guard page
+debugging for this misfeature.
+
+Add a common header file which defines the mapping stack size for all
+architectures. Will be used when converting architectures over to a
+generic kmap_local/atomic implementation.
+
+The array size is chosen with the following constraints in mind:
+
+    - The deepest nest level in one context is 3 according to code
+      inspection.
+
+    - The worst case nesting for the upcoming reemptible version would be:
+
+      2 maps in task context and a fault inside
+      2 maps in the fault handler
+      3 maps in softirq
+      2 maps in interrupt
+
+So a total of 16 is sufficient and probably overestimated.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/asm-generic/Kbuild      |  1 +
+ include/asm-generic/kmap_size.h | 12 ++++++++++++
+ 2 files changed, 13 insertions(+)
+ create mode 100644 include/asm-generic/kmap_size.h
+
+diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild
+index d1300c6e0a47..3114a6da7e56 100644
+--- a/include/asm-generic/Kbuild
++++ b/include/asm-generic/Kbuild
+@@ -31,6 +31,7 @@ mandatory-y += irq_regs.h
+ mandatory-y += irq_work.h
+ mandatory-y += kdebug.h
+ mandatory-y += kmap_types.h
++mandatory-y += kmap_size.h
+ mandatory-y += kprobes.h
+ mandatory-y += linkage.h
+ mandatory-y += local.h
+diff --git a/include/asm-generic/kmap_size.h b/include/asm-generic/kmap_size.h
+new file mode 100644
+index 000000000000..9d6c7786a645
+--- /dev/null
++++ b/include/asm-generic/kmap_size.h
+@@ -0,0 +1,12 @@
++/* SPDX-License-Identifier: GPL-2.0 */
++#ifndef _ASM_GENERIC_KMAP_SIZE_H
++#define _ASM_GENERIC_KMAP_SIZE_H
++
++/* For debug this provides guard pages between the maps */
++#ifdef CONFIG_DEBUG_HIGHMEM
++# define KM_MAX_IDX	33
++#else
++# define KM_MAX_IDX	16
++#endif
++
++#endif
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0029-highmem-Provide-generic-variant-of-kmap_atomic.patch b/debian/patches-rt/0029-highmem-Provide-generic-variant-of-kmap_atomic.patch
new file mode 100644
index 000000000..828708904
--- /dev/null
+++ b/debian/patches-rt/0029-highmem-Provide-generic-variant-of-kmap_atomic.patch
@@ -0,0 +1,346 @@
+From 4e1b14787f7a2c71a9347db23c402f5dbe2da206 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:18 +0100
+Subject: [PATCH 029/323] highmem: Provide generic variant of kmap_atomic*
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The kmap_atomic* interfaces in all architectures are pretty much the same
+except for post map operations (flush) and pre- and post unmap operations.
+
+Provide a generic variant for that.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Andrew Morton <akpm@linux-foundation.org>
+Cc: linux-mm@kvack.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/highmem.h |  82 ++++++++++++++++++-----
+ mm/Kconfig              |   3 +
+ mm/highmem.c            | 144 +++++++++++++++++++++++++++++++++++++++-
+ 3 files changed, 211 insertions(+), 18 deletions(-)
+
+diff --git a/include/linux/highmem.h b/include/linux/highmem.h
+index 3297bfca78ed..14d5b4020c8c 100644
+--- a/include/linux/highmem.h
++++ b/include/linux/highmem.h
+@@ -31,9 +31,16 @@ static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
+ 
+ #include <asm/kmap_types.h>
+ 
++/*
++ * Outside of CONFIG_HIGHMEM to support X86 32bit iomap_atomic() cruft.
++ */
++#ifdef CONFIG_KMAP_LOCAL
++void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot);
++void *__kmap_local_page_prot(struct page *page, pgprot_t prot);
++void kunmap_local_indexed(void *vaddr);
++#endif
++
+ #ifdef CONFIG_HIGHMEM
+-extern void *kmap_atomic_high_prot(struct page *page, pgprot_t prot);
+-extern void kunmap_atomic_high(void *kvaddr);
+ #include <asm/highmem.h>
+ 
+ #ifndef ARCH_HAS_KMAP_FLUSH_TLB
+@@ -81,6 +88,11 @@ static inline void kunmap(struct page *page)
+  * be used in IRQ contexts, so in some (very limited) cases we need
+  * it.
+  */
++
++#ifndef CONFIG_KMAP_LOCAL
++void *kmap_atomic_high_prot(struct page *page, pgprot_t prot);
++void kunmap_atomic_high(void *kvaddr);
++
+ static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
+ {
+ 	preempt_disable();
+@@ -89,7 +101,38 @@ static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
+ 		return page_address(page);
+ 	return kmap_atomic_high_prot(page, prot);
+ }
+-#define kmap_atomic(page)	kmap_atomic_prot(page, kmap_prot)
++
++static inline void __kunmap_atomic(void *vaddr)
++{
++	kunmap_atomic_high(vaddr);
++}
++#else /* !CONFIG_KMAP_LOCAL */
++
++static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
++{
++	preempt_disable();
++	pagefault_disable();
++	return __kmap_local_page_prot(page, prot);
++}
++
++static inline void *kmap_atomic_pfn(unsigned long pfn)
++{
++	preempt_disable();
++	pagefault_disable();
++	return __kmap_local_pfn_prot(pfn, kmap_prot);
++}
++
++static inline void __kunmap_atomic(void *addr)
++{
++	kunmap_local_indexed(addr);
++}
++
++#endif /* CONFIG_KMAP_LOCAL */
++
++static inline void *kmap_atomic(struct page *page)
++{
++	return kmap_atomic_prot(page, kmap_prot);
++}
+ 
+ /* declarations for linux/mm/highmem.c */
+ unsigned int nr_free_highpages(void);
+@@ -147,25 +190,33 @@ static inline void *kmap_atomic(struct page *page)
+ 	pagefault_disable();
+ 	return page_address(page);
+ }
+-#define kmap_atomic_prot(page, prot)	kmap_atomic(page)
+ 
+-static inline void kunmap_atomic_high(void *addr)
++static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
++{
++	return kmap_atomic(page);
++}
++
++static inline void *kmap_atomic_pfn(unsigned long pfn)
++{
++	return kmap_atomic(pfn_to_page(pfn));
++}
++
++static inline void __kunmap_atomic(void *addr)
+ {
+ 	/*
+ 	 * Mostly nothing to do in the CONFIG_HIGHMEM=n case as kunmap_atomic()
+-	 * handles re-enabling faults + preemption
++	 * handles re-enabling faults and preemption
+ 	 */
+ #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
+ 	kunmap_flush_on_unmap(addr);
+ #endif
+ }
+ 
+-#define kmap_atomic_pfn(pfn)	kmap_atomic(pfn_to_page(pfn))
+-
+ #define kmap_flush_unused()	do {} while(0)
+ 
+ #endif /* CONFIG_HIGHMEM */
+ 
++#if !defined(CONFIG_KMAP_LOCAL)
+ #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
+ 
+ DECLARE_PER_CPU(int, __kmap_atomic_idx);
+@@ -196,22 +247,21 @@ static inline void kmap_atomic_idx_pop(void)
+ 	__this_cpu_dec(__kmap_atomic_idx);
+ #endif
+ }
+-
++#endif
+ #endif
+ 
+ /*
+  * Prevent people trying to call kunmap_atomic() as if it were kunmap()
+  * kunmap_atomic() should get the return value of kmap_atomic, not the page.
+  */
+-#define kunmap_atomic(addr)                                     \
+-do {                                                            \
+-	BUILD_BUG_ON(__same_type((addr), struct page *));       \
+-	kunmap_atomic_high(addr);                                  \
+-	pagefault_enable();                                     \
+-	preempt_enable();                                       \
++#define kunmap_atomic(__addr)					\
++do {								\
++	BUILD_BUG_ON(__same_type((__addr), struct page *));	\
++	__kunmap_atomic(__addr);				\
++	pagefault_enable();					\
++	preempt_enable();					\
+ } while (0)
+ 
+-
+ /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
+ #ifndef clear_user_highpage
+ static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
+diff --git a/mm/Kconfig b/mm/Kconfig
+index 390165ffbb0f..8c49d09da214 100644
+--- a/mm/Kconfig
++++ b/mm/Kconfig
+@@ -859,4 +859,7 @@ config ARCH_HAS_HUGEPD
+ config MAPPING_DIRTY_HELPERS
+         bool
+ 
++config KMAP_LOCAL
++	bool
++
+ endmenu
+diff --git a/mm/highmem.c b/mm/highmem.c
+index 6abfd762eee7..bb4ce13ee7e7 100644
+--- a/mm/highmem.c
++++ b/mm/highmem.c
+@@ -31,9 +31,11 @@
+ #include <asm/tlbflush.h>
+ #include <linux/vmalloc.h>
+ 
++#ifndef CONFIG_KMAP_LOCAL
+ #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
+ DEFINE_PER_CPU(int, __kmap_atomic_idx);
+ #endif
++#endif
+ 
+ /*
+  * Virtual_count is not a pure "count".
+@@ -365,9 +367,147 @@ void kunmap_high(struct page *page)
+ 	if (need_wakeup)
+ 		wake_up(pkmap_map_wait);
+ }
+-
+ EXPORT_SYMBOL(kunmap_high);
+-#endif	/* CONFIG_HIGHMEM */
++#endif /* CONFIG_HIGHMEM */
++
++#ifdef CONFIG_KMAP_LOCAL
++
++#include <asm/kmap_size.h>
++
++static DEFINE_PER_CPU(int, __kmap_local_idx);
++
++static inline int kmap_local_idx_push(void)
++{
++	int idx = __this_cpu_inc_return(__kmap_local_idx) - 1;
++
++	WARN_ON_ONCE(in_irq() && !irqs_disabled());
++	BUG_ON(idx >= KM_MAX_IDX);
++	return idx;
++}
++
++static inline int kmap_local_idx(void)
++{
++	return __this_cpu_read(__kmap_local_idx) - 1;
++}
++
++static inline void kmap_local_idx_pop(void)
++{
++	int idx = __this_cpu_dec_return(__kmap_local_idx);
++
++	BUG_ON(idx < 0);
++}
++
++#ifndef arch_kmap_local_post_map
++# define arch_kmap_local_post_map(vaddr, pteval)	do { } while (0)
++#endif
++#ifndef arch_kmap_local_pre_unmap
++# define arch_kmap_local_pre_unmap(vaddr)		do { } while (0)
++#endif
++
++#ifndef arch_kmap_local_post_unmap
++# define arch_kmap_local_post_unmap(vaddr)		do { } while (0)
++#endif
++
++#ifndef arch_kmap_local_map_idx
++#define arch_kmap_local_map_idx(idx, pfn)	kmap_local_calc_idx(idx)
++#endif
++
++#ifndef arch_kmap_local_unmap_idx
++#define arch_kmap_local_unmap_idx(idx, vaddr)	kmap_local_calc_idx(idx)
++#endif
++
++#ifndef arch_kmap_local_high_get
++static inline void *arch_kmap_local_high_get(struct page *page)
++{
++	return NULL;
++}
++#endif
++
++/* Unmap a local mapping which was obtained by kmap_high_get() */
++static inline void kmap_high_unmap_local(unsigned long vaddr)
++{
++#ifdef ARCH_NEEDS_KMAP_HIGH_GET
++	if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP))
++		kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
++#endif
++}
++
++static inline int kmap_local_calc_idx(int idx)
++{
++	return idx + KM_MAX_IDX * smp_processor_id();
++}
++
++static pte_t *__kmap_pte;
++
++static pte_t *kmap_get_pte(void)
++{
++	if (!__kmap_pte)
++		__kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
++	return __kmap_pte;
++}
++
++void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot)
++{
++	pte_t pteval, *kmap_pte = kmap_get_pte();
++	unsigned long vaddr;
++	int idx;
++
++	preempt_disable();
++	idx = arch_kmap_local_map_idx(kmap_local_idx_push(), pfn);
++	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
++	BUG_ON(!pte_none(*(kmap_pte - idx)));
++	pteval = pfn_pte(pfn, prot);
++	set_pte_at(&init_mm, vaddr, kmap_pte - idx, pteval);
++	arch_kmap_local_post_map(vaddr, pteval);
++	preempt_enable();
++
++	return (void *)vaddr;
++}
++EXPORT_SYMBOL_GPL(__kmap_local_pfn_prot);
++
++void *__kmap_local_page_prot(struct page *page, pgprot_t prot)
++{
++	void *kmap;
++
++	if (!PageHighMem(page))
++		return page_address(page);
++
++	/* Try kmap_high_get() if architecture has it enabled */
++	kmap = arch_kmap_local_high_get(page);
++	if (kmap)
++		return kmap;
++
++	return __kmap_local_pfn_prot(page_to_pfn(page), prot);
++}
++EXPORT_SYMBOL(__kmap_local_page_prot);
++
++void kunmap_local_indexed(void *vaddr)
++{
++	unsigned long addr = (unsigned long) vaddr & PAGE_MASK;
++	pte_t *kmap_pte = kmap_get_pte();
++	int idx;
++
++	if (addr < __fix_to_virt(FIX_KMAP_END) ||
++	    addr > __fix_to_virt(FIX_KMAP_BEGIN)) {
++		WARN_ON_ONCE(addr < PAGE_OFFSET);
++
++		/* Handle mappings which were obtained by kmap_high_get() */
++		kmap_high_unmap_local(addr);
++		return;
++	}
++
++	preempt_disable();
++	idx = arch_kmap_local_unmap_idx(kmap_local_idx(), addr);
++	WARN_ON_ONCE(addr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
++
++	arch_kmap_local_pre_unmap(addr);
++	pte_clear(&init_mm, addr, kmap_pte - idx);
++	arch_kmap_local_post_unmap(addr);
++	kmap_local_idx_pop();
++	preempt_enable();
++}
++EXPORT_SYMBOL(kunmap_local_indexed);
++#endif
+ 
+ #if defined(HASHED_PAGE_VIRTUAL)
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0030-highmem-Make-DEBUG_HIGHMEM-functional.patch b/debian/patches-rt/0030-highmem-Make-DEBUG_HIGHMEM-functional.patch
new file mode 100644
index 000000000..139157832
--- /dev/null
+++ b/debian/patches-rt/0030-highmem-Make-DEBUG_HIGHMEM-functional.patch
@@ -0,0 +1,61 @@
+From 4c9348bc5b225c2de1552b059787335345d30d2c Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:19 +0100
+Subject: [PATCH 030/323] highmem: Make DEBUG_HIGHMEM functional
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+For some obscure reason when CONFIG_DEBUG_HIGHMEM is enabled the stack
+depth is increased from 20 to 41. But the only thing DEBUG_HIGHMEM does is
+to enable a few BUG_ON()'s in the mapping code.
+
+That's a leftover from the historical mapping code which had fixed entries
+for various purposes. DEBUG_HIGHMEM inserted guard mappings between the map
+types. But that got all ditched when kmap_atomic() switched to a stack
+based map management. Though the WITH_KM_FENCE magic survived without being
+functional. All the thing does today is to increase the stack depth.
+
+Add a working implementation to the generic kmap_local* implementation.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/highmem.c | 14 ++++++++++++--
+ 1 file changed, 12 insertions(+), 2 deletions(-)
+
+diff --git a/mm/highmem.c b/mm/highmem.c
+index bb4ce13ee7e7..67d2d5983cb0 100644
+--- a/mm/highmem.c
++++ b/mm/highmem.c
+@@ -376,9 +376,19 @@ EXPORT_SYMBOL(kunmap_high);
+ 
+ static DEFINE_PER_CPU(int, __kmap_local_idx);
+ 
++/*
++ * With DEBUG_HIGHMEM the stack depth is doubled and every second
++ * slot is unused which acts as a guard page
++ */
++#ifdef CONFIG_DEBUG_HIGHMEM
++# define KM_INCR	2
++#else
++# define KM_INCR	1
++#endif
++
+ static inline int kmap_local_idx_push(void)
+ {
+-	int idx = __this_cpu_inc_return(__kmap_local_idx) - 1;
++	int idx = __this_cpu_add_return(__kmap_local_idx, KM_INCR) - 1;
+ 
+ 	WARN_ON_ONCE(in_irq() && !irqs_disabled());
+ 	BUG_ON(idx >= KM_MAX_IDX);
+@@ -392,7 +402,7 @@ static inline int kmap_local_idx(void)
+ 
+ static inline void kmap_local_idx_pop(void)
+ {
+-	int idx = __this_cpu_dec_return(__kmap_local_idx);
++	int idx = __this_cpu_sub_return(__kmap_local_idx, KM_INCR);
+ 
+ 	BUG_ON(idx < 0);
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0031-x86-mm-highmem-Use-generic-kmap-atomic-implementatio.patch b/debian/patches-rt/0031-x86-mm-highmem-Use-generic-kmap-atomic-implementatio.patch
new file mode 100644
index 000000000..d381e36e5
--- /dev/null
+++ b/debian/patches-rt/0031-x86-mm-highmem-Use-generic-kmap-atomic-implementatio.patch
@@ -0,0 +1,389 @@
+From a6456b1e46c0a3b8ad0a9dd3afaeb69c037ad289 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:20 +0100
+Subject: [PATCH 031/323] x86/mm/highmem: Use generic kmap atomic
+ implementation
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Convert X86 to the generic kmap atomic implementation and make the
+iomap_atomic() naming convention consistent while at it.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: x86@kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/x86/Kconfig                      |  1 +
+ arch/x86/include/asm/fixmap.h         |  5 +--
+ arch/x86/include/asm/highmem.h        | 13 ++++--
+ arch/x86/include/asm/iomap.h          | 18 ++++----
+ arch/x86/include/asm/kmap_types.h     | 13 ------
+ arch/x86/include/asm/paravirt_types.h |  1 -
+ arch/x86/mm/highmem_32.c              | 59 ---------------------------
+ arch/x86/mm/init_32.c                 | 15 -------
+ arch/x86/mm/iomap_32.c                | 59 +++------------------------
+ include/linux/highmem.h               |  2 +-
+ include/linux/io-mapping.h            |  2 +-
+ mm/highmem.c                          |  2 +-
+ 12 files changed, 30 insertions(+), 160 deletions(-)
+ delete mode 100644 arch/x86/include/asm/kmap_types.h
+
+diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
+index 6dc670e36393..54e5284a6ae1 100644
+--- a/arch/x86/Kconfig
++++ b/arch/x86/Kconfig
+@@ -15,6 +15,7 @@ config X86_32
+ 	select CLKSRC_I8253
+ 	select CLONE_BACKWARDS
+ 	select HAVE_DEBUG_STACKOVERFLOW
++	select KMAP_LOCAL
+ 	select MODULES_USE_ELF_REL
+ 	select OLD_SIGACTION
+ 	select GENERIC_VDSO_32
+diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
+index 77217bd292bd..8eba66a33e39 100644
+--- a/arch/x86/include/asm/fixmap.h
++++ b/arch/x86/include/asm/fixmap.h
+@@ -31,7 +31,7 @@
+ #include <asm/pgtable_types.h>
+ #ifdef CONFIG_X86_32
+ #include <linux/threads.h>
+-#include <asm/kmap_types.h>
++#include <asm/kmap_size.h>
+ #else
+ #include <uapi/asm/vsyscall.h>
+ #endif
+@@ -94,7 +94,7 @@ enum fixed_addresses {
+ #endif
+ #ifdef CONFIG_X86_32
+ 	FIX_KMAP_BEGIN,	/* reserved pte's for temporary kernel mappings */
+-	FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
++	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1,
+ #ifdef CONFIG_PCI_MMCONFIG
+ 	FIX_PCIE_MCFG,
+ #endif
+@@ -151,7 +151,6 @@ extern void reserve_top_address(unsigned long reserve);
+ 
+ extern int fixmaps_set;
+ 
+-extern pte_t *kmap_pte;
+ extern pte_t *pkmap_page_table;
+ 
+ void __native_set_fixmap(enum fixed_addresses idx, pte_t pte);
+diff --git a/arch/x86/include/asm/highmem.h b/arch/x86/include/asm/highmem.h
+index 0f420b24e0fc..032e020853aa 100644
+--- a/arch/x86/include/asm/highmem.h
++++ b/arch/x86/include/asm/highmem.h
+@@ -23,7 +23,6 @@
+ 
+ #include <linux/interrupt.h>
+ #include <linux/threads.h>
+-#include <asm/kmap_types.h>
+ #include <asm/tlbflush.h>
+ #include <asm/paravirt.h>
+ #include <asm/fixmap.h>
+@@ -58,11 +57,17 @@ extern unsigned long highstart_pfn, highend_pfn;
+ #define PKMAP_NR(virt)  ((virt-PKMAP_BASE) >> PAGE_SHIFT)
+ #define PKMAP_ADDR(nr)  (PKMAP_BASE + ((nr) << PAGE_SHIFT))
+ 
+-void *kmap_atomic_pfn(unsigned long pfn);
+-void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot);
+-
+ #define flush_cache_kmaps()	do { } while (0)
+ 
++#define	arch_kmap_local_post_map(vaddr, pteval)		\
++	arch_flush_lazy_mmu_mode()
++
++#define	arch_kmap_local_post_unmap(vaddr)		\
++	do {						\
++		flush_tlb_one_kernel((vaddr));		\
++		arch_flush_lazy_mmu_mode();		\
++	} while (0)
++
+ extern void add_highpages_with_active_regions(int nid, unsigned long start_pfn,
+ 					unsigned long end_pfn);
+ 
+diff --git a/arch/x86/include/asm/iomap.h b/arch/x86/include/asm/iomap.h
+index bacf68c4d70e..0be7a30fd6bc 100644
+--- a/arch/x86/include/asm/iomap.h
++++ b/arch/x86/include/asm/iomap.h
+@@ -9,19 +9,21 @@
+ #include <linux/fs.h>
+ #include <linux/mm.h>
+ #include <linux/uaccess.h>
++#include <linux/highmem.h>
+ #include <asm/cacheflush.h>
+ #include <asm/tlbflush.h>
+ 
+-void __iomem *
+-iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot);
++void __iomem *iomap_atomic_pfn_prot(unsigned long pfn, pgprot_t prot);
+ 
+-void
+-iounmap_atomic(void __iomem *kvaddr);
++static inline void iounmap_atomic(void __iomem *vaddr)
++{
++	kunmap_local_indexed((void __force *)vaddr);
++	pagefault_enable();
++	preempt_enable();
++}
+ 
+-int
+-iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot);
++int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot);
+ 
+-void
+-iomap_free(resource_size_t base, unsigned long size);
++void iomap_free(resource_size_t base, unsigned long size);
+ 
+ #endif /* _ASM_X86_IOMAP_H */
+diff --git a/arch/x86/include/asm/kmap_types.h b/arch/x86/include/asm/kmap_types.h
+deleted file mode 100644
+index 04ab8266e347..000000000000
+--- a/arch/x86/include/asm/kmap_types.h
++++ /dev/null
+@@ -1,13 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-#ifndef _ASM_X86_KMAP_TYPES_H
+-#define _ASM_X86_KMAP_TYPES_H
+-
+-#if defined(CONFIG_X86_32) && defined(CONFIG_DEBUG_HIGHMEM)
+-#define  __WITH_KM_FENCE
+-#endif
+-
+-#include <asm-generic/kmap_types.h>
+-
+-#undef __WITH_KM_FENCE
+-
+-#endif /* _ASM_X86_KMAP_TYPES_H */
+diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
+index 903d71884fa2..130f428b0cc8 100644
+--- a/arch/x86/include/asm/paravirt_types.h
++++ b/arch/x86/include/asm/paravirt_types.h
+@@ -41,7 +41,6 @@
+ #ifndef __ASSEMBLY__
+ 
+ #include <asm/desc_defs.h>
+-#include <asm/kmap_types.h>
+ #include <asm/pgtable_types.h>
+ #include <asm/nospec-branch.h>
+ 
+diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c
+index 075fe51317b0..2c54b76d8f84 100644
+--- a/arch/x86/mm/highmem_32.c
++++ b/arch/x86/mm/highmem_32.c
+@@ -4,65 +4,6 @@
+ #include <linux/swap.h> /* for totalram_pages */
+ #include <linux/memblock.h>
+ 
+-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
+-{
+-	unsigned long vaddr;
+-	int idx, type;
+-
+-	type = kmap_atomic_idx_push();
+-	idx = type + KM_TYPE_NR*smp_processor_id();
+-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+-	BUG_ON(!pte_none(*(kmap_pte-idx)));
+-	set_pte(kmap_pte-idx, mk_pte(page, prot));
+-	arch_flush_lazy_mmu_mode();
+-
+-	return (void *)vaddr;
+-}
+-EXPORT_SYMBOL(kmap_atomic_high_prot);
+-
+-/*
+- * This is the same as kmap_atomic() but can map memory that doesn't
+- * have a struct page associated with it.
+- */
+-void *kmap_atomic_pfn(unsigned long pfn)
+-{
+-	return kmap_atomic_prot_pfn(pfn, kmap_prot);
+-}
+-EXPORT_SYMBOL_GPL(kmap_atomic_pfn);
+-
+-void kunmap_atomic_high(void *kvaddr)
+-{
+-	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+-
+-	if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
+-	    vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
+-		int idx, type;
+-
+-		type = kmap_atomic_idx();
+-		idx = type + KM_TYPE_NR * smp_processor_id();
+-
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-		WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
+-#endif
+-		/*
+-		 * Force other mappings to Oops if they'll try to access this
+-		 * pte without first remap it.  Keeping stale mappings around
+-		 * is a bad idea also, in case the page changes cacheability
+-		 * attributes or becomes a protected page in a hypervisor.
+-		 */
+-		kpte_clear_flush(kmap_pte-idx, vaddr);
+-		kmap_atomic_idx_pop();
+-		arch_flush_lazy_mmu_mode();
+-	}
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	else {
+-		BUG_ON(vaddr < PAGE_OFFSET);
+-		BUG_ON(vaddr >= (unsigned long)high_memory);
+-	}
+-#endif
+-}
+-EXPORT_SYMBOL(kunmap_atomic_high);
+-
+ void __init set_highmem_pages_init(void)
+ {
+ 	struct zone *zone;
+diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
+index 7c055259de3a..da31c2635ee4 100644
+--- a/arch/x86/mm/init_32.c
++++ b/arch/x86/mm/init_32.c
+@@ -394,19 +394,6 @@ kernel_physical_mapping_init(unsigned long start,
+ 	return last_map_addr;
+ }
+ 
+-pte_t *kmap_pte;
+-
+-static void __init kmap_init(void)
+-{
+-	unsigned long kmap_vstart;
+-
+-	/*
+-	 * Cache the first kmap pte:
+-	 */
+-	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
+-	kmap_pte = virt_to_kpte(kmap_vstart);
+-}
+-
+ #ifdef CONFIG_HIGHMEM
+ static void __init permanent_kmaps_init(pgd_t *pgd_base)
+ {
+@@ -712,8 +699,6 @@ void __init paging_init(void)
+ 
+ 	__flush_tlb_all();
+ 
+-	kmap_init();
+-
+ 	/*
+ 	 * NOTE: at this point the bootmem allocator is fully available.
+ 	 */
+diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c
+index f60398aeb644..e0a40d7cc66c 100644
+--- a/arch/x86/mm/iomap_32.c
++++ b/arch/x86/mm/iomap_32.c
+@@ -44,28 +44,7 @@ void iomap_free(resource_size_t base, unsigned long size)
+ }
+ EXPORT_SYMBOL_GPL(iomap_free);
+ 
+-void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
+-{
+-	unsigned long vaddr;
+-	int idx, type;
+-
+-	preempt_disable();
+-	pagefault_disable();
+-
+-	type = kmap_atomic_idx_push();
+-	idx = type + KM_TYPE_NR * smp_processor_id();
+-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+-	set_pte(kmap_pte - idx, pfn_pte(pfn, prot));
+-	arch_flush_lazy_mmu_mode();
+-
+-	return (void *)vaddr;
+-}
+-
+-/*
+- * Map 'pfn' using protections 'prot'
+- */
+-void __iomem *
+-iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
++void __iomem *iomap_atomic_pfn_prot(unsigned long pfn, pgprot_t prot)
+ {
+ 	/*
+ 	 * For non-PAT systems, translate non-WB request to UC- just in
+@@ -81,36 +60,8 @@ iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
+ 	/* Filter out unsupported __PAGE_KERNEL* bits: */
+ 	pgprot_val(prot) &= __default_kernel_pte_mask;
+ 
+-	return (void __force __iomem *) kmap_atomic_prot_pfn(pfn, prot);
+-}
+-EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn);
+-
+-void
+-iounmap_atomic(void __iomem *kvaddr)
+-{
+-	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+-
+-	if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
+-	    vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
+-		int idx, type;
+-
+-		type = kmap_atomic_idx();
+-		idx = type + KM_TYPE_NR * smp_processor_id();
+-
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-		WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
+-#endif
+-		/*
+-		 * Force other mappings to Oops if they'll try to access this
+-		 * pte without first remap it.  Keeping stale mappings around
+-		 * is a bad idea also, in case the page changes cacheability
+-		 * attributes or becomes a protected page in a hypervisor.
+-		 */
+-		kpte_clear_flush(kmap_pte-idx, vaddr);
+-		kmap_atomic_idx_pop();
+-	}
+-
+-	pagefault_enable();
+-	preempt_enable();
++	preempt_disable();
++	pagefault_disable();
++	return (void __force __iomem *)__kmap_local_pfn_prot(pfn, prot);
+ }
+-EXPORT_SYMBOL_GPL(iounmap_atomic);
++EXPORT_SYMBOL_GPL(iomap_atomic_pfn_prot);
+diff --git a/include/linux/highmem.h b/include/linux/highmem.h
+index 14d5b4020c8c..fbede783dc34 100644
+--- a/include/linux/highmem.h
++++ b/include/linux/highmem.h
+@@ -217,7 +217,7 @@ static inline void __kunmap_atomic(void *addr)
+ #endif /* CONFIG_HIGHMEM */
+ 
+ #if !defined(CONFIG_KMAP_LOCAL)
+-#if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
++#if defined(CONFIG_HIGHMEM)
+ 
+ DECLARE_PER_CPU(int, __kmap_atomic_idx);
+ 
+diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h
+index c75e4d3d8833..3b0940be72e9 100644
+--- a/include/linux/io-mapping.h
++++ b/include/linux/io-mapping.h
+@@ -69,7 +69,7 @@ io_mapping_map_atomic_wc(struct io_mapping *mapping,
+ 
+ 	BUG_ON(offset >= mapping->size);
+ 	phys_addr = mapping->base + offset;
+-	return iomap_atomic_prot_pfn(PHYS_PFN(phys_addr), mapping->prot);
++	return iomap_atomic_pfn_prot(PHYS_PFN(phys_addr), mapping->prot);
+ }
+ 
+ static inline void
+diff --git a/mm/highmem.c b/mm/highmem.c
+index 67d2d5983cb0..77677c6844f7 100644
+--- a/mm/highmem.c
++++ b/mm/highmem.c
+@@ -32,7 +32,7 @@
+ #include <linux/vmalloc.h>
+ 
+ #ifndef CONFIG_KMAP_LOCAL
+-#if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
++#ifdef CONFIG_HIGHMEM
+ DEFINE_PER_CPU(int, __kmap_atomic_idx);
+ #endif
+ #endif
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0032-arc-mm-highmem-Use-generic-kmap-atomic-implementatio.patch b/debian/patches-rt/0032-arc-mm-highmem-Use-generic-kmap-atomic-implementatio.patch
new file mode 100644
index 000000000..581f1da69
--- /dev/null
+++ b/debian/patches-rt/0032-arc-mm-highmem-Use-generic-kmap-atomic-implementatio.patch
@@ -0,0 +1,212 @@
+From 7eeaddc0ba0792dd0d8a1f5f167ff44230b77855 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:21 +0100
+Subject: [PATCH 032/323] arc/mm/highmem: Use generic kmap atomic
+ implementation
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Adopt the map ordering to match the other architectures and the generic
+code. Also make the maximum entries limited and not dependend on the number
+of CPUs. With the original implementation did the following calculation:
+
+   nr_slots = mapsize >> PAGE_SHIFT;
+
+The results in either 512 or 1024 total slots depending on
+configuration. The total slots have to be divided by the number of CPUs to
+get the number of slots per CPU (former KM_TYPE_NR). ARC supports up to 4k
+CPUs, so this just falls apart in random ways depending on the number of
+CPUs and the actual kmap (atomic) nesting. The comment in highmem.c:
+
+ * - fixmap anyhow needs a limited number of mappings. So 2M kvaddr == 256 PTE
+ *   slots across NR_CPUS would be more than sufficient (generic code defines
+ *   KM_TYPE_NR as 20).
+
+is just wrong. KM_TYPE_NR (now KM_MAX_IDX) is the number of slots per CPU
+because kmap_local/atomic() needs to support nested mappings (thread,
+softirq, interrupt). While KM_MAX_IDX might be overestimated, the above
+reasoning is just wrong and clearly the highmem code was never tested with
+any system with more than a few CPUs.
+
+Use the default number of slots and fail the build when it does not
+fit. Randomly failing at runtime is not a really good option.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Vineet Gupta <vgupta@synopsys.com>
+Cc: linux-snps-arc@lists.infradead.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/arc/Kconfig                  |  1 +
+ arch/arc/include/asm/highmem.h    | 26 +++++++++++----
+ arch/arc/include/asm/kmap_types.h | 14 --------
+ arch/arc/mm/highmem.c             | 54 +++----------------------------
+ 4 files changed, 26 insertions(+), 69 deletions(-)
+ delete mode 100644 arch/arc/include/asm/kmap_types.h
+
+diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
+index 0a89cc9def65..d8804001d550 100644
+--- a/arch/arc/Kconfig
++++ b/arch/arc/Kconfig
+@@ -507,6 +507,7 @@ config LINUX_RAM_BASE
+ config HIGHMEM
+ 	bool "High Memory Support"
+ 	select ARCH_DISCONTIGMEM_ENABLE
++	select KMAP_LOCAL
+ 	help
+ 	  With ARC 2G:2G address split, only upper 2G is directly addressable by
+ 	  kernel. Enable this to potentially allow access to rest of 2G and PAE
+diff --git a/arch/arc/include/asm/highmem.h b/arch/arc/include/asm/highmem.h
+index 6e5eafb3afdd..a6b8e2c352c4 100644
+--- a/arch/arc/include/asm/highmem.h
++++ b/arch/arc/include/asm/highmem.h
+@@ -9,17 +9,29 @@
+ #ifdef CONFIG_HIGHMEM
+ 
+ #include <uapi/asm/page.h>
+-#include <asm/kmap_types.h>
++#include <asm/kmap_size.h>
++
++#define FIXMAP_SIZE		PGDIR_SIZE
++#define PKMAP_SIZE		PGDIR_SIZE
+ 
+ /* start after vmalloc area */
+ #define FIXMAP_BASE		(PAGE_OFFSET - FIXMAP_SIZE - PKMAP_SIZE)
+-#define FIXMAP_SIZE		PGDIR_SIZE	/* only 1 PGD worth */
+-#define KM_TYPE_NR		((FIXMAP_SIZE >> PAGE_SHIFT)/NR_CPUS)
+-#define FIXMAP_ADDR(nr)		(FIXMAP_BASE + ((nr) << PAGE_SHIFT))
++
++#define FIX_KMAP_SLOTS		(KM_MAX_IDX * NR_CPUS)
++#define FIX_KMAP_BEGIN		(0UL)
++#define FIX_KMAP_END		((FIX_KMAP_BEGIN + FIX_KMAP_SLOTS) - 1)
++
++#define FIXADDR_TOP		(FIXMAP_BASE + (FIX_KMAP_END << PAGE_SHIFT))
++
++/*
++ * This should be converted to the asm-generic version, but of course this
++ * is needlessly different from all other architectures. Sigh - tglx
++ */
++#define __fix_to_virt(x)	(FIXADDR_TOP - ((x) << PAGE_SHIFT))
++#define __virt_to_fix(x)	(((FIXADDR_TOP - ((x) & PAGE_MASK))) >> PAGE_SHIFT)
+ 
+ /* start after fixmap area */
+ #define PKMAP_BASE		(FIXMAP_BASE + FIXMAP_SIZE)
+-#define PKMAP_SIZE		PGDIR_SIZE
+ #define LAST_PKMAP		(PKMAP_SIZE >> PAGE_SHIFT)
+ #define LAST_PKMAP_MASK		(LAST_PKMAP - 1)
+ #define PKMAP_ADDR(nr)		(PKMAP_BASE + ((nr) << PAGE_SHIFT))
+@@ -29,11 +41,13 @@
+ 
+ extern void kmap_init(void);
+ 
++#define arch_kmap_local_post_unmap(vaddr)			\
++	local_flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE)
++
+ static inline void flush_cache_kmaps(void)
+ {
+ 	flush_cache_all();
+ }
+-
+ #endif
+ 
+ #endif
+diff --git a/arch/arc/include/asm/kmap_types.h b/arch/arc/include/asm/kmap_types.h
+deleted file mode 100644
+index fecf7851ec32..000000000000
+--- a/arch/arc/include/asm/kmap_types.h
++++ /dev/null
+@@ -1,14 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0-only */
+-/*
+- * Copyright (C) 2015 Synopsys, Inc. (www.synopsys.com)
+- */
+-
+-#ifndef _ASM_KMAP_TYPES_H
+-#define _ASM_KMAP_TYPES_H
+-
+-/*
+- * We primarily need to define KM_TYPE_NR here but that in turn
+- * is a function of PGDIR_SIZE etc.
+- * To avoid circular deps issue, put everything in asm/highmem.h
+- */
+-#endif
+diff --git a/arch/arc/mm/highmem.c b/arch/arc/mm/highmem.c
+index 1b9f473c6369..c79912a6b196 100644
+--- a/arch/arc/mm/highmem.c
++++ b/arch/arc/mm/highmem.c
+@@ -36,9 +36,8 @@
+  *   This means each only has 1 PGDIR_SIZE worth of kvaddr mappings, which means
+  *   2M of kvaddr space for typical config (8K page and 11:8:13 traversal split)
+  *
+- * - fixmap anyhow needs a limited number of mappings. So 2M kvaddr == 256 PTE
+- *   slots across NR_CPUS would be more than sufficient (generic code defines
+- *   KM_TYPE_NR as 20).
++ * - The fixed KMAP slots for kmap_local/atomic() require KM_MAX_IDX slots per
++ *   CPU. So the number of CPUs sharing a single PTE page is limited.
+  *
+  * - pkmap being preemptible, in theory could do with more than 256 concurrent
+  *   mappings. However, generic pkmap code: map_new_virtual(), doesn't traverse
+@@ -47,48 +46,6 @@
+  */
+ 
+ extern pte_t * pkmap_page_table;
+-static pte_t * fixmap_page_table;
+-
+-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
+-{
+-	int idx, cpu_idx;
+-	unsigned long vaddr;
+-
+-	cpu_idx = kmap_atomic_idx_push();
+-	idx = cpu_idx + KM_TYPE_NR * smp_processor_id();
+-	vaddr = FIXMAP_ADDR(idx);
+-
+-	set_pte_at(&init_mm, vaddr, fixmap_page_table + idx,
+-		   mk_pte(page, prot));
+-
+-	return (void *)vaddr;
+-}
+-EXPORT_SYMBOL(kmap_atomic_high_prot);
+-
+-void kunmap_atomic_high(void *kv)
+-{
+-	unsigned long kvaddr = (unsigned long)kv;
+-
+-	if (kvaddr >= FIXMAP_BASE && kvaddr < (FIXMAP_BASE + FIXMAP_SIZE)) {
+-
+-		/*
+-		 * Because preemption is disabled, this vaddr can be associated
+-		 * with the current allocated index.
+-		 * But in case of multiple live kmap_atomic(), it still relies on
+-		 * callers to unmap in right order.
+-		 */
+-		int cpu_idx = kmap_atomic_idx();
+-		int idx = cpu_idx + KM_TYPE_NR * smp_processor_id();
+-
+-		WARN_ON(kvaddr != FIXMAP_ADDR(idx));
+-
+-		pte_clear(&init_mm, kvaddr, fixmap_page_table + idx);
+-		local_flush_tlb_kernel_range(kvaddr, kvaddr + PAGE_SIZE);
+-
+-		kmap_atomic_idx_pop();
+-	}
+-}
+-EXPORT_SYMBOL(kunmap_atomic_high);
+ 
+ static noinline pte_t * __init alloc_kmap_pgtable(unsigned long kvaddr)
+ {
+@@ -108,10 +65,9 @@ void __init kmap_init(void)
+ {
+ 	/* Due to recursive include hell, we can't do this in processor.h */
+ 	BUILD_BUG_ON(PAGE_OFFSET < (VMALLOC_END + FIXMAP_SIZE + PKMAP_SIZE));
++	BUILD_BUG_ON(LAST_PKMAP > PTRS_PER_PTE);
++	BUILD_BUG_ON(FIX_KMAP_SLOTS > PTRS_PER_PTE);
+ 
+-	BUILD_BUG_ON(KM_TYPE_NR > PTRS_PER_PTE);
+ 	pkmap_page_table = alloc_kmap_pgtable(PKMAP_BASE);
+-
+-	BUILD_BUG_ON(LAST_PKMAP > PTRS_PER_PTE);
+-	fixmap_page_table = alloc_kmap_pgtable(FIXMAP_BASE);
++	alloc_kmap_pgtable(FIXMAP_BASE);
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0033-ARM-highmem-Switch-to-generic-kmap-atomic.patch b/debian/patches-rt/0033-ARM-highmem-Switch-to-generic-kmap-atomic.patch
new file mode 100644
index 000000000..7f4d188e7
--- /dev/null
+++ b/debian/patches-rt/0033-ARM-highmem-Switch-to-generic-kmap-atomic.patch
@@ -0,0 +1,271 @@
+From 007968641a299ffd9fd631d7f67fc119aaf9ac5d Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:22 +0100
+Subject: [PATCH 033/323] ARM: highmem: Switch to generic kmap atomic
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+No reason having the same code in every architecture.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Russell King <linux@armlinux.org.uk>
+Cc: Arnd Bergmann <arnd@arndb.de>
+Cc: linux-arm-kernel@lists.infradead.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/arm/Kconfig                  |   1 +
+ arch/arm/include/asm/fixmap.h     |   4 +-
+ arch/arm/include/asm/highmem.h    |  34 ++++++---
+ arch/arm/include/asm/kmap_types.h |  10 ---
+ arch/arm/mm/Makefile              |   1 -
+ arch/arm/mm/highmem.c             | 121 ------------------------------
+ 6 files changed, 27 insertions(+), 144 deletions(-)
+ delete mode 100644 arch/arm/include/asm/kmap_types.h
+ delete mode 100644 arch/arm/mm/highmem.c
+
+diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
+index 335308aff6ce..c01251683018 100644
+--- a/arch/arm/Kconfig
++++ b/arch/arm/Kconfig
+@@ -1497,6 +1497,7 @@ config HAVE_ARCH_PFN_VALID
+ config HIGHMEM
+ 	bool "High Memory Support"
+ 	depends on MMU
++	select KMAP_LOCAL
+ 	help
+ 	  The address space of ARM processors is only 4 Gigabytes large
+ 	  and it has to accommodate user address space, kernel address
+diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h
+index 9575b404019c..707068f852c2 100644
+--- a/arch/arm/include/asm/fixmap.h
++++ b/arch/arm/include/asm/fixmap.h
+@@ -7,14 +7,14 @@
+ #define FIXADDR_TOP		(FIXADDR_END - PAGE_SIZE)
+ 
+ #include <linux/pgtable.h>
+-#include <asm/kmap_types.h>
++#include <asm/kmap_size.h>
+ 
+ enum fixed_addresses {
+ 	FIX_EARLYCON_MEM_BASE,
+ 	__end_of_permanent_fixed_addresses,
+ 
+ 	FIX_KMAP_BEGIN = __end_of_permanent_fixed_addresses,
+-	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1,
++	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1,
+ 
+ 	/* Support writing RO kernel text via kprobes, jump labels, etc. */
+ 	FIX_TEXT_POKE0,
+diff --git a/arch/arm/include/asm/highmem.h b/arch/arm/include/asm/highmem.h
+index 31811be38d78..b22dffa8c7eb 100644
+--- a/arch/arm/include/asm/highmem.h
++++ b/arch/arm/include/asm/highmem.h
+@@ -2,7 +2,8 @@
+ #ifndef _ASM_HIGHMEM_H
+ #define _ASM_HIGHMEM_H
+ 
+-#include <asm/kmap_types.h>
++#include <asm/kmap_size.h>
++#include <asm/fixmap.h>
+ 
+ #define PKMAP_BASE		(PAGE_OFFSET - PMD_SIZE)
+ #define LAST_PKMAP		PTRS_PER_PTE
+@@ -46,19 +47,32 @@ extern pte_t *pkmap_page_table;
+ 
+ #ifdef ARCH_NEEDS_KMAP_HIGH_GET
+ extern void *kmap_high_get(struct page *page);
+-#else
++
++static inline void *arch_kmap_local_high_get(struct page *page)
++{
++	if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM) && !cache_is_vivt())
++		return NULL;
++	return kmap_high_get(page);
++}
++#define arch_kmap_local_high_get arch_kmap_local_high_get
++
++#else /* ARCH_NEEDS_KMAP_HIGH_GET */
+ static inline void *kmap_high_get(struct page *page)
+ {
+ 	return NULL;
+ }
+-#endif
++#endif /* !ARCH_NEEDS_KMAP_HIGH_GET */
+ 
+-/*
+- * The following functions are already defined by <linux/highmem.h>
+- * when CONFIG_HIGHMEM is not set.
+- */
+-#ifdef CONFIG_HIGHMEM
+-extern void *kmap_atomic_pfn(unsigned long pfn);
+-#endif
++#define arch_kmap_local_post_map(vaddr, pteval)				\
++	local_flush_tlb_kernel_page(vaddr)
++
++#define arch_kmap_local_pre_unmap(vaddr)				\
++do {									\
++	if (cache_is_vivt())						\
++		__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);	\
++} while (0)
++
++#define arch_kmap_local_post_unmap(vaddr)				\
++	local_flush_tlb_kernel_page(vaddr)
+ 
+ #endif
+diff --git a/arch/arm/include/asm/kmap_types.h b/arch/arm/include/asm/kmap_types.h
+deleted file mode 100644
+index 5590940ee43d..000000000000
+--- a/arch/arm/include/asm/kmap_types.h
++++ /dev/null
+@@ -1,10 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-#ifndef __ARM_KMAP_TYPES_H
+-#define __ARM_KMAP_TYPES_H
+-
+-/*
+- * This is the "bare minimum".  AIO seems to require this.
+- */
+-#define KM_TYPE_NR 16
+-
+-#endif
+diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile
+index 7cb1699fbfc4..c4ce477c5261 100644
+--- a/arch/arm/mm/Makefile
++++ b/arch/arm/mm/Makefile
+@@ -19,7 +19,6 @@ obj-$(CONFIG_MODULES)		+= proc-syms.o
+ obj-$(CONFIG_DEBUG_VIRTUAL)	+= physaddr.o
+ 
+ obj-$(CONFIG_ALIGNMENT_TRAP)	+= alignment.o
+-obj-$(CONFIG_HIGHMEM)		+= highmem.o
+ obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
+ obj-$(CONFIG_ARM_PV_FIXUP)	+= pv-fixup-asm.o
+ 
+diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c
+deleted file mode 100644
+index 187fab227b50..000000000000
+--- a/arch/arm/mm/highmem.c
++++ /dev/null
+@@ -1,121 +0,0 @@
+-// SPDX-License-Identifier: GPL-2.0-only
+-/*
+- * arch/arm/mm/highmem.c -- ARM highmem support
+- *
+- * Author:	Nicolas Pitre
+- * Created:	september 8, 2008
+- * Copyright:	Marvell Semiconductors Inc.
+- */
+-
+-#include <linux/module.h>
+-#include <linux/highmem.h>
+-#include <linux/interrupt.h>
+-#include <asm/fixmap.h>
+-#include <asm/cacheflush.h>
+-#include <asm/tlbflush.h>
+-#include "mm.h"
+-
+-static inline void set_fixmap_pte(int idx, pte_t pte)
+-{
+-	unsigned long vaddr = __fix_to_virt(idx);
+-	pte_t *ptep = virt_to_kpte(vaddr);
+-
+-	set_pte_ext(ptep, pte, 0);
+-	local_flush_tlb_kernel_page(vaddr);
+-}
+-
+-static inline pte_t get_fixmap_pte(unsigned long vaddr)
+-{
+-	pte_t *ptep = virt_to_kpte(vaddr);
+-
+-	return *ptep;
+-}
+-
+-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
+-{
+-	unsigned int idx;
+-	unsigned long vaddr;
+-	void *kmap;
+-	int type;
+-
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	/*
+-	 * There is no cache coherency issue when non VIVT, so force the
+-	 * dedicated kmap usage for better debugging purposes in that case.
+-	 */
+-	if (!cache_is_vivt())
+-		kmap = NULL;
+-	else
+-#endif
+-		kmap = kmap_high_get(page);
+-	if (kmap)
+-		return kmap;
+-
+-	type = kmap_atomic_idx_push();
+-
+-	idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+-	vaddr = __fix_to_virt(idx);
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	/*
+-	 * With debugging enabled, kunmap_atomic forces that entry to 0.
+-	 * Make sure it was indeed properly unmapped.
+-	 */
+-	BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
+-#endif
+-	/*
+-	 * When debugging is off, kunmap_atomic leaves the previous mapping
+-	 * in place, so the contained TLB flush ensures the TLB is updated
+-	 * with the new mapping.
+-	 */
+-	set_fixmap_pte(idx, mk_pte(page, prot));
+-
+-	return (void *)vaddr;
+-}
+-EXPORT_SYMBOL(kmap_atomic_high_prot);
+-
+-void kunmap_atomic_high(void *kvaddr)
+-{
+-	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+-	int idx, type;
+-
+-	if (kvaddr >= (void *)FIXADDR_START) {
+-		type = kmap_atomic_idx();
+-		idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+-
+-		if (cache_is_vivt())
+-			__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-		BUG_ON(vaddr != __fix_to_virt(idx));
+-		set_fixmap_pte(idx, __pte(0));
+-#else
+-		(void) idx;  /* to kill a warning */
+-#endif
+-		kmap_atomic_idx_pop();
+-	} else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
+-		/* this address was obtained through kmap_high_get() */
+-		kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
+-	}
+-}
+-EXPORT_SYMBOL(kunmap_atomic_high);
+-
+-void *kmap_atomic_pfn(unsigned long pfn)
+-{
+-	unsigned long vaddr;
+-	int idx, type;
+-	struct page *page = pfn_to_page(pfn);
+-
+-	preempt_disable();
+-	pagefault_disable();
+-	if (!PageHighMem(page))
+-		return page_address(page);
+-
+-	type = kmap_atomic_idx_push();
+-	idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+-	vaddr = __fix_to_virt(idx);
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
+-#endif
+-	set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));
+-
+-	return (void *)vaddr;
+-}
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0034-csky-mm-highmem-Switch-to-generic-kmap-atomic.patch b/debian/patches-rt/0034-csky-mm-highmem-Switch-to-generic-kmap-atomic.patch
new file mode 100644
index 000000000..667836a1e
--- /dev/null
+++ b/debian/patches-rt/0034-csky-mm-highmem-Switch-to-generic-kmap-atomic.patch
@@ -0,0 +1,179 @@
+From 3af9ca89d4398239a71471cffb488e3104990e23 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:23 +0100
+Subject: [PATCH 034/323] csky/mm/highmem: Switch to generic kmap atomic
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+No reason having the same code in every architecture.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: linux-csky@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/csky/Kconfig               |  1 +
+ arch/csky/include/asm/fixmap.h  |  4 +-
+ arch/csky/include/asm/highmem.h |  6 ++-
+ arch/csky/mm/highmem.c          | 75 +--------------------------------
+ 4 files changed, 8 insertions(+), 78 deletions(-)
+
+diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
+index 7bf0a617e94c..c9f2533cc53d 100644
+--- a/arch/csky/Kconfig
++++ b/arch/csky/Kconfig
+@@ -286,6 +286,7 @@ config NR_CPUS
+ config HIGHMEM
+ 	bool "High Memory Support"
+ 	depends on !CPU_CK610
++	select KMAP_LOCAL
+ 	default y
+ 
+ config FORCE_MAX_ZONEORDER
+diff --git a/arch/csky/include/asm/fixmap.h b/arch/csky/include/asm/fixmap.h
+index 81f9477d5330..4b589cc20900 100644
+--- a/arch/csky/include/asm/fixmap.h
++++ b/arch/csky/include/asm/fixmap.h
+@@ -8,7 +8,7 @@
+ #include <asm/memory.h>
+ #ifdef CONFIG_HIGHMEM
+ #include <linux/threads.h>
+-#include <asm/kmap_types.h>
++#include <asm/kmap_size.h>
+ #endif
+ 
+ enum fixed_addresses {
+@@ -17,7 +17,7 @@ enum fixed_addresses {
+ #endif
+ #ifdef CONFIG_HIGHMEM
+ 	FIX_KMAP_BEGIN,
+-	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS) - 1,
++	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1,
+ #endif
+ 	__end_of_fixed_addresses
+ };
+diff --git a/arch/csky/include/asm/highmem.h b/arch/csky/include/asm/highmem.h
+index 14645e3d5cd5..1f4ed3f4c0d9 100644
+--- a/arch/csky/include/asm/highmem.h
++++ b/arch/csky/include/asm/highmem.h
+@@ -9,7 +9,7 @@
+ #include <linux/init.h>
+ #include <linux/interrupt.h>
+ #include <linux/uaccess.h>
+-#include <asm/kmap_types.h>
++#include <asm/kmap_size.h>
+ #include <asm/cache.h>
+ 
+ /* undef for production */
+@@ -32,10 +32,12 @@ extern pte_t *pkmap_page_table;
+ 
+ #define ARCH_HAS_KMAP_FLUSH_TLB
+ extern void kmap_flush_tlb(unsigned long addr);
+-extern void *kmap_atomic_pfn(unsigned long pfn);
+ 
+ #define flush_cache_kmaps() do {} while (0)
+ 
++#define arch_kmap_local_post_map(vaddr, pteval)	kmap_flush_tlb(vaddr)
++#define arch_kmap_local_post_unmap(vaddr)	kmap_flush_tlb(vaddr)
++
+ extern void kmap_init(void);
+ 
+ #endif /* __KERNEL__ */
+diff --git a/arch/csky/mm/highmem.c b/arch/csky/mm/highmem.c
+index 89c10800a002..4161df3c6c15 100644
+--- a/arch/csky/mm/highmem.c
++++ b/arch/csky/mm/highmem.c
+@@ -9,8 +9,6 @@
+ #include <asm/tlbflush.h>
+ #include <asm/cacheflush.h>
+ 
+-static pte_t *kmap_pte;
+-
+ unsigned long highstart_pfn, highend_pfn;
+ 
+ void kmap_flush_tlb(unsigned long addr)
+@@ -19,67 +17,7 @@ void kmap_flush_tlb(unsigned long addr)
+ }
+ EXPORT_SYMBOL(kmap_flush_tlb);
+ 
+-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
+-{
+-	unsigned long vaddr;
+-	int idx, type;
+-
+-	type = kmap_atomic_idx_push();
+-	idx = type + KM_TYPE_NR*smp_processor_id();
+-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	BUG_ON(!pte_none(*(kmap_pte - idx)));
+-#endif
+-	set_pte(kmap_pte-idx, mk_pte(page, prot));
+-	flush_tlb_one((unsigned long)vaddr);
+-
+-	return (void *)vaddr;
+-}
+-EXPORT_SYMBOL(kmap_atomic_high_prot);
+-
+-void kunmap_atomic_high(void *kvaddr)
+-{
+-	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+-	int idx;
+-
+-	if (vaddr < FIXADDR_START)
+-		return;
+-
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	idx = KM_TYPE_NR*smp_processor_id() + kmap_atomic_idx();
+-
+-	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
+-
+-	pte_clear(&init_mm, vaddr, kmap_pte - idx);
+-	flush_tlb_one(vaddr);
+-#else
+-	(void) idx; /* to kill a warning */
+-#endif
+-	kmap_atomic_idx_pop();
+-}
+-EXPORT_SYMBOL(kunmap_atomic_high);
+-
+-/*
+- * This is the same as kmap_atomic() but can map memory that doesn't
+- * have a struct page associated with it.
+- */
+-void *kmap_atomic_pfn(unsigned long pfn)
+-{
+-	unsigned long vaddr;
+-	int idx, type;
+-
+-	pagefault_disable();
+-
+-	type = kmap_atomic_idx_push();
+-	idx = type + KM_TYPE_NR*smp_processor_id();
+-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+-	set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
+-	flush_tlb_one(vaddr);
+-
+-	return (void *) vaddr;
+-}
+-
+-static void __init kmap_pages_init(void)
++void __init kmap_init(void)
+ {
+ 	unsigned long vaddr;
+ 	pgd_t *pgd;
+@@ -96,14 +34,3 @@ static void __init kmap_pages_init(void)
+ 	pte = pte_offset_kernel(pmd, vaddr);
+ 	pkmap_page_table = pte;
+ }
+-
+-void __init kmap_init(void)
+-{
+-	unsigned long vaddr;
+-
+-	kmap_pages_init();
+-
+-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN);
+-
+-	kmap_pte = pte_offset_kernel((pmd_t *)pgd_offset_k(vaddr), vaddr);
+-}
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0035-microblaze-mm-highmem-Switch-to-generic-kmap-atomic.patch b/debian/patches-rt/0035-microblaze-mm-highmem-Switch-to-generic-kmap-atomic.patch
new file mode 100644
index 000000000..80bd103c5
--- /dev/null
+++ b/debian/patches-rt/0035-microblaze-mm-highmem-Switch-to-generic-kmap-atomic.patch
@@ -0,0 +1,197 @@
+From bfdad55346f7206cf980bbd6cbc264082c54ae0c Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:24 +0100
+Subject: [PATCH 035/323] microblaze/mm/highmem: Switch to generic kmap atomic
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+No reason having the same code in every architecture.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Michal Simek <monstr@monstr.eu>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/microblaze/Kconfig               |  1 +
+ arch/microblaze/include/asm/fixmap.h  |  4 +-
+ arch/microblaze/include/asm/highmem.h |  6 ++-
+ arch/microblaze/mm/Makefile           |  1 -
+ arch/microblaze/mm/highmem.c          | 78 ---------------------------
+ arch/microblaze/mm/init.c             |  6 ---
+ 6 files changed, 8 insertions(+), 88 deletions(-)
+ delete mode 100644 arch/microblaze/mm/highmem.c
+
+diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
+index 33925ffed68f..7f6ca0ab4f81 100644
+--- a/arch/microblaze/Kconfig
++++ b/arch/microblaze/Kconfig
+@@ -155,6 +155,7 @@ config XILINX_UNCACHED_SHADOW
+ config HIGHMEM
+ 	bool "High memory support"
+ 	depends on MMU
++	select KMAP_LOCAL
+ 	help
+ 	  The address space of Microblaze processors is only 4 Gigabytes large
+ 	  and it has to accommodate user address space, kernel address
+diff --git a/arch/microblaze/include/asm/fixmap.h b/arch/microblaze/include/asm/fixmap.h
+index 0379ce5229e3..e6e9288bff76 100644
+--- a/arch/microblaze/include/asm/fixmap.h
++++ b/arch/microblaze/include/asm/fixmap.h
+@@ -20,7 +20,7 @@
+ #include <asm/page.h>
+ #ifdef CONFIG_HIGHMEM
+ #include <linux/threads.h>
+-#include <asm/kmap_types.h>
++#include <asm/kmap_size.h>
+ #endif
+ 
+ #define FIXADDR_TOP	((unsigned long)(-PAGE_SIZE))
+@@ -47,7 +47,7 @@ enum fixed_addresses {
+ 	FIX_HOLE,
+ #ifdef CONFIG_HIGHMEM
+ 	FIX_KMAP_BEGIN,	/* reserved pte's for temporary kernel mappings */
+-	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * num_possible_cpus()) - 1,
++	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * num_possible_cpus()) - 1,
+ #endif
+ 	__end_of_fixed_addresses
+ };
+diff --git a/arch/microblaze/include/asm/highmem.h b/arch/microblaze/include/asm/highmem.h
+index 284ca8fb54c1..4418633fb163 100644
+--- a/arch/microblaze/include/asm/highmem.h
++++ b/arch/microblaze/include/asm/highmem.h
+@@ -25,7 +25,6 @@
+ #include <linux/uaccess.h>
+ #include <asm/fixmap.h>
+ 
+-extern pte_t *kmap_pte;
+ extern pte_t *pkmap_page_table;
+ 
+ /*
+@@ -52,6 +51,11 @@ extern pte_t *pkmap_page_table;
+ 
+ #define flush_cache_kmaps()	{ flush_icache(); flush_dcache(); }
+ 
++#define arch_kmap_local_post_map(vaddr, pteval)	\
++	local_flush_tlb_page(NULL, vaddr);
++#define arch_kmap_local_post_unmap(vaddr)	\
++	local_flush_tlb_page(NULL, vaddr);
++
+ #endif /* __KERNEL__ */
+ 
+ #endif /* _ASM_HIGHMEM_H */
+diff --git a/arch/microblaze/mm/Makefile b/arch/microblaze/mm/Makefile
+index 1b16875cea70..8ced71100047 100644
+--- a/arch/microblaze/mm/Makefile
++++ b/arch/microblaze/mm/Makefile
+@@ -6,4 +6,3 @@
+ obj-y := consistent.o init.o
+ 
+ obj-$(CONFIG_MMU) += pgtable.o mmu_context.o fault.o
+-obj-$(CONFIG_HIGHMEM) += highmem.o
+diff --git a/arch/microblaze/mm/highmem.c b/arch/microblaze/mm/highmem.c
+deleted file mode 100644
+index 92e0890416c9..000000000000
+--- a/arch/microblaze/mm/highmem.c
++++ /dev/null
+@@ -1,78 +0,0 @@
+-// SPDX-License-Identifier: GPL-2.0
+-/*
+- * highmem.c: virtual kernel memory mappings for high memory
+- *
+- * PowerPC version, stolen from the i386 version.
+- *
+- * Used in CONFIG_HIGHMEM systems for memory pages which
+- * are not addressable by direct kernel virtual addresses.
+- *
+- * Copyright (C) 1999 Gerhard Wichert, Siemens AG
+- *		      Gerhard.Wichert@pdb.siemens.de
+- *
+- *
+- * Redesigned the x86 32-bit VM architecture to deal with
+- * up to 16 Terrabyte physical memory. With current x86 CPUs
+- * we now support up to 64 Gigabytes physical RAM.
+- *
+- * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
+- *
+- * Reworked for PowerPC by various contributors. Moved from
+- * highmem.h by Benjamin Herrenschmidt (c) 2009 IBM Corp.
+- */
+-
+-#include <linux/export.h>
+-#include <linux/highmem.h>
+-
+-/*
+- * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
+- * gives a more generic (and caching) interface. But kmap_atomic can
+- * be used in IRQ contexts, so in some (very limited) cases we need
+- * it.
+- */
+-#include <asm/tlbflush.h>
+-
+-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
+-{
+-
+-	unsigned long vaddr;
+-	int idx, type;
+-
+-	type = kmap_atomic_idx_push();
+-	idx = type + KM_TYPE_NR*smp_processor_id();
+-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	BUG_ON(!pte_none(*(kmap_pte-idx)));
+-#endif
+-	set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot));
+-	local_flush_tlb_page(NULL, vaddr);
+-
+-	return (void *) vaddr;
+-}
+-EXPORT_SYMBOL(kmap_atomic_high_prot);
+-
+-void kunmap_atomic_high(void *kvaddr)
+-{
+-	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+-	int type;
+-	unsigned int idx;
+-
+-	if (vaddr < __fix_to_virt(FIX_KMAP_END))
+-		return;
+-
+-	type = kmap_atomic_idx();
+-
+-	idx = type + KM_TYPE_NR * smp_processor_id();
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
+-#endif
+-	/*
+-	 * force other mappings to Oops if they'll try to access
+-	 * this pte without first remap it
+-	 */
+-	pte_clear(&init_mm, vaddr, kmap_pte-idx);
+-	local_flush_tlb_page(NULL, vaddr);
+-
+-	kmap_atomic_idx_pop();
+-}
+-EXPORT_SYMBOL(kunmap_atomic_high);
+diff --git a/arch/microblaze/mm/init.c b/arch/microblaze/mm/init.c
+index 45da639bd22c..1f4b5b34e600 100644
+--- a/arch/microblaze/mm/init.c
++++ b/arch/microblaze/mm/init.c
+@@ -49,17 +49,11 @@ unsigned long lowmem_size;
+ EXPORT_SYMBOL(min_low_pfn);
+ EXPORT_SYMBOL(max_low_pfn);
+ 
+-#ifdef CONFIG_HIGHMEM
+-pte_t *kmap_pte;
+-EXPORT_SYMBOL(kmap_pte);
+-
+ static void __init highmem_init(void)
+ {
+ 	pr_debug("%x\n", (u32)PKMAP_BASE);
+ 	map_page(PKMAP_BASE, 0, 0);	/* XXX gross */
+ 	pkmap_page_table = virt_to_kpte(PKMAP_BASE);
+-
+-	kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
+ }
+ 
+ static void highmem_setup(void)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0036-mips-mm-highmem-Switch-to-generic-kmap-atomic.patch b/debian/patches-rt/0036-mips-mm-highmem-Switch-to-generic-kmap-atomic.patch
new file mode 100644
index 000000000..998662451
--- /dev/null
+++ b/debian/patches-rt/0036-mips-mm-highmem-Switch-to-generic-kmap-atomic.patch
@@ -0,0 +1,219 @@
+From 5ff7160041ca1461c70a70237f3c6a4b09d54472 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:25 +0100
+Subject: [PATCH 036/323] mips/mm/highmem: Switch to generic kmap atomic
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+No reason having the same code in every architecture
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
+Cc: linux-mips@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/mips/Kconfig                  |  1 +
+ arch/mips/include/asm/fixmap.h     |  4 +-
+ arch/mips/include/asm/highmem.h    |  6 +--
+ arch/mips/include/asm/kmap_types.h | 13 -----
+ arch/mips/mm/highmem.c             | 77 ------------------------------
+ arch/mips/mm/init.c                |  4 --
+ 6 files changed, 6 insertions(+), 99 deletions(-)
+ delete mode 100644 arch/mips/include/asm/kmap_types.h
+
+diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
+index 18ebacf29889..0e02b2e6ee06 100644
+--- a/arch/mips/Kconfig
++++ b/arch/mips/Kconfig
+@@ -2733,6 +2733,7 @@ config WAR_MIPS34K_MISSED_ITLB
+ config HIGHMEM
+ 	bool "High Memory Support"
+ 	depends on 32BIT && CPU_SUPPORTS_HIGHMEM && SYS_SUPPORTS_HIGHMEM && !CPU_MIPS32_3_5_EVA
++	select KMAP_LOCAL
+ 
+ config CPU_SUPPORTS_HIGHMEM
+ 	bool
+diff --git a/arch/mips/include/asm/fixmap.h b/arch/mips/include/asm/fixmap.h
+index 743535be7528..beea14761cef 100644
+--- a/arch/mips/include/asm/fixmap.h
++++ b/arch/mips/include/asm/fixmap.h
+@@ -17,7 +17,7 @@
+ #include <spaces.h>
+ #ifdef CONFIG_HIGHMEM
+ #include <linux/threads.h>
+-#include <asm/kmap_types.h>
++#include <asm/kmap_size.h>
+ #endif
+ 
+ /*
+@@ -52,7 +52,7 @@ enum fixed_addresses {
+ #ifdef CONFIG_HIGHMEM
+ 	/* reserved pte's for temporary kernel mappings */
+ 	FIX_KMAP_BEGIN = FIX_CMAP_END + 1,
+-	FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
++	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1,
+ #endif
+ 	__end_of_fixed_addresses
+ };
+diff --git a/arch/mips/include/asm/highmem.h b/arch/mips/include/asm/highmem.h
+index 9f021cf51aa7..1716181ea66d 100644
+--- a/arch/mips/include/asm/highmem.h
++++ b/arch/mips/include/asm/highmem.h
+@@ -24,7 +24,7 @@
+ #include <linux/interrupt.h>
+ #include <linux/uaccess.h>
+ #include <asm/cpu-features.h>
+-#include <asm/kmap_types.h>
++#include <asm/kmap_size.h>
+ 
+ /* declarations for highmem.c */
+ extern unsigned long highstart_pfn, highend_pfn;
+@@ -48,11 +48,11 @@ extern pte_t *pkmap_page_table;
+ 
+ #define ARCH_HAS_KMAP_FLUSH_TLB
+ extern void kmap_flush_tlb(unsigned long addr);
+-extern void *kmap_atomic_pfn(unsigned long pfn);
+ 
+ #define flush_cache_kmaps()	BUG_ON(cpu_has_dc_aliases)
+ 
+-extern void kmap_init(void);
++#define arch_kmap_local_post_map(vaddr, pteval)	local_flush_tlb_one(vaddr)
++#define arch_kmap_local_post_unmap(vaddr)	local_flush_tlb_one(vaddr)
+ 
+ #endif /* __KERNEL__ */
+ 
+diff --git a/arch/mips/include/asm/kmap_types.h b/arch/mips/include/asm/kmap_types.h
+deleted file mode 100644
+index 16665dc2431b..000000000000
+--- a/arch/mips/include/asm/kmap_types.h
++++ /dev/null
+@@ -1,13 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-#ifndef _ASM_KMAP_TYPES_H
+-#define _ASM_KMAP_TYPES_H
+-
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-#define	 __WITH_KM_FENCE
+-#endif
+-
+-#include <asm-generic/kmap_types.h>
+-
+-#undef __WITH_KM_FENCE
+-
+-#endif
+diff --git a/arch/mips/mm/highmem.c b/arch/mips/mm/highmem.c
+index 5fec7f45d79a..57e2f08f00d0 100644
+--- a/arch/mips/mm/highmem.c
++++ b/arch/mips/mm/highmem.c
+@@ -8,8 +8,6 @@
+ #include <asm/fixmap.h>
+ #include <asm/tlbflush.h>
+ 
+-static pte_t *kmap_pte;
+-
+ unsigned long highstart_pfn, highend_pfn;
+ 
+ void kmap_flush_tlb(unsigned long addr)
+@@ -17,78 +15,3 @@ void kmap_flush_tlb(unsigned long addr)
+ 	flush_tlb_one(addr);
+ }
+ EXPORT_SYMBOL(kmap_flush_tlb);
+-
+-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
+-{
+-	unsigned long vaddr;
+-	int idx, type;
+-
+-	type = kmap_atomic_idx_push();
+-	idx = type + KM_TYPE_NR*smp_processor_id();
+-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	BUG_ON(!pte_none(*(kmap_pte - idx)));
+-#endif
+-	set_pte(kmap_pte-idx, mk_pte(page, prot));
+-	local_flush_tlb_one((unsigned long)vaddr);
+-
+-	return (void*) vaddr;
+-}
+-EXPORT_SYMBOL(kmap_atomic_high_prot);
+-
+-void kunmap_atomic_high(void *kvaddr)
+-{
+-	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+-	int type __maybe_unused;
+-
+-	if (vaddr < FIXADDR_START)
+-		return;
+-
+-	type = kmap_atomic_idx();
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	{
+-		int idx = type + KM_TYPE_NR * smp_processor_id();
+-
+-		BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
+-
+-		/*
+-		 * force other mappings to Oops if they'll try to access
+-		 * this pte without first remap it
+-		 */
+-		pte_clear(&init_mm, vaddr, kmap_pte-idx);
+-		local_flush_tlb_one(vaddr);
+-	}
+-#endif
+-	kmap_atomic_idx_pop();
+-}
+-EXPORT_SYMBOL(kunmap_atomic_high);
+-
+-/*
+- * This is the same as kmap_atomic() but can map memory that doesn't
+- * have a struct page associated with it.
+- */
+-void *kmap_atomic_pfn(unsigned long pfn)
+-{
+-	unsigned long vaddr;
+-	int idx, type;
+-
+-	preempt_disable();
+-	pagefault_disable();
+-
+-	type = kmap_atomic_idx_push();
+-	idx = type + KM_TYPE_NR*smp_processor_id();
+-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+-	set_pte(kmap_pte-idx, pfn_pte(pfn, PAGE_KERNEL));
+-	flush_tlb_one(vaddr);
+-
+-	return (void*) vaddr;
+-}
+-
+-void __init kmap_init(void)
+-{
+-	unsigned long kmap_vstart;
+-
+-	/* cache the first kmap pte */
+-	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
+-	kmap_pte = virt_to_kpte(kmap_vstart);
+-}
+diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
+index 07e84a774938..bc80893e5c0f 100644
+--- a/arch/mips/mm/init.c
++++ b/arch/mips/mm/init.c
+@@ -36,7 +36,6 @@
+ #include <asm/cachectl.h>
+ #include <asm/cpu.h>
+ #include <asm/dma.h>
+-#include <asm/kmap_types.h>
+ #include <asm/maar.h>
+ #include <asm/mmu_context.h>
+ #include <asm/sections.h>
+@@ -402,9 +401,6 @@ void __init paging_init(void)
+ 
+ 	pagetable_init();
+ 
+-#ifdef CONFIG_HIGHMEM
+-	kmap_init();
+-#endif
+ #ifdef CONFIG_ZONE_DMA
+ 	max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
+ #endif
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0037-nds32-mm-highmem-Switch-to-generic-kmap-atomic.patch b/debian/patches-rt/0037-nds32-mm-highmem-Switch-to-generic-kmap-atomic.patch
new file mode 100644
index 000000000..08d1dc198
--- /dev/null
+++ b/debian/patches-rt/0037-nds32-mm-highmem-Switch-to-generic-kmap-atomic.patch
@@ -0,0 +1,167 @@
+From bc36ab505c69bbf7d37b57cb983ca97b198c44df Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:26 +0100
+Subject: [PATCH 037/323] nds32/mm/highmem: Switch to generic kmap atomic
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The mapping code is odd and looks broken. See FIXME in the comment.
+
+Also fix the harmless off by one in the FIX_KMAP_END define.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Nick Hu <nickhu@andestech.com>
+Cc: Greentime Hu <green.hu@gmail.com>
+Cc: Vincent Chen <deanbo422@gmail.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/nds32/Kconfig.cpu           |  1 +
+ arch/nds32/include/asm/fixmap.h  |  4 +--
+ arch/nds32/include/asm/highmem.h | 22 +++++++++++----
+ arch/nds32/mm/Makefile           |  1 -
+ arch/nds32/mm/highmem.c          | 48 --------------------------------
+ 5 files changed, 19 insertions(+), 57 deletions(-)
+ delete mode 100644 arch/nds32/mm/highmem.c
+
+diff --git a/arch/nds32/Kconfig.cpu b/arch/nds32/Kconfig.cpu
+index f88a12fdf0f3..c10759952485 100644
+--- a/arch/nds32/Kconfig.cpu
++++ b/arch/nds32/Kconfig.cpu
+@@ -157,6 +157,7 @@ config HW_SUPPORT_UNALIGNMENT_ACCESS
+ config HIGHMEM
+ 	bool "High Memory Support"
+ 	depends on MMU && !CPU_CACHE_ALIASING
++	select KMAP_LOCAL
+ 	help
+ 	  The address space of Andes processors is only 4 Gigabytes large
+ 	  and it has to accommodate user address space, kernel address
+diff --git a/arch/nds32/include/asm/fixmap.h b/arch/nds32/include/asm/fixmap.h
+index 5a4bf11e5800..2fa09a2de428 100644
+--- a/arch/nds32/include/asm/fixmap.h
++++ b/arch/nds32/include/asm/fixmap.h
+@@ -6,7 +6,7 @@
+ 
+ #ifdef CONFIG_HIGHMEM
+ #include <linux/threads.h>
+-#include <asm/kmap_types.h>
++#include <asm/kmap_size.h>
+ #endif
+ 
+ enum fixed_addresses {
+@@ -14,7 +14,7 @@ enum fixed_addresses {
+ 	FIX_KMAP_RESERVED,
+ 	FIX_KMAP_BEGIN,
+ #ifdef CONFIG_HIGHMEM
+-	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_TYPE_NR * NR_CPUS),
++	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1,
+ #endif
+ 	FIX_EARLYCON_MEM_BASE,
+ 	__end_of_fixed_addresses
+diff --git a/arch/nds32/include/asm/highmem.h b/arch/nds32/include/asm/highmem.h
+index fe986d0e6e3f..16159a8716f2 100644
+--- a/arch/nds32/include/asm/highmem.h
++++ b/arch/nds32/include/asm/highmem.h
+@@ -5,7 +5,6 @@
+ #define _ASM_HIGHMEM_H
+ 
+ #include <asm/proc-fns.h>
+-#include <asm/kmap_types.h>
+ #include <asm/fixmap.h>
+ 
+ /*
+@@ -45,11 +44,22 @@ extern pte_t *pkmap_page_table;
+ extern void kmap_init(void);
+ 
+ /*
+- * The following functions are already defined by <linux/highmem.h>
+- * when CONFIG_HIGHMEM is not set.
++ * FIXME: The below looks broken vs. a kmap_atomic() in task context which
++ * is interupted and another kmap_atomic() happens in interrupt context.
++ * But what do I know about nds32. -- tglx
+  */
+-#ifdef CONFIG_HIGHMEM
+-extern void *kmap_atomic_pfn(unsigned long pfn);
+-#endif
++#define arch_kmap_local_post_map(vaddr, pteval)			\
++	do {							\
++		__nds32__tlbop_inv(vaddr);			\
++		__nds32__mtsr_dsb(vaddr, NDS32_SR_TLB_VPN);	\
++		__nds32__tlbop_rwr(pteval);			\
++		__nds32__isb();					\
++	} while (0)
++
++#define arch_kmap_local_pre_unmap(vaddr)			\
++	do {							\
++		__nds32__tlbop_inv(vaddr);			\
++		__nds32__isb();					\
++	} while (0)
+ 
+ #endif
+diff --git a/arch/nds32/mm/Makefile b/arch/nds32/mm/Makefile
+index 897ecaf5cf54..14fb2e8eb036 100644
+--- a/arch/nds32/mm/Makefile
++++ b/arch/nds32/mm/Makefile
+@@ -3,7 +3,6 @@ obj-y				:= extable.o tlb.o fault.o init.o mmap.o \
+                                    mm-nds32.o cacheflush.o proc.o
+ 
+ obj-$(CONFIG_ALIGNMENT_TRAP)	+= alignment.o
+-obj-$(CONFIG_HIGHMEM)           += highmem.o
+ 
+ ifdef CONFIG_FUNCTION_TRACER
+ CFLAGS_REMOVE_proc.o     = $(CC_FLAGS_FTRACE)
+diff --git a/arch/nds32/mm/highmem.c b/arch/nds32/mm/highmem.c
+deleted file mode 100644
+index 4284cd59e21a..000000000000
+--- a/arch/nds32/mm/highmem.c
++++ /dev/null
+@@ -1,48 +0,0 @@
+-// SPDX-License-Identifier: GPL-2.0
+-// Copyright (C) 2005-2017 Andes Technology Corporation
+-
+-#include <linux/export.h>
+-#include <linux/highmem.h>
+-#include <linux/sched.h>
+-#include <linux/smp.h>
+-#include <linux/interrupt.h>
+-#include <linux/memblock.h>
+-#include <asm/fixmap.h>
+-#include <asm/tlbflush.h>
+-
+-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
+-{
+-	unsigned int idx;
+-	unsigned long vaddr, pte;
+-	int type;
+-	pte_t *ptep;
+-
+-	type = kmap_atomic_idx_push();
+-
+-	idx = type + KM_TYPE_NR * smp_processor_id();
+-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+-	pte = (page_to_pfn(page) << PAGE_SHIFT) | prot;
+-	ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
+-	set_pte(ptep, pte);
+-
+-	__nds32__tlbop_inv(vaddr);
+-	__nds32__mtsr_dsb(vaddr, NDS32_SR_TLB_VPN);
+-	__nds32__tlbop_rwr(pte);
+-	__nds32__isb();
+-	return (void *)vaddr;
+-}
+-EXPORT_SYMBOL(kmap_atomic_high_prot);
+-
+-void kunmap_atomic_high(void *kvaddr)
+-{
+-	if (kvaddr >= (void *)FIXADDR_START) {
+-		unsigned long vaddr = (unsigned long)kvaddr;
+-		pte_t *ptep;
+-		kmap_atomic_idx_pop();
+-		__nds32__tlbop_inv(vaddr);
+-		__nds32__isb();
+-		ptep = pte_offset_kernel(pmd_off_k(vaddr), vaddr);
+-		set_pte(ptep, 0);
+-	}
+-}
+-EXPORT_SYMBOL(kunmap_atomic_high);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0038-powerpc-mm-highmem-Switch-to-generic-kmap-atomic.patch b/debian/patches-rt/0038-powerpc-mm-highmem-Switch-to-generic-kmap-atomic.patch
new file mode 100644
index 000000000..92e962c1f
--- /dev/null
+++ b/debian/patches-rt/0038-powerpc-mm-highmem-Switch-to-generic-kmap-atomic.patch
@@ -0,0 +1,221 @@
+From 6d7d749a6b27ada63e8be5d1903d336538b40702 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:27 +0100
+Subject: [PATCH 038/323] powerpc/mm/highmem: Switch to generic kmap atomic
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+No reason having the same code in every architecture
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Michael Ellerman <mpe@ellerman.id.au>
+Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
+Cc: Paul Mackerras <paulus@samba.org>
+Cc: linuxppc-dev@lists.ozlabs.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/powerpc/Kconfig                  |  1 +
+ arch/powerpc/include/asm/fixmap.h     |  4 +-
+ arch/powerpc/include/asm/highmem.h    |  7 ++-
+ arch/powerpc/include/asm/kmap_types.h | 13 ------
+ arch/powerpc/mm/Makefile              |  1 -
+ arch/powerpc/mm/highmem.c             | 67 ---------------------------
+ arch/powerpc/mm/mem.c                 |  7 ---
+ 7 files changed, 8 insertions(+), 92 deletions(-)
+ delete mode 100644 arch/powerpc/include/asm/kmap_types.h
+ delete mode 100644 arch/powerpc/mm/highmem.c
+
+diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
+index 78dd6be8b31d..b3ab6c2d9f66 100644
+--- a/arch/powerpc/Kconfig
++++ b/arch/powerpc/Kconfig
+@@ -410,6 +410,7 @@ menu "Kernel options"
+ config HIGHMEM
+ 	bool "High memory support"
+ 	depends on PPC32
++	select KMAP_LOCAL
+ 
+ source "kernel/Kconfig.hz"
+ 
+diff --git a/arch/powerpc/include/asm/fixmap.h b/arch/powerpc/include/asm/fixmap.h
+index 897cc68758d4..a832aeafe560 100644
+--- a/arch/powerpc/include/asm/fixmap.h
++++ b/arch/powerpc/include/asm/fixmap.h
+@@ -20,7 +20,7 @@
+ #include <asm/page.h>
+ #ifdef CONFIG_HIGHMEM
+ #include <linux/threads.h>
+-#include <asm/kmap_types.h>
++#include <asm/kmap_size.h>
+ #endif
+ 
+ #ifdef CONFIG_PPC64
+@@ -61,7 +61,7 @@ enum fixed_addresses {
+ 	FIX_EARLY_DEBUG_BASE = FIX_EARLY_DEBUG_TOP+(ALIGN(SZ_128K, PAGE_SIZE)/PAGE_SIZE)-1,
+ #ifdef CONFIG_HIGHMEM
+ 	FIX_KMAP_BEGIN,	/* reserved pte's for temporary kernel mappings */
+-	FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
++	FIX_KMAP_END = FIX_KMAP_BEGIN + (KM_MAX_IDX * NR_CPUS) - 1,
+ #endif
+ #ifdef CONFIG_PPC_8xx
+ 	/* For IMMR we need an aligned 512K area */
+diff --git a/arch/powerpc/include/asm/highmem.h b/arch/powerpc/include/asm/highmem.h
+index 104026f7d6bc..80a5ae771c65 100644
+--- a/arch/powerpc/include/asm/highmem.h
++++ b/arch/powerpc/include/asm/highmem.h
+@@ -24,12 +24,10 @@
+ #ifdef __KERNEL__
+ 
+ #include <linux/interrupt.h>
+-#include <asm/kmap_types.h>
+ #include <asm/cacheflush.h>
+ #include <asm/page.h>
+ #include <asm/fixmap.h>
+ 
+-extern pte_t *kmap_pte;
+ extern pte_t *pkmap_page_table;
+ 
+ /*
+@@ -60,6 +58,11 @@ extern pte_t *pkmap_page_table;
+ 
+ #define flush_cache_kmaps()	flush_cache_all()
+ 
++#define arch_kmap_local_post_map(vaddr, pteval)	\
++	local_flush_tlb_page(NULL, vaddr)
++#define arch_kmap_local_post_unmap(vaddr)	\
++	local_flush_tlb_page(NULL, vaddr)
++
+ #endif /* __KERNEL__ */
+ 
+ #endif /* _ASM_HIGHMEM_H */
+diff --git a/arch/powerpc/include/asm/kmap_types.h b/arch/powerpc/include/asm/kmap_types.h
+deleted file mode 100644
+index c8fa182d48c8..000000000000
+--- a/arch/powerpc/include/asm/kmap_types.h
++++ /dev/null
+@@ -1,13 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0-or-later */
+-#ifndef _ASM_POWERPC_KMAP_TYPES_H
+-#define _ASM_POWERPC_KMAP_TYPES_H
+-
+-#ifdef __KERNEL__
+-
+-/*
+- */
+-
+-#define KM_TYPE_NR 16
+-
+-#endif	/* __KERNEL__ */
+-#endif	/* _ASM_POWERPC_KMAP_TYPES_H */
+diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
+index 55b4a8bd408a..3b4e9e4e25ea 100644
+--- a/arch/powerpc/mm/Makefile
++++ b/arch/powerpc/mm/Makefile
+@@ -16,7 +16,6 @@ obj-$(CONFIG_NEED_MULTIPLE_NODES) += numa.o
+ obj-$(CONFIG_PPC_MM_SLICES)	+= slice.o
+ obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
+ obj-$(CONFIG_NOT_COHERENT_CACHE) += dma-noncoherent.o
+-obj-$(CONFIG_HIGHMEM)		+= highmem.o
+ obj-$(CONFIG_PPC_COPRO_BASE)	+= copro_fault.o
+ obj-$(CONFIG_PPC_PTDUMP)	+= ptdump/
+ obj-$(CONFIG_KASAN)		+= kasan/
+diff --git a/arch/powerpc/mm/highmem.c b/arch/powerpc/mm/highmem.c
+deleted file mode 100644
+index 624b4438aff9..000000000000
+--- a/arch/powerpc/mm/highmem.c
++++ /dev/null
+@@ -1,67 +0,0 @@
+-// SPDX-License-Identifier: GPL-2.0
+-/*
+- * highmem.c: virtual kernel memory mappings for high memory
+- *
+- * PowerPC version, stolen from the i386 version.
+- *
+- * Used in CONFIG_HIGHMEM systems for memory pages which
+- * are not addressable by direct kernel virtual addresses.
+- *
+- * Copyright (C) 1999 Gerhard Wichert, Siemens AG
+- *		      Gerhard.Wichert@pdb.siemens.de
+- *
+- *
+- * Redesigned the x86 32-bit VM architecture to deal with
+- * up to 16 Terrabyte physical memory. With current x86 CPUs
+- * we now support up to 64 Gigabytes physical RAM.
+- *
+- * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
+- *
+- * Reworked for PowerPC by various contributors. Moved from
+- * highmem.h by Benjamin Herrenschmidt (c) 2009 IBM Corp.
+- */
+-
+-#include <linux/highmem.h>
+-#include <linux/module.h>
+-
+-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
+-{
+-	unsigned long vaddr;
+-	int idx, type;
+-
+-	type = kmap_atomic_idx_push();
+-	idx = type + KM_TYPE_NR*smp_processor_id();
+-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+-	WARN_ON(IS_ENABLED(CONFIG_DEBUG_HIGHMEM) && !pte_none(*(kmap_pte - idx)));
+-	__set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot), 1);
+-	local_flush_tlb_page(NULL, vaddr);
+-
+-	return (void*) vaddr;
+-}
+-EXPORT_SYMBOL(kmap_atomic_high_prot);
+-
+-void kunmap_atomic_high(void *kvaddr)
+-{
+-	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+-
+-	if (vaddr < __fix_to_virt(FIX_KMAP_END))
+-		return;
+-
+-	if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM)) {
+-		int type = kmap_atomic_idx();
+-		unsigned int idx;
+-
+-		idx = type + KM_TYPE_NR * smp_processor_id();
+-		WARN_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
+-
+-		/*
+-		 * force other mappings to Oops if they'll try to access
+-		 * this pte without first remap it
+-		 */
+-		pte_clear(&init_mm, vaddr, kmap_pte-idx);
+-		local_flush_tlb_page(NULL, vaddr);
+-	}
+-
+-	kmap_atomic_idx_pop();
+-}
+-EXPORT_SYMBOL(kunmap_atomic_high);
+diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
+index 08e3422eb792..1faa0789871d 100644
+--- a/arch/powerpc/mm/mem.c
++++ b/arch/powerpc/mm/mem.c
+@@ -63,11 +63,6 @@
+ unsigned long long memory_limit;
+ bool init_mem_is_free;
+ 
+-#ifdef CONFIG_HIGHMEM
+-pte_t *kmap_pte;
+-EXPORT_SYMBOL(kmap_pte);
+-#endif
+-
+ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
+ 			      unsigned long size, pgprot_t vma_prot)
+ {
+@@ -237,8 +232,6 @@ void __init paging_init(void)
+ 
+ 	map_kernel_page(PKMAP_BASE, 0, __pgprot(0));	/* XXX gross */
+ 	pkmap_page_table = virt_to_kpte(PKMAP_BASE);
+-
+-	kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
+ #endif /* CONFIG_HIGHMEM */
+ 
+ 	printk(KERN_DEBUG "Top of RAM: 0x%llx, Total RAM: 0x%llx\n",
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0039-sparc-mm-highmem-Switch-to-generic-kmap-atomic.patch b/debian/patches-rt/0039-sparc-mm-highmem-Switch-to-generic-kmap-atomic.patch
new file mode 100644
index 000000000..5ac60d218
--- /dev/null
+++ b/debian/patches-rt/0039-sparc-mm-highmem-Switch-to-generic-kmap-atomic.patch
@@ -0,0 +1,254 @@
+From 859a29e0206dcd137ea0db376a846246f1071bfb Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:28 +0100
+Subject: [PATCH 039/323] sparc/mm/highmem: Switch to generic kmap atomic
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+No reason having the same code in every architecture
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: "David S. Miller" <davem@davemloft.net>
+Cc: sparclinux@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/sparc/Kconfig                  |   1 +
+ arch/sparc/include/asm/highmem.h    |   8 +-
+ arch/sparc/include/asm/kmap_types.h |  11 ---
+ arch/sparc/include/asm/vaddrs.h     |   4 +-
+ arch/sparc/mm/Makefile              |   3 -
+ arch/sparc/mm/highmem.c             | 115 ----------------------------
+ arch/sparc/mm/srmmu.c               |   2 -
+ 7 files changed, 8 insertions(+), 136 deletions(-)
+ delete mode 100644 arch/sparc/include/asm/kmap_types.h
+ delete mode 100644 arch/sparc/mm/highmem.c
+
+diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
+index 7e2ce4c8d657..1a6e4b187861 100644
+--- a/arch/sparc/Kconfig
++++ b/arch/sparc/Kconfig
+@@ -140,6 +140,7 @@ config MMU
+ config HIGHMEM
+ 	bool
+ 	default y if SPARC32
++	select KMAP_LOCAL
+ 
+ config ZONE_DMA
+ 	bool
+diff --git a/arch/sparc/include/asm/highmem.h b/arch/sparc/include/asm/highmem.h
+index 6c35f0d27ee1..875116209ec1 100644
+--- a/arch/sparc/include/asm/highmem.h
++++ b/arch/sparc/include/asm/highmem.h
+@@ -24,7 +24,6 @@
+ #include <linux/interrupt.h>
+ #include <linux/pgtable.h>
+ #include <asm/vaddrs.h>
+-#include <asm/kmap_types.h>
+ #include <asm/pgtsrmmu.h>
+ 
+ /* declarations for highmem.c */
+@@ -33,8 +32,6 @@ extern unsigned long highstart_pfn, highend_pfn;
+ #define kmap_prot __pgprot(SRMMU_ET_PTE | SRMMU_PRIV | SRMMU_CACHE)
+ extern pte_t *pkmap_page_table;
+ 
+-void kmap_init(void) __init;
+-
+ /*
+  * Right now we initialize only a single pte table. It can be extended
+  * easily, subsequent pte tables have to be allocated in one physical
+@@ -53,6 +50,11 @@ void kmap_init(void) __init;
+ 
+ #define flush_cache_kmaps()	flush_cache_all()
+ 
++/* FIXME: Use __flush_tlb_one(vaddr) instead of flush_cache_all() -- Anton */
++#define arch_kmap_local_post_map(vaddr, pteval)	flush_cache_all()
++#define arch_kmap_local_post_unmap(vaddr)	flush_cache_all()
++
++
+ #endif /* __KERNEL__ */
+ 
+ #endif /* _ASM_HIGHMEM_H */
+diff --git a/arch/sparc/include/asm/kmap_types.h b/arch/sparc/include/asm/kmap_types.h
+deleted file mode 100644
+index 55a99b6bd91e..000000000000
+--- a/arch/sparc/include/asm/kmap_types.h
++++ /dev/null
+@@ -1,11 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-#ifndef _ASM_KMAP_TYPES_H
+-#define _ASM_KMAP_TYPES_H
+-
+-/* Dummy header just to define km_type.  None of this
+- * is actually used on sparc.  -DaveM
+- */
+-
+-#include <asm-generic/kmap_types.h>
+-
+-#endif
+diff --git a/arch/sparc/include/asm/vaddrs.h b/arch/sparc/include/asm/vaddrs.h
+index 84d054b07a6f..4fec0341e2a8 100644
+--- a/arch/sparc/include/asm/vaddrs.h
++++ b/arch/sparc/include/asm/vaddrs.h
+@@ -32,13 +32,13 @@
+ #define SRMMU_NOCACHE_ALCRATIO	64	/* 256 pages per 64MB of system RAM */
+ 
+ #ifndef __ASSEMBLY__
+-#include <asm/kmap_types.h>
++#include <asm/kmap_size.h>
+ 
+ enum fixed_addresses {
+ 	FIX_HOLE,
+ #ifdef CONFIG_HIGHMEM
+ 	FIX_KMAP_BEGIN,
+-	FIX_KMAP_END = (KM_TYPE_NR * NR_CPUS),
++	FIX_KMAP_END = (KM_MAX_IDX * NR_CPUS),
+ #endif
+ 	__end_of_fixed_addresses
+ };
+diff --git a/arch/sparc/mm/Makefile b/arch/sparc/mm/Makefile
+index b078205b70e0..68db1f859b02 100644
+--- a/arch/sparc/mm/Makefile
++++ b/arch/sparc/mm/Makefile
+@@ -15,6 +15,3 @@ obj-$(CONFIG_SPARC32)   += leon_mm.o
+ 
+ # Only used by sparc64
+ obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
+-
+-# Only used by sparc32
+-obj-$(CONFIG_HIGHMEM)   += highmem.o
+diff --git a/arch/sparc/mm/highmem.c b/arch/sparc/mm/highmem.c
+deleted file mode 100644
+index 8f2a2afb048a..000000000000
+--- a/arch/sparc/mm/highmem.c
++++ /dev/null
+@@ -1,115 +0,0 @@
+-// SPDX-License-Identifier: GPL-2.0
+-/*
+- *  highmem.c: virtual kernel memory mappings for high memory
+- *
+- *  Provides kernel-static versions of atomic kmap functions originally
+- *  found as inlines in include/asm-sparc/highmem.h.  These became
+- *  needed as kmap_atomic() and kunmap_atomic() started getting
+- *  called from within modules.
+- *  -- Tomas Szepe <szepe@pinerecords.com>, September 2002
+- *
+- *  But kmap_atomic() and kunmap_atomic() cannot be inlined in
+- *  modules because they are loaded with btfixup-ped functions.
+- */
+-
+-/*
+- * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
+- * gives a more generic (and caching) interface. But kmap_atomic can
+- * be used in IRQ contexts, so in some (very limited) cases we need it.
+- *
+- * XXX This is an old text. Actually, it's good to use atomic kmaps,
+- * provided you remember that they are atomic and not try to sleep
+- * with a kmap taken, much like a spinlock. Non-atomic kmaps are
+- * shared by CPUs, and so precious, and establishing them requires IPI.
+- * Atomic kmaps are lightweight and we may have NCPUS more of them.
+- */
+-#include <linux/highmem.h>
+-#include <linux/export.h>
+-#include <linux/mm.h>
+-
+-#include <asm/cacheflush.h>
+-#include <asm/tlbflush.h>
+-#include <asm/vaddrs.h>
+-
+-static pte_t *kmap_pte;
+-
+-void __init kmap_init(void)
+-{
+-	unsigned long address = __fix_to_virt(FIX_KMAP_BEGIN);
+-
+-        /* cache the first kmap pte */
+-        kmap_pte = virt_to_kpte(address);
+-}
+-
+-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
+-{
+-	unsigned long vaddr;
+-	long idx, type;
+-
+-	type = kmap_atomic_idx_push();
+-	idx = type + KM_TYPE_NR*smp_processor_id();
+-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+-
+-/* XXX Fix - Anton */
+-#if 0
+-	__flush_cache_one(vaddr);
+-#else
+-	flush_cache_all();
+-#endif
+-
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	BUG_ON(!pte_none(*(kmap_pte-idx)));
+-#endif
+-	set_pte(kmap_pte-idx, mk_pte(page, prot));
+-/* XXX Fix - Anton */
+-#if 0
+-	__flush_tlb_one(vaddr);
+-#else
+-	flush_tlb_all();
+-#endif
+-
+-	return (void*) vaddr;
+-}
+-EXPORT_SYMBOL(kmap_atomic_high_prot);
+-
+-void kunmap_atomic_high(void *kvaddr)
+-{
+-	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
+-	int type;
+-
+-	if (vaddr < FIXADDR_START)
+-		return;
+-
+-	type = kmap_atomic_idx();
+-
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	{
+-		unsigned long idx;
+-
+-		idx = type + KM_TYPE_NR * smp_processor_id();
+-		BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx));
+-
+-		/* XXX Fix - Anton */
+-#if 0
+-		__flush_cache_one(vaddr);
+-#else
+-		flush_cache_all();
+-#endif
+-
+-		/*
+-		 * force other mappings to Oops if they'll try to access
+-		 * this pte without first remap it
+-		 */
+-		pte_clear(&init_mm, vaddr, kmap_pte-idx);
+-		/* XXX Fix - Anton */
+-#if 0
+-		__flush_tlb_one(vaddr);
+-#else
+-		flush_tlb_all();
+-#endif
+-	}
+-#endif
+-
+-	kmap_atomic_idx_pop();
+-}
+-EXPORT_SYMBOL(kunmap_atomic_high);
+diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c
+index 0070f8b9a753..a03caa5f6628 100644
+--- a/arch/sparc/mm/srmmu.c
++++ b/arch/sparc/mm/srmmu.c
+@@ -971,8 +971,6 @@ void __init srmmu_paging_init(void)
+ 
+ 	sparc_context_init(num_contexts);
+ 
+-	kmap_init();
+-
+ 	{
+ 		unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0040-xtensa-mm-highmem-Switch-to-generic-kmap-atomic.patch b/debian/patches-rt/0040-xtensa-mm-highmem-Switch-to-generic-kmap-atomic.patch
new file mode 100644
index 000000000..c17ef447f
--- /dev/null
+++ b/debian/patches-rt/0040-xtensa-mm-highmem-Switch-to-generic-kmap-atomic.patch
@@ -0,0 +1,166 @@
+From 716b526a73eff1c6b44a898c5e66ee2569f7280d Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:29 +0100
+Subject: [PATCH 040/323] xtensa/mm/highmem: Switch to generic kmap atomic
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+No reason having the same code in every architecture
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Chris Zankel <chris@zankel.net>
+Cc: Max Filippov <jcmvbkbc@gmail.com>
+Cc: linux-xtensa@linux-xtensa.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/xtensa/Kconfig               |  1 +
+ arch/xtensa/include/asm/fixmap.h  |  4 +--
+ arch/xtensa/include/asm/highmem.h | 12 ++++++--
+ arch/xtensa/mm/highmem.c          | 46 ++++---------------------------
+ 4 files changed, 18 insertions(+), 45 deletions(-)
+
+diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
+index 87e08ad38ea7..03cbf6b53622 100644
+--- a/arch/xtensa/Kconfig
++++ b/arch/xtensa/Kconfig
+@@ -666,6 +666,7 @@ endchoice
+ config HIGHMEM
+ 	bool "High Memory Support"
+ 	depends on MMU
++	select KMAP_LOCAL
+ 	help
+ 	  Linux can use the full amount of RAM in the system by
+ 	  default. However, the default MMUv2 setup only maps the
+diff --git a/arch/xtensa/include/asm/fixmap.h b/arch/xtensa/include/asm/fixmap.h
+index a06ffb0c61c7..92049b61c351 100644
+--- a/arch/xtensa/include/asm/fixmap.h
++++ b/arch/xtensa/include/asm/fixmap.h
+@@ -16,7 +16,7 @@
+ #ifdef CONFIG_HIGHMEM
+ #include <linux/threads.h>
+ #include <linux/pgtable.h>
+-#include <asm/kmap_types.h>
++#include <asm/kmap_size.h>
+ #endif
+ 
+ /*
+@@ -39,7 +39,7 @@ enum fixed_addresses {
+ 	/* reserved pte's for temporary kernel mappings */
+ 	FIX_KMAP_BEGIN,
+ 	FIX_KMAP_END = FIX_KMAP_BEGIN +
+-		(KM_TYPE_NR * NR_CPUS * DCACHE_N_COLORS) - 1,
++		(KM_MAX_IDX * NR_CPUS * DCACHE_N_COLORS) - 1,
+ #endif
+ 	__end_of_fixed_addresses
+ };
+diff --git a/arch/xtensa/include/asm/highmem.h b/arch/xtensa/include/asm/highmem.h
+index eac503215f17..0fc3b1cebc56 100644
+--- a/arch/xtensa/include/asm/highmem.h
++++ b/arch/xtensa/include/asm/highmem.h
+@@ -16,9 +16,8 @@
+ #include <linux/pgtable.h>
+ #include <asm/cacheflush.h>
+ #include <asm/fixmap.h>
+-#include <asm/kmap_types.h>
+ 
+-#define PKMAP_BASE		((FIXADDR_START - \
++#define PKMAP_BASE		((FIXADDR_START -			\
+ 				  (LAST_PKMAP + 1) * PAGE_SIZE) & PMD_MASK)
+ #define LAST_PKMAP		(PTRS_PER_PTE * DCACHE_N_COLORS)
+ #define LAST_PKMAP_MASK		(LAST_PKMAP - 1)
+@@ -68,6 +67,15 @@ static inline void flush_cache_kmaps(void)
+ 	flush_cache_all();
+ }
+ 
++enum fixed_addresses kmap_local_map_idx(int type, unsigned long pfn);
++#define arch_kmap_local_map_idx		kmap_local_map_idx
++
++enum fixed_addresses kmap_local_unmap_idx(int type, unsigned long addr);
++#define arch_kmap_local_unmap_idx	kmap_local_unmap_idx
++
++#define arch_kmap_local_post_unmap(vaddr)	\
++	local_flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE)
++
+ void kmap_init(void);
+ 
+ #endif
+diff --git a/arch/xtensa/mm/highmem.c b/arch/xtensa/mm/highmem.c
+index 673196fe862e..0735ca5e8f86 100644
+--- a/arch/xtensa/mm/highmem.c
++++ b/arch/xtensa/mm/highmem.c
+@@ -12,8 +12,6 @@
+ #include <linux/highmem.h>
+ #include <asm/tlbflush.h>
+ 
+-static pte_t *kmap_pte;
+-
+ #if DCACHE_WAY_SIZE > PAGE_SIZE
+ unsigned int last_pkmap_nr_arr[DCACHE_N_COLORS];
+ wait_queue_head_t pkmap_map_wait_arr[DCACHE_N_COLORS];
+@@ -33,59 +31,25 @@ static inline void kmap_waitqueues_init(void)
+ 
+ static inline enum fixed_addresses kmap_idx(int type, unsigned long color)
+ {
+-	return (type + KM_TYPE_NR * smp_processor_id()) * DCACHE_N_COLORS +
++	return (type + KM_MAX_IDX * smp_processor_id()) * DCACHE_N_COLORS +
+ 		color;
+ }
+ 
+-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
++enum fixed_addresses kmap_local_map_idx(int type, unsigned long pfn)
+ {
+-	enum fixed_addresses idx;
+-	unsigned long vaddr;
+-
+-	idx = kmap_idx(kmap_atomic_idx_push(),
+-		       DCACHE_ALIAS(page_to_phys(page)));
+-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	BUG_ON(!pte_none(*(kmap_pte + idx)));
+-#endif
+-	set_pte(kmap_pte + idx, mk_pte(page, prot));
+-
+-	return (void *)vaddr;
++	return kmap_idx(type, DCACHE_ALIAS(pfn << PAGE_SHIFT));
+ }
+-EXPORT_SYMBOL(kmap_atomic_high_prot);
+ 
+-void kunmap_atomic_high(void *kvaddr)
++enum fixed_addresses kmap_local_unmap_idx(int type, unsigned long addr)
+ {
+-	if (kvaddr >= (void *)FIXADDR_START &&
+-	    kvaddr < (void *)FIXADDR_TOP) {
+-		int idx = kmap_idx(kmap_atomic_idx(),
+-				   DCACHE_ALIAS((unsigned long)kvaddr));
+-
+-		/*
+-		 * Force other mappings to Oops if they'll try to access this
+-		 * pte without first remap it.  Keeping stale mappings around
+-		 * is a bad idea also, in case the page changes cacheability
+-		 * attributes or becomes a protected page in a hypervisor.
+-		 */
+-		pte_clear(&init_mm, kvaddr, kmap_pte + idx);
+-		local_flush_tlb_kernel_range((unsigned long)kvaddr,
+-					     (unsigned long)kvaddr + PAGE_SIZE);
+-
+-		kmap_atomic_idx_pop();
+-	}
++	return kmap_idx(type, DCACHE_ALIAS(addr));
+ }
+-EXPORT_SYMBOL(kunmap_atomic_high);
+ 
+ void __init kmap_init(void)
+ {
+-	unsigned long kmap_vstart;
+-
+ 	/* Check if this memory layout is broken because PKMAP overlaps
+ 	 * page table.
+ 	 */
+ 	BUILD_BUG_ON(PKMAP_BASE < TLBTEMP_BASE_1 + TLBTEMP_SIZE);
+-	/* cache the first kmap pte */
+-	kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
+-	kmap_pte = virt_to_kpte(kmap_vstart);
+ 	kmap_waitqueues_init();
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0041-highmem-Get-rid-of-kmap_types.h.patch b/debian/patches-rt/0041-highmem-Get-rid-of-kmap_types.h.patch
new file mode 100644
index 000000000..d492fb27f
--- /dev/null
+++ b/debian/patches-rt/0041-highmem-Get-rid-of-kmap_types.h.patch
@@ -0,0 +1,189 @@
+From 78d1ee2f2f990b4876ce2e64c637a660911a903d Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:30 +0100
+Subject: [PATCH 041/323] highmem: Get rid of kmap_types.h
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The header is not longer used and on alpha, ia64, openrisc, parisc and um
+it was completely unused anyway as these architectures have no highmem
+support.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/alpha/include/asm/kmap_types.h  | 15 ---------------
+ arch/ia64/include/asm/kmap_types.h   | 13 -------------
+ arch/openrisc/mm/init.c              |  1 -
+ arch/openrisc/mm/ioremap.c           |  1 -
+ arch/parisc/include/asm/kmap_types.h | 13 -------------
+ arch/um/include/asm/fixmap.h         |  1 -
+ arch/um/include/asm/kmap_types.h     | 13 -------------
+ include/asm-generic/Kbuild           |  1 -
+ include/asm-generic/kmap_types.h     | 11 -----------
+ include/linux/highmem.h              |  2 --
+ 10 files changed, 71 deletions(-)
+ delete mode 100644 arch/alpha/include/asm/kmap_types.h
+ delete mode 100644 arch/ia64/include/asm/kmap_types.h
+ delete mode 100644 arch/parisc/include/asm/kmap_types.h
+ delete mode 100644 arch/um/include/asm/kmap_types.h
+ delete mode 100644 include/asm-generic/kmap_types.h
+
+diff --git a/arch/alpha/include/asm/kmap_types.h b/arch/alpha/include/asm/kmap_types.h
+deleted file mode 100644
+index 651714b45729..000000000000
+--- a/arch/alpha/include/asm/kmap_types.h
++++ /dev/null
+@@ -1,15 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-#ifndef _ASM_KMAP_TYPES_H
+-#define _ASM_KMAP_TYPES_H
+-
+-/* Dummy header just to define km_type. */
+-
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-#define  __WITH_KM_FENCE
+-#endif
+-
+-#include <asm-generic/kmap_types.h>
+-
+-#undef __WITH_KM_FENCE
+-
+-#endif
+diff --git a/arch/ia64/include/asm/kmap_types.h b/arch/ia64/include/asm/kmap_types.h
+deleted file mode 100644
+index 5c268cf7c2bd..000000000000
+--- a/arch/ia64/include/asm/kmap_types.h
++++ /dev/null
+@@ -1,13 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-#ifndef _ASM_IA64_KMAP_TYPES_H
+-#define _ASM_IA64_KMAP_TYPES_H
+-
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-#define  __WITH_KM_FENCE
+-#endif
+-
+-#include <asm-generic/kmap_types.h>
+-
+-#undef __WITH_KM_FENCE
+-
+-#endif /* _ASM_IA64_KMAP_TYPES_H */
+diff --git a/arch/openrisc/mm/init.c b/arch/openrisc/mm/init.c
+index 5e88c351e6a4..f3fa02b8838a 100644
+--- a/arch/openrisc/mm/init.c
++++ b/arch/openrisc/mm/init.c
+@@ -33,7 +33,6 @@
+ #include <asm/io.h>
+ #include <asm/tlb.h>
+ #include <asm/mmu_context.h>
+-#include <asm/kmap_types.h>
+ #include <asm/fixmap.h>
+ #include <asm/tlbflush.h>
+ #include <asm/sections.h>
+diff --git a/arch/openrisc/mm/ioremap.c b/arch/openrisc/mm/ioremap.c
+index a978590d802d..5aed97a18bac 100644
+--- a/arch/openrisc/mm/ioremap.c
++++ b/arch/openrisc/mm/ioremap.c
+@@ -15,7 +15,6 @@
+ #include <linux/io.h>
+ #include <linux/pgtable.h>
+ #include <asm/pgalloc.h>
+-#include <asm/kmap_types.h>
+ #include <asm/fixmap.h>
+ #include <asm/bug.h>
+ #include <linux/sched.h>
+diff --git a/arch/parisc/include/asm/kmap_types.h b/arch/parisc/include/asm/kmap_types.h
+deleted file mode 100644
+index 3e70b5cd1123..000000000000
+--- a/arch/parisc/include/asm/kmap_types.h
++++ /dev/null
+@@ -1,13 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-#ifndef _ASM_KMAP_TYPES_H
+-#define _ASM_KMAP_TYPES_H
+-
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-#define  __WITH_KM_FENCE
+-#endif
+-
+-#include <asm-generic/kmap_types.h>
+-
+-#undef __WITH_KM_FENCE
+-
+-#endif
+diff --git a/arch/um/include/asm/fixmap.h b/arch/um/include/asm/fixmap.h
+index 2c697a145ac1..2efac5827188 100644
+--- a/arch/um/include/asm/fixmap.h
++++ b/arch/um/include/asm/fixmap.h
+@@ -3,7 +3,6 @@
+ #define __UM_FIXMAP_H
+ 
+ #include <asm/processor.h>
+-#include <asm/kmap_types.h>
+ #include <asm/archparam.h>
+ #include <asm/page.h>
+ #include <linux/threads.h>
+diff --git a/arch/um/include/asm/kmap_types.h b/arch/um/include/asm/kmap_types.h
+deleted file mode 100644
+index b0bd12de1d23..000000000000
+--- a/arch/um/include/asm/kmap_types.h
++++ /dev/null
+@@ -1,13 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-/* 
+- * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+- */
+-
+-#ifndef __UM_KMAP_TYPES_H
+-#define __UM_KMAP_TYPES_H
+-
+-/* No more #include "asm/arch/kmap_types.h" ! */
+-
+-#define KM_TYPE_NR 14
+-
+-#endif
+diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild
+index 3114a6da7e56..267f6dfb8960 100644
+--- a/include/asm-generic/Kbuild
++++ b/include/asm-generic/Kbuild
+@@ -30,7 +30,6 @@ mandatory-y += irq.h
+ mandatory-y += irq_regs.h
+ mandatory-y += irq_work.h
+ mandatory-y += kdebug.h
+-mandatory-y += kmap_types.h
+ mandatory-y += kmap_size.h
+ mandatory-y += kprobes.h
+ mandatory-y += linkage.h
+diff --git a/include/asm-generic/kmap_types.h b/include/asm-generic/kmap_types.h
+deleted file mode 100644
+index 9f95b7b63d19..000000000000
+--- a/include/asm-generic/kmap_types.h
++++ /dev/null
+@@ -1,11 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-#ifndef _ASM_GENERIC_KMAP_TYPES_H
+-#define _ASM_GENERIC_KMAP_TYPES_H
+-
+-#ifdef __WITH_KM_FENCE
+-# define KM_TYPE_NR 41
+-#else
+-# define KM_TYPE_NR 20
+-#endif
+-
+-#endif
+diff --git a/include/linux/highmem.h b/include/linux/highmem.h
+index fbede783dc34..a5ce45dceae0 100644
+--- a/include/linux/highmem.h
++++ b/include/linux/highmem.h
+@@ -29,8 +29,6 @@ static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
+ }
+ #endif
+ 
+-#include <asm/kmap_types.h>
+-
+ /*
+  * Outside of CONFIG_HIGHMEM to support X86 32bit iomap_atomic() cruft.
+  */
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0042-mm-highmem-Remove-the-old-kmap_atomic-cruft.patch b/debian/patches-rt/0042-mm-highmem-Remove-the-old-kmap_atomic-cruft.patch
new file mode 100644
index 000000000..112ed0a87
--- /dev/null
+++ b/debian/patches-rt/0042-mm-highmem-Remove-the-old-kmap_atomic-cruft.patch
@@ -0,0 +1,139 @@
+From 2840eec439f3e1788047259d10994b555020de40 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:31 +0100
+Subject: [PATCH 042/323] mm/highmem: Remove the old kmap_atomic cruft
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+All users gone.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/highmem.h | 63 +++--------------------------------------
+ mm/highmem.c            |  7 +----
+ 2 files changed, 5 insertions(+), 65 deletions(-)
+
+diff --git a/include/linux/highmem.h b/include/linux/highmem.h
+index a5ce45dceae0..e632774cce87 100644
+--- a/include/linux/highmem.h
++++ b/include/linux/highmem.h
+@@ -86,31 +86,16 @@ static inline void kunmap(struct page *page)
+  * be used in IRQ contexts, so in some (very limited) cases we need
+  * it.
+  */
+-
+-#ifndef CONFIG_KMAP_LOCAL
+-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot);
+-void kunmap_atomic_high(void *kvaddr);
+-
+ static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
+ {
+ 	preempt_disable();
+ 	pagefault_disable();
+-	if (!PageHighMem(page))
+-		return page_address(page);
+-	return kmap_atomic_high_prot(page, prot);
+-}
+-
+-static inline void __kunmap_atomic(void *vaddr)
+-{
+-	kunmap_atomic_high(vaddr);
++	return __kmap_local_page_prot(page, prot);
+ }
+-#else /* !CONFIG_KMAP_LOCAL */
+ 
+-static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
++static inline void *kmap_atomic(struct page *page)
+ {
+-	preempt_disable();
+-	pagefault_disable();
+-	return __kmap_local_page_prot(page, prot);
++	return kmap_atomic_prot(page, kmap_prot);
+ }
+ 
+ static inline void *kmap_atomic_pfn(unsigned long pfn)
+@@ -125,13 +110,6 @@ static inline void __kunmap_atomic(void *addr)
+ 	kunmap_local_indexed(addr);
+ }
+ 
+-#endif /* CONFIG_KMAP_LOCAL */
+-
+-static inline void *kmap_atomic(struct page *page)
+-{
+-	return kmap_atomic_prot(page, kmap_prot);
+-}
+-
+ /* declarations for linux/mm/highmem.c */
+ unsigned int nr_free_highpages(void);
+ extern atomic_long_t _totalhigh_pages;
+@@ -212,41 +190,8 @@ static inline void __kunmap_atomic(void *addr)
+ 
+ #define kmap_flush_unused()	do {} while(0)
+ 
+-#endif /* CONFIG_HIGHMEM */
+-
+-#if !defined(CONFIG_KMAP_LOCAL)
+-#if defined(CONFIG_HIGHMEM)
+-
+-DECLARE_PER_CPU(int, __kmap_atomic_idx);
+-
+-static inline int kmap_atomic_idx_push(void)
+-{
+-	int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
+-
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	WARN_ON_ONCE(in_irq() && !irqs_disabled());
+-	BUG_ON(idx >= KM_TYPE_NR);
+-#endif
+-	return idx;
+-}
+-
+-static inline int kmap_atomic_idx(void)
+-{
+-	return __this_cpu_read(__kmap_atomic_idx) - 1;
+-}
+ 
+-static inline void kmap_atomic_idx_pop(void)
+-{
+-#ifdef CONFIG_DEBUG_HIGHMEM
+-	int idx = __this_cpu_dec_return(__kmap_atomic_idx);
+-
+-	BUG_ON(idx < 0);
+-#else
+-	__this_cpu_dec(__kmap_atomic_idx);
+-#endif
+-}
+-#endif
+-#endif
++#endif /* CONFIG_HIGHMEM */
+ 
+ /*
+  * Prevent people trying to call kunmap_atomic() as if it were kunmap()
+diff --git a/mm/highmem.c b/mm/highmem.c
+index 77677c6844f7..499dfafd36b7 100644
+--- a/mm/highmem.c
++++ b/mm/highmem.c
+@@ -31,12 +31,6 @@
+ #include <asm/tlbflush.h>
+ #include <linux/vmalloc.h>
+ 
+-#ifndef CONFIG_KMAP_LOCAL
+-#ifdef CONFIG_HIGHMEM
+-DEFINE_PER_CPU(int, __kmap_atomic_idx);
+-#endif
+-#endif
+-
+ /*
+  * Virtual_count is not a pure "count".
+  *  0 means that it is not mapped, and has not been mapped
+@@ -410,6 +404,7 @@ static inline void kmap_local_idx_pop(void)
+ #ifndef arch_kmap_local_post_map
+ # define arch_kmap_local_post_map(vaddr, pteval)	do { } while (0)
+ #endif
++
+ #ifndef arch_kmap_local_pre_unmap
+ # define arch_kmap_local_pre_unmap(vaddr)		do { } while (0)
+ #endif
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0043-io-mapping-Cleanup-atomic-iomap.patch b/debian/patches-rt/0043-io-mapping-Cleanup-atomic-iomap.patch
new file mode 100644
index 000000000..08ec0b108
--- /dev/null
+++ b/debian/patches-rt/0043-io-mapping-Cleanup-atomic-iomap.patch
@@ -0,0 +1,90 @@
+From d1b454a9410a5cb2d9dcd0ef4bc330d04847f302 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:32 +0100
+Subject: [PATCH 043/323] io-mapping: Cleanup atomic iomap
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Switch the atomic iomap implementation over to kmap_local and stick the
+preempt/pagefault mechanics into the generic code similar to the
+kmap_atomic variants.
+
+Rename the x86 map function in preparation for a non-atomic variant.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/x86/include/asm/iomap.h | 9 +--------
+ arch/x86/mm/iomap_32.c       | 6 ++----
+ include/linux/io-mapping.h   | 8 ++++++--
+ 3 files changed, 9 insertions(+), 14 deletions(-)
+
+diff --git a/arch/x86/include/asm/iomap.h b/arch/x86/include/asm/iomap.h
+index 0be7a30fd6bc..e2de092fc38c 100644
+--- a/arch/x86/include/asm/iomap.h
++++ b/arch/x86/include/asm/iomap.h
+@@ -13,14 +13,7 @@
+ #include <asm/cacheflush.h>
+ #include <asm/tlbflush.h>
+ 
+-void __iomem *iomap_atomic_pfn_prot(unsigned long pfn, pgprot_t prot);
+-
+-static inline void iounmap_atomic(void __iomem *vaddr)
+-{
+-	kunmap_local_indexed((void __force *)vaddr);
+-	pagefault_enable();
+-	preempt_enable();
+-}
++void __iomem *__iomap_local_pfn_prot(unsigned long pfn, pgprot_t prot);
+ 
+ int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot);
+ 
+diff --git a/arch/x86/mm/iomap_32.c b/arch/x86/mm/iomap_32.c
+index e0a40d7cc66c..9aaa756ddf21 100644
+--- a/arch/x86/mm/iomap_32.c
++++ b/arch/x86/mm/iomap_32.c
+@@ -44,7 +44,7 @@ void iomap_free(resource_size_t base, unsigned long size)
+ }
+ EXPORT_SYMBOL_GPL(iomap_free);
+ 
+-void __iomem *iomap_atomic_pfn_prot(unsigned long pfn, pgprot_t prot)
++void __iomem *__iomap_local_pfn_prot(unsigned long pfn, pgprot_t prot)
+ {
+ 	/*
+ 	 * For non-PAT systems, translate non-WB request to UC- just in
+@@ -60,8 +60,6 @@ void __iomem *iomap_atomic_pfn_prot(unsigned long pfn, pgprot_t prot)
+ 	/* Filter out unsupported __PAGE_KERNEL* bits: */
+ 	pgprot_val(prot) &= __default_kernel_pte_mask;
+ 
+-	preempt_disable();
+-	pagefault_disable();
+ 	return (void __force __iomem *)__kmap_local_pfn_prot(pfn, prot);
+ }
+-EXPORT_SYMBOL_GPL(iomap_atomic_pfn_prot);
++EXPORT_SYMBOL_GPL(__iomap_local_pfn_prot);
+diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h
+index 3b0940be72e9..60e7c83e4904 100644
+--- a/include/linux/io-mapping.h
++++ b/include/linux/io-mapping.h
+@@ -69,13 +69,17 @@ io_mapping_map_atomic_wc(struct io_mapping *mapping,
+ 
+ 	BUG_ON(offset >= mapping->size);
+ 	phys_addr = mapping->base + offset;
+-	return iomap_atomic_pfn_prot(PHYS_PFN(phys_addr), mapping->prot);
++	preempt_disable();
++	pagefault_disable();
++	return __iomap_local_pfn_prot(PHYS_PFN(phys_addr), mapping->prot);
+ }
+ 
+ static inline void
+ io_mapping_unmap_atomic(void __iomem *vaddr)
+ {
+-	iounmap_atomic(vaddr);
++	kunmap_local_indexed((void __force *)vaddr);
++	pagefault_enable();
++	preempt_enable();
+ }
+ 
+ static inline void __iomem *
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0044-Documentation-io-mapping-Remove-outdated-blurb.patch b/debian/patches-rt/0044-Documentation-io-mapping-Remove-outdated-blurb.patch
new file mode 100644
index 000000000..4ea660fff
--- /dev/null
+++ b/debian/patches-rt/0044-Documentation-io-mapping-Remove-outdated-blurb.patch
@@ -0,0 +1,48 @@
+From edd5c644d78fbd912f6386c97ed2b4eaf2b58b47 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:33 +0100
+Subject: [PATCH 044/323] Documentation/io-mapping: Remove outdated blurb
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The implementation details in the documentation are outdated and not really
+helpful. Remove them.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ Documentation/driver-api/io-mapping.rst | 22 ----------------------
+ 1 file changed, 22 deletions(-)
+
+diff --git a/Documentation/driver-api/io-mapping.rst b/Documentation/driver-api/io-mapping.rst
+index a966239f04e4..e33b88268554 100644
+--- a/Documentation/driver-api/io-mapping.rst
++++ b/Documentation/driver-api/io-mapping.rst
+@@ -73,25 +73,3 @@ for pages mapped with io_mapping_map_wc.
+ At driver close time, the io_mapping object must be freed::
+ 
+ 	void io_mapping_free(struct io_mapping *mapping)
+-
+-Current Implementation
+-======================
+-
+-The initial implementation of these functions uses existing mapping
+-mechanisms and so provides only an abstraction layer and no new
+-functionality.
+-
+-On 64-bit processors, io_mapping_create_wc calls ioremap_wc for the whole
+-range, creating a permanent kernel-visible mapping to the resource. The
+-map_atomic and map functions add the requested offset to the base of the
+-virtual address returned by ioremap_wc.
+-
+-On 32-bit processors with HIGHMEM defined, io_mapping_map_atomic_wc uses
+-kmap_atomic_pfn to map the specified page in an atomic fashion;
+-kmap_atomic_pfn isn't really supposed to be used with device pages, but it
+-provides an efficient mapping for this usage.
+-
+-On 32-bit processors without HIGHMEM defined, io_mapping_map_atomic_wc and
+-io_mapping_map_wc both use ioremap_wc, a terribly inefficient function which
+-performs an IPI to inform all processors about the new mapping. This results
+-in a significant performance penalty.
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0045-highmem-High-implementation-details-and-document-API.patch b/debian/patches-rt/0045-highmem-High-implementation-details-and-document-API.patch
new file mode 100644
index 000000000..723dd45e7
--- /dev/null
+++ b/debian/patches-rt/0045-highmem-High-implementation-details-and-document-API.patch
@@ -0,0 +1,544 @@
+From e9f16e3d48ba9b1d37ae050de3e84e147133b84c Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:34 +0100
+Subject: [PATCH 045/323] highmem: High implementation details and document API
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Move the gory details of kmap & al into a private header and only document
+the interfaces which are usable by drivers.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/highmem-internal.h | 174 ++++++++++++++++++++
+ include/linux/highmem.h          | 266 +++++++++++--------------------
+ mm/highmem.c                     |  11 +-
+ 3 files changed, 274 insertions(+), 177 deletions(-)
+ create mode 100644 include/linux/highmem-internal.h
+
+diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h
+new file mode 100644
+index 000000000000..6ceed907b14e
+--- /dev/null
++++ b/include/linux/highmem-internal.h
+@@ -0,0 +1,174 @@
++/* SPDX-License-Identifier: GPL-2.0 */
++#ifndef _LINUX_HIGHMEM_INTERNAL_H
++#define _LINUX_HIGHMEM_INTERNAL_H
++
++/*
++ * Outside of CONFIG_HIGHMEM to support X86 32bit iomap_atomic() cruft.
++ */
++#ifdef CONFIG_KMAP_LOCAL
++void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot);
++void *__kmap_local_page_prot(struct page *page, pgprot_t prot);
++void kunmap_local_indexed(void *vaddr);
++#endif
++
++#ifdef CONFIG_HIGHMEM
++#include <asm/highmem.h>
++
++#ifndef ARCH_HAS_KMAP_FLUSH_TLB
++static inline void kmap_flush_tlb(unsigned long addr) { }
++#endif
++
++#ifndef kmap_prot
++#define kmap_prot PAGE_KERNEL
++#endif
++
++void *kmap_high(struct page *page);
++void kunmap_high(struct page *page);
++void __kmap_flush_unused(void);
++struct page *__kmap_to_page(void *addr);
++
++static inline void *kmap(struct page *page)
++{
++	void *addr;
++
++	might_sleep();
++	if (!PageHighMem(page))
++		addr = page_address(page);
++	else
++		addr = kmap_high(page);
++	kmap_flush_tlb((unsigned long)addr);
++	return addr;
++}
++
++static inline void kunmap(struct page *page)
++{
++	might_sleep();
++	if (!PageHighMem(page))
++		return;
++	kunmap_high(page);
++}
++
++static inline struct page *kmap_to_page(void *addr)
++{
++	return __kmap_to_page(addr);
++}
++
++static inline void kmap_flush_unused(void)
++{
++	__kmap_flush_unused();
++}
++
++static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
++{
++	preempt_disable();
++	pagefault_disable();
++	return __kmap_local_page_prot(page, prot);
++}
++
++static inline void *kmap_atomic(struct page *page)
++{
++	return kmap_atomic_prot(page, kmap_prot);
++}
++
++static inline void *kmap_atomic_pfn(unsigned long pfn)
++{
++	preempt_disable();
++	pagefault_disable();
++	return __kmap_local_pfn_prot(pfn, kmap_prot);
++}
++
++static inline void __kunmap_atomic(void *addr)
++{
++	kunmap_local_indexed(addr);
++	pagefault_enable();
++	preempt_enable();
++}
++
++unsigned int __nr_free_highpages(void);
++extern atomic_long_t _totalhigh_pages;
++
++static inline unsigned int nr_free_highpages(void)
++{
++	return __nr_free_highpages();
++}
++
++static inline unsigned long totalhigh_pages(void)
++{
++	return (unsigned long)atomic_long_read(&_totalhigh_pages);
++}
++
++static inline void totalhigh_pages_inc(void)
++{
++	atomic_long_inc(&_totalhigh_pages);
++}
++
++static inline void totalhigh_pages_add(long count)
++{
++	atomic_long_add(count, &_totalhigh_pages);
++}
++
++#else /* CONFIG_HIGHMEM */
++
++static inline struct page *kmap_to_page(void *addr)
++{
++	return virt_to_page(addr);
++}
++
++static inline void *kmap(struct page *page)
++{
++	might_sleep();
++	return page_address(page);
++}
++
++static inline void kunmap_high(struct page *page) { }
++static inline void kmap_flush_unused(void) { }
++
++static inline void kunmap(struct page *page)
++{
++#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
++	kunmap_flush_on_unmap(page_address(page));
++#endif
++}
++
++static inline void *kmap_atomic(struct page *page)
++{
++	preempt_disable();
++	pagefault_disable();
++	return page_address(page);
++}
++
++static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
++{
++	return kmap_atomic(page);
++}
++
++static inline void *kmap_atomic_pfn(unsigned long pfn)
++{
++	return kmap_atomic(pfn_to_page(pfn));
++}
++
++static inline void __kunmap_atomic(void *addr)
++{
++#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
++	kunmap_flush_on_unmap(addr);
++#endif
++	pagefault_enable();
++	preempt_enable();
++}
++
++static inline unsigned int nr_free_highpages(void) { return 0; }
++static inline unsigned long totalhigh_pages(void) { return 0UL; }
++
++#endif /* CONFIG_HIGHMEM */
++
++/*
++ * Prevent people trying to call kunmap_atomic() as if it were kunmap()
++ * kunmap_atomic() should get the return value of kmap_atomic, not the page.
++ */
++#define kunmap_atomic(__addr)					\
++do {								\
++	BUILD_BUG_ON(__same_type((__addr), struct page *));	\
++	__kunmap_atomic(__addr);				\
++} while (0)
++
++#endif
+diff --git a/include/linux/highmem.h b/include/linux/highmem.h
+index e632774cce87..5c888525b4c5 100644
+--- a/include/linux/highmem.h
++++ b/include/linux/highmem.h
+@@ -11,199 +11,125 @@
+ 
+ #include <asm/cacheflush.h>
+ 
+-#ifndef ARCH_HAS_FLUSH_ANON_PAGE
+-static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
+-{
+-}
+-#endif
+-
+-#ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
+-static inline void flush_kernel_dcache_page(struct page *page)
+-{
+-}
+-static inline void flush_kernel_vmap_range(void *vaddr, int size)
+-{
+-}
+-static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
+-{
+-}
+-#endif
++#include "highmem-internal.h"
+ 
+-/*
+- * Outside of CONFIG_HIGHMEM to support X86 32bit iomap_atomic() cruft.
++/**
++ * kmap - Map a page for long term usage
++ * @page:	Pointer to the page to be mapped
++ *
++ * Returns: The virtual address of the mapping
++ *
++ * Can only be invoked from preemptible task context because on 32bit
++ * systems with CONFIG_HIGHMEM enabled this function might sleep.
++ *
++ * For systems with CONFIG_HIGHMEM=n and for pages in the low memory area
++ * this returns the virtual address of the direct kernel mapping.
++ *
++ * The returned virtual address is globally visible and valid up to the
++ * point where it is unmapped via kunmap(). The pointer can be handed to
++ * other contexts.
++ *
++ * For highmem pages on 32bit systems this can be slow as the mapping space
++ * is limited and protected by a global lock. In case that there is no
++ * mapping slot available the function blocks until a slot is released via
++ * kunmap().
+  */
+-#ifdef CONFIG_KMAP_LOCAL
+-void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot);
+-void *__kmap_local_page_prot(struct page *page, pgprot_t prot);
+-void kunmap_local_indexed(void *vaddr);
+-#endif
+-
+-#ifdef CONFIG_HIGHMEM
+-#include <asm/highmem.h>
++static inline void *kmap(struct page *page);
+ 
+-#ifndef ARCH_HAS_KMAP_FLUSH_TLB
+-static inline void kmap_flush_tlb(unsigned long addr) { }
+-#endif
+-
+-#ifndef kmap_prot
+-#define kmap_prot PAGE_KERNEL
+-#endif
+-
+-void *kmap_high(struct page *page);
+-static inline void *kmap(struct page *page)
+-{
+-	void *addr;
+-
+-	might_sleep();
+-	if (!PageHighMem(page))
+-		addr = page_address(page);
+-	else
+-		addr = kmap_high(page);
+-	kmap_flush_tlb((unsigned long)addr);
+-	return addr;
+-}
++/**
++ * kunmap - Unmap the virtual address mapped by kmap()
++ * @addr:	Virtual address to be unmapped
++ *
++ * Counterpart to kmap(). A NOOP for CONFIG_HIGHMEM=n and for mappings of
++ * pages in the low memory area.
++ */
++static inline void kunmap(struct page *page);
+ 
+-void kunmap_high(struct page *page);
++/**
++ * kmap_to_page - Get the page for a kmap'ed address
++ * @addr:	The address to look up
++ *
++ * Returns: The page which is mapped to @addr.
++ */
++static inline struct page *kmap_to_page(void *addr);
+ 
+-static inline void kunmap(struct page *page)
+-{
+-	might_sleep();
+-	if (!PageHighMem(page))
+-		return;
+-	kunmap_high(page);
+-}
++/**
++ * kmap_flush_unused - Flush all unused kmap mappings in order to
++ *		       remove stray mappings
++ */
++static inline void kmap_flush_unused(void);
+ 
+-/*
+- * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
+- * no global lock is needed and because the kmap code must perform a global TLB
+- * invalidation when the kmap pool wraps.
++/**
++ * kmap_atomic - Atomically map a page for temporary usage
++ * @page:	Pointer to the page to be mapped
++ *
++ * Returns: The virtual address of the mapping
++ *
++ * Side effect: On return pagefaults and preemption are disabled.
++ *
++ * Can be invoked from any context.
+  *
+- * However when holding an atomic kmap it is not legal to sleep, so atomic
+- * kmaps are appropriate for short, tight code paths only.
++ * Requires careful handling when nesting multiple mappings because the map
++ * management is stack based. The unmap has to be in the reverse order of
++ * the map operation:
+  *
+- * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
+- * gives a more generic (and caching) interface. But kmap_atomic can
+- * be used in IRQ contexts, so in some (very limited) cases we need
+- * it.
++ * addr1 = kmap_atomic(page1);
++ * addr2 = kmap_atomic(page2);
++ * ...
++ * kunmap_atomic(addr2);
++ * kunmap_atomic(addr1);
++ *
++ * Unmapping addr1 before addr2 is invalid and causes malfunction.
++ *
++ * Contrary to kmap() mappings the mapping is only valid in the context of
++ * the caller and cannot be handed to other contexts.
++ *
++ * On CONFIG_HIGHMEM=n kernels and for low memory pages this returns the
++ * virtual address of the direct mapping. Only real highmem pages are
++ * temporarily mapped.
++ *
++ * While it is significantly faster than kmap() it comes with restrictions
++ * about the pointer validity and the side effects of disabling page faults
++ * and preemption. Use it only when absolutely necessary, e.g. from non
++ * preemptible contexts.
+  */
+-static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
+-{
+-	preempt_disable();
+-	pagefault_disable();
+-	return __kmap_local_page_prot(page, prot);
+-}
++static inline void *kmap_atomic(struct page *page);
+ 
+-static inline void *kmap_atomic(struct page *page)
+-{
+-	return kmap_atomic_prot(page, kmap_prot);
+-}
+-
+-static inline void *kmap_atomic_pfn(unsigned long pfn)
+-{
+-	preempt_disable();
+-	pagefault_disable();
+-	return __kmap_local_pfn_prot(pfn, kmap_prot);
+-}
+-
+-static inline void __kunmap_atomic(void *addr)
+-{
+-	kunmap_local_indexed(addr);
+-}
+-
+-/* declarations for linux/mm/highmem.c */
+-unsigned int nr_free_highpages(void);
+-extern atomic_long_t _totalhigh_pages;
+-static inline unsigned long totalhigh_pages(void)
+-{
+-	return (unsigned long)atomic_long_read(&_totalhigh_pages);
+-}
+-
+-static inline void totalhigh_pages_inc(void)
+-{
+-	atomic_long_inc(&_totalhigh_pages);
+-}
+-
+-static inline void totalhigh_pages_add(long count)
+-{
+-	atomic_long_add(count, &_totalhigh_pages);
+-}
+-
+-void kmap_flush_unused(void);
+-
+-struct page *kmap_to_page(void *addr);
+-
+-#else /* CONFIG_HIGHMEM */
+-
+-static inline unsigned int nr_free_highpages(void) { return 0; }
+-
+-static inline struct page *kmap_to_page(void *addr)
+-{
+-	return virt_to_page(addr);
+-}
+-
+-static inline unsigned long totalhigh_pages(void) { return 0UL; }
++/**
++ * kunmap_atomic - Unmap the virtual address mapped by kmap_atomic()
++ * @addr:	Virtual address to be unmapped
++ *
++ * Counterpart to kmap_atomic().
++ *
++ * Undoes the side effects of kmap_atomic(), i.e. reenabling pagefaults and
++ * preemption.
++ *
++ * Other than that a NOOP for CONFIG_HIGHMEM=n and for mappings of pages
++ * in the low memory area. For real highmen pages the mapping which was
++ * established with kmap_atomic() is destroyed.
++ */
+ 
+-static inline void *kmap(struct page *page)
+-{
+-	might_sleep();
+-	return page_address(page);
+-}
++/* Highmem related interfaces for management code */
++static inline unsigned int nr_free_highpages(void);
++static inline unsigned long totalhigh_pages(void);
+ 
+-static inline void kunmap_high(struct page *page)
++#ifndef ARCH_HAS_FLUSH_ANON_PAGE
++static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
+ {
+ }
+-
+-static inline void kunmap(struct page *page)
+-{
+-#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
+-	kunmap_flush_on_unmap(page_address(page));
+ #endif
+-}
+ 
+-static inline void *kmap_atomic(struct page *page)
++#ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
++static inline void flush_kernel_dcache_page(struct page *page)
+ {
+-	preempt_disable();
+-	pagefault_disable();
+-	return page_address(page);
+ }
+-
+-static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
++static inline void flush_kernel_vmap_range(void *vaddr, int size)
+ {
+-	return kmap_atomic(page);
+ }
+-
+-static inline void *kmap_atomic_pfn(unsigned long pfn)
++static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
+ {
+-	return kmap_atomic(pfn_to_page(pfn));
+ }
+-
+-static inline void __kunmap_atomic(void *addr)
+-{
+-	/*
+-	 * Mostly nothing to do in the CONFIG_HIGHMEM=n case as kunmap_atomic()
+-	 * handles re-enabling faults and preemption
+-	 */
+-#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
+-	kunmap_flush_on_unmap(addr);
+ #endif
+-}
+-
+-#define kmap_flush_unused()	do {} while(0)
+-
+-
+-#endif /* CONFIG_HIGHMEM */
+-
+-/*
+- * Prevent people trying to call kunmap_atomic() as if it were kunmap()
+- * kunmap_atomic() should get the return value of kmap_atomic, not the page.
+- */
+-#define kunmap_atomic(__addr)					\
+-do {								\
+-	BUILD_BUG_ON(__same_type((__addr), struct page *));	\
+-	__kunmap_atomic(__addr);				\
+-	pagefault_enable();					\
+-	preempt_enable();					\
+-} while (0)
+ 
+ /* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
+ #ifndef clear_user_highpage
+diff --git a/mm/highmem.c b/mm/highmem.c
+index 499dfafd36b7..54bd233846c9 100644
+--- a/mm/highmem.c
++++ b/mm/highmem.c
+@@ -104,7 +104,7 @@ static inline wait_queue_head_t *get_pkmap_wait_queue_head(unsigned int color)
+ atomic_long_t _totalhigh_pages __read_mostly;
+ EXPORT_SYMBOL(_totalhigh_pages);
+ 
+-unsigned int nr_free_highpages (void)
++unsigned int __nr_free_highpages (void)
+ {
+ 	struct zone *zone;
+ 	unsigned int pages = 0;
+@@ -141,7 +141,7 @@ pte_t * pkmap_page_table;
+ 		do { spin_unlock(&kmap_lock); (void)(flags); } while (0)
+ #endif
+ 
+-struct page *kmap_to_page(void *vaddr)
++struct page *__kmap_to_page(void *vaddr)
+ {
+ 	unsigned long addr = (unsigned long)vaddr;
+ 
+@@ -152,7 +152,7 @@ struct page *kmap_to_page(void *vaddr)
+ 
+ 	return virt_to_page(addr);
+ }
+-EXPORT_SYMBOL(kmap_to_page);
++EXPORT_SYMBOL(__kmap_to_page);
+ 
+ static void flush_all_zero_pkmaps(void)
+ {
+@@ -194,10 +194,7 @@ static void flush_all_zero_pkmaps(void)
+ 		flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP));
+ }
+ 
+-/**
+- * kmap_flush_unused - flush all unused kmap mappings in order to remove stray mappings
+- */
+-void kmap_flush_unused(void)
++void __kmap_flush_unused(void)
+ {
+ 	lock_kmap();
+ 	flush_all_zero_pkmaps();
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0046-sched-Make-migrate_disable-enable-independent-of-RT.patch b/debian/patches-rt/0046-sched-Make-migrate_disable-enable-independent-of-RT.patch
new file mode 100644
index 000000000..ed3660a63
--- /dev/null
+++ b/debian/patches-rt/0046-sched-Make-migrate_disable-enable-independent-of-RT.patch
@@ -0,0 +1,293 @@
+From 2a81a49976b336ce93ef823a5db96ce960096478 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:35 +0100
+Subject: [PATCH 046/323] sched: Make migrate_disable/enable() independent of
+ RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Now that the scheduler can deal with migrate disable properly, there is no
+real compelling reason to make it only available for RT.
+
+There are quite some code pathes which needlessly disable preemption in
+order to prevent migration and some constructs like kmap_atomic() enforce
+it implicitly.
+
+Making it available independent of RT allows to provide a preemptible
+variant of kmap_atomic() and makes the code more consistent in general.
+
+FIXME: Rework the comment in preempt.h
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Peter Zijlstra <peterz@infradead.org>
+Cc: Ingo Molnar <mingo@kernel.org>
+Cc: Juri Lelli <juri.lelli@redhat.com>
+Cc: Vincent Guittot <vincent.guittot@linaro.org>
+Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
+Cc: Steven Rostedt <rostedt@goodmis.org>
+Cc: Ben Segall <bsegall@google.com>
+Cc: Mel Gorman <mgorman@suse.de>
+Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/kernel.h  | 21 ++++++++++++-------
+ include/linux/preempt.h | 38 +++-------------------------------
+ include/linux/sched.h   |  2 +-
+ kernel/sched/core.c     | 45 ++++++++++++++++++++++++++++++++---------
+ kernel/sched/sched.h    |  4 ++--
+ lib/smp_processor_id.c  |  2 +-
+ 6 files changed, 56 insertions(+), 56 deletions(-)
+
+diff --git a/include/linux/kernel.h b/include/linux/kernel.h
+index cdd6ed5bbcf2..55d48d5627c7 100644
+--- a/include/linux/kernel.h
++++ b/include/linux/kernel.h
+@@ -207,6 +207,7 @@ extern int _cond_resched(void);
+ extern void ___might_sleep(const char *file, int line, int preempt_offset);
+ extern void __might_sleep(const char *file, int line, int preempt_offset);
+ extern void __cant_sleep(const char *file, int line, int preempt_offset);
++extern void __cant_migrate(const char *file, int line);
+ 
+ /**
+  * might_sleep - annotation for functions that can sleep
+@@ -230,6 +231,18 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset);
+ # define cant_sleep() \
+ 	do { __cant_sleep(__FILE__, __LINE__, 0); } while (0)
+ # define sched_annotate_sleep()	(current->task_state_change = 0)
++
++/**
++ * cant_migrate - annotation for functions that cannot migrate
++ *
++ * Will print a stack trace if executed in code which is migratable
++ */
++# define cant_migrate()							\
++	do {								\
++		if (IS_ENABLED(CONFIG_SMP))				\
++			__cant_migrate(__FILE__, __LINE__);		\
++	} while (0)
++
+ /**
+  * non_block_start - annotate the start of section where sleeping is prohibited
+  *
+@@ -254,6 +267,7 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset);
+ 				   int preempt_offset) { }
+ # define might_sleep() do { might_resched(); } while (0)
+ # define cant_sleep() do { } while (0)
++# define cant_migrate()		do { } while (0)
+ # define sched_annotate_sleep() do { } while (0)
+ # define non_block_start() do { } while (0)
+ # define non_block_end() do { } while (0)
+@@ -261,13 +275,6 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset);
+ 
+ #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
+ 
+-#ifndef CONFIG_PREEMPT_RT
+-# define cant_migrate()		cant_sleep()
+-#else
+-  /* Placeholder for now */
+-# define cant_migrate()		do { } while (0)
+-#endif
+-
+ /**
+  * abs - return absolute value of an argument
+  * @x: the value.  If it is unsigned type, it is converted to signed type first.
+diff --git a/include/linux/preempt.h b/include/linux/preempt.h
+index 8b43922e65df..6df63cbe8bb0 100644
+--- a/include/linux/preempt.h
++++ b/include/linux/preempt.h
+@@ -322,7 +322,7 @@ static inline void preempt_notifier_init(struct preempt_notifier *notifier,
+ 
+ #endif
+ 
+-#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
++#ifdef CONFIG_SMP
+ 
+ /*
+  * Migrate-Disable and why it is undesired.
+@@ -382,43 +382,11 @@ static inline void preempt_notifier_init(struct preempt_notifier *notifier,
+ extern void migrate_disable(void);
+ extern void migrate_enable(void);
+ 
+-#elif defined(CONFIG_PREEMPT_RT)
++#else
+ 
+ static inline void migrate_disable(void) { }
+ static inline void migrate_enable(void) { }
+ 
+-#else /* !CONFIG_PREEMPT_RT */
+-
+-/**
+- * migrate_disable - Prevent migration of the current task
+- *
+- * Maps to preempt_disable() which also disables preemption. Use
+- * migrate_disable() to annotate that the intent is to prevent migration,
+- * but not necessarily preemption.
+- *
+- * Can be invoked nested like preempt_disable() and needs the corresponding
+- * number of migrate_enable() invocations.
+- */
+-static __always_inline void migrate_disable(void)
+-{
+-	preempt_disable();
+-}
+-
+-/**
+- * migrate_enable - Allow migration of the current task
+- *
+- * Counterpart to migrate_disable().
+- *
+- * As migrate_disable() can be invoked nested, only the outermost invocation
+- * reenables migration.
+- *
+- * Currently mapped to preempt_enable().
+- */
+-static __always_inline void migrate_enable(void)
+-{
+-	preempt_enable();
+-}
+-
+-#endif /* CONFIG_SMP && CONFIG_PREEMPT_RT */
++#endif /* CONFIG_SMP */
+ 
+ #endif /* __LINUX_PREEMPT_H */
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index 7ca1f3e740dd..bff48e9f32db 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -727,7 +727,7 @@ struct task_struct {
+ 	const cpumask_t			*cpus_ptr;
+ 	cpumask_t			cpus_mask;
+ 	void				*migration_pending;
+-#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
++#ifdef CONFIG_SMP
+ 	unsigned short			migration_disabled;
+ #endif
+ 	unsigned short			migration_flags;
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index c1e52319669d..8a6135a0b2ee 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1710,8 +1710,6 @@ void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
+ 
+ #ifdef CONFIG_SMP
+ 
+-#ifdef CONFIG_PREEMPT_RT
+-
+ static void
+ __do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask, u32 flags);
+ 
+@@ -1786,8 +1784,6 @@ static inline bool rq_has_pinned_tasks(struct rq *rq)
+ 	return rq->nr_pinned;
+ }
+ 
+-#endif
+-
+ /*
+  * Per-CPU kthreads are allowed to run on !active && online CPUs, see
+  * __set_cpus_allowed_ptr() and select_fallback_rq().
+@@ -2868,7 +2864,7 @@ void sched_set_stop_task(int cpu, struct task_struct *stop)
+ 	}
+ }
+ 
+-#else
++#else /* CONFIG_SMP */
+ 
+ static inline int __set_cpus_allowed_ptr(struct task_struct *p,
+ 					 const struct cpumask *new_mask,
+@@ -2877,10 +2873,6 @@ static inline int __set_cpus_allowed_ptr(struct task_struct *p,
+ 	return set_cpus_allowed_ptr(p, new_mask);
+ }
+ 
+-#endif /* CONFIG_SMP */
+-
+-#if !defined(CONFIG_SMP) || !defined(CONFIG_PREEMPT_RT)
+-
+ static inline void migrate_disable_switch(struct rq *rq, struct task_struct *p) { }
+ 
+ static inline bool rq_has_pinned_tasks(struct rq *rq)
+@@ -2888,7 +2880,7 @@ static inline bool rq_has_pinned_tasks(struct rq *rq)
+ 	return false;
+ }
+ 
+-#endif
++#endif /* !CONFIG_SMP */
+ 
+ static void
+ ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
+@@ -7902,6 +7894,39 @@ void __cant_sleep(const char *file, int line, int preempt_offset)
+ 	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+ }
+ EXPORT_SYMBOL_GPL(__cant_sleep);
++
++#ifdef CONFIG_SMP
++void __cant_migrate(const char *file, int line)
++{
++	static unsigned long prev_jiffy;
++
++	if (irqs_disabled())
++		return;
++
++	if (is_migration_disabled(current))
++		return;
++
++	if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
++		return;
++
++	if (preempt_count() > 0)
++		return;
++
++	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
++		return;
++	prev_jiffy = jiffies;
++
++	pr_err("BUG: assuming non migratable context at %s:%d\n", file, line);
++	pr_err("in_atomic(): %d, irqs_disabled(): %d, migration_disabled() %u pid: %d, name: %s\n",
++	       in_atomic(), irqs_disabled(), is_migration_disabled(current),
++	       current->pid, current->comm);
++
++	debug_show_held_locks(current);
++	dump_stack();
++	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
++}
++EXPORT_SYMBOL_GPL(__cant_migrate);
++#endif
+ #endif
+ 
+ #ifdef CONFIG_MAGIC_SYSRQ
+diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
+index 69ef7cac3d29..c26b1c7009f4 100644
+--- a/kernel/sched/sched.h
++++ b/kernel/sched/sched.h
+@@ -1058,7 +1058,7 @@ struct rq {
+ 	struct cpuidle_state	*idle_state;
+ #endif
+ 
+-#if defined(CONFIG_PREEMPT_RT) && defined(CONFIG_SMP)
++#ifdef CONFIG_SMP
+ 	unsigned int		nr_pinned;
+ #endif
+ 	unsigned int		push_busy;
+@@ -1094,7 +1094,7 @@ static inline int cpu_of(struct rq *rq)
+ 
+ static inline bool is_migration_disabled(struct task_struct *p)
+ {
+-#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
++#ifdef CONFIG_SMP
+ 	return p->migration_disabled;
+ #else
+ 	return false;
+diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
+index dbb96ebf661f..0c0c42b14370 100644
+--- a/lib/smp_processor_id.c
++++ b/lib/smp_processor_id.c
+@@ -26,7 +26,7 @@ unsigned int check_preemption_disabled(const char *what1, const char *what2)
+ 	if (current->nr_cpus_allowed == 1)
+ 		goto out;
+ 
+-#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
++#ifdef CONFIG_SMP
+ 	if (current->migration_disabled)
+ 		goto out;
+ #endif
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0047-sched-highmem-Store-local-kmaps-in-task-struct.patch b/debian/patches-rt/0047-sched-highmem-Store-local-kmaps-in-task-struct.patch
new file mode 100644
index 000000000..ecd08de62
--- /dev/null
+++ b/debian/patches-rt/0047-sched-highmem-Store-local-kmaps-in-task-struct.patch
@@ -0,0 +1,309 @@
+From 7aa261f53a405c0862f4857b46ef3344bbe6385f Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:36 +0100
+Subject: [PATCH 047/323] sched: highmem: Store local kmaps in task struct
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Instead of storing the map per CPU provide and use per task storage. That
+prepares for local kmaps which are preemptible.
+
+The context switch code is preparatory and not yet in use because
+kmap_atomic() runs with preemption disabled. Will be made usable in the
+next step.
+
+The context switch logic is safe even when an interrupt happens after
+clearing or before restoring the kmaps. The kmap index in task struct is
+not modified so any nesting kmap in an interrupt will use unused indices
+and on return the counter is the same as before.
+
+Also add an assert into the return to user space code. Going back to user
+space with an active kmap local is a nono.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/highmem-internal.h | 10 ++++
+ include/linux/sched.h            |  9 +++
+ kernel/entry/common.c            |  2 +
+ kernel/fork.c                    |  1 +
+ kernel/sched/core.c              | 18 ++++++
+ mm/highmem.c                     | 99 ++++++++++++++++++++++++++++----
+ 6 files changed, 129 insertions(+), 10 deletions(-)
+
+diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h
+index 6ceed907b14e..c5a22177db85 100644
+--- a/include/linux/highmem-internal.h
++++ b/include/linux/highmem-internal.h
+@@ -9,6 +9,16 @@
+ void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot);
+ void *__kmap_local_page_prot(struct page *page, pgprot_t prot);
+ void kunmap_local_indexed(void *vaddr);
++void kmap_local_fork(struct task_struct *tsk);
++void __kmap_local_sched_out(void);
++void __kmap_local_sched_in(void);
++static inline void kmap_assert_nomap(void)
++{
++	DEBUG_LOCKS_WARN_ON(current->kmap_ctrl.idx);
++}
++#else
++static inline void kmap_local_fork(struct task_struct *tsk) { }
++static inline void kmap_assert_nomap(void) { }
+ #endif
+ 
+ #ifdef CONFIG_HIGHMEM
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index bff48e9f32db..82de1ab42497 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -34,6 +34,7 @@
+ #include <linux/rseq.h>
+ #include <linux/seqlock.h>
+ #include <linux/kcsan.h>
++#include <asm/kmap_size.h>
+ 
+ /* task_struct member predeclarations (sorted alphabetically): */
+ struct audit_context;
+@@ -641,6 +642,13 @@ struct wake_q_node {
+ 	struct wake_q_node *next;
+ };
+ 
++struct kmap_ctrl {
++#ifdef CONFIG_KMAP_LOCAL
++	int				idx;
++	pte_t				pteval[KM_MAX_IDX];
++#endif
++};
++
+ struct task_struct {
+ #ifdef CONFIG_THREAD_INFO_IN_TASK
+ 	/*
+@@ -1323,6 +1331,7 @@ struct task_struct {
+ 	unsigned int			sequential_io;
+ 	unsigned int			sequential_io_avg;
+ #endif
++	struct kmap_ctrl		kmap_ctrl;
+ #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+ 	unsigned long			task_state_change;
+ #endif
+diff --git a/kernel/entry/common.c b/kernel/entry/common.c
+index 09f58853f692..e6a66de1202a 100644
+--- a/kernel/entry/common.c
++++ b/kernel/entry/common.c
+@@ -2,6 +2,7 @@
+ 
+ #include <linux/context_tracking.h>
+ #include <linux/entry-common.h>
++#include <linux/highmem.h>
+ #include <linux/livepatch.h>
+ #include <linux/audit.h>
+ 
+@@ -202,6 +203,7 @@ static void exit_to_user_mode_prepare(struct pt_regs *regs)
+ 
+ 	/* Ensure that the address limit is intact and no locks are held */
+ 	addr_limit_user_check();
++	kmap_assert_nomap();
+ 	lockdep_assert_irqs_disabled();
+ 	lockdep_sys_exit();
+ }
+diff --git a/kernel/fork.c b/kernel/fork.c
+index 633b0af1d1a7..32b9d7205ac1 100644
+--- a/kernel/fork.c
++++ b/kernel/fork.c
+@@ -942,6 +942,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
+ 	account_kernel_stack(tsk, 1);
+ 
+ 	kcov_task_init(tsk);
++	kmap_local_fork(tsk);
+ 
+ #ifdef CONFIG_FAULT_INJECTION
+ 	tsk->fail_nth = 0;
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 8a6135a0b2ee..390b51366f5e 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -4092,6 +4092,22 @@ static inline void finish_lock_switch(struct rq *rq)
+ # define finish_arch_post_lock_switch()	do { } while (0)
+ #endif
+ 
++static inline void kmap_local_sched_out(void)
++{
++#ifdef CONFIG_KMAP_LOCAL
++	if (unlikely(current->kmap_ctrl.idx))
++		__kmap_local_sched_out();
++#endif
++}
++
++static inline void kmap_local_sched_in(void)
++{
++#ifdef CONFIG_KMAP_LOCAL
++	if (unlikely(current->kmap_ctrl.idx))
++		__kmap_local_sched_in();
++#endif
++}
++
+ /**
+  * prepare_task_switch - prepare to switch tasks
+  * @rq: the runqueue preparing to switch
+@@ -4114,6 +4130,7 @@ prepare_task_switch(struct rq *rq, struct task_struct *prev,
+ 	perf_event_task_sched_out(prev, next);
+ 	rseq_preempt(prev);
+ 	fire_sched_out_preempt_notifiers(prev, next);
++	kmap_local_sched_out();
+ 	prepare_task(next);
+ 	prepare_arch_switch(next);
+ }
+@@ -4180,6 +4197,7 @@ static struct rq *finish_task_switch(struct task_struct *prev)
+ 	finish_lock_switch(rq);
+ 	finish_arch_post_lock_switch();
+ 	kcov_finish_switch(current);
++	kmap_local_sched_in();
+ 
+ 	fire_sched_in_preempt_notifiers(current);
+ 	/*
+diff --git a/mm/highmem.c b/mm/highmem.c
+index 54bd233846c9..d7a1c80001d0 100644
+--- a/mm/highmem.c
++++ b/mm/highmem.c
+@@ -365,8 +365,6 @@ EXPORT_SYMBOL(kunmap_high);
+ 
+ #include <asm/kmap_size.h>
+ 
+-static DEFINE_PER_CPU(int, __kmap_local_idx);
+-
+ /*
+  * With DEBUG_HIGHMEM the stack depth is doubled and every second
+  * slot is unused which acts as a guard page
+@@ -379,23 +377,21 @@ static DEFINE_PER_CPU(int, __kmap_local_idx);
+ 
+ static inline int kmap_local_idx_push(void)
+ {
+-	int idx = __this_cpu_add_return(__kmap_local_idx, KM_INCR) - 1;
+-
+ 	WARN_ON_ONCE(in_irq() && !irqs_disabled());
+-	BUG_ON(idx >= KM_MAX_IDX);
+-	return idx;
++	current->kmap_ctrl.idx += KM_INCR;
++	BUG_ON(current->kmap_ctrl.idx >= KM_MAX_IDX);
++	return current->kmap_ctrl.idx - 1;
+ }
+ 
+ static inline int kmap_local_idx(void)
+ {
+-	return __this_cpu_read(__kmap_local_idx) - 1;
++	return current->kmap_ctrl.idx - 1;
+ }
+ 
+ static inline void kmap_local_idx_pop(void)
+ {
+-	int idx = __this_cpu_sub_return(__kmap_local_idx, KM_INCR);
+-
+-	BUG_ON(idx < 0);
++	current->kmap_ctrl.idx -= KM_INCR;
++	BUG_ON(current->kmap_ctrl.idx < 0);
+ }
+ 
+ #ifndef arch_kmap_local_post_map
+@@ -461,6 +457,7 @@ void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot)
+ 	pteval = pfn_pte(pfn, prot);
+ 	set_pte_at(&init_mm, vaddr, kmap_pte - idx, pteval);
+ 	arch_kmap_local_post_map(vaddr, pteval);
++	current->kmap_ctrl.pteval[kmap_local_idx()] = pteval;
+ 	preempt_enable();
+ 
+ 	return (void *)vaddr;
+@@ -505,10 +502,92 @@ void kunmap_local_indexed(void *vaddr)
+ 	arch_kmap_local_pre_unmap(addr);
+ 	pte_clear(&init_mm, addr, kmap_pte - idx);
+ 	arch_kmap_local_post_unmap(addr);
++	current->kmap_ctrl.pteval[kmap_local_idx()] = __pte(0);
+ 	kmap_local_idx_pop();
+ 	preempt_enable();
+ }
+ EXPORT_SYMBOL(kunmap_local_indexed);
++
++/*
++ * Invoked before switch_to(). This is safe even when during or after
++ * clearing the maps an interrupt which needs a kmap_local happens because
++ * the task::kmap_ctrl.idx is not modified by the unmapping code so a
++ * nested kmap_local will use the next unused index and restore the index
++ * on unmap. The already cleared kmaps of the outgoing task are irrelevant
++ * because the interrupt context does not know about them. The same applies
++ * when scheduling back in for an interrupt which happens before the
++ * restore is complete.
++ */
++void __kmap_local_sched_out(void)
++{
++	struct task_struct *tsk = current;
++	pte_t *kmap_pte = kmap_get_pte();
++	int i;
++
++	/* Clear kmaps */
++	for (i = 0; i < tsk->kmap_ctrl.idx; i++) {
++		pte_t pteval = tsk->kmap_ctrl.pteval[i];
++		unsigned long addr;
++		int idx;
++
++		/* With debug all even slots are unmapped and act as guard */
++		if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM) && !(i & 0x01)) {
++			WARN_ON_ONCE(!pte_none(pteval));
++			continue;
++		}
++		if (WARN_ON_ONCE(pte_none(pteval)))
++			continue;
++
++		/*
++		 * This is a horrible hack for XTENSA to calculate the
++		 * coloured PTE index. Uses the PFN encoded into the pteval
++		 * and the map index calculation because the actual mapped
++		 * virtual address is not stored in task::kmap_ctrl.
++		 * For any sane architecture this is optimized out.
++		 */
++		idx = arch_kmap_local_map_idx(i, pte_pfn(pteval));
++
++		addr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
++		arch_kmap_local_pre_unmap(addr);
++		pte_clear(&init_mm, addr, kmap_pte - idx);
++		arch_kmap_local_post_unmap(addr);
++	}
++}
++
++void __kmap_local_sched_in(void)
++{
++	struct task_struct *tsk = current;
++	pte_t *kmap_pte = kmap_get_pte();
++	int i;
++
++	/* Restore kmaps */
++	for (i = 0; i < tsk->kmap_ctrl.idx; i++) {
++		pte_t pteval = tsk->kmap_ctrl.pteval[i];
++		unsigned long addr;
++		int idx;
++
++		/* With debug all even slots are unmapped and act as guard */
++		if (IS_ENABLED(CONFIG_DEBUG_HIGHMEM) && !(i & 0x01)) {
++			WARN_ON_ONCE(!pte_none(pteval));
++			continue;
++		}
++		if (WARN_ON_ONCE(pte_none(pteval)))
++			continue;
++
++		/* See comment in __kmap_local_sched_out() */
++		idx = arch_kmap_local_map_idx(i, pte_pfn(pteval));
++		addr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
++		set_pte_at(&init_mm, addr, kmap_pte - idx, pteval);
++		arch_kmap_local_post_map(addr, pteval);
++	}
++}
++
++void kmap_local_fork(struct task_struct *tsk)
++{
++	if (WARN_ON_ONCE(tsk->kmap_ctrl.idx))
++		memset(&tsk->kmap_ctrl, 0, sizeof(tsk->kmap_ctrl));
++}
++
+ #endif
+ 
+ #if defined(HASHED_PAGE_VIRTUAL)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0048-mm-highmem-Provide-kmap_local.patch b/debian/patches-rt/0048-mm-highmem-Provide-kmap_local.patch
new file mode 100644
index 000000000..aa15ab4ec
--- /dev/null
+++ b/debian/patches-rt/0048-mm-highmem-Provide-kmap_local.patch
@@ -0,0 +1,207 @@
+From 452c4c8536ea017ed0f82287834e7cfa2f751488 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:37 +0100
+Subject: [PATCH 048/323] mm/highmem: Provide kmap_local*
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Now that the kmap atomic index is stored in task struct provide a
+preemptible variant. On context switch the maps of an outgoing task are
+removed and the map of the incoming task are restored. That's obviously
+slow, but highmem is slow anyway.
+
+The kmap_local.*() functions can be invoked from both preemptible and
+atomic context. kmap local sections disable migration to keep the resulting
+virtual mapping address correct, but disable neither pagefaults nor
+preemption.
+
+A wholesale conversion of kmap_atomic to be fully preemptible is not
+possible because some of the usage sites might rely on the preemption
+disable for serialization or on the implicit pagefault disable. Needs to be
+done on a case by case basis.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/highmem-internal.h | 48 ++++++++++++++++++++++++++++++++
+ include/linux/highmem.h          | 43 +++++++++++++++++-----------
+ mm/highmem.c                     |  6 ++++
+ 3 files changed, 81 insertions(+), 16 deletions(-)
+
+diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h
+index c5a22177db85..1bbe96dc8be6 100644
+--- a/include/linux/highmem-internal.h
++++ b/include/linux/highmem-internal.h
+@@ -68,6 +68,26 @@ static inline void kmap_flush_unused(void)
+ 	__kmap_flush_unused();
+ }
+ 
++static inline void *kmap_local_page(struct page *page)
++{
++	return __kmap_local_page_prot(page, kmap_prot);
++}
++
++static inline void *kmap_local_page_prot(struct page *page, pgprot_t prot)
++{
++	return __kmap_local_page_prot(page, prot);
++}
++
++static inline void *kmap_local_pfn(unsigned long pfn)
++{
++	return __kmap_local_pfn_prot(pfn, kmap_prot);
++}
++
++static inline void __kunmap_local(void *vaddr)
++{
++	kunmap_local_indexed(vaddr);
++}
++
+ static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
+ {
+ 	preempt_disable();
+@@ -140,6 +160,28 @@ static inline void kunmap(struct page *page)
+ #endif
+ }
+ 
++static inline void *kmap_local_page(struct page *page)
++{
++	return page_address(page);
++}
++
++static inline void *kmap_local_page_prot(struct page *page, pgprot_t prot)
++{
++	return kmap_local_page(page);
++}
++
++static inline void *kmap_local_pfn(unsigned long pfn)
++{
++	return kmap_local_page(pfn_to_page(pfn));
++}
++
++static inline void __kunmap_local(void *addr)
++{
++#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
++	kunmap_flush_on_unmap(addr);
++#endif
++}
++
+ static inline void *kmap_atomic(struct page *page)
+ {
+ 	preempt_disable();
+@@ -181,4 +223,10 @@ do {								\
+ 	__kunmap_atomic(__addr);				\
+ } while (0)
+ 
++#define kunmap_local(__addr)					\
++do {								\
++	BUILD_BUG_ON(__same_type((__addr), struct page *));	\
++	__kunmap_local(__addr);					\
++} while (0)
++
+ #endif
+diff --git a/include/linux/highmem.h b/include/linux/highmem.h
+index 5c888525b4c5..7a3c6d4b79d8 100644
+--- a/include/linux/highmem.h
++++ b/include/linux/highmem.h
+@@ -60,24 +60,22 @@ static inline struct page *kmap_to_page(void *addr);
+ static inline void kmap_flush_unused(void);
+ 
+ /**
+- * kmap_atomic - Atomically map a page for temporary usage
++ * kmap_local_page - Map a page for temporary usage
+  * @page:	Pointer to the page to be mapped
+  *
+  * Returns: The virtual address of the mapping
+  *
+- * Side effect: On return pagefaults and preemption are disabled.
+- *
+  * Can be invoked from any context.
+  *
+  * Requires careful handling when nesting multiple mappings because the map
+  * management is stack based. The unmap has to be in the reverse order of
+  * the map operation:
+  *
+- * addr1 = kmap_atomic(page1);
+- * addr2 = kmap_atomic(page2);
++ * addr1 = kmap_local_page(page1);
++ * addr2 = kmap_local_page(page2);
+  * ...
+- * kunmap_atomic(addr2);
+- * kunmap_atomic(addr1);
++ * kunmap_local(addr2);
++ * kunmap_local(addr1);
+  *
+  * Unmapping addr1 before addr2 is invalid and causes malfunction.
+  *
+@@ -88,10 +86,26 @@ static inline void kmap_flush_unused(void);
+  * virtual address of the direct mapping. Only real highmem pages are
+  * temporarily mapped.
+  *
+- * While it is significantly faster than kmap() it comes with restrictions
+- * about the pointer validity and the side effects of disabling page faults
+- * and preemption. Use it only when absolutely necessary, e.g. from non
+- * preemptible contexts.
++ * While it is significantly faster than kmap() for the higmem case it
++ * comes with restrictions about the pointer validity. Only use when really
++ * necessary.
++ *
++ * On HIGHMEM enabled systems mapping a highmem page has the side effect of
++ * disabling migration in order to keep the virtual address stable across
++ * preemption. No caller of kmap_local_page() can rely on this side effect.
++ */
++static inline void *kmap_local_page(struct page *page);
++
++/**
++ * kmap_atomic - Atomically map a page for temporary usage - Deprecated!
++ * @page:	Pointer to the page to be mapped
++ *
++ * Returns: The virtual address of the mapping
++ *
++ * Effectively a wrapper around kmap_local_page() which disables pagefaults
++ * and preemption.
++ *
++ * Do not use in new code. Use kmap_local_page() instead.
+  */
+ static inline void *kmap_atomic(struct page *page);
+ 
+@@ -101,12 +115,9 @@ static inline void *kmap_atomic(struct page *page);
+  *
+  * Counterpart to kmap_atomic().
+  *
+- * Undoes the side effects of kmap_atomic(), i.e. reenabling pagefaults and
++ * Effectively a wrapper around kunmap_local() which additionally undoes
++ * the side effects of kmap_atomic(), i.e. reenabling pagefaults and
+  * preemption.
+- *
+- * Other than that a NOOP for CONFIG_HIGHMEM=n and for mappings of pages
+- * in the low memory area. For real highmen pages the mapping which was
+- * established with kmap_atomic() is destroyed.
+  */
+ 
+ /* Highmem related interfaces for management code */
+diff --git a/mm/highmem.c b/mm/highmem.c
+index d7a1c80001d0..8db577e5290c 100644
+--- a/mm/highmem.c
++++ b/mm/highmem.c
+@@ -450,6 +450,11 @@ void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot)
+ 	unsigned long vaddr;
+ 	int idx;
+ 
++	/*
++	 * Disable migration so resulting virtual address is stable
++	 * accross preemption.
++	 */
++	migrate_disable();
+ 	preempt_disable();
+ 	idx = arch_kmap_local_map_idx(kmap_local_idx_push(), pfn);
+ 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+@@ -505,6 +510,7 @@ void kunmap_local_indexed(void *vaddr)
+ 	current->kmap_ctrl.pteval[kmap_local_idx()] = __pte(0);
+ 	kmap_local_idx_pop();
+ 	preempt_enable();
++	migrate_enable();
+ }
+ EXPORT_SYMBOL(kunmap_local_indexed);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0049-io-mapping-Provide-iomap_local-variant.patch b/debian/patches-rt/0049-io-mapping-Provide-iomap_local-variant.patch
new file mode 100644
index 000000000..1419b16fb
--- /dev/null
+++ b/debian/patches-rt/0049-io-mapping-Provide-iomap_local-variant.patch
@@ -0,0 +1,179 @@
+From 223ef1707ad3b008f96df3f4d263d2cdeed3ef65 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:38 +0100
+Subject: [PATCH 049/323] io-mapping: Provide iomap_local variant
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Similar to kmap local provide a iomap local variant which only disables
+migration, but neither disables pagefaults nor preemption.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ Documentation/driver-api/io-mapping.rst | 74 +++++++++++++++----------
+ include/linux/io-mapping.h              | 30 +++++++++-
+ 2 files changed, 73 insertions(+), 31 deletions(-)
+
+diff --git a/Documentation/driver-api/io-mapping.rst b/Documentation/driver-api/io-mapping.rst
+index e33b88268554..a0cfb15988df 100644
+--- a/Documentation/driver-api/io-mapping.rst
++++ b/Documentation/driver-api/io-mapping.rst
+@@ -20,55 +20,71 @@ A mapping object is created during driver initialization using::
+ mappable, while 'size' indicates how large a mapping region to
+ enable. Both are in bytes.
+ 
+-This _wc variant provides a mapping which may only be used
+-with the io_mapping_map_atomic_wc or io_mapping_map_wc.
++This _wc variant provides a mapping which may only be used with
++io_mapping_map_atomic_wc(), io_mapping_map_local_wc() or
++io_mapping_map_wc().
+ 
+-With this mapping object, individual pages can be mapped either atomically
+-or not, depending on the necessary scheduling environment. Of course, atomic
+-maps are more efficient::
++With this mapping object, individual pages can be mapped either temporarily
++or long term, depending on the requirements. Of course, temporary maps are
++more efficient. They come in two flavours::
++
++	void *io_mapping_map_local_wc(struct io_mapping *mapping,
++				      unsigned long offset)
+ 
+ 	void *io_mapping_map_atomic_wc(struct io_mapping *mapping,
+ 				       unsigned long offset)
+ 
+-'offset' is the offset within the defined mapping region.
+-Accessing addresses beyond the region specified in the
+-creation function yields undefined results. Using an offset
+-which is not page aligned yields an undefined result. The
+-return value points to a single page in CPU address space.
++'offset' is the offset within the defined mapping region.  Accessing
++addresses beyond the region specified in the creation function yields
++undefined results. Using an offset which is not page aligned yields an
++undefined result. The return value points to a single page in CPU address
++space.
+ 
+-This _wc variant returns a write-combining map to the
+-page and may only be used with mappings created by
+-io_mapping_create_wc
++This _wc variant returns a write-combining map to the page and may only be
++used with mappings created by io_mapping_create_wc()
+ 
+-Note that the task may not sleep while holding this page
+-mapped.
++Temporary mappings are only valid in the context of the caller. The mapping
++is not guaranteed to be globaly visible.
+ 
+-::
++io_mapping_map_local_wc() has a side effect on X86 32bit as it disables
++migration to make the mapping code work. No caller can rely on this side
++effect.
+ 
+-	void io_mapping_unmap_atomic(void *vaddr)
++io_mapping_map_atomic_wc() has the side effect of disabling preemption and
++pagefaults. Don't use in new code. Use io_mapping_map_local_wc() instead.
+ 
+-'vaddr' must be the value returned by the last
+-io_mapping_map_atomic_wc call. This unmaps the specified
+-page and allows the task to sleep once again.
++Nested mappings need to be undone in reverse order because the mapping
++code uses a stack for keeping track of them::
+ 
+-If you need to sleep while holding the lock, you can use the non-atomic
+-variant, although they may be significantly slower.
++ addr1 = io_mapping_map_local_wc(map1, offset1);
++ addr2 = io_mapping_map_local_wc(map2, offset2);
++ ...
++ io_mapping_unmap_local(addr2);
++ io_mapping_unmap_local(addr1);
+ 
+-::
++The mappings are released with::
++
++	void io_mapping_unmap_local(void *vaddr)
++	void io_mapping_unmap_atomic(void *vaddr)
++
++'vaddr' must be the value returned by the last io_mapping_map_local_wc() or
++io_mapping_map_atomic_wc() call. This unmaps the specified mapping and
++undoes the side effects of the mapping functions.
++
++If you need to sleep while holding a mapping, you can use the regular
++variant, although this may be significantly slower::
+ 
+ 	void *io_mapping_map_wc(struct io_mapping *mapping,
+ 				unsigned long offset)
+ 
+-This works like io_mapping_map_atomic_wc except it allows
+-the task to sleep while holding the page mapped.
+-
++This works like io_mapping_map_atomic/local_wc() except it has no side
++effects and the pointer is globaly visible.
+ 
+-::
++The mappings are released with::
+ 
+ 	void io_mapping_unmap(void *vaddr)
+ 
+-This works like io_mapping_unmap_atomic, except it is used
+-for pages mapped with io_mapping_map_wc.
++Use for pages mapped with io_mapping_map_wc().
+ 
+ At driver close time, the io_mapping object must be freed::
+ 
+diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h
+index 60e7c83e4904..c093e81310a9 100644
+--- a/include/linux/io-mapping.h
++++ b/include/linux/io-mapping.h
+@@ -82,6 +82,21 @@ io_mapping_unmap_atomic(void __iomem *vaddr)
+ 	preempt_enable();
+ }
+ 
++static inline void __iomem *
++io_mapping_map_local_wc(struct io_mapping *mapping, unsigned long offset)
++{
++	resource_size_t phys_addr;
++
++	BUG_ON(offset >= mapping->size);
++	phys_addr = mapping->base + offset;
++	return __iomap_local_pfn_prot(PHYS_PFN(phys_addr), mapping->prot);
++}
++
++static inline void io_mapping_unmap_local(void __iomem *vaddr)
++{
++	kunmap_local_indexed((void __force *)vaddr);
++}
++
+ static inline void __iomem *
+ io_mapping_map_wc(struct io_mapping *mapping,
+ 		  unsigned long offset,
+@@ -101,7 +116,7 @@ io_mapping_unmap(void __iomem *vaddr)
+ 	iounmap(vaddr);
+ }
+ 
+-#else
++#else  /* HAVE_ATOMIC_IOMAP */
+ 
+ #include <linux/uaccess.h>
+ 
+@@ -166,7 +181,18 @@ io_mapping_unmap_atomic(void __iomem *vaddr)
+ 	preempt_enable();
+ }
+ 
+-#endif /* HAVE_ATOMIC_IOMAP */
++static inline void __iomem *
++io_mapping_map_local_wc(struct io_mapping *mapping, unsigned long offset)
++{
++	return io_mapping_map_wc(mapping, offset, PAGE_SIZE);
++}
++
++static inline void io_mapping_unmap_local(void __iomem *vaddr)
++{
++	io_mapping_unmap(vaddr);
++}
++
++#endif /* !HAVE_ATOMIC_IOMAP */
+ 
+ static inline struct io_mapping *
+ io_mapping_create_wc(resource_size_t base,
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0050-x86-crashdump-32-Simplify-copy_oldmem_page.patch b/debian/patches-rt/0050-x86-crashdump-32-Simplify-copy_oldmem_page.patch
new file mode 100644
index 000000000..6f57ef059
--- /dev/null
+++ b/debian/patches-rt/0050-x86-crashdump-32-Simplify-copy_oldmem_page.patch
@@ -0,0 +1,99 @@
+From 9d9dd47b77d859a1261ac0dc98d94018bb5bb6a0 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:39 +0100
+Subject: [PATCH 050/323] x86/crashdump/32: Simplify copy_oldmem_page()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Replace kmap_atomic_pfn() with kmap_local_pfn() which is preemptible and
+can take page faults.
+
+Remove the indirection of the dump page and the related cruft which is not
+longer required.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/x86/kernel/crash_dump_32.c | 48 +++++++--------------------------
+ 1 file changed, 10 insertions(+), 38 deletions(-)
+
+diff --git a/arch/x86/kernel/crash_dump_32.c b/arch/x86/kernel/crash_dump_32.c
+index 33ee47670b99..5fcac46aaf6b 100644
+--- a/arch/x86/kernel/crash_dump_32.c
++++ b/arch/x86/kernel/crash_dump_32.c
+@@ -13,8 +13,6 @@
+ 
+ #include <linux/uaccess.h>
+ 
+-static void *kdump_buf_page;
+-
+ static inline bool is_crashed_pfn_valid(unsigned long pfn)
+ {
+ #ifndef CONFIG_X86_PAE
+@@ -41,15 +39,11 @@ static inline bool is_crashed_pfn_valid(unsigned long pfn)
+  * @userbuf: if set, @buf is in user address space, use copy_to_user(),
+  *	otherwise @buf is in kernel address space, use memcpy().
+  *
+- * Copy a page from "oldmem". For this page, there is no pte mapped
+- * in the current kernel. We stitch up a pte, similar to kmap_atomic.
+- *
+- * Calling copy_to_user() in atomic context is not desirable. Hence first
+- * copying the data to a pre-allocated kernel page and then copying to user
+- * space in non-atomic context.
++ * Copy a page from "oldmem". For this page, there might be no pte mapped
++ * in the current kernel.
+  */
+-ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
+-                               size_t csize, unsigned long offset, int userbuf)
++ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
++			 unsigned long offset, int userbuf)
+ {
+ 	void  *vaddr;
+ 
+@@ -59,38 +53,16 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
+ 	if (!is_crashed_pfn_valid(pfn))
+ 		return -EFAULT;
+ 
+-	vaddr = kmap_atomic_pfn(pfn);
++	vaddr = kmap_local_pfn(pfn);
+ 
+ 	if (!userbuf) {
+-		memcpy(buf, (vaddr + offset), csize);
+-		kunmap_atomic(vaddr);
++		memcpy(buf, vaddr + offset, csize);
+ 	} else {
+-		if (!kdump_buf_page) {
+-			printk(KERN_WARNING "Kdump: Kdump buffer page not"
+-				" allocated\n");
+-			kunmap_atomic(vaddr);
+-			return -EFAULT;
+-		}
+-		copy_page(kdump_buf_page, vaddr);
+-		kunmap_atomic(vaddr);
+-		if (copy_to_user(buf, (kdump_buf_page + offset), csize))
+-			return -EFAULT;
++		if (copy_to_user(buf, vaddr + offset, csize))
++			csize = -EFAULT;
+ 	}
+ 
+-	return csize;
+-}
++	kunmap_local(vaddr);
+ 
+-static int __init kdump_buf_page_init(void)
+-{
+-	int ret = 0;
+-
+-	kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
+-	if (!kdump_buf_page) {
+-		printk(KERN_WARNING "Kdump: Failed to allocate kdump buffer"
+-			 " page\n");
+-		ret = -ENOMEM;
+-	}
+-
+-	return ret;
++	return csize;
+ }
+-arch_initcall(kdump_buf_page_init);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0051-mips-crashdump-Simplify-copy_oldmem_page.patch b/debian/patches-rt/0051-mips-crashdump-Simplify-copy_oldmem_page.patch
new file mode 100644
index 000000000..837a4a04e
--- /dev/null
+++ b/debian/patches-rt/0051-mips-crashdump-Simplify-copy_oldmem_page.patch
@@ -0,0 +1,95 @@
+From 1aeac707162ce43fc0ae9c45df5a8a4535de2332 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:40 +0100
+Subject: [PATCH 051/323] mips/crashdump: Simplify copy_oldmem_page()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Replace kmap_atomic_pfn() with kmap_local_pfn() which is preemptible and
+can take page faults.
+
+Remove the indirection of the dump page and the related cruft which is not
+longer required.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
+Cc: linux-mips@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/mips/kernel/crash_dump.c | 42 ++++++-----------------------------
+ 1 file changed, 7 insertions(+), 35 deletions(-)
+
+diff --git a/arch/mips/kernel/crash_dump.c b/arch/mips/kernel/crash_dump.c
+index 01b2bd95ba1f..9aba83e1eeb4 100644
+--- a/arch/mips/kernel/crash_dump.c
++++ b/arch/mips/kernel/crash_dump.c
+@@ -5,8 +5,6 @@
+ #include <linux/uaccess.h>
+ #include <linux/slab.h>
+ 
+-static void *kdump_buf_page;
+-
+ /**
+  * copy_oldmem_page - copy one page from "oldmem"
+  * @pfn: page frame number to be copied
+@@ -17,51 +15,25 @@ static void *kdump_buf_page;
+  * @userbuf: if set, @buf is in user address space, use copy_to_user(),
+  *	otherwise @buf is in kernel address space, use memcpy().
+  *
+- * Copy a page from "oldmem". For this page, there is no pte mapped
++ * Copy a page from "oldmem". For this page, there might be no pte mapped
+  * in the current kernel.
+- *
+- * Calling copy_to_user() in atomic context is not desirable. Hence first
+- * copying the data to a pre-allocated kernel page and then copying to user
+- * space in non-atomic context.
+  */
+-ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
+-			 size_t csize, unsigned long offset, int userbuf)
++ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
++			 unsigned long offset, int userbuf)
+ {
+ 	void  *vaddr;
+ 
+ 	if (!csize)
+ 		return 0;
+ 
+-	vaddr = kmap_atomic_pfn(pfn);
++	vaddr = kmap_local_pfn(pfn);
+ 
+ 	if (!userbuf) {
+-		memcpy(buf, (vaddr + offset), csize);
+-		kunmap_atomic(vaddr);
++		memcpy(buf, vaddr + offset, csize);
+ 	} else {
+-		if (!kdump_buf_page) {
+-			pr_warn("Kdump: Kdump buffer page not allocated\n");
+-
+-			return -EFAULT;
+-		}
+-		copy_page(kdump_buf_page, vaddr);
+-		kunmap_atomic(vaddr);
+-		if (copy_to_user(buf, (kdump_buf_page + offset), csize))
+-			return -EFAULT;
++		if (copy_to_user(buf, vaddr + offset, csize))
++			csize = -EFAULT;
+ 	}
+ 
+ 	return csize;
+ }
+-
+-static int __init kdump_buf_page_init(void)
+-{
+-	int ret = 0;
+-
+-	kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
+-	if (!kdump_buf_page) {
+-		pr_warn("Kdump: Failed to allocate kdump buffer page\n");
+-		ret = -ENOMEM;
+-	}
+-
+-	return ret;
+-}
+-arch_initcall(kdump_buf_page_init);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0052-ARM-mm-Replace-kmap_atomic_pfn.patch b/debian/patches-rt/0052-ARM-mm-Replace-kmap_atomic_pfn.patch
new file mode 100644
index 000000000..ba46ccc69
--- /dev/null
+++ b/debian/patches-rt/0052-ARM-mm-Replace-kmap_atomic_pfn.patch
@@ -0,0 +1,71 @@
+From d74735ac58543c778598c75bccd45aa527acf03c Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:41 +0100
+Subject: [PATCH 052/323] ARM: mm: Replace kmap_atomic_pfn()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+There is no requirement to disable pagefaults and preemption for these
+cache management mappings.
+
+Replace kmap_atomic_pfn() with kmap_local_pfn(). This allows to remove
+kmap_atomic_pfn() in the next step.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Russell King <linux@armlinux.org.uk>
+Cc: linux-arm-kernel@lists.infradead.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/arm/mm/cache-feroceon-l2.c | 6 +++---
+ arch/arm/mm/cache-xsc3l2.c      | 4 ++--
+ 2 files changed, 5 insertions(+), 5 deletions(-)
+
+diff --git a/arch/arm/mm/cache-feroceon-l2.c b/arch/arm/mm/cache-feroceon-l2.c
+index 5c1b7a7b9af6..87328766e910 100644
+--- a/arch/arm/mm/cache-feroceon-l2.c
++++ b/arch/arm/mm/cache-feroceon-l2.c
+@@ -49,9 +49,9 @@ static inline unsigned long l2_get_va(unsigned long paddr)
+ 	 * we simply install a virtual mapping for it only for the
+ 	 * TLB lookup to occur, hence no need to flush the untouched
+ 	 * memory mapping afterwards (note: a cache flush may happen
+-	 * in some circumstances depending on the path taken in kunmap_atomic).
++	 * in some circumstances depending on the path taken in kunmap_local).
+ 	 */
+-	void *vaddr = kmap_atomic_pfn(paddr >> PAGE_SHIFT);
++	void *vaddr = kmap_local_pfn(paddr >> PAGE_SHIFT);
+ 	return (unsigned long)vaddr + (paddr & ~PAGE_MASK);
+ #else
+ 	return __phys_to_virt(paddr);
+@@ -61,7 +61,7 @@ static inline unsigned long l2_get_va(unsigned long paddr)
+ static inline void l2_put_va(unsigned long vaddr)
+ {
+ #ifdef CONFIG_HIGHMEM
+-	kunmap_atomic((void *)vaddr);
++	kunmap_local((void *)vaddr);
+ #endif
+ }
+ 
+diff --git a/arch/arm/mm/cache-xsc3l2.c b/arch/arm/mm/cache-xsc3l2.c
+index d20d7af02d10..0e0a3abd8174 100644
+--- a/arch/arm/mm/cache-xsc3l2.c
++++ b/arch/arm/mm/cache-xsc3l2.c
+@@ -59,7 +59,7 @@ static inline void l2_unmap_va(unsigned long va)
+ {
+ #ifdef CONFIG_HIGHMEM
+ 	if (va != -1)
+-		kunmap_atomic((void *)va);
++		kunmap_local((void *)va);
+ #endif
+ }
+ 
+@@ -75,7 +75,7 @@ static inline unsigned long l2_map_va(unsigned long pa, unsigned long prev_va)
+ 		 * in place for it.
+ 		 */
+ 		l2_unmap_va(prev_va);
+-		va = (unsigned long)kmap_atomic_pfn(pa >> PAGE_SHIFT);
++		va = (unsigned long)kmap_local_pfn(pa >> PAGE_SHIFT);
+ 	}
+ 	return va + (pa_offset >> (32 - PAGE_SHIFT));
+ #else
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0053-highmem-Remove-kmap_atomic_pfn.patch b/debian/patches-rt/0053-highmem-Remove-kmap_atomic_pfn.patch
new file mode 100644
index 000000000..a43566a1c
--- /dev/null
+++ b/debian/patches-rt/0053-highmem-Remove-kmap_atomic_pfn.patch
@@ -0,0 +1,47 @@
+From 766aabba108ec5697bed86d6ec633151b7f3618e Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:42 +0100
+Subject: [PATCH 053/323] highmem: Remove kmap_atomic_pfn()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+No more users.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/highmem-internal.h | 12 ------------
+ 1 file changed, 12 deletions(-)
+
+diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h
+index 1bbe96dc8be6..3590af5aad96 100644
+--- a/include/linux/highmem-internal.h
++++ b/include/linux/highmem-internal.h
+@@ -100,13 +100,6 @@ static inline void *kmap_atomic(struct page *page)
+ 	return kmap_atomic_prot(page, kmap_prot);
+ }
+ 
+-static inline void *kmap_atomic_pfn(unsigned long pfn)
+-{
+-	preempt_disable();
+-	pagefault_disable();
+-	return __kmap_local_pfn_prot(pfn, kmap_prot);
+-}
+-
+ static inline void __kunmap_atomic(void *addr)
+ {
+ 	kunmap_local_indexed(addr);
+@@ -194,11 +187,6 @@ static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
+ 	return kmap_atomic(page);
+ }
+ 
+-static inline void *kmap_atomic_pfn(unsigned long pfn)
+-{
+-	return kmap_atomic(pfn_to_page(pfn));
+-}
+-
+ static inline void __kunmap_atomic(void *addr)
+ {
+ #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0054-drm-ttm-Replace-kmap_atomic-usage.patch b/debian/patches-rt/0054-drm-ttm-Replace-kmap_atomic-usage.patch
new file mode 100644
index 000000000..3043aa642
--- /dev/null
+++ b/debian/patches-rt/0054-drm-ttm-Replace-kmap_atomic-usage.patch
@@ -0,0 +1,74 @@
+From 818c332a89ac4310c59f7ad122bdb4a6e0aac518 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:43 +0100
+Subject: [PATCH 054/323] drm/ttm: Replace kmap_atomic() usage
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+There is no reason to disable pagefaults and preemption as a side effect of
+kmap_atomic_prot().
+
+Use kmap_local_page_prot() instead and document the reasoning for the
+mapping usage with the given pgprot.
+
+Remove the NULL pointer check for the map. These functions return a valid
+address for valid pages and the return was bogus anyway as it would have
+left preemption and pagefaults disabled.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Christian Koenig <christian.koenig@amd.com>
+Cc: Huang Rui <ray.huang@amd.com>
+Cc: David Airlie <airlied@linux.ie>
+Cc: Daniel Vetter <daniel@ffwll.ch>
+Cc: dri-devel@lists.freedesktop.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/gpu/drm/ttm/ttm_bo_util.c | 20 ++++++++++++--------
+ 1 file changed, 12 insertions(+), 8 deletions(-)
+
+diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
+index 1968df9743fc..79b9c883431a 100644
+--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
++++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
+@@ -181,13 +181,15 @@ static int ttm_copy_io_ttm_page(struct ttm_tt *ttm, void *src,
+ 		return -ENOMEM;
+ 
+ 	src = (void *)((unsigned long)src + (page << PAGE_SHIFT));
+-	dst = kmap_atomic_prot(d, prot);
+-	if (!dst)
+-		return -ENOMEM;
++	/*
++	 * Ensure that a highmem page is mapped with the correct
++	 * pgprot. For non highmem the mapping is already there.
++	 */
++	dst = kmap_local_page_prot(d, prot);
+ 
+ 	memcpy_fromio(dst, src, PAGE_SIZE);
+ 
+-	kunmap_atomic(dst);
++	kunmap_local(dst);
+ 
+ 	return 0;
+ }
+@@ -203,13 +205,15 @@ static int ttm_copy_ttm_io_page(struct ttm_tt *ttm, void *dst,
+ 		return -ENOMEM;
+ 
+ 	dst = (void *)((unsigned long)dst + (page << PAGE_SHIFT));
+-	src = kmap_atomic_prot(s, prot);
+-	if (!src)
+-		return -ENOMEM;
++	/*
++	 * Ensure that a highmem page is mapped with the correct
++	 * pgprot. For non highmem the mapping is already there.
++	 */
++	src = kmap_local_page_prot(s, prot);
+ 
+ 	memcpy_toio(dst, src, PAGE_SIZE);
+ 
+-	kunmap_atomic(src);
++	kunmap_local(src);
+ 
+ 	return 0;
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0055-drm-vmgfx-Replace-kmap_atomic.patch b/debian/patches-rt/0055-drm-vmgfx-Replace-kmap_atomic.patch
new file mode 100644
index 000000000..613e94a91
--- /dev/null
+++ b/debian/patches-rt/0055-drm-vmgfx-Replace-kmap_atomic.patch
@@ -0,0 +1,104 @@
+From 3c21a2a16d681c2be78f257f660f1c8c1b50f7c3 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:44 +0100
+Subject: [PATCH 055/323] drm/vmgfx: Replace kmap_atomic()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+There is no reason to disable pagefaults and preemption as a side effect of
+kmap_atomic_prot().
+
+Use kmap_local_page_prot() instead and document the reasoning for the
+mapping usage with the given pgprot.
+
+Remove the NULL pointer check for the map. These functions return a valid
+address for valid pages and the return was bogus anyway as it would have
+left preemption and pagefaults disabled.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
+Cc: Roland Scheidegger <sroland@vmware.com>
+Cc: David Airlie <airlied@linux.ie>
+Cc: Daniel Vetter <daniel@ffwll.ch>
+Cc: dri-devel@lists.freedesktop.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/gpu/drm/vmwgfx/vmwgfx_blit.c | 30 +++++++++++-----------------
+ 1 file changed, 12 insertions(+), 18 deletions(-)
+
+diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_blit.c b/drivers/gpu/drm/vmwgfx/vmwgfx_blit.c
+index e8d66182cd7b..71dba228f68e 100644
+--- a/drivers/gpu/drm/vmwgfx/vmwgfx_blit.c
++++ b/drivers/gpu/drm/vmwgfx/vmwgfx_blit.c
+@@ -375,12 +375,12 @@ static int vmw_bo_cpu_blit_line(struct vmw_bo_blit_line_data *d,
+ 		copy_size = min_t(u32, copy_size, PAGE_SIZE - src_page_offset);
+ 
+ 		if (unmap_src) {
+-			kunmap_atomic(d->src_addr);
++			kunmap_local(d->src_addr);
+ 			d->src_addr = NULL;
+ 		}
+ 
+ 		if (unmap_dst) {
+-			kunmap_atomic(d->dst_addr);
++			kunmap_local(d->dst_addr);
+ 			d->dst_addr = NULL;
+ 		}
+ 
+@@ -388,12 +388,8 @@ static int vmw_bo_cpu_blit_line(struct vmw_bo_blit_line_data *d,
+ 			if (WARN_ON_ONCE(dst_page >= d->dst_num_pages))
+ 				return -EINVAL;
+ 
+-			d->dst_addr =
+-				kmap_atomic_prot(d->dst_pages[dst_page],
+-						 d->dst_prot);
+-			if (!d->dst_addr)
+-				return -ENOMEM;
+-
++			d->dst_addr = kmap_local_page_prot(d->dst_pages[dst_page],
++							   d->dst_prot);
+ 			d->mapped_dst = dst_page;
+ 		}
+ 
+@@ -401,12 +397,8 @@ static int vmw_bo_cpu_blit_line(struct vmw_bo_blit_line_data *d,
+ 			if (WARN_ON_ONCE(src_page >= d->src_num_pages))
+ 				return -EINVAL;
+ 
+-			d->src_addr =
+-				kmap_atomic_prot(d->src_pages[src_page],
+-						 d->src_prot);
+-			if (!d->src_addr)
+-				return -ENOMEM;
+-
++			d->src_addr = kmap_local_page_prot(d->src_pages[src_page],
++							   d->src_prot);
+ 			d->mapped_src = src_page;
+ 		}
+ 		diff->do_cpy(diff, d->dst_addr + dst_page_offset,
+@@ -436,8 +428,10 @@ static int vmw_bo_cpu_blit_line(struct vmw_bo_blit_line_data *d,
+  *
+  * Performs a CPU blit from one buffer object to another avoiding a full
+  * bo vmap which may exhaust- or fragment vmalloc space.
+- * On supported architectures (x86), we're using kmap_atomic which avoids
+- * cross-processor TLB- and cache flushes and may, on non-HIGHMEM systems
++ *
++ * On supported architectures (x86), we're using kmap_local_prot() which
++ * avoids cross-processor TLB- and cache flushes. kmap_local_prot() will
++ * either map a highmem page with the proper pgprot on HIGHMEM=y systems or
+  * reference already set-up mappings.
+  *
+  * Neither of the buffer objects may be placed in PCI memory
+@@ -500,9 +494,9 @@ int vmw_bo_cpu_blit(struct ttm_buffer_object *dst,
+ 	}
+ out:
+ 	if (d.src_addr)
+-		kunmap_atomic(d.src_addr);
++		kunmap_local(d.src_addr);
+ 	if (d.dst_addr)
+-		kunmap_atomic(d.dst_addr);
++		kunmap_local(d.dst_addr);
+ 
+ 	return ret;
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0056-highmem-Remove-kmap_atomic_prot.patch b/debian/patches-rt/0056-highmem-Remove-kmap_atomic_prot.patch
new file mode 100644
index 000000000..f9038b30b
--- /dev/null
+++ b/debian/patches-rt/0056-highmem-Remove-kmap_atomic_prot.patch
@@ -0,0 +1,52 @@
+From acac3af33fa7522e3be0f030ec1d80cca2cf215d Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:45 +0100
+Subject: [PATCH 056/323] highmem: Remove kmap_atomic_prot()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+No more users.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/highmem-internal.h | 14 ++------------
+ 1 file changed, 2 insertions(+), 12 deletions(-)
+
+diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h
+index 3590af5aad96..bd15bf9164c2 100644
+--- a/include/linux/highmem-internal.h
++++ b/include/linux/highmem-internal.h
+@@ -88,16 +88,11 @@ static inline void __kunmap_local(void *vaddr)
+ 	kunmap_local_indexed(vaddr);
+ }
+ 
+-static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
++static inline void *kmap_atomic(struct page *page)
+ {
+ 	preempt_disable();
+ 	pagefault_disable();
+-	return __kmap_local_page_prot(page, prot);
+-}
+-
+-static inline void *kmap_atomic(struct page *page)
+-{
+-	return kmap_atomic_prot(page, kmap_prot);
++	return __kmap_local_page_prot(page, kmap_prot);
+ }
+ 
+ static inline void __kunmap_atomic(void *addr)
+@@ -182,11 +177,6 @@ static inline void *kmap_atomic(struct page *page)
+ 	return page_address(page);
+ }
+ 
+-static inline void *kmap_atomic_prot(struct page *page, pgprot_t prot)
+-{
+-	return kmap_atomic(page);
+-}
+-
+ static inline void __kunmap_atomic(void *addr)
+ {
+ #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0057-drm-qxl-Replace-io_mapping_map_atomic_wc.patch b/debian/patches-rt/0057-drm-qxl-Replace-io_mapping_map_atomic_wc.patch
new file mode 100644
index 000000000..3d78f15fd
--- /dev/null
+++ b/debian/patches-rt/0057-drm-qxl-Replace-io_mapping_map_atomic_wc.patch
@@ -0,0 +1,257 @@
+From 2c90fccccea4cffb6ab5cd779da693cfe82194b8 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:46 +0100
+Subject: [PATCH 057/323] drm/qxl: Replace io_mapping_map_atomic_wc()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+None of these mapping requires the side effect of disabling pagefaults and
+preemption.
+
+Use io_mapping_map_local_wc() instead, rename the related functions
+accordingly and clean up qxl_process_single_command() to use a plain
+copy_from_user() as the local maps are not disabling pagefaults.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Dave Airlie <airlied@redhat.com>
+Cc: Gerd Hoffmann <kraxel@redhat.com>
+Cc: David Airlie <airlied@linux.ie>
+Cc: Daniel Vetter <daniel@ffwll.ch>
+Cc: virtualization@lists.linux-foundation.org
+Cc: spice-devel@lists.freedesktop.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/gpu/drm/qxl/qxl_image.c   | 18 +++++++++---------
+ drivers/gpu/drm/qxl/qxl_ioctl.c   | 27 +++++++++++++--------------
+ drivers/gpu/drm/qxl/qxl_object.c  | 12 ++++++------
+ drivers/gpu/drm/qxl/qxl_object.h  |  4 ++--
+ drivers/gpu/drm/qxl/qxl_release.c |  4 ++--
+ 5 files changed, 32 insertions(+), 33 deletions(-)
+
+diff --git a/drivers/gpu/drm/qxl/qxl_image.c b/drivers/gpu/drm/qxl/qxl_image.c
+index 60ab7151b84d..93f92ccd42e5 100644
+--- a/drivers/gpu/drm/qxl/qxl_image.c
++++ b/drivers/gpu/drm/qxl/qxl_image.c
+@@ -124,12 +124,12 @@ qxl_image_init_helper(struct qxl_device *qdev,
+ 				  wrong (check the bitmaps are sent correctly
+ 				  first) */
+ 
+-	ptr = qxl_bo_kmap_atomic_page(qdev, chunk_bo, 0);
++	ptr = qxl_bo_kmap_local_page(qdev, chunk_bo, 0);
+ 	chunk = ptr;
+ 	chunk->data_size = height * chunk_stride;
+ 	chunk->prev_chunk = 0;
+ 	chunk->next_chunk = 0;
+-	qxl_bo_kunmap_atomic_page(qdev, chunk_bo, ptr);
++	qxl_bo_kunmap_local_page(qdev, chunk_bo, ptr);
+ 
+ 	{
+ 		void *k_data, *i_data;
+@@ -143,7 +143,7 @@ qxl_image_init_helper(struct qxl_device *qdev,
+ 			i_data = (void *)data;
+ 
+ 			while (remain > 0) {
+-				ptr = qxl_bo_kmap_atomic_page(qdev, chunk_bo, page << PAGE_SHIFT);
++				ptr = qxl_bo_kmap_local_page(qdev, chunk_bo, page << PAGE_SHIFT);
+ 
+ 				if (page == 0) {
+ 					chunk = ptr;
+@@ -157,7 +157,7 @@ qxl_image_init_helper(struct qxl_device *qdev,
+ 
+ 				memcpy(k_data, i_data, size);
+ 
+-				qxl_bo_kunmap_atomic_page(qdev, chunk_bo, ptr);
++				qxl_bo_kunmap_local_page(qdev, chunk_bo, ptr);
+ 				i_data += size;
+ 				remain -= size;
+ 				page++;
+@@ -175,10 +175,10 @@ qxl_image_init_helper(struct qxl_device *qdev,
+ 					page_offset = offset_in_page(out_offset);
+ 					size = min((int)(PAGE_SIZE - page_offset), remain);
+ 
+-					ptr = qxl_bo_kmap_atomic_page(qdev, chunk_bo, page_base);
++					ptr = qxl_bo_kmap_local_page(qdev, chunk_bo, page_base);
+ 					k_data = ptr + page_offset;
+ 					memcpy(k_data, i_data, size);
+-					qxl_bo_kunmap_atomic_page(qdev, chunk_bo, ptr);
++					qxl_bo_kunmap_local_page(qdev, chunk_bo, ptr);
+ 					remain -= size;
+ 					i_data += size;
+ 					out_offset += size;
+@@ -189,7 +189,7 @@ qxl_image_init_helper(struct qxl_device *qdev,
+ 	qxl_bo_kunmap(chunk_bo);
+ 
+ 	image_bo = dimage->bo;
+-	ptr = qxl_bo_kmap_atomic_page(qdev, image_bo, 0);
++	ptr = qxl_bo_kmap_local_page(qdev, image_bo, 0);
+ 	image = ptr;
+ 
+ 	image->descriptor.id = 0;
+@@ -212,7 +212,7 @@ qxl_image_init_helper(struct qxl_device *qdev,
+ 		break;
+ 	default:
+ 		DRM_ERROR("unsupported image bit depth\n");
+-		qxl_bo_kunmap_atomic_page(qdev, image_bo, ptr);
++		qxl_bo_kunmap_local_page(qdev, image_bo, ptr);
+ 		return -EINVAL;
+ 	}
+ 	image->u.bitmap.flags = QXL_BITMAP_TOP_DOWN;
+@@ -222,7 +222,7 @@ qxl_image_init_helper(struct qxl_device *qdev,
+ 	image->u.bitmap.palette = 0;
+ 	image->u.bitmap.data = qxl_bo_physical_address(qdev, chunk_bo, 0);
+ 
+-	qxl_bo_kunmap_atomic_page(qdev, image_bo, ptr);
++	qxl_bo_kunmap_local_page(qdev, image_bo, ptr);
+ 
+ 	return 0;
+ }
+diff --git a/drivers/gpu/drm/qxl/qxl_ioctl.c b/drivers/gpu/drm/qxl/qxl_ioctl.c
+index 5cea6eea72ab..785023081b79 100644
+--- a/drivers/gpu/drm/qxl/qxl_ioctl.c
++++ b/drivers/gpu/drm/qxl/qxl_ioctl.c
+@@ -89,11 +89,11 @@ apply_reloc(struct qxl_device *qdev, struct qxl_reloc_info *info)
+ {
+ 	void *reloc_page;
+ 
+-	reloc_page = qxl_bo_kmap_atomic_page(qdev, info->dst_bo, info->dst_offset & PAGE_MASK);
++	reloc_page = qxl_bo_kmap_local_page(qdev, info->dst_bo, info->dst_offset & PAGE_MASK);
+ 	*(uint64_t *)(reloc_page + (info->dst_offset & ~PAGE_MASK)) = qxl_bo_physical_address(qdev,
+ 											      info->src_bo,
+ 											      info->src_offset);
+-	qxl_bo_kunmap_atomic_page(qdev, info->dst_bo, reloc_page);
++	qxl_bo_kunmap_local_page(qdev, info->dst_bo, reloc_page);
+ }
+ 
+ static void
+@@ -105,9 +105,9 @@ apply_surf_reloc(struct qxl_device *qdev, struct qxl_reloc_info *info)
+ 	if (info->src_bo && !info->src_bo->is_primary)
+ 		id = info->src_bo->surface_id;
+ 
+-	reloc_page = qxl_bo_kmap_atomic_page(qdev, info->dst_bo, info->dst_offset & PAGE_MASK);
++	reloc_page = qxl_bo_kmap_local_page(qdev, info->dst_bo, info->dst_offset & PAGE_MASK);
+ 	*(uint32_t *)(reloc_page + (info->dst_offset & ~PAGE_MASK)) = id;
+-	qxl_bo_kunmap_atomic_page(qdev, info->dst_bo, reloc_page);
++	qxl_bo_kunmap_local_page(qdev, info->dst_bo, reloc_page);
+ }
+ 
+ /* return holding the reference to this object */
+@@ -149,7 +149,6 @@ static int qxl_process_single_command(struct qxl_device *qdev,
+ 	struct qxl_bo *cmd_bo;
+ 	void *fb_cmd;
+ 	int i, ret, num_relocs;
+-	int unwritten;
+ 
+ 	switch (cmd->type) {
+ 	case QXL_CMD_DRAW:
+@@ -185,21 +184,21 @@ static int qxl_process_single_command(struct qxl_device *qdev,
+ 		goto out_free_reloc;
+ 
+ 	/* TODO copy slow path code from i915 */
+-	fb_cmd = qxl_bo_kmap_atomic_page(qdev, cmd_bo, (release->release_offset & PAGE_MASK));
+-	unwritten = __copy_from_user_inatomic_nocache
+-		(fb_cmd + sizeof(union qxl_release_info) + (release->release_offset & ~PAGE_MASK),
+-		 u64_to_user_ptr(cmd->command), cmd->command_size);
++	fb_cmd = qxl_bo_kmap_local_page(qdev, cmd_bo, (release->release_offset & PAGE_MASK));
+ 
+-	{
++	if (copy_from_user(fb_cmd + sizeof(union qxl_release_info) +
++			   (release->release_offset & ~PAGE_MASK),
++			   u64_to_user_ptr(cmd->command), cmd->command_size)) {
++		ret = -EFAULT;
++	} else {
+ 		struct qxl_drawable *draw = fb_cmd;
+ 
+ 		draw->mm_time = qdev->rom->mm_clock;
+ 	}
+ 
+-	qxl_bo_kunmap_atomic_page(qdev, cmd_bo, fb_cmd);
+-	if (unwritten) {
+-		DRM_ERROR("got unwritten %d\n", unwritten);
+-		ret = -EFAULT;
++	qxl_bo_kunmap_local_page(qdev, cmd_bo, fb_cmd);
++	if (ret) {
++		DRM_ERROR("copy from user failed %d\n", ret);
+ 		goto out_free_release;
+ 	}
+ 
+diff --git a/drivers/gpu/drm/qxl/qxl_object.c b/drivers/gpu/drm/qxl/qxl_object.c
+index 544a9e4df2a8..5ee5171d46ef 100644
+--- a/drivers/gpu/drm/qxl/qxl_object.c
++++ b/drivers/gpu/drm/qxl/qxl_object.c
+@@ -173,8 +173,8 @@ int qxl_bo_kmap(struct qxl_bo *bo, void **ptr)
+ 	return 0;
+ }
+ 
+-void *qxl_bo_kmap_atomic_page(struct qxl_device *qdev,
+-			      struct qxl_bo *bo, int page_offset)
++void *qxl_bo_kmap_local_page(struct qxl_device *qdev,
++			     struct qxl_bo *bo, int page_offset)
+ {
+ 	unsigned long offset;
+ 	void *rptr;
+@@ -189,7 +189,7 @@ void *qxl_bo_kmap_atomic_page(struct qxl_device *qdev,
+ 		goto fallback;
+ 
+ 	offset = bo->tbo.mem.start << PAGE_SHIFT;
+-	return io_mapping_map_atomic_wc(map, offset + page_offset);
++	return io_mapping_map_local_wc(map, offset + page_offset);
+ fallback:
+ 	if (bo->kptr) {
+ 		rptr = bo->kptr + (page_offset * PAGE_SIZE);
+@@ -215,14 +215,14 @@ void qxl_bo_kunmap(struct qxl_bo *bo)
+ 	ttm_bo_kunmap(&bo->kmap);
+ }
+ 
+-void qxl_bo_kunmap_atomic_page(struct qxl_device *qdev,
+-			       struct qxl_bo *bo, void *pmap)
++void qxl_bo_kunmap_local_page(struct qxl_device *qdev,
++			      struct qxl_bo *bo, void *pmap)
+ {
+ 	if ((bo->tbo.mem.mem_type != TTM_PL_VRAM) &&
+ 	    (bo->tbo.mem.mem_type != TTM_PL_PRIV))
+ 		goto fallback;
+ 
+-	io_mapping_unmap_atomic(pmap);
++	io_mapping_unmap_local(pmap);
+ 	return;
+  fallback:
+ 	qxl_bo_kunmap(bo);
+diff --git a/drivers/gpu/drm/qxl/qxl_object.h b/drivers/gpu/drm/qxl/qxl_object.h
+index 5762ea40d047..6ae89b1b36f4 100644
+--- a/drivers/gpu/drm/qxl/qxl_object.h
++++ b/drivers/gpu/drm/qxl/qxl_object.h
+@@ -89,8 +89,8 @@ extern int qxl_bo_create(struct qxl_device *qdev,
+ 			 struct qxl_bo **bo_ptr);
+ extern int qxl_bo_kmap(struct qxl_bo *bo, void **ptr);
+ extern void qxl_bo_kunmap(struct qxl_bo *bo);
+-void *qxl_bo_kmap_atomic_page(struct qxl_device *qdev, struct qxl_bo *bo, int page_offset);
+-void qxl_bo_kunmap_atomic_page(struct qxl_device *qdev, struct qxl_bo *bo, void *map);
++void *qxl_bo_kmap_local_page(struct qxl_device *qdev, struct qxl_bo *bo, int page_offset);
++void qxl_bo_kunmap_local_page(struct qxl_device *qdev, struct qxl_bo *bo, void *map);
+ extern struct qxl_bo *qxl_bo_ref(struct qxl_bo *bo);
+ extern void qxl_bo_unref(struct qxl_bo **bo);
+ extern int qxl_bo_pin(struct qxl_bo *bo);
+diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
+index b2a475a0ca4a..b665a33b449b 100644
+--- a/drivers/gpu/drm/qxl/qxl_release.c
++++ b/drivers/gpu/drm/qxl/qxl_release.c
+@@ -414,7 +414,7 @@ union qxl_release_info *qxl_release_map(struct qxl_device *qdev,
+ 	union qxl_release_info *info;
+ 	struct qxl_bo *bo = release->release_bo;
+ 
+-	ptr = qxl_bo_kmap_atomic_page(qdev, bo, release->release_offset & PAGE_MASK);
++	ptr = qxl_bo_kmap_local_page(qdev, bo, release->release_offset & PAGE_MASK);
+ 	if (!ptr)
+ 		return NULL;
+ 	info = ptr + (release->release_offset & ~PAGE_MASK);
+@@ -429,7 +429,7 @@ void qxl_release_unmap(struct qxl_device *qdev,
+ 	void *ptr;
+ 
+ 	ptr = ((void *)info) - (release->release_offset & ~PAGE_MASK);
+-	qxl_bo_kunmap_atomic_page(qdev, bo, ptr);
++	qxl_bo_kunmap_local_page(qdev, bo, ptr);
+ }
+ 
+ void qxl_release_fence_buffer_objects(struct qxl_release *release)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0058-drm-nouveau-device-Replace-io_mapping_map_atomic_wc.patch b/debian/patches-rt/0058-drm-nouveau-device-Replace-io_mapping_map_atomic_wc.patch
new file mode 100644
index 000000000..1fbd4e19c
--- /dev/null
+++ b/debian/patches-rt/0058-drm-nouveau-device-Replace-io_mapping_map_atomic_wc.patch
@@ -0,0 +1,54 @@
+From fa246d15bcd167ad99886a776912530c0ca8d6a7 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:47 +0100
+Subject: [PATCH 058/323] drm/nouveau/device: Replace
+ io_mapping_map_atomic_wc()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Neither fbmem_peek() nor fbmem_poke() require to disable pagefaults and
+preemption as a side effect of io_mapping_map_atomic_wc().
+
+Use io_mapping_map_local_wc() instead.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Ben Skeggs <bskeggs@redhat.com>
+Cc: David Airlie <airlied@linux.ie>
+Cc: Daniel Vetter <daniel@ffwll.ch>
+Cc: dri-devel@lists.freedesktop.org
+Cc: nouveau@lists.freedesktop.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/gpu/drm/nouveau/nvkm/subdev/devinit/fbmem.h | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/devinit/fbmem.h b/drivers/gpu/drm/nouveau/nvkm/subdev/devinit/fbmem.h
+index 6c5bbff12eb4..411f91ee20fa 100644
+--- a/drivers/gpu/drm/nouveau/nvkm/subdev/devinit/fbmem.h
++++ b/drivers/gpu/drm/nouveau/nvkm/subdev/devinit/fbmem.h
+@@ -60,19 +60,19 @@ fbmem_fini(struct io_mapping *fb)
+ static inline u32
+ fbmem_peek(struct io_mapping *fb, u32 off)
+ {
+-	u8 __iomem *p = io_mapping_map_atomic_wc(fb, off & PAGE_MASK);
++	u8 __iomem *p = io_mapping_map_local_wc(fb, off & PAGE_MASK);
+ 	u32 val = ioread32(p + (off & ~PAGE_MASK));
+-	io_mapping_unmap_atomic(p);
++	io_mapping_unmap_local(p);
+ 	return val;
+ }
+ 
+ static inline void
+ fbmem_poke(struct io_mapping *fb, u32 off, u32 val)
+ {
+-	u8 __iomem *p = io_mapping_map_atomic_wc(fb, off & PAGE_MASK);
++	u8 __iomem *p = io_mapping_map_local_wc(fb, off & PAGE_MASK);
+ 	iowrite32(val, p + (off & ~PAGE_MASK));
+ 	wmb();
+-	io_mapping_unmap_atomic(p);
++	io_mapping_unmap_local(p);
+ }
+ 
+ static inline bool
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0059-drm-i915-Replace-io_mapping_map_atomic_wc.patch b/debian/patches-rt/0059-drm-i915-Replace-io_mapping_map_atomic_wc.patch
new file mode 100644
index 000000000..91fbfdde2
--- /dev/null
+++ b/debian/patches-rt/0059-drm-i915-Replace-io_mapping_map_atomic_wc.patch
@@ -0,0 +1,173 @@
+From 012c96110910f68af41e3914aabb92283a885215 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:48 +0100
+Subject: [PATCH 059/323] drm/i915: Replace io_mapping_map_atomic_wc()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+None of these mapping requires the side effect of disabling pagefaults and
+preemption.
+
+Use io_mapping_map_local_wc() instead, and clean up gtt_user_read() and
+gtt_user_write() to use a plain copy_from_user() as the local maps are not
+disabling pagefaults.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Jani Nikula <jani.nikula@linux.intel.com>
+Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
+Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
+Cc: David Airlie <airlied@linux.ie>
+Cc: Daniel Vetter <daniel@ffwll.ch>
+Cc: intel-gfx@lists.freedesktop.org
+Cc: dri-devel@lists.freedesktop.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ .../gpu/drm/i915/gem/i915_gem_execbuffer.c    |  7 ++--
+ drivers/gpu/drm/i915/i915_gem.c               | 40 ++++++-------------
+ drivers/gpu/drm/i915/selftests/i915_gem.c     |  4 +-
+ drivers/gpu/drm/i915/selftests/i915_gem_gtt.c |  8 ++--
+ 4 files changed, 22 insertions(+), 37 deletions(-)
+
+diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+index 0c083af5a59d..2abf043d3d9d 100644
+--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
++++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+@@ -1080,7 +1080,7 @@ static void reloc_cache_reset(struct reloc_cache *cache, struct i915_execbuffer
+ 		struct i915_ggtt *ggtt = cache_to_ggtt(cache);
+ 
+ 		intel_gt_flush_ggtt_writes(ggtt->vm.gt);
+-		io_mapping_unmap_atomic((void __iomem *)vaddr);
++		io_mapping_unmap_local((void __iomem *)vaddr);
+ 
+ 		if (drm_mm_node_allocated(&cache->node)) {
+ 			ggtt->vm.clear_range(&ggtt->vm,
+@@ -1146,7 +1146,7 @@ static void *reloc_iomap(struct drm_i915_gem_object *obj,
+ 
+ 	if (cache->vaddr) {
+ 		intel_gt_flush_ggtt_writes(ggtt->vm.gt);
+-		io_mapping_unmap_atomic((void __force __iomem *) unmask_page(cache->vaddr));
++		io_mapping_unmap_local((void __force __iomem *) unmask_page(cache->vaddr));
+ 	} else {
+ 		struct i915_vma *vma;
+ 		int err;
+@@ -1194,8 +1194,7 @@ static void *reloc_iomap(struct drm_i915_gem_object *obj,
+ 		offset += page << PAGE_SHIFT;
+ 	}
+ 
+-	vaddr = (void __force *)io_mapping_map_atomic_wc(&ggtt->iomap,
+-							 offset);
++	vaddr = (void __force *)io_mapping_map_local_wc(&ggtt->iomap, offset);
+ 	cache->page = page;
+ 	cache->vaddr = (unsigned long)vaddr;
+ 
+diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
+index 58276694c848..88944c3b1bc8 100644
+--- a/drivers/gpu/drm/i915/i915_gem.c
++++ b/drivers/gpu/drm/i915/i915_gem.c
+@@ -355,22 +355,15 @@ gtt_user_read(struct io_mapping *mapping,
+ 	      char __user *user_data, int length)
+ {
+ 	void __iomem *vaddr;
+-	unsigned long unwritten;
++	bool fail = false;
+ 
+ 	/* We can use the cpu mem copy function because this is X86. */
+-	vaddr = io_mapping_map_atomic_wc(mapping, base);
+-	unwritten = __copy_to_user_inatomic(user_data,
+-					    (void __force *)vaddr + offset,
+-					    length);
+-	io_mapping_unmap_atomic(vaddr);
+-	if (unwritten) {
+-		vaddr = io_mapping_map_wc(mapping, base, PAGE_SIZE);
+-		unwritten = copy_to_user(user_data,
+-					 (void __force *)vaddr + offset,
+-					 length);
+-		io_mapping_unmap(vaddr);
+-	}
+-	return unwritten;
++	vaddr = io_mapping_map_local_wc(mapping, base);
++	if (copy_to_user(user_data, (void __force *)vaddr + offset, length))
++		fail = true;
++	io_mapping_unmap_local(vaddr);
++
++	return fail;
+ }
+ 
+ static int
+@@ -539,21 +532,14 @@ ggtt_write(struct io_mapping *mapping,
+ 	   char __user *user_data, int length)
+ {
+ 	void __iomem *vaddr;
+-	unsigned long unwritten;
++	bool fail = false;
+ 
+ 	/* We can use the cpu mem copy function because this is X86. */
+-	vaddr = io_mapping_map_atomic_wc(mapping, base);
+-	unwritten = __copy_from_user_inatomic_nocache((void __force *)vaddr + offset,
+-						      user_data, length);
+-	io_mapping_unmap_atomic(vaddr);
+-	if (unwritten) {
+-		vaddr = io_mapping_map_wc(mapping, base, PAGE_SIZE);
+-		unwritten = copy_from_user((void __force *)vaddr + offset,
+-					   user_data, length);
+-		io_mapping_unmap(vaddr);
+-	}
+-
+-	return unwritten;
++	vaddr = io_mapping_map_local_wc(mapping, base);
++	if (copy_from_user((void __force *)vaddr + offset, user_data, length))
++		fail = true;
++	io_mapping_unmap_local(vaddr);
++	return fail;
+ }
+ 
+ /**
+diff --git a/drivers/gpu/drm/i915/selftests/i915_gem.c b/drivers/gpu/drm/i915/selftests/i915_gem.c
+index 412e21604a05..432493183d20 100644
+--- a/drivers/gpu/drm/i915/selftests/i915_gem.c
++++ b/drivers/gpu/drm/i915/selftests/i915_gem.c
+@@ -57,12 +57,12 @@ static void trash_stolen(struct drm_i915_private *i915)
+ 
+ 		ggtt->vm.insert_page(&ggtt->vm, dma, slot, I915_CACHE_NONE, 0);
+ 
+-		s = io_mapping_map_atomic_wc(&ggtt->iomap, slot);
++		s = io_mapping_map_local_wc(&ggtt->iomap, slot);
+ 		for (x = 0; x < PAGE_SIZE / sizeof(u32); x++) {
+ 			prng = next_pseudo_random32(prng);
+ 			iowrite32(prng, &s[x]);
+ 		}
+-		io_mapping_unmap_atomic(s);
++		io_mapping_unmap_local(s);
+ 	}
+ 
+ 	ggtt->vm.clear_range(&ggtt->vm, slot, PAGE_SIZE);
+diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+index 65e28c4cd4ce..ca483285f267 100644
+--- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
++++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+@@ -1201,9 +1201,9 @@ static int igt_ggtt_page(void *arg)
+ 		u64 offset = tmp.start + order[n] * PAGE_SIZE;
+ 		u32 __iomem *vaddr;
+ 
+-		vaddr = io_mapping_map_atomic_wc(&ggtt->iomap, offset);
++		vaddr = io_mapping_map_local_wc(&ggtt->iomap, offset);
+ 		iowrite32(n, vaddr + n);
+-		io_mapping_unmap_atomic(vaddr);
++		io_mapping_unmap_local(vaddr);
+ 	}
+ 	intel_gt_flush_ggtt_writes(ggtt->vm.gt);
+ 
+@@ -1213,9 +1213,9 @@ static int igt_ggtt_page(void *arg)
+ 		u32 __iomem *vaddr;
+ 		u32 val;
+ 
+-		vaddr = io_mapping_map_atomic_wc(&ggtt->iomap, offset);
++		vaddr = io_mapping_map_local_wc(&ggtt->iomap, offset);
+ 		val = ioread32(vaddr + n);
+-		io_mapping_unmap_atomic(vaddr);
++		io_mapping_unmap_local(vaddr);
+ 
+ 		if (val != n) {
+ 			pr_err("insert page failed: found %d, expected %d\n",
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0060-io-mapping-Remove-io_mapping_map_atomic_wc.patch b/debian/patches-rt/0060-io-mapping-Remove-io_mapping_map_atomic_wc.patch
new file mode 100644
index 000000000..f8374350f
--- /dev/null
+++ b/debian/patches-rt/0060-io-mapping-Remove-io_mapping_map_atomic_wc.patch
@@ -0,0 +1,140 @@
+From 925f92c53f78436e9242942d1a31a1ecc61ba740 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 3 Nov 2020 10:27:49 +0100
+Subject: [PATCH 060/323] io-mapping: Remove io_mapping_map_atomic_wc()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+No more users. Get rid of it and remove the traces in documentation.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ Documentation/driver-api/io-mapping.rst | 22 +++++--------
+ include/linux/io-mapping.h              | 42 ++-----------------------
+ 2 files changed, 9 insertions(+), 55 deletions(-)
+
+diff --git a/Documentation/driver-api/io-mapping.rst b/Documentation/driver-api/io-mapping.rst
+index a0cfb15988df..a7830c59481f 100644
+--- a/Documentation/driver-api/io-mapping.rst
++++ b/Documentation/driver-api/io-mapping.rst
+@@ -21,19 +21,15 @@ mappable, while 'size' indicates how large a mapping region to
+ enable. Both are in bytes.
+ 
+ This _wc variant provides a mapping which may only be used with
+-io_mapping_map_atomic_wc(), io_mapping_map_local_wc() or
+-io_mapping_map_wc().
++io_mapping_map_local_wc() or io_mapping_map_wc().
+ 
+ With this mapping object, individual pages can be mapped either temporarily
+ or long term, depending on the requirements. Of course, temporary maps are
+-more efficient. They come in two flavours::
++more efficient.
+ 
+ 	void *io_mapping_map_local_wc(struct io_mapping *mapping,
+ 				      unsigned long offset)
+ 
+-	void *io_mapping_map_atomic_wc(struct io_mapping *mapping,
+-				       unsigned long offset)
+-
+ 'offset' is the offset within the defined mapping region.  Accessing
+ addresses beyond the region specified in the creation function yields
+ undefined results. Using an offset which is not page aligned yields an
+@@ -50,9 +46,6 @@ io_mapping_map_local_wc() has a side effect on X86 32bit as it disables
+ migration to make the mapping code work. No caller can rely on this side
+ effect.
+ 
+-io_mapping_map_atomic_wc() has the side effect of disabling preemption and
+-pagefaults. Don't use in new code. Use io_mapping_map_local_wc() instead.
+-
+ Nested mappings need to be undone in reverse order because the mapping
+ code uses a stack for keeping track of them::
+ 
+@@ -65,11 +58,10 @@ code uses a stack for keeping track of them::
+ The mappings are released with::
+ 
+ 	void io_mapping_unmap_local(void *vaddr)
+-	void io_mapping_unmap_atomic(void *vaddr)
+ 
+-'vaddr' must be the value returned by the last io_mapping_map_local_wc() or
+-io_mapping_map_atomic_wc() call. This unmaps the specified mapping and
+-undoes the side effects of the mapping functions.
++'vaddr' must be the value returned by the last io_mapping_map_local_wc()
++call. This unmaps the specified mapping and undoes eventual side effects of
++the mapping function.
+ 
+ If you need to sleep while holding a mapping, you can use the regular
+ variant, although this may be significantly slower::
+@@ -77,8 +69,8 @@ variant, although this may be significantly slower::
+ 	void *io_mapping_map_wc(struct io_mapping *mapping,
+ 				unsigned long offset)
+ 
+-This works like io_mapping_map_atomic/local_wc() except it has no side
+-effects and the pointer is globaly visible.
++This works like io_mapping_map_local_wc() except it has no side effects and
++the pointer is globaly visible.
+ 
+ The mappings are released with::
+ 
+diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h
+index c093e81310a9..4bb8223f2f82 100644
+--- a/include/linux/io-mapping.h
++++ b/include/linux/io-mapping.h
+@@ -60,28 +60,7 @@ io_mapping_fini(struct io_mapping *mapping)
+ 	iomap_free(mapping->base, mapping->size);
+ }
+ 
+-/* Atomic map/unmap */
+-static inline void __iomem *
+-io_mapping_map_atomic_wc(struct io_mapping *mapping,
+-			 unsigned long offset)
+-{
+-	resource_size_t phys_addr;
+-
+-	BUG_ON(offset >= mapping->size);
+-	phys_addr = mapping->base + offset;
+-	preempt_disable();
+-	pagefault_disable();
+-	return __iomap_local_pfn_prot(PHYS_PFN(phys_addr), mapping->prot);
+-}
+-
+-static inline void
+-io_mapping_unmap_atomic(void __iomem *vaddr)
+-{
+-	kunmap_local_indexed((void __force *)vaddr);
+-	pagefault_enable();
+-	preempt_enable();
+-}
+-
++/* Temporary mappings which are only valid in the current context */
+ static inline void __iomem *
+ io_mapping_map_local_wc(struct io_mapping *mapping, unsigned long offset)
+ {
+@@ -163,24 +142,7 @@ io_mapping_unmap(void __iomem *vaddr)
+ {
+ }
+ 
+-/* Atomic map/unmap */
+-static inline void __iomem *
+-io_mapping_map_atomic_wc(struct io_mapping *mapping,
+-			 unsigned long offset)
+-{
+-	preempt_disable();
+-	pagefault_disable();
+-	return io_mapping_map_wc(mapping, offset, PAGE_SIZE);
+-}
+-
+-static inline void
+-io_mapping_unmap_atomic(void __iomem *vaddr)
+-{
+-	io_mapping_unmap(vaddr);
+-	pagefault_enable();
+-	preempt_enable();
+-}
+-
++/* Temporary mappings which are only valid in the current context */
+ static inline void __iomem *
+ io_mapping_map_local_wc(struct io_mapping *mapping, unsigned long offset)
+ {
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0061-mm-highmem-Take-kmap_high_get-properly-into-account.patch b/debian/patches-rt/0061-mm-highmem-Take-kmap_high_get-properly-into-account.patch
new file mode 100644
index 000000000..5970ff263
--- /dev/null
+++ b/debian/patches-rt/0061-mm-highmem-Take-kmap_high_get-properly-into-account.patch
@@ -0,0 +1,72 @@
+From 3df53841fc978eae47eb80dbb4ccaefa880589a7 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 12 Nov 2020 11:59:32 +0100
+Subject: [PATCH 061/323] mm/highmem: Take kmap_high_get() properly into
+ account
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+kunmap_local() warns when the virtual address to unmap is below
+PAGE_OFFSET. This is correct except for the case that the mapping was
+obtained via kmap_high_get() because the PKMAP addresses are right below
+PAGE_OFFSET.
+
+Cure it by skipping the WARN_ON() when the unmap was handled by
+kunmap_high().
+
+Fixes: 298fa1ad5571 ("highmem: Provide generic variant of kmap_atomic*")
+Reported-by: vtolkm@googlemail.com
+Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
+Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Cc: Andrew Morton <akpm@linux-foundation.org>
+Link: https://lore.kernel.org/r/87y2j6n8mj.fsf@nanos.tec.linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/highmem.c | 19 +++++++++++++------
+ 1 file changed, 13 insertions(+), 6 deletions(-)
+
+diff --git a/mm/highmem.c b/mm/highmem.c
+index 8db577e5290c..72b9a2d95c72 100644
+--- a/mm/highmem.c
++++ b/mm/highmem.c
+@@ -422,12 +422,15 @@ static inline void *arch_kmap_local_high_get(struct page *page)
+ #endif
+ 
+ /* Unmap a local mapping which was obtained by kmap_high_get() */
+-static inline void kmap_high_unmap_local(unsigned long vaddr)
++static inline bool kmap_high_unmap_local(unsigned long vaddr)
+ {
+ #ifdef ARCH_NEEDS_KMAP_HIGH_GET
+-	if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP))
++	if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
+ 		kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
++		return true;
++	}
+ #endif
++	return false;
+ }
+ 
+ static inline int kmap_local_calc_idx(int idx)
+@@ -493,10 +496,14 @@ void kunmap_local_indexed(void *vaddr)
+ 
+ 	if (addr < __fix_to_virt(FIX_KMAP_END) ||
+ 	    addr > __fix_to_virt(FIX_KMAP_BEGIN)) {
+-		WARN_ON_ONCE(addr < PAGE_OFFSET);
+-
+-		/* Handle mappings which were obtained by kmap_high_get() */
+-		kmap_high_unmap_local(addr);
++		/*
++		 * Handle mappings which were obtained by kmap_high_get()
++		 * first as the virtual address of such mappings is below
++		 * PAGE_OFFSET. Warn for all other addresses which are in
++		 * the user space part of the virtual address space.
++		 */
++		if (!kmap_high_unmap_local(addr))
++			WARN_ON_ONCE(addr < PAGE_OFFSET);
+ 		return;
+ 	}
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0062-highmem-Don-t-disable-preemption-on-RT-in-kmap_atomi.patch b/debian/patches-rt/0062-highmem-Don-t-disable-preemption-on-RT-in-kmap_atomi.patch
new file mode 100644
index 000000000..cecb34498
--- /dev/null
+++ b/debian/patches-rt/0062-highmem-Don-t-disable-preemption-on-RT-in-kmap_atomi.patch
@@ -0,0 +1,71 @@
+From 09d7bcb6eee1e7c9351535a20f60929daca8632d Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 30 Oct 2020 13:59:06 +0100
+Subject: [PATCH 062/323] highmem: Don't disable preemption on RT in
+ kmap_atomic()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Disabling preemption makes it impossible to acquire sleeping locks within
+kmap_atomic() section.
+For PREEMPT_RT it is sufficient to disable migration.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/highmem-internal.h | 20 ++++++++++++++++----
+ 1 file changed, 16 insertions(+), 4 deletions(-)
+
+diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h
+index bd15bf9164c2..f9bc6acd3679 100644
+--- a/include/linux/highmem-internal.h
++++ b/include/linux/highmem-internal.h
+@@ -90,7 +90,10 @@ static inline void __kunmap_local(void *vaddr)
+ 
+ static inline void *kmap_atomic(struct page *page)
+ {
+-	preempt_disable();
++	if (IS_ENABLED(CONFIG_PREEMPT_RT))
++		migrate_disable();
++	else
++		preempt_disable();
+ 	pagefault_disable();
+ 	return __kmap_local_page_prot(page, kmap_prot);
+ }
+@@ -99,7 +102,10 @@ static inline void __kunmap_atomic(void *addr)
+ {
+ 	kunmap_local_indexed(addr);
+ 	pagefault_enable();
+-	preempt_enable();
++	if (IS_ENABLED(CONFIG_PREEMPT_RT))
++		migrate_enable();
++	else
++		preempt_enable();
+ }
+ 
+ unsigned int __nr_free_highpages(void);
+@@ -172,7 +178,10 @@ static inline void __kunmap_local(void *addr)
+ 
+ static inline void *kmap_atomic(struct page *page)
+ {
+-	preempt_disable();
++	if (IS_ENABLED(CONFIG_PREEMPT_RT))
++		migrate_disable();
++	else
++		preempt_disable();
+ 	pagefault_disable();
+ 	return page_address(page);
+ }
+@@ -183,7 +192,10 @@ static inline void __kunmap_atomic(void *addr)
+ 	kunmap_flush_on_unmap(addr);
+ #endif
+ 	pagefault_enable();
+-	preempt_enable();
++	if (IS_ENABLED(CONFIG_PREEMPT_RT))
++		migrate_enable();
++	else
++		preempt_enable();
+ }
+ 
+ static inline unsigned int nr_free_highpages(void) { return 0; }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0063-blk-mq-Don-t-complete-on-a-remote-CPU-in-force-threa.patch b/debian/patches-rt/0063-blk-mq-Don-t-complete-on-a-remote-CPU-in-force-threa.patch
new file mode 100644
index 000000000..8623209ab
--- /dev/null
+++ b/debian/patches-rt/0063-blk-mq-Don-t-complete-on-a-remote-CPU-in-force-threa.patch
@@ -0,0 +1,48 @@
+From f7d87d26b4c9bfd083484542889f392867c1c85b Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 4 Dec 2020 20:13:54 +0100
+Subject: [PATCH 063/323] blk-mq: Don't complete on a remote CPU in force
+ threaded mode
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+With force threaded interrupts enabled, raising softirq from an SMP
+function call will always result in waking the ksoftirqd thread. This is
+not optimal given that the thread runs at SCHED_OTHER priority.
+
+Completing the request in hard IRQ-context on PREEMPT_RT (which enforces
+the force threaded mode) is bad because the completion handler may
+acquire sleeping locks which violate the locking context.
+
+Disable request completing on a remote CPU in force threaded mode.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Reviewed-by: Christoph Hellwig <hch@lst.de>
+Reviewed-by: Daniel Wagner <dwagner@suse.de>
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ block/blk-mq.c | 8 ++++++++
+ 1 file changed, 8 insertions(+)
+
+diff --git a/block/blk-mq.c b/block/blk-mq.c
+index e153a36c9ba3..cc41373cf346 100644
+--- a/block/blk-mq.c
++++ b/block/blk-mq.c
+@@ -652,6 +652,14 @@ static inline bool blk_mq_complete_need_ipi(struct request *rq)
+ 	if (!IS_ENABLED(CONFIG_SMP) ||
+ 	    !test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags))
+ 		return false;
++	/*
++	 * With force threaded interrupts enabled, raising softirq from an SMP
++	 * function call will always result in waking the ksoftirqd thread.
++	 * This is probably worse than completing the request on a different
++	 * cache domain.
++	 */
++	if (force_irqthreads)
++		return false;
+ 
+ 	/* same CPU or cache domain?  Complete locally */
+ 	if (cpu == rq->mq_ctx->cpu ||
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0064-blk-mq-Always-complete-remote-completions-requests-i.patch b/debian/patches-rt/0064-blk-mq-Always-complete-remote-completions-requests-i.patch
new file mode 100644
index 000000000..92574e87b
--- /dev/null
+++ b/debian/patches-rt/0064-blk-mq-Always-complete-remote-completions-requests-i.patch
@@ -0,0 +1,49 @@
+From 4397e4a75ac6456a0dd8cf0a99c8250845b022d6 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Sat, 23 Jan 2021 21:10:26 +0100
+Subject: [PATCH 064/323] blk-mq: Always complete remote completions requests
+ in softirq
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Controllers with multiple queues have their IRQ-handelers pinned to a
+CPU. The core shouldn't need to complete the request on a remote CPU.
+
+Remove this case and always raise the softirq to complete the request.
+
+Reviewed-by: Christoph Hellwig <hch@lst.de>
+Reviewed-by: Daniel Wagner <dwagner@suse.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ block/blk-mq.c | 14 +-------------
+ 1 file changed, 1 insertion(+), 13 deletions(-)
+
+diff --git a/block/blk-mq.c b/block/blk-mq.c
+index cc41373cf346..87b8377a74fc 100644
+--- a/block/blk-mq.c
++++ b/block/blk-mq.c
+@@ -630,19 +630,7 @@ static void __blk_mq_complete_request_remote(void *data)
+ {
+ 	struct request *rq = data;
+ 
+-	/*
+-	 * For most of single queue controllers, there is only one irq vector
+-	 * for handling I/O completion, and the only irq's affinity is set
+-	 * to all possible CPUs.  On most of ARCHs, this affinity means the irq
+-	 * is handled on one specific CPU.
+-	 *
+-	 * So complete I/O requests in softirq context in case of single queue
+-	 * devices to avoid degrading I/O performance due to irqsoff latency.
+-	 */
+-	if (rq->q->nr_hw_queues == 1)
+-		blk_mq_trigger_softirq(rq);
+-	else
+-		rq->q->mq_ops->complete(rq);
++	blk_mq_trigger_softirq(rq);
+ }
+ 
+ static inline bool blk_mq_complete_need_ipi(struct request *rq)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0065-blk-mq-Use-llist_head-for-blk_cpu_done.patch b/debian/patches-rt/0065-blk-mq-Use-llist_head-for-blk_cpu_done.patch
new file mode 100644
index 000000000..b7faea536
--- /dev/null
+++ b/debian/patches-rt/0065-blk-mq-Use-llist_head-for-blk_cpu_done.patch
@@ -0,0 +1,201 @@
+From a958b1b96b5419f3d9372de0c7851daae941bf47 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Sat, 23 Jan 2021 21:10:27 +0100
+Subject: [PATCH 065/323] blk-mq: Use llist_head for blk_cpu_done
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+With llist_head it is possible to avoid the locking (the irq-off region)
+when items are added. This makes it possible to add items on a remote
+CPU without additional locking.
+llist_add() returns true if the list was previously empty. This can be
+used to invoke the SMP function call / raise sofirq only if the first
+item was added (otherwise it is already pending).
+This simplifies the code a little and reduces the IRQ-off regions.
+
+blk_mq_raise_softirq() needs a preempt-disable section to ensure the
+request is enqueued on the same CPU as the softirq is raised.
+Some callers (USB-storage) invoke this path in preemptible context.
+
+Reviewed-by: Christoph Hellwig <hch@lst.de>
+Reviewed-by: Daniel Wagner <dwagner@suse.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ block/blk-mq.c         | 101 ++++++++++++++++++-----------------------
+ include/linux/blkdev.h |   2 +-
+ 2 files changed, 44 insertions(+), 59 deletions(-)
+
+diff --git a/block/blk-mq.c b/block/blk-mq.c
+index 87b8377a74fc..a6618bf45992 100644
+--- a/block/blk-mq.c
++++ b/block/blk-mq.c
+@@ -41,7 +41,7 @@
+ #include "blk-mq-sched.h"
+ #include "blk-rq-qos.h"
+ 
+-static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
++static DEFINE_PER_CPU(struct llist_head, blk_cpu_done);
+ 
+ static void blk_mq_poll_stats_start(struct request_queue *q);
+ static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb);
+@@ -569,68 +569,29 @@ void blk_mq_end_request(struct request *rq, blk_status_t error)
+ }
+ EXPORT_SYMBOL(blk_mq_end_request);
+ 
+-/*
+- * Softirq action handler - move entries to local list and loop over them
+- * while passing them to the queue registered handler.
+- */
+-static __latent_entropy void blk_done_softirq(struct softirq_action *h)
++static void blk_complete_reqs(struct llist_head *list)
+ {
+-	struct list_head *cpu_list, local_list;
+-
+-	local_irq_disable();
+-	cpu_list = this_cpu_ptr(&blk_cpu_done);
+-	list_replace_init(cpu_list, &local_list);
+-	local_irq_enable();
+-
+-	while (!list_empty(&local_list)) {
+-		struct request *rq;
++	struct llist_node *entry = llist_reverse_order(llist_del_all(list));
++	struct request *rq, *next;
+ 
+-		rq = list_entry(local_list.next, struct request, ipi_list);
+-		list_del_init(&rq->ipi_list);
++	llist_for_each_entry_safe(rq, next, entry, ipi_list)
+ 		rq->q->mq_ops->complete(rq);
+-	}
+ }
+ 
+-static void blk_mq_trigger_softirq(struct request *rq)
++static __latent_entropy void blk_done_softirq(struct softirq_action *h)
+ {
+-	struct list_head *list;
+-	unsigned long flags;
+-
+-	local_irq_save(flags);
+-	list = this_cpu_ptr(&blk_cpu_done);
+-	list_add_tail(&rq->ipi_list, list);
+-
+-	/*
+-	 * If the list only contains our just added request, signal a raise of
+-	 * the softirq.  If there are already entries there, someone already
+-	 * raised the irq but it hasn't run yet.
+-	 */
+-	if (list->next == &rq->ipi_list)
+-		raise_softirq_irqoff(BLOCK_SOFTIRQ);
+-	local_irq_restore(flags);
++	blk_complete_reqs(this_cpu_ptr(&blk_cpu_done));
+ }
+ 
+ static int blk_softirq_cpu_dead(unsigned int cpu)
+ {
+-	/*
+-	 * If a CPU goes away, splice its entries to the current CPU
+-	 * and trigger a run of the softirq
+-	 */
+-	local_irq_disable();
+-	list_splice_init(&per_cpu(blk_cpu_done, cpu),
+-			 this_cpu_ptr(&blk_cpu_done));
+-	raise_softirq_irqoff(BLOCK_SOFTIRQ);
+-	local_irq_enable();
+-
++	blk_complete_reqs(&per_cpu(blk_cpu_done, cpu));
+ 	return 0;
+ }
+ 
+-
+ static void __blk_mq_complete_request_remote(void *data)
+ {
+-	struct request *rq = data;
+-
+-	blk_mq_trigger_softirq(rq);
++	__raise_softirq_irqoff(BLOCK_SOFTIRQ);
+ }
+ 
+ static inline bool blk_mq_complete_need_ipi(struct request *rq)
+@@ -659,6 +620,32 @@ static inline bool blk_mq_complete_need_ipi(struct request *rq)
+ 	return cpu_online(rq->mq_ctx->cpu);
+ }
+ 
++static void blk_mq_complete_send_ipi(struct request *rq)
++{
++	struct llist_head *list;
++	unsigned int cpu;
++
++	cpu = rq->mq_ctx->cpu;
++	list = &per_cpu(blk_cpu_done, cpu);
++	if (llist_add(&rq->ipi_list, list)) {
++		rq->csd.func = __blk_mq_complete_request_remote;
++		rq->csd.info = rq;
++		rq->csd.flags = 0;
++		smp_call_function_single_async(cpu, &rq->csd);
++	}
++}
++
++static void blk_mq_raise_softirq(struct request *rq)
++{
++	struct llist_head *list;
++
++	preempt_disable();
++	list = this_cpu_ptr(&blk_cpu_done);
++	if (llist_add(&rq->ipi_list, list))
++		raise_softirq(BLOCK_SOFTIRQ);
++	preempt_enable();
++}
++
+ bool blk_mq_complete_request_remote(struct request *rq)
+ {
+ 	WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
+@@ -671,17 +658,15 @@ bool blk_mq_complete_request_remote(struct request *rq)
+ 		return false;
+ 
+ 	if (blk_mq_complete_need_ipi(rq)) {
+-		rq->csd.func = __blk_mq_complete_request_remote;
+-		rq->csd.info = rq;
+-		rq->csd.flags = 0;
+-		smp_call_function_single_async(rq->mq_ctx->cpu, &rq->csd);
+-	} else {
+-		if (rq->q->nr_hw_queues > 1)
+-			return false;
+-		blk_mq_trigger_softirq(rq);
++		blk_mq_complete_send_ipi(rq);
++		return true;
+ 	}
+ 
+-	return true;
++	if (rq->q->nr_hw_queues == 1) {
++		blk_mq_raise_softirq(rq);
++		return true;
++	}
++	return false;
+ }
+ EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote);
+ 
+@@ -3980,7 +3965,7 @@ static int __init blk_mq_init(void)
+ 	int i;
+ 
+ 	for_each_possible_cpu(i)
+-		INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
++		init_llist_head(&per_cpu(blk_cpu_done, i));
+ 	open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
+ 
+ 	cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD,
+diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
+index 98fdf5a31fd6..b35193aec5e3 100644
+--- a/include/linux/blkdev.h
++++ b/include/linux/blkdev.h
+@@ -161,7 +161,7 @@ struct request {
+ 	 */
+ 	union {
+ 		struct hlist_node hash;	/* merge hash */
+-		struct list_head ipi_list;
++		struct llist_node ipi_list;
+ 	};
+ 
+ 	/*
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0066-lib-test_lockup-Minimum-fix-to-get-it-compiled-on-PR.patch b/debian/patches-rt/0066-lib-test_lockup-Minimum-fix-to-get-it-compiled-on-PR.patch
new file mode 100644
index 000000000..e52831303
--- /dev/null
+++ b/debian/patches-rt/0066-lib-test_lockup-Minimum-fix-to-get-it-compiled-on-PR.patch
@@ -0,0 +1,65 @@
+From 11e632bdd63b66d70c365424a1ceb502cb0c02ef Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 28 Oct 2020 18:55:27 +0100
+Subject: [PATCH 066/323] lib/test_lockup: Minimum fix to get it compiled on
+ PREEMPT_RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+On PREEMPT_RT the locks are quite different so they can't be tested as
+it is done below. The alternative is test for the waitlock within
+rtmutex.
+
+This is the bare minim to get it compiled. Problems which exists on
+PREEMP_RT:
+- none of the locks (spinlock_t, rwlock_t, mutex_t, rw_semaphore) may be
+  acquired with disabled preemption or interrupts.
+  If I read the code correct the it is possible to acquire a mutex with
+  disabled interrupts.
+  I don't know how to obtain a lock pointer. Technically they are not
+  exported to userland.
+
+- memory can not be allocated with disabled premption or interrupts even
+  with GFP_ATOMIC.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ lib/test_lockup.c | 16 ++++++++++++++++
+ 1 file changed, 16 insertions(+)
+
+diff --git a/lib/test_lockup.c b/lib/test_lockup.c
+index 78a630bbd03d..d27a80502204 100644
+--- a/lib/test_lockup.c
++++ b/lib/test_lockup.c
+@@ -485,6 +485,21 @@ static int __init test_lockup_init(void)
+ 		return -EINVAL;
+ 
+ #ifdef CONFIG_DEBUG_SPINLOCK
++#ifdef CONFIG_PREEMPT_RT
++	if (test_magic(lock_spinlock_ptr,
++		       offsetof(spinlock_t, lock.wait_lock.magic),
++		       SPINLOCK_MAGIC) ||
++	    test_magic(lock_rwlock_ptr,
++		       offsetof(rwlock_t, rtmutex.wait_lock.magic),
++		       SPINLOCK_MAGIC) ||
++	    test_magic(lock_mutex_ptr,
++		       offsetof(struct mutex, lock.wait_lock.magic),
++		       SPINLOCK_MAGIC) ||
++	    test_magic(lock_rwsem_ptr,
++		       offsetof(struct rw_semaphore, rtmutex.wait_lock.magic),
++		       SPINLOCK_MAGIC))
++		return -EINVAL;
++#else
+ 	if (test_magic(lock_spinlock_ptr,
+ 		       offsetof(spinlock_t, rlock.magic),
+ 		       SPINLOCK_MAGIC) ||
+@@ -498,6 +513,7 @@ static int __init test_lockup_init(void)
+ 		       offsetof(struct rw_semaphore, wait_lock.magic),
+ 		       SPINLOCK_MAGIC))
+ 		return -EINVAL;
++#endif
+ #endif
+ 
+ 	if ((wait_state != TASK_RUNNING ||
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0067-timers-Don-t-block-on-expiry_lock-for-TIMER_IRQSAFE.patch b/debian/patches-rt/0067-timers-Don-t-block-on-expiry_lock-for-TIMER_IRQSAFE.patch
new file mode 100644
index 000000000..01c62e677
--- /dev/null
+++ b/debian/patches-rt/0067-timers-Don-t-block-on-expiry_lock-for-TIMER_IRQSAFE.patch
@@ -0,0 +1,60 @@
+From a7d720657001cb31fc09699861f12726418a4bf8 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 2 Nov 2020 14:14:24 +0100
+Subject: [PATCH 067/323] timers: Don't block on ->expiry_lock for
+ TIMER_IRQSAFE
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+PREEMPT_RT does not spin and wait until a running timer completes its
+callback but instead it blocks on a sleeping lock to prevent a deadlock.
+
+This blocking can not be done for workqueue's IRQ_SAFE timer which will
+be canceled in an IRQ-off region. It has to happen to in IRQ-off region
+because changing the PENDING bit and clearing the timer must not be
+interrupted to avoid a busy-loop.
+
+The callback invocation of IRQSAFE timer is not preempted on PREEMPT_RT
+so there is no need to synchronize on timer_base::expiry_lock.
+
+Don't acquire the timer_base::expiry_lock for TIMER_IRQSAFE flagged
+timer.
+Add a lockdep annotation to ensure that this function is always invoked
+in preemptible context on PREEMPT_RT.
+
+Reported-by: Mike Galbraith <efault@gmx.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Cc: stable-rt@vger.kernel.org
+---
+ kernel/time/timer.c | 9 ++++++++-
+ 1 file changed, 8 insertions(+), 1 deletion(-)
+
+diff --git a/kernel/time/timer.c b/kernel/time/timer.c
+index e87e638c31bd..a4fdc7cfb723 100644
+--- a/kernel/time/timer.c
++++ b/kernel/time/timer.c
+@@ -1287,7 +1287,7 @@ static void del_timer_wait_running(struct timer_list *timer)
+ 	u32 tf;
+ 
+ 	tf = READ_ONCE(timer->flags);
+-	if (!(tf & TIMER_MIGRATING)) {
++	if (!(tf & (TIMER_MIGRATING | TIMER_IRQSAFE))) {
+ 		struct timer_base *base = get_timer_base(tf);
+ 
+ 		/*
+@@ -1371,6 +1371,13 @@ int del_timer_sync(struct timer_list *timer)
+ 	 */
+ 	WARN_ON(in_irq() && !(timer->flags & TIMER_IRQSAFE));
+ 
++	/*
++	 * Must be able to sleep on PREEMPT_RT because of the slowpath in
++	 * del_timer_wait_running().
++	 */
++	if (IS_ENABLED(CONFIG_PREEMPT_RT) && !(timer->flags & TIMER_IRQSAFE))
++		lockdep_assert_preemption_enabled();
++
+ 	do {
+ 		ret = try_to_del_timer_sync(timer);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0068-kthread-Move-prio-affinite-change-into-the-newly-cre.patch b/debian/patches-rt/0068-kthread-Move-prio-affinite-change-into-the-newly-cre.patch
new file mode 100644
index 000000000..ee2883f8e
--- /dev/null
+++ b/debian/patches-rt/0068-kthread-Move-prio-affinite-change-into-the-newly-cre.patch
@@ -0,0 +1,86 @@
+From b0fd4a90cb328b61c6fe14df3a7fc4a79745fd2f Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 9 Nov 2020 21:30:41 +0100
+Subject: [PATCH 068/323] kthread: Move prio/affinite change into the newly
+ created thread
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+With enabled threaded interrupts the nouveau driver reported the
+following:
+| Chain exists of:
+|   &mm->mmap_lock#2 --> &device->mutex --> &cpuset_rwsem
+|
+|  Possible unsafe locking scenario:
+|
+|        CPU0                    CPU1
+|        ----                    ----
+|   lock(&cpuset_rwsem);
+|                                lock(&device->mutex);
+|                                lock(&cpuset_rwsem);
+|   lock(&mm->mmap_lock#2);
+
+The device->mutex is nvkm_device::mutex.
+
+Unblocking the lockchain at `cpuset_rwsem' is probably the easiest thing
+to do.
+Move the priority reset to the start of the newly created thread.
+
+Fixes: 710da3c8ea7df ("sched/core: Prevent race condition between cpuset and __sched_setscheduler()")
+Reported-by: Mike Galbraith <efault@gmx.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Link: https://lkml.kernel.org/r/a23a826af7c108ea5651e73b8fbae5e653f16e86.camel@gmx.de
+---
+ kernel/kthread.c | 16 ++++++++--------
+ 1 file changed, 8 insertions(+), 8 deletions(-)
+
+diff --git a/kernel/kthread.c b/kernel/kthread.c
+index 508fe5278285..3ce6a31db7b4 100644
+--- a/kernel/kthread.c
++++ b/kernel/kthread.c
+@@ -264,6 +264,7 @@ EXPORT_SYMBOL_GPL(kthread_parkme);
+ 
+ static int kthread(void *_create)
+ {
++	static const struct sched_param param = { .sched_priority = 0 };
+ 	/* Copy data: it's on kthread's stack */
+ 	struct kthread_create_info *create = _create;
+ 	int (*threadfn)(void *data) = create->threadfn;
+@@ -294,6 +295,13 @@ static int kthread(void *_create)
+ 	init_completion(&self->parked);
+ 	current->vfork_done = &self->exited;
+ 
++	/*
++	 * The new thread inherited kthreadd's priority and CPU mask. Reset
++	 * back to default in case they have been changed.
++	 */
++	sched_setscheduler_nocheck(current, SCHED_NORMAL, &param);
++	set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_KTHREAD));
++
+ 	/* OK, tell user we're spawned, wait for stop or wakeup */
+ 	__set_current_state(TASK_UNINTERRUPTIBLE);
+ 	create->result = current;
+@@ -391,7 +399,6 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data),
+ 	}
+ 	task = create->result;
+ 	if (!IS_ERR(task)) {
+-		static const struct sched_param param = { .sched_priority = 0 };
+ 		char name[TASK_COMM_LEN];
+ 
+ 		/*
+@@ -400,13 +407,6 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data),
+ 		 */
+ 		vsnprintf(name, sizeof(name), namefmt, args);
+ 		set_task_comm(task, name);
+-		/*
+-		 * root may have changed our (kthreadd's) priority or CPU mask.
+-		 * The kernel thread should not inherit these properties.
+-		 */
+-		sched_setscheduler_nocheck(task, SCHED_NORMAL, &param);
+-		set_cpus_allowed_ptr(task,
+-				     housekeeping_cpumask(HK_FLAG_KTHREAD));
+ 	}
+ 	kfree(create);
+ 	return task;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0069-genirq-Move-prio-assignment-into-the-newly-created-t.patch b/debian/patches-rt/0069-genirq-Move-prio-assignment-into-the-newly-created-t.patch
new file mode 100644
index 000000000..f09b701ab
--- /dev/null
+++ b/debian/patches-rt/0069-genirq-Move-prio-assignment-into-the-newly-created-t.patch
@@ -0,0 +1,63 @@
+From 617294b2f33cec584f48c12d914fcc982f317be5 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Mon, 9 Nov 2020 23:32:39 +0100
+Subject: [PATCH 069/323] genirq: Move prio assignment into the newly created
+ thread
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+With enabled threaded interrupts the nouveau driver reported the
+following:
+| Chain exists of:
+|   &mm->mmap_lock#2 --> &device->mutex --> &cpuset_rwsem
+|
+|  Possible unsafe locking scenario:
+|
+|        CPU0                    CPU1
+|        ----                    ----
+|   lock(&cpuset_rwsem);
+|                                lock(&device->mutex);
+|                                lock(&cpuset_rwsem);
+|   lock(&mm->mmap_lock#2);
+
+The device->mutex is nvkm_device::mutex.
+
+Unblocking the lockchain at `cpuset_rwsem' is probably the easiest thing
+to do.
+Move the priority assignment to the start of the newly created thread.
+
+Fixes: 710da3c8ea7df ("sched/core: Prevent race condition between cpuset and __sched_setscheduler()")
+Reported-by: Mike Galbraith <efault@gmx.de>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+[bigeasy: Patch description]
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Link: https://lkml.kernel.org/r/a23a826af7c108ea5651e73b8fbae5e653f16e86.camel@gmx.de
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ kernel/irq/manage.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
+index 0159925054fa..5ec167fb77b9 100644
+--- a/kernel/irq/manage.c
++++ b/kernel/irq/manage.c
+@@ -1201,6 +1201,8 @@ static int irq_thread(void *data)
+ 
+ 	irq_thread_set_ready(desc, action);
+ 
++	sched_set_fifo(current);
++
+ 	if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
+ 					&action->thread_flags))
+ 		handler_fn = irq_forced_thread_fn;
+@@ -1366,8 +1368,6 @@ setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary)
+ 	if (IS_ERR(t))
+ 		return PTR_ERR(t);
+ 
+-	sched_set_fifo(t);
+-
+ 	/*
+ 	 * We keep the reference to the task struct even if
+ 	 * the thread dies to avoid that the interrupt code
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0070-notifier-Make-atomic_notifiers-use-raw_spinlock.patch b/debian/patches-rt/0070-notifier-Make-atomic_notifiers-use-raw_spinlock.patch
new file mode 100644
index 000000000..74ee5109b
--- /dev/null
+++ b/debian/patches-rt/0070-notifier-Make-atomic_notifiers-use-raw_spinlock.patch
@@ -0,0 +1,132 @@
+From f603fbc6eaf37d836e3498b47cef43965730bcda Mon Sep 17 00:00:00 2001
+From: Valentin Schneider <valentin.schneider@arm.com>
+Date: Sun, 22 Nov 2020 20:19:04 +0000
+Subject: [PATCH 070/323] notifier: Make atomic_notifiers use raw_spinlock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Booting a recent PREEMPT_RT kernel (v5.10-rc3-rt7-rebase) on my arm64 Juno
+leads to the idle task blocking on an RT sleeping spinlock down some
+notifier path:
+
+  [    1.809101] BUG: scheduling while atomic: swapper/5/0/0x00000002
+  [    1.809116] Modules linked in:
+  [    1.809123] Preemption disabled at:
+  [    1.809125] secondary_start_kernel (arch/arm64/kernel/smp.c:227)
+  [    1.809146] CPU: 5 PID: 0 Comm: swapper/5 Tainted: G        W         5.10.0-rc3-rt7 #168
+  [    1.809153] Hardware name: ARM Juno development board (r0) (DT)
+  [    1.809158] Call trace:
+  [    1.809160] dump_backtrace (arch/arm64/kernel/stacktrace.c:100 (discriminator 1))
+  [    1.809170] show_stack (arch/arm64/kernel/stacktrace.c:198)
+  [    1.809178] dump_stack (lib/dump_stack.c:122)
+  [    1.809188] __schedule_bug (kernel/sched/core.c:4886)
+  [    1.809197] __schedule (./arch/arm64/include/asm/preempt.h:18 kernel/sched/core.c:4913 kernel/sched/core.c:5040)
+  [    1.809204] preempt_schedule_lock (kernel/sched/core.c:5365 (discriminator 1))
+  [    1.809210] rt_spin_lock_slowlock_locked (kernel/locking/rtmutex.c:1072)
+  [    1.809217] rt_spin_lock_slowlock (kernel/locking/rtmutex.c:1110)
+  [    1.809224] rt_spin_lock (./include/linux/rcupdate.h:647 kernel/locking/rtmutex.c:1139)
+  [    1.809231] atomic_notifier_call_chain_robust (kernel/notifier.c:71 kernel/notifier.c:118 kernel/notifier.c:186)
+  [    1.809240] cpu_pm_enter (kernel/cpu_pm.c:39 kernel/cpu_pm.c:93)
+  [    1.809249] psci_enter_idle_state (drivers/cpuidle/cpuidle-psci.c:52 drivers/cpuidle/cpuidle-psci.c:129)
+  [    1.809258] cpuidle_enter_state (drivers/cpuidle/cpuidle.c:238)
+  [    1.809267] cpuidle_enter (drivers/cpuidle/cpuidle.c:353)
+  [    1.809275] do_idle (kernel/sched/idle.c:132 kernel/sched/idle.c:213 kernel/sched/idle.c:273)
+  [    1.809282] cpu_startup_entry (kernel/sched/idle.c:368 (discriminator 1))
+  [    1.809288] secondary_start_kernel (arch/arm64/kernel/smp.c:273)
+
+Two points worth noting:
+
+1) That this is conceptually the same issue as pointed out in:
+   313c8c16ee62 ("PM / CPU: replace raw_notifier with atomic_notifier")
+2) Only the _robust() variant of atomic_notifier callchains suffer from
+   this
+
+AFAICT only the cpu_pm_notifier_chain really needs to be changed, but
+singling it out would mean introducing a new (truly) non-blocking API. At
+the same time, callers that are fine with any blocking within the call
+chain should use blocking notifiers, so patching up all atomic_notifier's
+doesn't seem *too* crazy to me.
+
+Fixes: 70d932985757 ("notifier: Fix broken error handling pattern")
+Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
+Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
+Link: https://lkml.kernel.org/r/20201122201904.30940-1-valentin.schneider@arm.com
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/notifier.h |  6 +++---
+ kernel/notifier.c        | 12 ++++++------
+ 2 files changed, 9 insertions(+), 9 deletions(-)
+
+diff --git a/include/linux/notifier.h b/include/linux/notifier.h
+index 2fb373a5c1ed..723bc2df6388 100644
+--- a/include/linux/notifier.h
++++ b/include/linux/notifier.h
+@@ -58,7 +58,7 @@ struct notifier_block {
+ };
+ 
+ struct atomic_notifier_head {
+-	spinlock_t lock;
++	raw_spinlock_t lock;
+ 	struct notifier_block __rcu *head;
+ };
+ 
+@@ -78,7 +78,7 @@ struct srcu_notifier_head {
+ };
+ 
+ #define ATOMIC_INIT_NOTIFIER_HEAD(name) do {	\
+-		spin_lock_init(&(name)->lock);	\
++		raw_spin_lock_init(&(name)->lock);	\
+ 		(name)->head = NULL;		\
+ 	} while (0)
+ #define BLOCKING_INIT_NOTIFIER_HEAD(name) do {	\
+@@ -95,7 +95,7 @@ extern void srcu_init_notifier_head(struct srcu_notifier_head *nh);
+ 		cleanup_srcu_struct(&(name)->srcu);
+ 
+ #define ATOMIC_NOTIFIER_INIT(name) {				\
+-		.lock = __SPIN_LOCK_UNLOCKED(name.lock),	\
++		.lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock),	\
+ 		.head = NULL }
+ #define BLOCKING_NOTIFIER_INIT(name) {				\
+ 		.rwsem = __RWSEM_INITIALIZER((name).rwsem),	\
+diff --git a/kernel/notifier.c b/kernel/notifier.c
+index 1b019cbca594..c20782f07643 100644
+--- a/kernel/notifier.c
++++ b/kernel/notifier.c
+@@ -142,9 +142,9 @@ int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
+ 	unsigned long flags;
+ 	int ret;
+ 
+-	spin_lock_irqsave(&nh->lock, flags);
++	raw_spin_lock_irqsave(&nh->lock, flags);
+ 	ret = notifier_chain_register(&nh->head, n);
+-	spin_unlock_irqrestore(&nh->lock, flags);
++	raw_spin_unlock_irqrestore(&nh->lock, flags);
+ 	return ret;
+ }
+ EXPORT_SYMBOL_GPL(atomic_notifier_chain_register);
+@@ -164,9 +164,9 @@ int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
+ 	unsigned long flags;
+ 	int ret;
+ 
+-	spin_lock_irqsave(&nh->lock, flags);
++	raw_spin_lock_irqsave(&nh->lock, flags);
+ 	ret = notifier_chain_unregister(&nh->head, n);
+-	spin_unlock_irqrestore(&nh->lock, flags);
++	raw_spin_unlock_irqrestore(&nh->lock, flags);
+ 	synchronize_rcu();
+ 	return ret;
+ }
+@@ -182,9 +182,9 @@ int atomic_notifier_call_chain_robust(struct atomic_notifier_head *nh,
+ 	 * Musn't use RCU; because then the notifier list can
+ 	 * change between the up and down traversal.
+ 	 */
+-	spin_lock_irqsave(&nh->lock, flags);
++	raw_spin_lock_irqsave(&nh->lock, flags);
+ 	ret = notifier_call_chain_robust(&nh->head, val_up, val_down, v);
+-	spin_unlock_irqrestore(&nh->lock, flags);
++	raw_spin_unlock_irqrestore(&nh->lock, flags);
+ 
+ 	return ret;
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0071-rcu-Make-RCU_BOOST-default-on-CONFIG_PREEMPT_RT.patch b/debian/patches-rt/0071-rcu-Make-RCU_BOOST-default-on-CONFIG_PREEMPT_RT.patch
new file mode 100644
index 000000000..c6be2d81c
--- /dev/null
+++ b/debian/patches-rt/0071-rcu-Make-RCU_BOOST-default-on-CONFIG_PREEMPT_RT.patch
@@ -0,0 +1,41 @@
+From b9c110646f281f521cc06039710f979b363478b9 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 15 Dec 2020 15:16:45 +0100
+Subject: [PATCH 071/323] rcu: Make RCU_BOOST default on CONFIG_PREEMPT_RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+On PREEMPT_RT kernels, RCU callbacks are deferred to the `rcuc' kthread.
+This can stall RCU grace periods due to lengthy preemption not only of RCU
+readers but also of 'rcuc' kthreads, either of which prevent grace periods
+from completing, which can in turn result in OOM.  Because PREEMPT_RT
+kernels have more kthreads that can block grace periods, it is more
+important for such kernels to enable RCU_BOOST.
+
+This commit therefore makes RCU_BOOST the default on PREEMPT_RT.
+RCU_BOOST can still be manually disabled if need be.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/rcu/Kconfig | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
+index cd6e11403f1b..0c71197857f6 100644
+--- a/kernel/rcu/Kconfig
++++ b/kernel/rcu/Kconfig
+@@ -189,8 +189,8 @@ config RCU_FAST_NO_HZ
+ 
+ config RCU_BOOST
+ 	bool "Enable RCU priority boosting"
+-	depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT
+-	default n
++	depends on (RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT) || PREEMPT_RT
++	default y if PREEMPT_RT
+ 	help
+ 	  This option boosts the priority of preempted RCU readers that
+ 	  block the current preemptible RCU grace period for too long.
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0072-rcu-Unconditionally-use-rcuc-threads-on-PREEMPT_RT.patch b/debian/patches-rt/0072-rcu-Unconditionally-use-rcuc-threads-on-PREEMPT_RT.patch
new file mode 100644
index 000000000..2c85d9dd0
--- /dev/null
+++ b/debian/patches-rt/0072-rcu-Unconditionally-use-rcuc-threads-on-PREEMPT_RT.patch
@@ -0,0 +1,66 @@
+From 8cc685c333f0deef6d724211a7f0ff37648d24c7 Mon Sep 17 00:00:00 2001
+From: Scott Wood <swood@redhat.com>
+Date: Tue, 15 Dec 2020 15:16:46 +0100
+Subject: [PATCH 072/323] rcu: Unconditionally use rcuc threads on PREEMPT_RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+PREEMPT_RT systems have long used the rcutree.use_softirq kernel
+boot parameter to avoid use of RCU_SOFTIRQ handlers, which can disrupt
+real-time applications by invoking callbacks during return from interrupts
+that arrived while executing time-critical code.  This kernel boot
+parameter instead runs RCU core processing in an 'rcuc' kthread, thus
+allowing the scheduler to do its job of avoiding disrupting time-critical
+code.
+
+This commit therefore disables the rcutree.use_softirq kernel boot
+parameter on PREEMPT_RT systems, thus forcing such systems to do RCU
+core processing in 'rcuc' kthreads.  This approach has long been in
+use by users of the -rt patchset, and there have been no complaints.
+There is therefore no way for the system administrator to override this
+choice, at least without modifying and rebuilding the kernel.
+
+Signed-off-by: Scott Wood <swood@redhat.com>
+[bigeasy: Reword commit message]
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+[ paulmck: Update kernel-parameters.txt accordingly. ]
+Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ Documentation/admin-guide/kernel-parameters.txt | 4 ++++
+ kernel/rcu/tree.c                               | 4 +++-
+ 2 files changed, 7 insertions(+), 1 deletion(-)
+
+diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
+index f1f7c068cf65..c2afb3304825 100644
+--- a/Documentation/admin-guide/kernel-parameters.txt
++++ b/Documentation/admin-guide/kernel-parameters.txt
+@@ -4191,6 +4191,10 @@
+ 			value, meaning that RCU_SOFTIRQ is used by default.
+ 			Specify rcutree.use_softirq=0 to use rcuc kthreads.
+ 
++			But note that CONFIG_PREEMPT_RT=y kernels disable
++			this kernel boot parameter, forcibly setting it
++			to zero.
++
+ 	rcutree.rcu_fanout_exact= [KNL]
+ 			Disable autobalancing of the rcu_node combining
+ 			tree.  This is used by rcutorture, and might
+diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
+index 06bfe61d3cd3..39b3b56ad92d 100644
+--- a/kernel/rcu/tree.c
++++ b/kernel/rcu/tree.c
+@@ -101,8 +101,10 @@ static struct rcu_state rcu_state = {
+ static bool dump_tree;
+ module_param(dump_tree, bool, 0444);
+ /* By default, use RCU_SOFTIRQ instead of rcuc kthreads. */
+-static bool use_softirq = true;
++static bool use_softirq = !IS_ENABLED(CONFIG_PREEMPT_RT);
++#ifndef CONFIG_PREEMPT_RT
+ module_param(use_softirq, bool, 0444);
++#endif
+ /* Control rcu_node-tree auto-balancing at boot time. */
+ static bool rcu_fanout_exact;
+ module_param(rcu_fanout_exact, bool, 0444);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0073-rcu-Enable-rcu_normal_after_boot-unconditionally-for.patch b/debian/patches-rt/0073-rcu-Enable-rcu_normal_after_boot-unconditionally-for.patch
new file mode 100644
index 000000000..ec9afba35
--- /dev/null
+++ b/debian/patches-rt/0073-rcu-Enable-rcu_normal_after_boot-unconditionally-for.patch
@@ -0,0 +1,72 @@
+From be1e6f72a91c1c6b65594bba32401b029c7699b8 Mon Sep 17 00:00:00 2001
+From: Julia Cartwright <julia@ni.com>
+Date: Tue, 15 Dec 2020 15:16:47 +0100
+Subject: [PATCH 073/323] rcu: Enable rcu_normal_after_boot unconditionally for
+ RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Expedited RCU grace periods send IPIs to all non-idle CPUs, and thus can
+disrupt time-critical code in real-time applications.  However, there
+is a portion of boot-time processing (presumably before any real-time
+applications have started) where expedited RCU grace periods are the only
+option.  And so it is that experience with the -rt patchset indicates that
+PREEMPT_RT systems should always set the rcupdate.rcu_normal_after_boot
+kernel boot parameter.
+
+This commit therefore makes the post-boot application environment safe
+for real-time applications by making PREEMPT_RT systems disable the
+rcupdate.rcu_normal_after_boot kernel boot parameter and acting as
+if this parameter had been set.  This means that post-boot calls to
+synchronize_rcu_expedited() will be treated as if they were instead
+calls to synchronize_rcu(), thus preventing the IPIs, and thus avoiding
+disrupting real-time applications.
+
+Suggested-by: Luiz Capitulino <lcapitulino@redhat.com>
+Acked-by: Paul E. McKenney <paulmck@linux.ibm.com>
+Signed-off-by: Julia Cartwright <julia@ni.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+[ paulmck: Update kernel-parameters.txt accordingly. ]
+Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
+ kernel/rcu/update.c                             | 4 +++-
+ 2 files changed, 10 insertions(+), 1 deletion(-)
+
+diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
+index c2afb3304825..23fd09f5351d 100644
+--- a/Documentation/admin-guide/kernel-parameters.txt
++++ b/Documentation/admin-guide/kernel-parameters.txt
+@@ -4573,6 +4573,13 @@
+ 			only normal grace-period primitives.  No effect
+ 			on CONFIG_TINY_RCU kernels.
+ 
++			But note that CONFIG_PREEMPT_RT=y kernels enables
++			this kernel boot parameter, forcibly setting
++			it to the value one, that is, converting any
++			post-boot attempt at an expedited RCU grace
++			period to instead use normal non-expedited
++			grace-period processing.
++
+ 	rcupdate.rcu_task_ipi_delay= [KNL]
+ 			Set time in jiffies during which RCU tasks will
+ 			avoid sending IPIs, starting with the beginning
+diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
+index 849f0aa99333..dd94a602a6d2 100644
+--- a/kernel/rcu/update.c
++++ b/kernel/rcu/update.c
+@@ -56,8 +56,10 @@
+ #ifndef CONFIG_TINY_RCU
+ module_param(rcu_expedited, int, 0);
+ module_param(rcu_normal, int, 0);
+-static int rcu_normal_after_boot;
++static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT);
++#ifndef CONFIG_PREEMPT_RT
+ module_param(rcu_normal_after_boot, int, 0);
++#endif
+ #endif /* #ifndef CONFIG_TINY_RCU */
+ 
+ #ifdef CONFIG_DEBUG_LOCK_ALLOC
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0074-doc-Update-RCU-s-requirements-page-about-the-PREEMPT.patch b/debian/patches-rt/0074-doc-Update-RCU-s-requirements-page-about-the-PREEMPT.patch
new file mode 100644
index 000000000..81d863443
--- /dev/null
+++ b/debian/patches-rt/0074-doc-Update-RCU-s-requirements-page-about-the-PREEMPT.patch
@@ -0,0 +1,35 @@
+From 98e9f8e6202660f2965bc68d54447861280e81b9 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 15 Dec 2020 15:16:48 +0100
+Subject: [PATCH 074/323] doc: Update RCU's requirements page about the
+ PREEMPT_RT wiki.
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The PREEMPT_RT wiki moved from kernel.org to the Linux Foundation wiki.
+The kernel.org wiki is read only.
+
+This commit therefore updates the URL of the active PREEMPT_RT wiki.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ Documentation/RCU/Design/Requirements/Requirements.rst | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/Documentation/RCU/Design/Requirements/Requirements.rst b/Documentation/RCU/Design/Requirements/Requirements.rst
+index 1ae79a10a8de..0f7e0237ea14 100644
+--- a/Documentation/RCU/Design/Requirements/Requirements.rst
++++ b/Documentation/RCU/Design/Requirements/Requirements.rst
+@@ -2289,7 +2289,7 @@ decides to throw at it.
+ 
+ The Linux kernel is used for real-time workloads, especially in
+ conjunction with the `-rt
+-patchset <https://rt.wiki.kernel.org/index.php/Main_Page>`__. The
++patchset <https://wiki.linuxfoundation.org/realtime/>`__. The
+ real-time-latency response requirements are such that the traditional
+ approach of disabling preemption across RCU read-side critical sections
+ is inappropriate. Kernels built with ``CONFIG_PREEMPT=y`` therefore use
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0075-doc-Use-CONFIG_PREEMPTION.patch b/debian/patches-rt/0075-doc-Use-CONFIG_PREEMPTION.patch
new file mode 100644
index 000000000..3ddcf14fa
--- /dev/null
+++ b/debian/patches-rt/0075-doc-Use-CONFIG_PREEMPTION.patch
@@ -0,0 +1,250 @@
+From d9780d88d268b12562427ef709de6ab2b8c85188 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 15 Dec 2020 15:16:49 +0100
+Subject: [PATCH 075/323] doc: Use CONFIG_PREEMPTION
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
+Both PREEMPT and PREEMPT_RT require the same functionality which today
+depends on CONFIG_PREEMPT.
+
+Update the documents and mention CONFIG_PREEMPTION. Spell out
+CONFIG_PREEMPT_RT (instead PREEMPT_RT) since it is an option now.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ .../Expedited-Grace-Periods.rst               |  4 ++--
+ .../RCU/Design/Requirements/Requirements.rst  | 24 +++++++++----------
+ Documentation/RCU/checklist.rst               |  2 +-
+ Documentation/RCU/rcubarrier.rst              |  6 ++---
+ Documentation/RCU/stallwarn.rst               |  4 ++--
+ Documentation/RCU/whatisRCU.rst               | 10 ++++----
+ 6 files changed, 25 insertions(+), 25 deletions(-)
+
+diff --git a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.rst b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.rst
+index 72f0f6fbd53c..6f89cf1e567d 100644
+--- a/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.rst
++++ b/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.rst
+@@ -38,7 +38,7 @@ sections.
+ RCU-preempt Expedited Grace Periods
+ ===================================
+ 
+-``CONFIG_PREEMPT=y`` kernels implement RCU-preempt.
++``CONFIG_PREEMPTION=y`` kernels implement RCU-preempt.
+ The overall flow of the handling of a given CPU by an RCU-preempt
+ expedited grace period is shown in the following diagram:
+ 
+@@ -112,7 +112,7 @@ things.
+ RCU-sched Expedited Grace Periods
+ ---------------------------------
+ 
+-``CONFIG_PREEMPT=n`` kernels implement RCU-sched. The overall flow of
++``CONFIG_PREEMPTION=n`` kernels implement RCU-sched. The overall flow of
+ the handling of a given CPU by an RCU-sched expedited grace period is
+ shown in the following diagram:
+ 
+diff --git a/Documentation/RCU/Design/Requirements/Requirements.rst b/Documentation/RCU/Design/Requirements/Requirements.rst
+index 0f7e0237ea14..17d38480ef5c 100644
+--- a/Documentation/RCU/Design/Requirements/Requirements.rst
++++ b/Documentation/RCU/Design/Requirements/Requirements.rst
+@@ -78,7 +78,7 @@ RCU treats a nested set as one big RCU read-side critical section.
+ Production-quality implementations of ``rcu_read_lock()`` and
+ ``rcu_read_unlock()`` are extremely lightweight, and in fact have
+ exactly zero overhead in Linux kernels built for production use with
+-``CONFIG_PREEMPT=n``.
++``CONFIG_PREEMPTION=n``.
+ 
+ This guarantee allows ordering to be enforced with extremely low
+ overhead to readers, for example:
+@@ -1182,7 +1182,7 @@ and has become decreasingly so as memory sizes have expanded and memory
+ costs have plummeted. However, as I learned from Matt Mackall's
+ `bloatwatch <http://elinux.org/Linux_Tiny-FAQ>`__ efforts, memory
+ footprint is critically important on single-CPU systems with
+-non-preemptible (``CONFIG_PREEMPT=n``) kernels, and thus `tiny
++non-preemptible (``CONFIG_PREEMPTION=n``) kernels, and thus `tiny
+ RCU <https://lkml.kernel.org/g/20090113221724.GA15307@linux.vnet.ibm.com>`__
+ was born. Josh Triplett has since taken over the small-memory banner
+ with his `Linux kernel tinification <https://tiny.wiki.kernel.org/>`__
+@@ -1498,7 +1498,7 @@ limitations.
+ 
+ Implementations of RCU for which ``rcu_read_lock()`` and
+ ``rcu_read_unlock()`` generate no code, such as Linux-kernel RCU when
+-``CONFIG_PREEMPT=n``, can be nested arbitrarily deeply. After all, there
++``CONFIG_PREEMPTION=n``, can be nested arbitrarily deeply. After all, there
+ is no overhead. Except that if all these instances of
+ ``rcu_read_lock()`` and ``rcu_read_unlock()`` are visible to the
+ compiler, compilation will eventually fail due to exhausting memory,
+@@ -1771,7 +1771,7 @@ implementation can be a no-op.
+ 
+ However, once the scheduler has spawned its first kthread, this early
+ boot trick fails for ``synchronize_rcu()`` (as well as for
+-``synchronize_rcu_expedited()``) in ``CONFIG_PREEMPT=y`` kernels. The
++``synchronize_rcu_expedited()``) in ``CONFIG_PREEMPTION=y`` kernels. The
+ reason is that an RCU read-side critical section might be preempted,
+ which means that a subsequent ``synchronize_rcu()`` really does have to
+ wait for something, as opposed to simply returning immediately.
+@@ -2010,7 +2010,7 @@ the following:
+        5 rcu_read_unlock();
+        6 do_something_with(v, user_v);
+ 
+-If the compiler did make this transformation in a ``CONFIG_PREEMPT=n`` kernel
++If the compiler did make this transformation in a ``CONFIG_PREEMPTION=n`` kernel
+ build, and if ``get_user()`` did page fault, the result would be a quiescent
+ state in the middle of an RCU read-side critical section.  This misplaced
+ quiescent state could result in line 4 being a use-after-free access,
+@@ -2292,7 +2292,7 @@ conjunction with the `-rt
+ patchset <https://wiki.linuxfoundation.org/realtime/>`__. The
+ real-time-latency response requirements are such that the traditional
+ approach of disabling preemption across RCU read-side critical sections
+-is inappropriate. Kernels built with ``CONFIG_PREEMPT=y`` therefore use
++is inappropriate. Kernels built with ``CONFIG_PREEMPTION=y`` therefore use
+ an RCU implementation that allows RCU read-side critical sections to be
+ preempted. This requirement made its presence known after users made it
+ clear that an earlier `real-time
+@@ -2414,7 +2414,7 @@ includes ``rcu_read_lock_bh()``, ``rcu_read_unlock_bh()``,
+ ``call_rcu_bh()``, ``rcu_barrier_bh()``, and
+ ``rcu_read_lock_bh_held()``. However, the update-side APIs are now
+ simple wrappers for other RCU flavors, namely RCU-sched in
+-CONFIG_PREEMPT=n kernels and RCU-preempt otherwise.
++CONFIG_PREEMPTION=n kernels and RCU-preempt otherwise.
+ 
+ Sched Flavor (Historical)
+ ~~~~~~~~~~~~~~~~~~~~~~~~~
+@@ -2432,11 +2432,11 @@ not have this property, given that any point in the code outside of an
+ RCU read-side critical section can be a quiescent state. Therefore,
+ *RCU-sched* was created, which follows “classic” RCU in that an
+ RCU-sched grace period waits for pre-existing interrupt and NMI
+-handlers. In kernels built with ``CONFIG_PREEMPT=n``, the RCU and
++handlers. In kernels built with ``CONFIG_PREEMPTION=n``, the RCU and
+ RCU-sched APIs have identical implementations, while kernels built with
+-``CONFIG_PREEMPT=y`` provide a separate implementation for each.
++``CONFIG_PREEMPTION=y`` provide a separate implementation for each.
+ 
+-Note well that in ``CONFIG_PREEMPT=y`` kernels,
++Note well that in ``CONFIG_PREEMPTION=y`` kernels,
+ ``rcu_read_lock_sched()`` and ``rcu_read_unlock_sched()`` disable and
+ re-enable preemption, respectively. This means that if there was a
+ preemption attempt during the RCU-sched read-side critical section,
+@@ -2599,10 +2599,10 @@ userspace execution also delimit tasks-RCU read-side critical sections.
+ 
+ The tasks-RCU API is quite compact, consisting only of
+ ``call_rcu_tasks()``, ``synchronize_rcu_tasks()``, and
+-``rcu_barrier_tasks()``. In ``CONFIG_PREEMPT=n`` kernels, trampolines
++``rcu_barrier_tasks()``. In ``CONFIG_PREEMPTION=n`` kernels, trampolines
+ cannot be preempted, so these APIs map to ``call_rcu()``,
+ ``synchronize_rcu()``, and ``rcu_barrier()``, respectively. In
+-``CONFIG_PREEMPT=y`` kernels, trampolines can be preempted, and these
++``CONFIG_PREEMPTION=y`` kernels, trampolines can be preempted, and these
+ three APIs are therefore implemented by separate functions that check
+ for voluntary context switches.
+ 
+diff --git a/Documentation/RCU/checklist.rst b/Documentation/RCU/checklist.rst
+index 2efed9926c3f..7ed4956043bd 100644
+--- a/Documentation/RCU/checklist.rst
++++ b/Documentation/RCU/checklist.rst
+@@ -214,7 +214,7 @@ over a rather long period of time, but improvements are always welcome!
+ 	the rest of the system.
+ 
+ 7.	As of v4.20, a given kernel implements only one RCU flavor,
+-	which is RCU-sched for PREEMPT=n and RCU-preempt for PREEMPT=y.
++	which is RCU-sched for PREEMPTION=n and RCU-preempt for PREEMPTION=y.
+ 	If the updater uses call_rcu() or synchronize_rcu(),
+ 	then the corresponding readers my use rcu_read_lock() and
+ 	rcu_read_unlock(), rcu_read_lock_bh() and rcu_read_unlock_bh(),
+diff --git a/Documentation/RCU/rcubarrier.rst b/Documentation/RCU/rcubarrier.rst
+index f64f4413a47c..3b4a24877496 100644
+--- a/Documentation/RCU/rcubarrier.rst
++++ b/Documentation/RCU/rcubarrier.rst
+@@ -9,7 +9,7 @@ RCU (read-copy update) is a synchronization mechanism that can be thought
+ of as a replacement for read-writer locking (among other things), but with
+ very low-overhead readers that are immune to deadlock, priority inversion,
+ and unbounded latency. RCU read-side critical sections are delimited
+-by rcu_read_lock() and rcu_read_unlock(), which, in non-CONFIG_PREEMPT
++by rcu_read_lock() and rcu_read_unlock(), which, in non-CONFIG_PREEMPTION
+ kernels, generate no code whatsoever.
+ 
+ This means that RCU writers are unaware of the presence of concurrent
+@@ -329,10 +329,10 @@ Answer: This cannot happen. The reason is that on_each_cpu() has its last
+ 	to smp_call_function() and further to smp_call_function_on_cpu(),
+ 	causing this latter to spin until the cross-CPU invocation of
+ 	rcu_barrier_func() has completed. This by itself would prevent
+-	a grace period from completing on non-CONFIG_PREEMPT kernels,
++	a grace period from completing on non-CONFIG_PREEMPTION kernels,
+ 	since each CPU must undergo a context switch (or other quiescent
+ 	state) before the grace period can complete. However, this is
+-	of no use in CONFIG_PREEMPT kernels.
++	of no use in CONFIG_PREEMPTION kernels.
+ 
+ 	Therefore, on_each_cpu() disables preemption across its call
+ 	to smp_call_function() and also across the local call to
+diff --git a/Documentation/RCU/stallwarn.rst b/Documentation/RCU/stallwarn.rst
+index c9ab6af4d3be..e97d1b4876ef 100644
+--- a/Documentation/RCU/stallwarn.rst
++++ b/Documentation/RCU/stallwarn.rst
+@@ -25,7 +25,7 @@ warnings:
+ 
+ -	A CPU looping with bottom halves disabled.
+ 
+--	For !CONFIG_PREEMPT kernels, a CPU looping anywhere in the kernel
++-	For !CONFIG_PREEMPTION kernels, a CPU looping anywhere in the kernel
+ 	without invoking schedule().  If the looping in the kernel is
+ 	really expected and desirable behavior, you might need to add
+ 	some calls to cond_resched().
+@@ -44,7 +44,7 @@ warnings:
+ 	result in the ``rcu_.*kthread starved for`` console-log message,
+ 	which will include additional debugging information.
+ 
+--	A CPU-bound real-time task in a CONFIG_PREEMPT kernel, which might
++-	A CPU-bound real-time task in a CONFIG_PREEMPTION kernel, which might
+ 	happen to preempt a low-priority task in the middle of an RCU
+ 	read-side critical section.   This is especially damaging if
+ 	that low-priority task is not permitted to run on any other CPU,
+diff --git a/Documentation/RCU/whatisRCU.rst b/Documentation/RCU/whatisRCU.rst
+index fb3ff76c3e73..3b2b1479fd0f 100644
+--- a/Documentation/RCU/whatisRCU.rst
++++ b/Documentation/RCU/whatisRCU.rst
+@@ -684,7 +684,7 @@ Quick Quiz #1:
+ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ This section presents a "toy" RCU implementation that is based on
+ "classic RCU".  It is also short on performance (but only for updates) and
+-on features such as hotplug CPU and the ability to run in CONFIG_PREEMPT
++on features such as hotplug CPU and the ability to run in CONFIG_PREEMPTION
+ kernels.  The definitions of rcu_dereference() and rcu_assign_pointer()
+ are the same as those shown in the preceding section, so they are omitted.
+ ::
+@@ -740,7 +740,7 @@ Quick Quiz #2:
+ Quick Quiz #3:
+ 		If it is illegal to block in an RCU read-side
+ 		critical section, what the heck do you do in
+-		PREEMPT_RT, where normal spinlocks can block???
++		CONFIG_PREEMPT_RT, where normal spinlocks can block???
+ 
+ :ref:`Answers to Quick Quiz <8_whatisRCU>`
+ 
+@@ -1094,7 +1094,7 @@ Quick Quiz #2:
+ 		overhead is **negative**.
+ 
+ Answer:
+-		Imagine a single-CPU system with a non-CONFIG_PREEMPT
++		Imagine a single-CPU system with a non-CONFIG_PREEMPTION
+ 		kernel where a routing table is used by process-context
+ 		code, but can be updated by irq-context code (for example,
+ 		by an "ICMP REDIRECT" packet).	The usual way of handling
+@@ -1121,10 +1121,10 @@ Answer:
+ Quick Quiz #3:
+ 		If it is illegal to block in an RCU read-side
+ 		critical section, what the heck do you do in
+-		PREEMPT_RT, where normal spinlocks can block???
++		CONFIG_PREEMPT_RT, where normal spinlocks can block???
+ 
+ Answer:
+-		Just as PREEMPT_RT permits preemption of spinlock
++		Just as CONFIG_PREEMPT_RT permits preemption of spinlock
+ 		critical sections, it permits preemption of RCU
+ 		read-side critical sections.  It also permits
+ 		spinlocks blocking while in RCU read-side critical
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0076-tracing-Merge-irqflags-preempt-counter.patch b/debian/patches-rt/0076-tracing-Merge-irqflags-preempt-counter.patch
new file mode 100644
index 000000000..8cd083750
--- /dev/null
+++ b/debian/patches-rt/0076-tracing-Merge-irqflags-preempt-counter.patch
@@ -0,0 +1,1900 @@
+From 1ab76ef52a7db4158a5d86604c2a318cfe847e9d Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 3 Feb 2021 11:05:23 -0500
+Subject: [PATCH 076/323] tracing: Merge irqflags + preempt counter.
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The state of the interrupts (irqflags) and the preemption counter are
+both passed down to tracing_generic_entry_update(). Only one bit of
+irqflags is actually required: The on/off state. The complete 32bit
+of the preemption counter isn't needed. Just whether of the upper bits
+(softirq, hardirq and NMI) are set and the preemption depth is needed.
+
+The irqflags and the preemption counter could be evaluated early and the
+information stored in an integer `trace_ctx'.
+tracing_generic_entry_update() would use the upper bits as the
+TRACE_FLAG_* and the lower 8bit as the disabled-preemption depth
+(considering that one must be substracted from the counter in one
+special cases).
+
+The actual preemption value is not used except for the tracing record.
+The `irqflags' variable is mostly used only for the tracing record. An
+exception here is for instance wakeup_tracer_call() or
+probe_wakeup_sched_switch() which explicilty disable interrupts and use
+that `irqflags' to save (and restore) the IRQ state and to record the
+state.
+
+Struct trace_event_buffer has also the `pc' and flags' members which can
+be replaced with `trace_ctx' since their actual value is not used
+outside of trace recording.
+
+This will reduce tracing_generic_entry_update() to simply assign values
+to struct trace_entry. The evaluation of the TRACE_FLAG_* bits is moved
+to _tracing_gen_ctx_flags() which replaces preempt_count() and
+local_save_flags() invocations.
+
+As an example, ftrace_syscall_enter() may invoke:
+- trace_buffer_lock_reserve() -> … -> tracing_generic_entry_update()
+- event_trigger_unlock_commit()
+  -> ftrace_trace_stack() -> … -> tracing_generic_entry_update()
+  -> ftrace_trace_userstack() -> … -> tracing_generic_entry_update()
+
+In this case the TRACE_FLAG_* bits were evaluated three times. By using
+the `trace_ctx' they are evaluated once and assigned three times.
+
+A build with all tracers enabled on x86-64 with and without the patch:
+
+    text     data      bss      dec      hex    filename
+21970669 17084168  7639260 46694097  2c87ed1 vmlinux.old
+21970293 17084168  7639260 46693721  2c87d59 vmlinux.new
+
+text shrank by 379 bytes, data remained constant.
+
+Link: https://lkml.kernel.org/r/20210125194511.3924915-2-bigeasy@linutronix.de
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/trace_events.h         |  25 +++-
+ kernel/trace/blktrace.c              |  17 +--
+ kernel/trace/trace.c                 | 206 +++++++++++++++------------
+ kernel/trace/trace.h                 |  38 +++--
+ kernel/trace/trace_branch.c          |   6 +-
+ kernel/trace/trace_event_perf.c      |   5 +-
+ kernel/trace/trace_events.c          |  18 +--
+ kernel/trace/trace_events_inject.c   |   6 +-
+ kernel/trace/trace_functions.c       |  28 ++--
+ kernel/trace/trace_functions_graph.c |  32 ++---
+ kernel/trace/trace_hwlat.c           |   7 +-
+ kernel/trace/trace_irqsoff.c         |  86 +++++------
+ kernel/trace/trace_kprobe.c          |  10 +-
+ kernel/trace/trace_mmiotrace.c       |  14 +-
+ kernel/trace/trace_sched_wakeup.c    |  71 +++++----
+ kernel/trace/trace_syscalls.c        |  20 ++-
+ kernel/trace/trace_uprobe.c          |   4 +-
+ 17 files changed, 286 insertions(+), 307 deletions(-)
+
+diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
+index f7ed0471d5a8..2a98c40526a0 100644
+--- a/include/linux/trace_events.h
++++ b/include/linux/trace_events.h
+@@ -152,17 +152,29 @@ enum print_line_t {
+ 
+ enum print_line_t trace_handle_return(struct trace_seq *s);
+ 
+-void tracing_generic_entry_update(struct trace_entry *entry,
+-				  unsigned short type,
+-				  unsigned long flags,
+-				  int pc);
++static inline void tracing_generic_entry_update(struct trace_entry *entry,
++						unsigned short type,
++						unsigned int trace_ctx)
++{
++	struct task_struct *tsk = current;
++
++	entry->preempt_count		= trace_ctx & 0xff;
++	entry->pid			= (tsk) ? tsk->pid : 0;
++	entry->type			= type;
++	entry->flags =			trace_ctx >> 16;
++}
++
++unsigned int tracing_gen_ctx_flags(unsigned long irqflags);
++unsigned int tracing_gen_ctx(void);
++unsigned int tracing_gen_ctx_dec(void);
++
+ struct trace_event_file;
+ 
+ struct ring_buffer_event *
+ trace_event_buffer_lock_reserve(struct trace_buffer **current_buffer,
+ 				struct trace_event_file *trace_file,
+ 				int type, unsigned long len,
+-				unsigned long flags, int pc);
++				unsigned int trace_ctx);
+ 
+ #define TRACE_RECORD_CMDLINE	BIT(0)
+ #define TRACE_RECORD_TGID	BIT(1)
+@@ -236,8 +248,7 @@ struct trace_event_buffer {
+ 	struct ring_buffer_event	*event;
+ 	struct trace_event_file		*trace_file;
+ 	void				*entry;
+-	unsigned long			flags;
+-	int				pc;
++	unsigned int			trace_ctx;
+ 	struct pt_regs			*regs;
+ };
+ 
+diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
+index ab912cc60760..a95a2027eefd 100644
+--- a/kernel/trace/blktrace.c
++++ b/kernel/trace/blktrace.c
+@@ -72,17 +72,17 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action,
+ 	struct blk_io_trace *t;
+ 	struct ring_buffer_event *event = NULL;
+ 	struct trace_buffer *buffer = NULL;
+-	int pc = 0;
++	unsigned int trace_ctx = 0;
+ 	int cpu = smp_processor_id();
+ 	bool blk_tracer = blk_tracer_enabled;
+ 	ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
+ 
+ 	if (blk_tracer) {
+ 		buffer = blk_tr->array_buffer.buffer;
+-		pc = preempt_count();
++		trace_ctx = tracing_gen_ctx_flags(0);
+ 		event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
+ 						  sizeof(*t) + len + cgid_len,
+-						  0, pc);
++						  trace_ctx);
+ 		if (!event)
+ 			return;
+ 		t = ring_buffer_event_data(event);
+@@ -107,7 +107,7 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action,
+ 		memcpy((void *) t + sizeof(*t) + cgid_len, data, len);
+ 
+ 		if (blk_tracer)
+-			trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
++			trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
+ 	}
+ }
+ 
+@@ -222,8 +222,9 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
+ 	struct blk_io_trace *t;
+ 	unsigned long flags = 0;
+ 	unsigned long *sequence;
++	unsigned int trace_ctx = 0;
+ 	pid_t pid;
+-	int cpu, pc = 0;
++	int cpu;
+ 	bool blk_tracer = blk_tracer_enabled;
+ 	ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
+ 
+@@ -252,10 +253,10 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
+ 		tracing_record_cmdline(current);
+ 
+ 		buffer = blk_tr->array_buffer.buffer;
+-		pc = preempt_count();
++		trace_ctx = tracing_gen_ctx_flags(0);
+ 		event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
+ 						  sizeof(*t) + pdu_len + cgid_len,
+-						  0, pc);
++						  trace_ctx);
+ 		if (!event)
+ 			return;
+ 		t = ring_buffer_event_data(event);
+@@ -301,7 +302,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
+ 			memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
+ 
+ 		if (blk_tracer) {
+-			trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
++			trace_buffer_unlock_commit(blk_tr, buffer, event, trace_ctx);
+ 			return;
+ 		}
+ 	}
+diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
+index 4e0411b19ef9..376eb8a1c913 100644
+--- a/kernel/trace/trace.c
++++ b/kernel/trace/trace.c
+@@ -176,7 +176,7 @@ static union trace_eval_map_item *trace_eval_maps;
+ int tracing_set_tracer(struct trace_array *tr, const char *buf);
+ static void ftrace_trace_userstack(struct trace_array *tr,
+ 				   struct trace_buffer *buffer,
+-				   unsigned long flags, int pc);
++				   unsigned int trace_ctx);
+ 
+ #define MAX_TRACER_SIZE		100
+ static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
+@@ -909,23 +909,23 @@ static inline void trace_access_lock_init(void)
+ 
+ #ifdef CONFIG_STACKTRACE
+ static void __ftrace_trace_stack(struct trace_buffer *buffer,
+-				 unsigned long flags,
+-				 int skip, int pc, struct pt_regs *regs);
++				 unsigned int trace_ctx,
++				 int skip, struct pt_regs *regs);
+ static inline void ftrace_trace_stack(struct trace_array *tr,
+ 				      struct trace_buffer *buffer,
+-				      unsigned long flags,
+-				      int skip, int pc, struct pt_regs *regs);
++				      unsigned int trace_ctx,
++				      int skip, struct pt_regs *regs);
+ 
+ #else
+ static inline void __ftrace_trace_stack(struct trace_buffer *buffer,
+-					unsigned long flags,
+-					int skip, int pc, struct pt_regs *regs)
++					unsigned int trace_ctx,
++					int skip, struct pt_regs *regs)
+ {
+ }
+ static inline void ftrace_trace_stack(struct trace_array *tr,
+ 				      struct trace_buffer *buffer,
+-				      unsigned long flags,
+-				      int skip, int pc, struct pt_regs *regs)
++				      unsigned long trace_ctx,
++				      int skip, struct pt_regs *regs)
+ {
+ }
+ 
+@@ -933,24 +933,24 @@ static inline void ftrace_trace_stack(struct trace_array *tr,
+ 
+ static __always_inline void
+ trace_event_setup(struct ring_buffer_event *event,
+-		  int type, unsigned long flags, int pc)
++		  int type, unsigned int trace_ctx)
+ {
+ 	struct trace_entry *ent = ring_buffer_event_data(event);
+ 
+-	tracing_generic_entry_update(ent, type, flags, pc);
++	tracing_generic_entry_update(ent, type, trace_ctx);
+ }
+ 
+ static __always_inline struct ring_buffer_event *
+ __trace_buffer_lock_reserve(struct trace_buffer *buffer,
+ 			  int type,
+ 			  unsigned long len,
+-			  unsigned long flags, int pc)
++			  unsigned int trace_ctx)
+ {
+ 	struct ring_buffer_event *event;
+ 
+ 	event = ring_buffer_lock_reserve(buffer, len);
+ 	if (event != NULL)
+-		trace_event_setup(event, type, flags, pc);
++		trace_event_setup(event, type, trace_ctx);
+ 
+ 	return event;
+ }
+@@ -1011,25 +1011,22 @@ int __trace_puts(unsigned long ip, const char *str, int size)
+ 	struct ring_buffer_event *event;
+ 	struct trace_buffer *buffer;
+ 	struct print_entry *entry;
+-	unsigned long irq_flags;
++	unsigned int trace_ctx;
+ 	int alloc;
+-	int pc;
+ 
+ 	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
+ 		return 0;
+ 
+-	pc = preempt_count();
+-
+ 	if (unlikely(tracing_selftest_running || tracing_disabled))
+ 		return 0;
+ 
+ 	alloc = sizeof(*entry) + size + 2; /* possible \n added */
+ 
+-	local_save_flags(irq_flags);
++	trace_ctx = tracing_gen_ctx();
+ 	buffer = global_trace.array_buffer.buffer;
+ 	ring_buffer_nest_start(buffer);
+-	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc, 
+-					    irq_flags, pc);
++	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
++					    trace_ctx);
+ 	if (!event) {
+ 		size = 0;
+ 		goto out;
+@@ -1048,7 +1045,7 @@ int __trace_puts(unsigned long ip, const char *str, int size)
+ 		entry->buf[size] = '\0';
+ 
+ 	__buffer_unlock_commit(buffer, event);
+-	ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
++	ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL);
+  out:
+ 	ring_buffer_nest_end(buffer);
+ 	return size;
+@@ -1065,25 +1062,22 @@ int __trace_bputs(unsigned long ip, const char *str)
+ 	struct ring_buffer_event *event;
+ 	struct trace_buffer *buffer;
+ 	struct bputs_entry *entry;
+-	unsigned long irq_flags;
++	unsigned int trace_ctx;
+ 	int size = sizeof(struct bputs_entry);
+ 	int ret = 0;
+-	int pc;
+ 
+ 	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
+ 		return 0;
+ 
+-	pc = preempt_count();
+-
+ 	if (unlikely(tracing_selftest_running || tracing_disabled))
+ 		return 0;
+ 
+-	local_save_flags(irq_flags);
++	trace_ctx = tracing_gen_ctx();
+ 	buffer = global_trace.array_buffer.buffer;
+ 
+ 	ring_buffer_nest_start(buffer);
+ 	event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
+-					    irq_flags, pc);
++					    trace_ctx);
+ 	if (!event)
+ 		goto out;
+ 
+@@ -1092,7 +1086,7 @@ int __trace_bputs(unsigned long ip, const char *str)
+ 	entry->str			= str;
+ 
+ 	__buffer_unlock_commit(buffer, event);
+-	ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
++	ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL);
+ 
+ 	ret = 1;
+  out:
+@@ -2581,36 +2575,69 @@ enum print_line_t trace_handle_return(struct trace_seq *s)
+ }
+ EXPORT_SYMBOL_GPL(trace_handle_return);
+ 
+-void
+-tracing_generic_entry_update(struct trace_entry *entry, unsigned short type,
+-			     unsigned long flags, int pc)
++unsigned int tracing_gen_ctx_flags(unsigned long irqflags)
+ {
+-	struct task_struct *tsk = current;
++	unsigned int trace_flags = 0;
++	unsigned int pc;
++
++	pc = preempt_count();
+ 
+-	entry->preempt_count		= pc & 0xff;
+-	entry->pid			= (tsk) ? tsk->pid : 0;
+-	entry->type			= type;
+-	entry->flags =
+ #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
+-		(irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
++	if (irqs_disabled_flags(irqflags))
++		trace_flags |= TRACE_FLAG_IRQS_OFF;
+ #else
+-		TRACE_FLAG_IRQS_NOSUPPORT |
++	trace_flags |= TRACE_FLAG_IRQS_NOSUPPORT;
+ #endif
+-		((pc & NMI_MASK    ) ? TRACE_FLAG_NMI     : 0) |
+-		((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
+-		((pc & SOFTIRQ_OFFSET) ? TRACE_FLAG_SOFTIRQ : 0) |
+-		(tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
+-		(test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
++
++	if (pc & NMI_MASK)
++		trace_flags |= TRACE_FLAG_NMI;
++	if (pc & HARDIRQ_MASK)
++		trace_flags |= TRACE_FLAG_HARDIRQ;
++
++	if (pc & SOFTIRQ_OFFSET)
++		trace_flags |= TRACE_FLAG_SOFTIRQ;
++
++	if (tif_need_resched())
++		trace_flags |= TRACE_FLAG_NEED_RESCHED;
++	if (test_preempt_need_resched())
++		trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
++	return (trace_flags << 16) | (pc & 0xff);
++}
++
++unsigned int tracing_gen_ctx(void)
++{
++	unsigned long irqflags;
++
++#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
++	local_save_flags(irqflags);
++#else
++	irqflags = 0;
++#endif
++	return tracing_gen_ctx_flags(irqflags);
++}
++
++unsigned int tracing_gen_ctx_dec(void)
++{
++	unsigned int trace_ctx;
++
++	trace_ctx = tracing_gen_ctx();
++
++	/*
++	 * Subtract one from the preeption counter if preemption is enabled,
++	 * see trace_event_buffer_reserve()for details.
++	 */
++	if (IS_ENABLED(CONFIG_PREEMPTION))
++		trace_ctx--;
++	return trace_ctx;
+ }
+-EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
+ 
+ struct ring_buffer_event *
+ trace_buffer_lock_reserve(struct trace_buffer *buffer,
+ 			  int type,
+ 			  unsigned long len,
+-			  unsigned long flags, int pc)
++			  unsigned int trace_ctx)
+ {
+-	return __trace_buffer_lock_reserve(buffer, type, len, flags, pc);
++	return __trace_buffer_lock_reserve(buffer, type, len, trace_ctx);
+ }
+ 
+ DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
+@@ -2729,7 +2756,7 @@ struct ring_buffer_event *
+ trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
+ 			  struct trace_event_file *trace_file,
+ 			  int type, unsigned long len,
+-			  unsigned long flags, int pc)
++			  unsigned int trace_ctx)
+ {
+ 	struct ring_buffer_event *entry;
+ 	int val;
+@@ -2742,7 +2769,7 @@ trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
+ 		/* Try to use the per cpu buffer first */
+ 		val = this_cpu_inc_return(trace_buffered_event_cnt);
+ 		if ((len < (PAGE_SIZE - sizeof(*entry) - sizeof(entry->array[0]))) && val == 1) {
+-			trace_event_setup(entry, type, flags, pc);
++			trace_event_setup(entry, type, trace_ctx);
+ 			entry->array[0] = len;
+ 			return entry;
+ 		}
+@@ -2750,7 +2777,7 @@ trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
+ 	}
+ 
+ 	entry = __trace_buffer_lock_reserve(*current_rb,
+-					    type, len, flags, pc);
++					    type, len, trace_ctx);
+ 	/*
+ 	 * If tracing is off, but we have triggers enabled
+ 	 * we still need to look at the event data. Use the temp_buffer
+@@ -2759,8 +2786,8 @@ trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
+ 	 */
+ 	if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
+ 		*current_rb = temp_buffer;
+-		entry = __trace_buffer_lock_reserve(*current_rb,
+-						    type, len, flags, pc);
++		entry = __trace_buffer_lock_reserve(*current_rb, type, len,
++						    trace_ctx);
+ 	}
+ 	return entry;
+ }
+@@ -2846,7 +2873,7 @@ void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
+ 		ftrace_exports(fbuffer->event, TRACE_EXPORT_EVENT);
+ 	event_trigger_unlock_commit_regs(fbuffer->trace_file, fbuffer->buffer,
+ 				    fbuffer->event, fbuffer->entry,
+-				    fbuffer->flags, fbuffer->pc, fbuffer->regs);
++				    fbuffer->trace_ctx, fbuffer->regs);
+ }
+ EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
+ 
+@@ -2862,7 +2889,7 @@ EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
+ void trace_buffer_unlock_commit_regs(struct trace_array *tr,
+ 				     struct trace_buffer *buffer,
+ 				     struct ring_buffer_event *event,
+-				     unsigned long flags, int pc,
++				     unsigned int trace_ctx,
+ 				     struct pt_regs *regs)
+ {
+ 	__buffer_unlock_commit(buffer, event);
+@@ -2873,8 +2900,8 @@ void trace_buffer_unlock_commit_regs(struct trace_array *tr,
+ 	 * and mmiotrace, but that's ok if they lose a function or
+ 	 * two. They are not that meaningful.
+ 	 */
+-	ftrace_trace_stack(tr, buffer, flags, regs ? 0 : STACK_SKIP, pc, regs);
+-	ftrace_trace_userstack(tr, buffer, flags, pc);
++	ftrace_trace_stack(tr, buffer, trace_ctx, regs ? 0 : STACK_SKIP, regs);
++	ftrace_trace_userstack(tr, buffer, trace_ctx);
+ }
+ 
+ /*
+@@ -2888,9 +2915,8 @@ trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer,
+ }
+ 
+ void
+-trace_function(struct trace_array *tr,
+-	       unsigned long ip, unsigned long parent_ip, unsigned long flags,
+-	       int pc)
++trace_function(struct trace_array *tr, unsigned long ip, unsigned long
++	       parent_ip, unsigned int trace_ctx)
+ {
+ 	struct trace_event_call *call = &event_function;
+ 	struct trace_buffer *buffer = tr->array_buffer.buffer;
+@@ -2898,7 +2924,7 @@ trace_function(struct trace_array *tr,
+ 	struct ftrace_entry *entry;
+ 
+ 	event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
+-					    flags, pc);
++					    trace_ctx);
+ 	if (!event)
+ 		return;
+ 	entry	= ring_buffer_event_data(event);
+@@ -2932,8 +2958,8 @@ static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks);
+ static DEFINE_PER_CPU(int, ftrace_stack_reserve);
+ 
+ static void __ftrace_trace_stack(struct trace_buffer *buffer,
+-				 unsigned long flags,
+-				 int skip, int pc, struct pt_regs *regs)
++				 unsigned int trace_ctx,
++				 int skip, struct pt_regs *regs)
+ {
+ 	struct trace_event_call *call = &event_kernel_stack;
+ 	struct ring_buffer_event *event;
+@@ -2981,7 +3007,7 @@ static void __ftrace_trace_stack(struct trace_buffer *buffer,
+ 	size = nr_entries * sizeof(unsigned long);
+ 	event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
+ 				    (sizeof(*entry) - sizeof(entry->caller)) + size,
+-				    flags, pc);
++				    trace_ctx);
+ 	if (!event)
+ 		goto out;
+ 	entry = ring_buffer_event_data(event);
+@@ -3002,22 +3028,22 @@ static void __ftrace_trace_stack(struct trace_buffer *buffer,
+ 
+ static inline void ftrace_trace_stack(struct trace_array *tr,
+ 				      struct trace_buffer *buffer,
+-				      unsigned long flags,
+-				      int skip, int pc, struct pt_regs *regs)
++				      unsigned int trace_ctx,
++				      int skip, struct pt_regs *regs)
+ {
+ 	if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
+ 		return;
+ 
+-	__ftrace_trace_stack(buffer, flags, skip, pc, regs);
++	__ftrace_trace_stack(buffer, trace_ctx, skip, regs);
+ }
+ 
+-void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
+-		   int pc)
++void __trace_stack(struct trace_array *tr, unsigned int trace_ctx,
++		   int skip)
+ {
+ 	struct trace_buffer *buffer = tr->array_buffer.buffer;
+ 
+ 	if (rcu_is_watching()) {
+-		__ftrace_trace_stack(buffer, flags, skip, pc, NULL);
++		__ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
+ 		return;
+ 	}
+ 
+@@ -3031,7 +3057,7 @@ void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
+ 		return;
+ 
+ 	rcu_irq_enter_irqson();
+-	__ftrace_trace_stack(buffer, flags, skip, pc, NULL);
++	__ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
+ 	rcu_irq_exit_irqson();
+ }
+ 
+@@ -3041,19 +3067,15 @@ void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
+  */
+ void trace_dump_stack(int skip)
+ {
+-	unsigned long flags;
+-
+ 	if (tracing_disabled || tracing_selftest_running)
+ 		return;
+ 
+-	local_save_flags(flags);
+-
+ #ifndef CONFIG_UNWINDER_ORC
+ 	/* Skip 1 to skip this function. */
+ 	skip++;
+ #endif
+ 	__ftrace_trace_stack(global_trace.array_buffer.buffer,
+-			     flags, skip, preempt_count(), NULL);
++			     tracing_gen_ctx(), skip, NULL);
+ }
+ EXPORT_SYMBOL_GPL(trace_dump_stack);
+ 
+@@ -3062,7 +3084,7 @@ static DEFINE_PER_CPU(int, user_stack_count);
+ 
+ static void
+ ftrace_trace_userstack(struct trace_array *tr,
+-		       struct trace_buffer *buffer, unsigned long flags, int pc)
++		       struct trace_buffer *buffer, unsigned int trace_ctx)
+ {
+ 	struct trace_event_call *call = &event_user_stack;
+ 	struct ring_buffer_event *event;
+@@ -3089,7 +3111,7 @@ ftrace_trace_userstack(struct trace_array *tr,
+ 	__this_cpu_inc(user_stack_count);
+ 
+ 	event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
+-					    sizeof(*entry), flags, pc);
++					    sizeof(*entry), trace_ctx);
+ 	if (!event)
+ 		goto out_drop_count;
+ 	entry	= ring_buffer_event_data(event);
+@@ -3109,7 +3131,7 @@ ftrace_trace_userstack(struct trace_array *tr,
+ #else /* CONFIG_USER_STACKTRACE_SUPPORT */
+ static void ftrace_trace_userstack(struct trace_array *tr,
+ 				   struct trace_buffer *buffer,
+-				   unsigned long flags, int pc)
++				   unsigned int trace_ctx)
+ {
+ }
+ #endif /* !CONFIG_USER_STACKTRACE_SUPPORT */
+@@ -3239,9 +3261,9 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
+ 	struct trace_buffer *buffer;
+ 	struct trace_array *tr = &global_trace;
+ 	struct bprint_entry *entry;
+-	unsigned long flags;
++	unsigned int trace_ctx;
+ 	char *tbuffer;
+-	int len = 0, size, pc;
++	int len = 0, size;
+ 
+ 	if (unlikely(tracing_selftest_running || tracing_disabled))
+ 		return 0;
+@@ -3249,7 +3271,7 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
+ 	/* Don't pollute graph traces with trace_vprintk internals */
+ 	pause_graph_tracing();
+ 
+-	pc = preempt_count();
++	trace_ctx = tracing_gen_ctx();
+ 	preempt_disable_notrace();
+ 
+ 	tbuffer = get_trace_buf();
+@@ -3263,12 +3285,11 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
+ 	if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
+ 		goto out_put;
+ 
+-	local_save_flags(flags);
+ 	size = sizeof(*entry) + sizeof(u32) * len;
+ 	buffer = tr->array_buffer.buffer;
+ 	ring_buffer_nest_start(buffer);
+ 	event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
+-					    flags, pc);
++					    trace_ctx);
+ 	if (!event)
+ 		goto out;
+ 	entry = ring_buffer_event_data(event);
+@@ -3278,7 +3299,7 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
+ 	memcpy(entry->buf, tbuffer, sizeof(u32) * len);
+ 	if (!call_filter_check_discard(call, entry, buffer, event)) {
+ 		__buffer_unlock_commit(buffer, event);
+-		ftrace_trace_stack(tr, buffer, flags, 6, pc, NULL);
++		ftrace_trace_stack(tr, buffer, trace_ctx, 6, NULL);
+ 	}
+ 
+ out:
+@@ -3301,9 +3322,9 @@ __trace_array_vprintk(struct trace_buffer *buffer,
+ {
+ 	struct trace_event_call *call = &event_print;
+ 	struct ring_buffer_event *event;
+-	int len = 0, size, pc;
++	int len = 0, size;
+ 	struct print_entry *entry;
+-	unsigned long flags;
++	unsigned int trace_ctx;
+ 	char *tbuffer;
+ 
+ 	if (tracing_disabled || tracing_selftest_running)
+@@ -3312,7 +3333,7 @@ __trace_array_vprintk(struct trace_buffer *buffer,
+ 	/* Don't pollute graph traces with trace_vprintk internals */
+ 	pause_graph_tracing();
+ 
+-	pc = preempt_count();
++	trace_ctx = tracing_gen_ctx();
+ 	preempt_disable_notrace();
+ 
+ 
+@@ -3324,11 +3345,10 @@ __trace_array_vprintk(struct trace_buffer *buffer,
+ 
+ 	len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
+ 
+-	local_save_flags(flags);
+ 	size = sizeof(*entry) + len + 1;
+ 	ring_buffer_nest_start(buffer);
+ 	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
+-					    flags, pc);
++					    trace_ctx);
+ 	if (!event)
+ 		goto out;
+ 	entry = ring_buffer_event_data(event);
+@@ -3337,7 +3357,7 @@ __trace_array_vprintk(struct trace_buffer *buffer,
+ 	memcpy(&entry->buf, tbuffer, len + 1);
+ 	if (!call_filter_check_discard(call, entry, buffer, event)) {
+ 		__buffer_unlock_commit(buffer, event);
+-		ftrace_trace_stack(&global_trace, buffer, flags, 6, pc, NULL);
++		ftrace_trace_stack(&global_trace, buffer, trace_ctx, 6, NULL);
+ 	}
+ 
+ out:
+@@ -6831,7 +6851,6 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
+ 	enum event_trigger_type tt = ETT_NONE;
+ 	struct trace_buffer *buffer;
+ 	struct print_entry *entry;
+-	unsigned long irq_flags;
+ 	ssize_t written;
+ 	int size;
+ 	int len;
+@@ -6851,7 +6870,6 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
+ 
+ 	BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
+ 
+-	local_save_flags(irq_flags);
+ 	size = sizeof(*entry) + cnt + 2; /* add '\0' and possible '\n' */
+ 
+ 	/* If less than "<faulted>", then make sure we can still add that */
+@@ -6860,7 +6878,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
+ 
+ 	buffer = tr->array_buffer.buffer;
+ 	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
+-					    irq_flags, preempt_count());
++					    tracing_gen_ctx());
+ 	if (unlikely(!event))
+ 		/* Ring buffer disabled, return as if not open for write */
+ 		return -EBADF;
+@@ -6912,7 +6930,6 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
+ 	struct ring_buffer_event *event;
+ 	struct trace_buffer *buffer;
+ 	struct raw_data_entry *entry;
+-	unsigned long irq_flags;
+ 	ssize_t written;
+ 	int size;
+ 	int len;
+@@ -6934,14 +6951,13 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
+ 
+ 	BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
+ 
+-	local_save_flags(irq_flags);
+ 	size = sizeof(*entry) + cnt;
+ 	if (cnt < FAULT_SIZE_ID)
+ 		size += FAULT_SIZE_ID - cnt;
+ 
+ 	buffer = tr->array_buffer.buffer;
+ 	event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
+-					    irq_flags, preempt_count());
++					    tracing_gen_ctx());
+ 	if (!event)
+ 		/* Ring buffer disabled, return as if not open for write */
+ 		return -EBADF;
+diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
+index 7c90872f2435..27ed42bccd7f 100644
+--- a/kernel/trace/trace.h
++++ b/kernel/trace/trace.h
+@@ -750,8 +750,7 @@ struct ring_buffer_event *
+ trace_buffer_lock_reserve(struct trace_buffer *buffer,
+ 			  int type,
+ 			  unsigned long len,
+-			  unsigned long flags,
+-			  int pc);
++			  unsigned int trace_ctx);
+ 
+ struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
+ 						struct trace_array_cpu *data);
+@@ -778,11 +777,11 @@ unsigned long trace_total_entries(struct trace_array *tr);
+ void trace_function(struct trace_array *tr,
+ 		    unsigned long ip,
+ 		    unsigned long parent_ip,
+-		    unsigned long flags, int pc);
++		    unsigned int trace_ctx);
+ void trace_graph_function(struct trace_array *tr,
+ 		    unsigned long ip,
+ 		    unsigned long parent_ip,
+-		    unsigned long flags, int pc);
++		    unsigned int trace_ctx);
+ void trace_latency_header(struct seq_file *m);
+ void trace_default_header(struct seq_file *m);
+ void print_trace_header(struct seq_file *m, struct trace_iterator *iter);
+@@ -850,11 +849,10 @@ static inline void latency_fsnotify(struct trace_array *tr) { }
+ #endif
+ 
+ #ifdef CONFIG_STACKTRACE
+-void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
+-		   int pc);
++void __trace_stack(struct trace_array *tr, unsigned int trace_ctx, int skip);
+ #else
+-static inline void __trace_stack(struct trace_array *tr, unsigned long flags,
+-				 int skip, int pc)
++static inline void __trace_stack(struct trace_array *tr, unsigned int trace_ctx,
++				 int skip)
+ {
+ }
+ #endif /* CONFIG_STACKTRACE */
+@@ -994,10 +992,10 @@ extern void graph_trace_open(struct trace_iterator *iter);
+ extern void graph_trace_close(struct trace_iterator *iter);
+ extern int __trace_graph_entry(struct trace_array *tr,
+ 			       struct ftrace_graph_ent *trace,
+-			       unsigned long flags, int pc);
++			       unsigned int trace_ctx);
+ extern void __trace_graph_return(struct trace_array *tr,
+ 				 struct ftrace_graph_ret *trace,
+-				 unsigned long flags, int pc);
++				 unsigned int trace_ctx);
+ 
+ #ifdef CONFIG_DYNAMIC_FTRACE
+ extern struct ftrace_hash __rcu *ftrace_graph_hash;
+@@ -1460,15 +1458,15 @@ extern int call_filter_check_discard(struct trace_event_call *call, void *rec,
+ void trace_buffer_unlock_commit_regs(struct trace_array *tr,
+ 				     struct trace_buffer *buffer,
+ 				     struct ring_buffer_event *event,
+-				     unsigned long flags, int pc,
++				     unsigned int trcace_ctx,
+ 				     struct pt_regs *regs);
+ 
+ static inline void trace_buffer_unlock_commit(struct trace_array *tr,
+ 					      struct trace_buffer *buffer,
+ 					      struct ring_buffer_event *event,
+-					      unsigned long flags, int pc)
++					      unsigned int trace_ctx)
+ {
+-	trace_buffer_unlock_commit_regs(tr, buffer, event, flags, pc, NULL);
++	trace_buffer_unlock_commit_regs(tr, buffer, event, trace_ctx, NULL);
+ }
+ 
+ DECLARE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
+@@ -1541,8 +1539,7 @@ __event_trigger_test_discard(struct trace_event_file *file,
+  * @buffer: The ring buffer that the event is being written to
+  * @event: The event meta data in the ring buffer
+  * @entry: The event itself
+- * @irq_flags: The state of the interrupts at the start of the event
+- * @pc: The state of the preempt count at the start of the event.
++ * @trace_ctx: The tracing context flags.
+  *
+  * This is a helper function to handle triggers that require data
+  * from the event itself. It also tests the event against filters and
+@@ -1552,12 +1549,12 @@ static inline void
+ event_trigger_unlock_commit(struct trace_event_file *file,
+ 			    struct trace_buffer *buffer,
+ 			    struct ring_buffer_event *event,
+-			    void *entry, unsigned long irq_flags, int pc)
++			    void *entry, unsigned int trace_ctx)
+ {
+ 	enum event_trigger_type tt = ETT_NONE;
+ 
+ 	if (!__event_trigger_test_discard(file, buffer, event, entry, &tt))
+-		trace_buffer_unlock_commit(file->tr, buffer, event, irq_flags, pc);
++		trace_buffer_unlock_commit(file->tr, buffer, event, trace_ctx);
+ 
+ 	if (tt)
+ 		event_triggers_post_call(file, tt);
+@@ -1569,8 +1566,7 @@ event_trigger_unlock_commit(struct trace_event_file *file,
+  * @buffer: The ring buffer that the event is being written to
+  * @event: The event meta data in the ring buffer
+  * @entry: The event itself
+- * @irq_flags: The state of the interrupts at the start of the event
+- * @pc: The state of the preempt count at the start of the event.
++ * @trace_ctx: The tracing context flags.
+  *
+  * This is a helper function to handle triggers that require data
+  * from the event itself. It also tests the event against filters and
+@@ -1583,14 +1579,14 @@ static inline void
+ event_trigger_unlock_commit_regs(struct trace_event_file *file,
+ 				 struct trace_buffer *buffer,
+ 				 struct ring_buffer_event *event,
+-				 void *entry, unsigned long irq_flags, int pc,
++				 void *entry, unsigned int trace_ctx,
+ 				 struct pt_regs *regs)
+ {
+ 	enum event_trigger_type tt = ETT_NONE;
+ 
+ 	if (!__event_trigger_test_discard(file, buffer, event, entry, &tt))
+ 		trace_buffer_unlock_commit_regs(file->tr, buffer, event,
+-						irq_flags, pc, regs);
++						trace_ctx, regs);
+ 
+ 	if (tt)
+ 		event_triggers_post_call(file, tt);
+diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
+index eff099123aa2..e47fdb4c92fb 100644
+--- a/kernel/trace/trace_branch.c
++++ b/kernel/trace/trace_branch.c
+@@ -37,7 +37,7 @@ probe_likely_condition(struct ftrace_likely_data *f, int val, int expect)
+ 	struct ring_buffer_event *event;
+ 	struct trace_branch *entry;
+ 	unsigned long flags;
+-	int pc;
++	unsigned int trace_ctx;
+ 	const char *p;
+ 
+ 	if (current->trace_recursion & TRACE_BRANCH_BIT)
+@@ -59,10 +59,10 @@ probe_likely_condition(struct ftrace_likely_data *f, int val, int expect)
+ 	if (atomic_read(&data->disabled))
+ 		goto out;
+ 
+-	pc = preempt_count();
++	trace_ctx = tracing_gen_ctx_flags(flags);
+ 	buffer = tr->array_buffer.buffer;
+ 	event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH,
+-					  sizeof(*entry), flags, pc);
++					  sizeof(*entry), trace_ctx);
+ 	if (!event)
+ 		goto out;
+ 
+diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
+index 643e0b19920d..0443dd61667b 100644
+--- a/kernel/trace/trace_event_perf.c
++++ b/kernel/trace/trace_event_perf.c
+@@ -421,11 +421,8 @@ NOKPROBE_SYMBOL(perf_trace_buf_alloc);
+ void perf_trace_buf_update(void *record, u16 type)
+ {
+ 	struct trace_entry *entry = record;
+-	int pc = preempt_count();
+-	unsigned long flags;
+ 
+-	local_save_flags(flags);
+-	tracing_generic_entry_update(entry, type, flags, pc);
++	tracing_generic_entry_update(entry, type, tracing_gen_ctx());
+ }
+ NOKPROBE_SYMBOL(perf_trace_buf_update);
+ 
+diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
+index 4b5a8d7275be..df64b92c5edc 100644
+--- a/kernel/trace/trace_events.c
++++ b/kernel/trace/trace_events.c
+@@ -259,22 +259,19 @@ void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
+ 	    trace_event_ignore_this_pid(trace_file))
+ 		return NULL;
+ 
+-	local_save_flags(fbuffer->flags);
+-	fbuffer->pc = preempt_count();
+ 	/*
+ 	 * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
+ 	 * preemption (adding one to the preempt_count). Since we are
+ 	 * interested in the preempt_count at the time the tracepoint was
+ 	 * hit, we need to subtract one to offset the increment.
+ 	 */
+-	if (IS_ENABLED(CONFIG_PREEMPTION))
+-		fbuffer->pc--;
++	fbuffer->trace_ctx = tracing_gen_ctx_dec();
+ 	fbuffer->trace_file = trace_file;
+ 
+ 	fbuffer->event =
+ 		trace_event_buffer_lock_reserve(&fbuffer->buffer, trace_file,
+ 						event_call->event.type, len,
+-						fbuffer->flags, fbuffer->pc);
++						fbuffer->trace_ctx);
+ 	if (!fbuffer->event)
+ 		return NULL;
+ 
+@@ -3709,12 +3706,11 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip,
+ 	struct trace_buffer *buffer;
+ 	struct ring_buffer_event *event;
+ 	struct ftrace_entry *entry;
+-	unsigned long flags;
++	unsigned int trace_ctx;
+ 	long disabled;
+ 	int cpu;
+-	int pc;
+ 
+-	pc = preempt_count();
++	trace_ctx = tracing_gen_ctx();
+ 	preempt_disable_notrace();
+ 	cpu = raw_smp_processor_id();
+ 	disabled = atomic_inc_return(&per_cpu(ftrace_test_event_disable, cpu));
+@@ -3722,11 +3718,9 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip,
+ 	if (disabled != 1)
+ 		goto out;
+ 
+-	local_save_flags(flags);
+-
+ 	event = trace_event_buffer_lock_reserve(&buffer, &event_trace_file,
+ 						TRACE_FN, sizeof(*entry),
+-						flags, pc);
++						trace_ctx);
+ 	if (!event)
+ 		goto out;
+ 	entry	= ring_buffer_event_data(event);
+@@ -3734,7 +3728,7 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip,
+ 	entry->parent_ip		= parent_ip;
+ 
+ 	event_trigger_unlock_commit(&event_trace_file, buffer, event,
+-				    entry, flags, pc);
++				    entry, trace_ctx);
+  out:
+ 	atomic_dec(&per_cpu(ftrace_test_event_disable, cpu));
+ 	preempt_enable_notrace();
+diff --git a/kernel/trace/trace_events_inject.c b/kernel/trace/trace_events_inject.c
+index 149c7dc6a447..b1fce64e126c 100644
+--- a/kernel/trace/trace_events_inject.c
++++ b/kernel/trace/trace_events_inject.c
+@@ -192,7 +192,6 @@ static void *trace_alloc_entry(struct trace_event_call *call, int *size)
+ static int parse_entry(char *str, struct trace_event_call *call, void **pentry)
+ {
+ 	struct ftrace_event_field *field;
+-	unsigned long irq_flags;
+ 	void *entry = NULL;
+ 	int entry_size;
+ 	u64 val = 0;
+@@ -203,9 +202,8 @@ static int parse_entry(char *str, struct trace_event_call *call, void **pentry)
+ 	if (!entry)
+ 		return -ENOMEM;
+ 
+-	local_save_flags(irq_flags);
+-	tracing_generic_entry_update(entry, call->event.type, irq_flags,
+-				     preempt_count());
++	tracing_generic_entry_update(entry, call->event.type,
++				     tracing_gen_ctx());
+ 
+ 	while ((len = parse_field(str, call, &field, &val)) > 0) {
+ 		if (is_function_field(field))
+diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
+index 93e20ed642e5..8606cb73341e 100644
+--- a/kernel/trace/trace_functions.c
++++ b/kernel/trace/trace_functions.c
+@@ -133,15 +133,14 @@ function_trace_call(unsigned long ip, unsigned long parent_ip,
+ {
+ 	struct trace_array *tr = op->private;
+ 	struct trace_array_cpu *data;
+-	unsigned long flags;
++	unsigned int trace_ctx;
+ 	int bit;
+ 	int cpu;
+-	int pc;
+ 
+ 	if (unlikely(!tr->function_enabled))
+ 		return;
+ 
+-	pc = preempt_count();
++	trace_ctx = tracing_gen_ctx();
+ 	preempt_disable_notrace();
+ 
+ 	bit = trace_test_and_set_recursion(TRACE_FTRACE_START);
+@@ -150,10 +149,9 @@ function_trace_call(unsigned long ip, unsigned long parent_ip,
+ 
+ 	cpu = smp_processor_id();
+ 	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+-	if (!atomic_read(&data->disabled)) {
+-		local_save_flags(flags);
+-		trace_function(tr, ip, parent_ip, flags, pc);
+-	}
++	if (!atomic_read(&data->disabled))
++		trace_function(tr, ip, parent_ip, trace_ctx);
++
+ 	trace_clear_recursion(bit);
+ 
+  out:
+@@ -187,7 +185,7 @@ function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
+ 	unsigned long flags;
+ 	long disabled;
+ 	int cpu;
+-	int pc;
++	unsigned int trace_ctx;
+ 
+ 	if (unlikely(!tr->function_enabled))
+ 		return;
+@@ -202,9 +200,9 @@ function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
+ 	disabled = atomic_inc_return(&data->disabled);
+ 
+ 	if (likely(disabled == 1)) {
+-		pc = preempt_count();
+-		trace_function(tr, ip, parent_ip, flags, pc);
+-		__trace_stack(tr, flags, STACK_SKIP, pc);
++		trace_ctx = tracing_gen_ctx_flags(flags);
++		trace_function(tr, ip, parent_ip, trace_ctx);
++		__trace_stack(tr, trace_ctx, STACK_SKIP);
+ 	}
+ 
+ 	atomic_dec(&data->disabled);
+@@ -407,13 +405,11 @@ ftrace_traceoff(unsigned long ip, unsigned long parent_ip,
+ 
+ static __always_inline void trace_stack(struct trace_array *tr)
+ {
+-	unsigned long flags;
+-	int pc;
++	unsigned int trace_ctx;
+ 
+-	local_save_flags(flags);
+-	pc = preempt_count();
++	trace_ctx = tracing_gen_ctx();
+ 
+-	__trace_stack(tr, flags, FTRACE_STACK_SKIP, pc);
++	__trace_stack(tr, trace_ctx, FTRACE_STACK_SKIP);
+ }
+ 
+ static void
+diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
+index 60d66278aa0d..b086ba8bb3d6 100644
+--- a/kernel/trace/trace_functions_graph.c
++++ b/kernel/trace/trace_functions_graph.c
+@@ -96,8 +96,7 @@ print_graph_duration(struct trace_array *tr, unsigned long long duration,
+ 
+ int __trace_graph_entry(struct trace_array *tr,
+ 				struct ftrace_graph_ent *trace,
+-				unsigned long flags,
+-				int pc)
++				unsigned int trace_ctx)
+ {
+ 	struct trace_event_call *call = &event_funcgraph_entry;
+ 	struct ring_buffer_event *event;
+@@ -105,7 +104,7 @@ int __trace_graph_entry(struct trace_array *tr,
+ 	struct ftrace_graph_ent_entry *entry;
+ 
+ 	event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
+-					  sizeof(*entry), flags, pc);
++					  sizeof(*entry), trace_ctx);
+ 	if (!event)
+ 		return 0;
+ 	entry	= ring_buffer_event_data(event);
+@@ -129,10 +128,10 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
+ 	struct trace_array *tr = graph_array;
+ 	struct trace_array_cpu *data;
+ 	unsigned long flags;
++	unsigned int trace_ctx;
+ 	long disabled;
+ 	int ret;
+ 	int cpu;
+-	int pc;
+ 
+ 	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT))
+ 		return 0;
+@@ -174,8 +173,8 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
+ 	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+ 	disabled = atomic_inc_return(&data->disabled);
+ 	if (likely(disabled == 1)) {
+-		pc = preempt_count();
+-		ret = __trace_graph_entry(tr, trace, flags, pc);
++		trace_ctx = tracing_gen_ctx_flags(flags);
++		ret = __trace_graph_entry(tr, trace, trace_ctx);
+ 	} else {
+ 		ret = 0;
+ 	}
+@@ -188,7 +187,7 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
+ 
+ static void
+ __trace_graph_function(struct trace_array *tr,
+-		unsigned long ip, unsigned long flags, int pc)
++		unsigned long ip, unsigned int trace_ctx)
+ {
+ 	u64 time = trace_clock_local();
+ 	struct ftrace_graph_ent ent = {
+@@ -202,22 +201,21 @@ __trace_graph_function(struct trace_array *tr,
+ 		.rettime  = time,
+ 	};
+ 
+-	__trace_graph_entry(tr, &ent, flags, pc);
+-	__trace_graph_return(tr, &ret, flags, pc);
++	__trace_graph_entry(tr, &ent, trace_ctx);
++	__trace_graph_return(tr, &ret, trace_ctx);
+ }
+ 
+ void
+ trace_graph_function(struct trace_array *tr,
+ 		unsigned long ip, unsigned long parent_ip,
+-		unsigned long flags, int pc)
++		unsigned int trace_ctx)
+ {
+-	__trace_graph_function(tr, ip, flags, pc);
++	__trace_graph_function(tr, ip, trace_ctx);
+ }
+ 
+ void __trace_graph_return(struct trace_array *tr,
+ 				struct ftrace_graph_ret *trace,
+-				unsigned long flags,
+-				int pc)
++				unsigned int trace_ctx)
+ {
+ 	struct trace_event_call *call = &event_funcgraph_exit;
+ 	struct ring_buffer_event *event;
+@@ -225,7 +223,7 @@ void __trace_graph_return(struct trace_array *tr,
+ 	struct ftrace_graph_ret_entry *entry;
+ 
+ 	event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
+-					  sizeof(*entry), flags, pc);
++					  sizeof(*entry), trace_ctx);
+ 	if (!event)
+ 		return;
+ 	entry	= ring_buffer_event_data(event);
+@@ -239,9 +237,9 @@ void trace_graph_return(struct ftrace_graph_ret *trace)
+ 	struct trace_array *tr = graph_array;
+ 	struct trace_array_cpu *data;
+ 	unsigned long flags;
++	unsigned int trace_ctx;
+ 	long disabled;
+ 	int cpu;
+-	int pc;
+ 
+ 	ftrace_graph_addr_finish(trace);
+ 
+@@ -255,8 +253,8 @@ void trace_graph_return(struct ftrace_graph_ret *trace)
+ 	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+ 	disabled = atomic_inc_return(&data->disabled);
+ 	if (likely(disabled == 1)) {
+-		pc = preempt_count();
+-		__trace_graph_return(tr, trace, flags, pc);
++		trace_ctx = tracing_gen_ctx_flags(flags);
++		__trace_graph_return(tr, trace, trace_ctx);
+ 	}
+ 	atomic_dec(&data->disabled);
+ 	local_irq_restore(flags);
+diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
+index d071fc271eef..4c01c5d8b9a7 100644
+--- a/kernel/trace/trace_hwlat.c
++++ b/kernel/trace/trace_hwlat.c
+@@ -108,14 +108,9 @@ static void trace_hwlat_sample(struct hwlat_sample *sample)
+ 	struct trace_buffer *buffer = tr->array_buffer.buffer;
+ 	struct ring_buffer_event *event;
+ 	struct hwlat_entry *entry;
+-	unsigned long flags;
+-	int pc;
+-
+-	pc = preempt_count();
+-	local_save_flags(flags);
+ 
+ 	event = trace_buffer_lock_reserve(buffer, TRACE_HWLAT, sizeof(*entry),
+-					  flags, pc);
++					  tracing_gen_ctx());
+ 	if (!event)
+ 		return;
+ 	entry	= ring_buffer_event_data(event);
+diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
+index 619a60944bb6..4a11967c8daa 100644
+--- a/kernel/trace/trace_irqsoff.c
++++ b/kernel/trace/trace_irqsoff.c
+@@ -143,11 +143,14 @@ irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip,
+ 	struct trace_array *tr = irqsoff_trace;
+ 	struct trace_array_cpu *data;
+ 	unsigned long flags;
++	unsigned int trace_ctx;
+ 
+ 	if (!func_prolog_dec(tr, &data, &flags))
+ 		return;
+ 
+-	trace_function(tr, ip, parent_ip, flags, preempt_count());
++	trace_ctx = tracing_gen_ctx_flags(flags);
++
++	trace_function(tr, ip, parent_ip, trace_ctx);
+ 
+ 	atomic_dec(&data->disabled);
+ }
+@@ -177,8 +180,8 @@ static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
+ 	struct trace_array *tr = irqsoff_trace;
+ 	struct trace_array_cpu *data;
+ 	unsigned long flags;
++	unsigned int trace_ctx;
+ 	int ret;
+-	int pc;
+ 
+ 	if (ftrace_graph_ignore_func(trace))
+ 		return 0;
+@@ -195,8 +198,8 @@ static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
+ 	if (!func_prolog_dec(tr, &data, &flags))
+ 		return 0;
+ 
+-	pc = preempt_count();
+-	ret = __trace_graph_entry(tr, trace, flags, pc);
++	trace_ctx = tracing_gen_ctx_flags(flags);
++	ret = __trace_graph_entry(tr, trace, trace_ctx);
+ 	atomic_dec(&data->disabled);
+ 
+ 	return ret;
+@@ -207,15 +210,15 @@ static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
+ 	struct trace_array *tr = irqsoff_trace;
+ 	struct trace_array_cpu *data;
+ 	unsigned long flags;
+-	int pc;
++	unsigned int trace_ctx;
+ 
+ 	ftrace_graph_addr_finish(trace);
+ 
+ 	if (!func_prolog_dec(tr, &data, &flags))
+ 		return;
+ 
+-	pc = preempt_count();
+-	__trace_graph_return(tr, trace, flags, pc);
++	trace_ctx = tracing_gen_ctx_flags(flags);
++	__trace_graph_return(tr, trace, trace_ctx);
+ 	atomic_dec(&data->disabled);
+ }
+ 
+@@ -268,12 +271,12 @@ static void irqsoff_print_header(struct seq_file *s)
+ static void
+ __trace_function(struct trace_array *tr,
+ 		 unsigned long ip, unsigned long parent_ip,
+-		 unsigned long flags, int pc)
++		 unsigned int trace_ctx)
+ {
+ 	if (is_graph(tr))
+-		trace_graph_function(tr, ip, parent_ip, flags, pc);
++		trace_graph_function(tr, ip, parent_ip, trace_ctx);
+ 	else
+-		trace_function(tr, ip, parent_ip, flags, pc);
++		trace_function(tr, ip, parent_ip, trace_ctx);
+ }
+ 
+ #else
+@@ -323,15 +326,13 @@ check_critical_timing(struct trace_array *tr,
+ {
+ 	u64 T0, T1, delta;
+ 	unsigned long flags;
+-	int pc;
++	unsigned int trace_ctx;
+ 
+ 	T0 = data->preempt_timestamp;
+ 	T1 = ftrace_now(cpu);
+ 	delta = T1-T0;
+ 
+-	local_save_flags(flags);
+-
+-	pc = preempt_count();
++	trace_ctx = tracing_gen_ctx();
+ 
+ 	if (!report_latency(tr, delta))
+ 		goto out;
+@@ -342,9 +343,9 @@ check_critical_timing(struct trace_array *tr,
+ 	if (!report_latency(tr, delta))
+ 		goto out_unlock;
+ 
+-	__trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
++	__trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx);
+ 	/* Skip 5 functions to get to the irq/preempt enable function */
+-	__trace_stack(tr, flags, 5, pc);
++	__trace_stack(tr, trace_ctx, 5);
+ 
+ 	if (data->critical_sequence != max_sequence)
+ 		goto out_unlock;
+@@ -364,16 +365,15 @@ check_critical_timing(struct trace_array *tr,
+ out:
+ 	data->critical_sequence = max_sequence;
+ 	data->preempt_timestamp = ftrace_now(cpu);
+-	__trace_function(tr, CALLER_ADDR0, parent_ip, flags, pc);
++	__trace_function(tr, CALLER_ADDR0, parent_ip, trace_ctx);
+ }
+ 
+ static nokprobe_inline void
+-start_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
++start_critical_timing(unsigned long ip, unsigned long parent_ip)
+ {
+ 	int cpu;
+ 	struct trace_array *tr = irqsoff_trace;
+ 	struct trace_array_cpu *data;
+-	unsigned long flags;
+ 
+ 	if (!tracer_enabled || !tracing_is_enabled())
+ 		return;
+@@ -394,9 +394,7 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
+ 	data->preempt_timestamp = ftrace_now(cpu);
+ 	data->critical_start = parent_ip ? : ip;
+ 
+-	local_save_flags(flags);
+-
+-	__trace_function(tr, ip, parent_ip, flags, pc);
++	__trace_function(tr, ip, parent_ip, tracing_gen_ctx());
+ 
+ 	per_cpu(tracing_cpu, cpu) = 1;
+ 
+@@ -404,12 +402,12 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
+ }
+ 
+ static nokprobe_inline void
+-stop_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
++stop_critical_timing(unsigned long ip, unsigned long parent_ip)
+ {
+ 	int cpu;
+ 	struct trace_array *tr = irqsoff_trace;
+ 	struct trace_array_cpu *data;
+-	unsigned long flags;
++	unsigned int trace_ctx;
+ 
+ 	cpu = raw_smp_processor_id();
+ 	/* Always clear the tracing cpu on stopping the trace */
+@@ -429,8 +427,8 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
+ 
+ 	atomic_inc(&data->disabled);
+ 
+-	local_save_flags(flags);
+-	__trace_function(tr, ip, parent_ip, flags, pc);
++	trace_ctx = tracing_gen_ctx();
++	__trace_function(tr, ip, parent_ip, trace_ctx);
+ 	check_critical_timing(tr, data, parent_ip ? : ip, cpu);
+ 	data->critical_start = 0;
+ 	atomic_dec(&data->disabled);
+@@ -439,20 +437,16 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip, int pc)
+ /* start and stop critical timings used to for stoppage (in idle) */
+ void start_critical_timings(void)
+ {
+-	int pc = preempt_count();
+-
+-	if (preempt_trace(pc) || irq_trace())
+-		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1, pc);
++	if (preempt_trace(preempt_count()) || irq_trace())
++		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+ }
+ EXPORT_SYMBOL_GPL(start_critical_timings);
+ NOKPROBE_SYMBOL(start_critical_timings);
+ 
+ void stop_critical_timings(void)
+ {
+-	int pc = preempt_count();
+-
+-	if (preempt_trace(pc) || irq_trace())
+-		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1, pc);
++	if (preempt_trace(preempt_count()) || irq_trace())
++		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
+ }
+ EXPORT_SYMBOL_GPL(stop_critical_timings);
+ NOKPROBE_SYMBOL(stop_critical_timings);
+@@ -614,19 +608,15 @@ static void irqsoff_tracer_stop(struct trace_array *tr)
+  */
+ void tracer_hardirqs_on(unsigned long a0, unsigned long a1)
+ {
+-	unsigned int pc = preempt_count();
+-
+-	if (!preempt_trace(pc) && irq_trace())
+-		stop_critical_timing(a0, a1, pc);
++	if (!preempt_trace(preempt_count()) && irq_trace())
++		stop_critical_timing(a0, a1);
+ }
+ NOKPROBE_SYMBOL(tracer_hardirqs_on);
+ 
+ void tracer_hardirqs_off(unsigned long a0, unsigned long a1)
+ {
+-	unsigned int pc = preempt_count();
+-
+-	if (!preempt_trace(pc) && irq_trace())
+-		start_critical_timing(a0, a1, pc);
++	if (!preempt_trace(preempt_count()) && irq_trace())
++		start_critical_timing(a0, a1);
+ }
+ NOKPROBE_SYMBOL(tracer_hardirqs_off);
+ 
+@@ -666,18 +656,14 @@ static struct tracer irqsoff_tracer __read_mostly =
+ #ifdef CONFIG_PREEMPT_TRACER
+ void tracer_preempt_on(unsigned long a0, unsigned long a1)
+ {
+-	int pc = preempt_count();
+-
+-	if (preempt_trace(pc) && !irq_trace())
+-		stop_critical_timing(a0, a1, pc);
++	if (preempt_trace(preempt_count()) && !irq_trace())
++		stop_critical_timing(a0, a1);
+ }
+ 
+ void tracer_preempt_off(unsigned long a0, unsigned long a1)
+ {
+-	int pc = preempt_count();
+-
+-	if (preempt_trace(pc) && !irq_trace())
+-		start_critical_timing(a0, a1, pc);
++	if (preempt_trace(preempt_count()) && !irq_trace())
++		start_critical_timing(a0, a1);
+ }
+ 
+ static int preemptoff_tracer_init(struct trace_array *tr)
+diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
+index 718357289899..a2478605e761 100644
+--- a/kernel/trace/trace_kprobe.c
++++ b/kernel/trace/trace_kprobe.c
+@@ -1394,8 +1394,7 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
+ 	if (trace_trigger_soft_disabled(trace_file))
+ 		return;
+ 
+-	local_save_flags(fbuffer.flags);
+-	fbuffer.pc = preempt_count();
++	fbuffer.trace_ctx = tracing_gen_ctx();
+ 	fbuffer.trace_file = trace_file;
+ 
+ 	dsize = __get_data_size(&tk->tp, regs);
+@@ -1404,7 +1403,7 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
+ 		trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
+ 					call->event.type,
+ 					sizeof(*entry) + tk->tp.size + dsize,
+-					fbuffer.flags, fbuffer.pc);
++					fbuffer.trace_ctx);
+ 	if (!fbuffer.event)
+ 		return;
+ 
+@@ -1442,8 +1441,7 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
+ 	if (trace_trigger_soft_disabled(trace_file))
+ 		return;
+ 
+-	local_save_flags(fbuffer.flags);
+-	fbuffer.pc = preempt_count();
++	fbuffer.trace_ctx = tracing_gen_ctx();
+ 	fbuffer.trace_file = trace_file;
+ 
+ 	dsize = __get_data_size(&tk->tp, regs);
+@@ -1451,7 +1449,7 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
+ 		trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
+ 					call->event.type,
+ 					sizeof(*entry) + tk->tp.size + dsize,
+-					fbuffer.flags, fbuffer.pc);
++					fbuffer.trace_ctx);
+ 	if (!fbuffer.event)
+ 		return;
+ 
+diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
+index 84582bf1ed5f..7221ae0b4c47 100644
+--- a/kernel/trace/trace_mmiotrace.c
++++ b/kernel/trace/trace_mmiotrace.c
+@@ -300,10 +300,11 @@ static void __trace_mmiotrace_rw(struct trace_array *tr,
+ 	struct trace_buffer *buffer = tr->array_buffer.buffer;
+ 	struct ring_buffer_event *event;
+ 	struct trace_mmiotrace_rw *entry;
+-	int pc = preempt_count();
++	unsigned int trace_ctx;
+ 
++	trace_ctx = tracing_gen_ctx_flags(0);
+ 	event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW,
+-					  sizeof(*entry), 0, pc);
++					  sizeof(*entry), trace_ctx);
+ 	if (!event) {
+ 		atomic_inc(&dropped_count);
+ 		return;
+@@ -312,7 +313,7 @@ static void __trace_mmiotrace_rw(struct trace_array *tr,
+ 	entry->rw			= *rw;
+ 
+ 	if (!call_filter_check_discard(call, entry, buffer, event))
+-		trace_buffer_unlock_commit(tr, buffer, event, 0, pc);
++		trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
+ }
+ 
+ void mmio_trace_rw(struct mmiotrace_rw *rw)
+@@ -330,10 +331,11 @@ static void __trace_mmiotrace_map(struct trace_array *tr,
+ 	struct trace_buffer *buffer = tr->array_buffer.buffer;
+ 	struct ring_buffer_event *event;
+ 	struct trace_mmiotrace_map *entry;
+-	int pc = preempt_count();
++	unsigned int trace_ctx;
+ 
++	trace_ctx = tracing_gen_ctx_flags(0);
+ 	event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP,
+-					  sizeof(*entry), 0, pc);
++					  sizeof(*entry), trace_ctx);
+ 	if (!event) {
+ 		atomic_inc(&dropped_count);
+ 		return;
+@@ -342,7 +344,7 @@ static void __trace_mmiotrace_map(struct trace_array *tr,
+ 	entry->map			= *map;
+ 
+ 	if (!call_filter_check_discard(call, entry, buffer, event))
+-		trace_buffer_unlock_commit(tr, buffer, event, 0, pc);
++		trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
+ }
+ 
+ void mmio_trace_mapping(struct mmiotrace_map *map)
+diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
+index 037e1e863b17..c1f582e0e97f 100644
+--- a/kernel/trace/trace_sched_wakeup.c
++++ b/kernel/trace/trace_sched_wakeup.c
+@@ -67,7 +67,7 @@ static bool function_enabled;
+ static int
+ func_prolog_preempt_disable(struct trace_array *tr,
+ 			    struct trace_array_cpu **data,
+-			    int *pc)
++			    unsigned int *trace_ctx)
+ {
+ 	long disabled;
+ 	int cpu;
+@@ -75,7 +75,7 @@ func_prolog_preempt_disable(struct trace_array *tr,
+ 	if (likely(!wakeup_task))
+ 		return 0;
+ 
+-	*pc = preempt_count();
++	*trace_ctx = tracing_gen_ctx();
+ 	preempt_disable_notrace();
+ 
+ 	cpu = raw_smp_processor_id();
+@@ -116,8 +116,8 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
+ {
+ 	struct trace_array *tr = wakeup_trace;
+ 	struct trace_array_cpu *data;
+-	unsigned long flags;
+-	int pc, ret = 0;
++	unsigned int trace_ctx;
++	int ret = 0;
+ 
+ 	if (ftrace_graph_ignore_func(trace))
+ 		return 0;
+@@ -131,11 +131,10 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
+ 	if (ftrace_graph_notrace_addr(trace->func))
+ 		return 1;
+ 
+-	if (!func_prolog_preempt_disable(tr, &data, &pc))
++	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
+ 		return 0;
+ 
+-	local_save_flags(flags);
+-	ret = __trace_graph_entry(tr, trace, flags, pc);
++	ret = __trace_graph_entry(tr, trace, trace_ctx);
+ 	atomic_dec(&data->disabled);
+ 	preempt_enable_notrace();
+ 
+@@ -146,16 +145,14 @@ static void wakeup_graph_return(struct ftrace_graph_ret *trace)
+ {
+ 	struct trace_array *tr = wakeup_trace;
+ 	struct trace_array_cpu *data;
+-	unsigned long flags;
+-	int pc;
++	unsigned int trace_ctx;
+ 
+ 	ftrace_graph_addr_finish(trace);
+ 
+-	if (!func_prolog_preempt_disable(tr, &data, &pc))
++	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
+ 		return;
+ 
+-	local_save_flags(flags);
+-	__trace_graph_return(tr, trace, flags, pc);
++	__trace_graph_return(tr, trace, trace_ctx);
+ 	atomic_dec(&data->disabled);
+ 
+ 	preempt_enable_notrace();
+@@ -219,13 +216,13 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip,
+ 	struct trace_array *tr = wakeup_trace;
+ 	struct trace_array_cpu *data;
+ 	unsigned long flags;
+-	int pc;
++	unsigned int trace_ctx;
+ 
+-	if (!func_prolog_preempt_disable(tr, &data, &pc))
++	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
+ 		return;
+ 
+ 	local_irq_save(flags);
+-	trace_function(tr, ip, parent_ip, flags, pc);
++	trace_function(tr, ip, parent_ip, trace_ctx);
+ 	local_irq_restore(flags);
+ 
+ 	atomic_dec(&data->disabled);
+@@ -305,12 +302,12 @@ static void wakeup_print_header(struct seq_file *s)
+ static void
+ __trace_function(struct trace_array *tr,
+ 		 unsigned long ip, unsigned long parent_ip,
+-		 unsigned long flags, int pc)
++		 unsigned int trace_ctx)
+ {
+ 	if (is_graph(tr))
+-		trace_graph_function(tr, ip, parent_ip, flags, pc);
++		trace_graph_function(tr, ip, parent_ip, trace_ctx);
+ 	else
+-		trace_function(tr, ip, parent_ip, flags, pc);
++		trace_function(tr, ip, parent_ip, trace_ctx);
+ }
+ 
+ static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set)
+@@ -377,7 +374,7 @@ static void
+ tracing_sched_switch_trace(struct trace_array *tr,
+ 			   struct task_struct *prev,
+ 			   struct task_struct *next,
+-			   unsigned long flags, int pc)
++			   unsigned int trace_ctx)
+ {
+ 	struct trace_event_call *call = &event_context_switch;
+ 	struct trace_buffer *buffer = tr->array_buffer.buffer;
+@@ -385,7 +382,7 @@ tracing_sched_switch_trace(struct trace_array *tr,
+ 	struct ctx_switch_entry *entry;
+ 
+ 	event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
+-					  sizeof(*entry), flags, pc);
++					  sizeof(*entry), trace_ctx);
+ 	if (!event)
+ 		return;
+ 	entry	= ring_buffer_event_data(event);
+@@ -398,14 +395,14 @@ tracing_sched_switch_trace(struct trace_array *tr,
+ 	entry->next_cpu	= task_cpu(next);
+ 
+ 	if (!call_filter_check_discard(call, entry, buffer, event))
+-		trace_buffer_unlock_commit(tr, buffer, event, flags, pc);
++		trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
+ }
+ 
+ static void
+ tracing_sched_wakeup_trace(struct trace_array *tr,
+ 			   struct task_struct *wakee,
+ 			   struct task_struct *curr,
+-			   unsigned long flags, int pc)
++			   unsigned int trace_ctx)
+ {
+ 	struct trace_event_call *call = &event_wakeup;
+ 	struct ring_buffer_event *event;
+@@ -413,7 +410,7 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
+ 	struct trace_buffer *buffer = tr->array_buffer.buffer;
+ 
+ 	event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
+-					  sizeof(*entry), flags, pc);
++					  sizeof(*entry), trace_ctx);
+ 	if (!event)
+ 		return;
+ 	entry	= ring_buffer_event_data(event);
+@@ -426,7 +423,7 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
+ 	entry->next_cpu			= task_cpu(wakee);
+ 
+ 	if (!call_filter_check_discard(call, entry, buffer, event))
+-		trace_buffer_unlock_commit(tr, buffer, event, flags, pc);
++		trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
+ }
+ 
+ static void notrace
+@@ -438,7 +435,7 @@ probe_wakeup_sched_switch(void *ignore, bool preempt,
+ 	unsigned long flags;
+ 	long disabled;
+ 	int cpu;
+-	int pc;
++	unsigned int trace_ctx;
+ 
+ 	tracing_record_cmdline(prev);
+ 
+@@ -457,8 +454,6 @@ probe_wakeup_sched_switch(void *ignore, bool preempt,
+ 	if (next != wakeup_task)
+ 		return;
+ 
+-	pc = preempt_count();
+-
+ 	/* disable local data, not wakeup_cpu data */
+ 	cpu = raw_smp_processor_id();
+ 	disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
+@@ -466,6 +461,8 @@ probe_wakeup_sched_switch(void *ignore, bool preempt,
+ 		goto out;
+ 
+ 	local_irq_save(flags);
++	trace_ctx = tracing_gen_ctx_flags(flags);
++
+ 	arch_spin_lock(&wakeup_lock);
+ 
+ 	/* We could race with grabbing wakeup_lock */
+@@ -475,9 +472,9 @@ probe_wakeup_sched_switch(void *ignore, bool preempt,
+ 	/* The task we are waiting for is waking up */
+ 	data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
+ 
+-	__trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc);
+-	tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc);
+-	__trace_stack(wakeup_trace, flags, 0, pc);
++	__trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, trace_ctx);
++	tracing_sched_switch_trace(wakeup_trace, prev, next, trace_ctx);
++	__trace_stack(wakeup_trace, trace_ctx, 0);
+ 
+ 	T0 = data->preempt_timestamp;
+ 	T1 = ftrace_now(cpu);
+@@ -529,9 +526,8 @@ probe_wakeup(void *ignore, struct task_struct *p)
+ {
+ 	struct trace_array_cpu *data;
+ 	int cpu = smp_processor_id();
+-	unsigned long flags;
+ 	long disabled;
+-	int pc;
++	unsigned int trace_ctx;
+ 
+ 	if (likely(!tracer_enabled))
+ 		return;
+@@ -552,11 +548,12 @@ probe_wakeup(void *ignore, struct task_struct *p)
+ 	    (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio)))
+ 		return;
+ 
+-	pc = preempt_count();
+ 	disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->array_buffer.data, cpu)->disabled);
+ 	if (unlikely(disabled != 1))
+ 		goto out;
+ 
++	trace_ctx = tracing_gen_ctx();
++
+ 	/* interrupts should be off from try_to_wake_up */
+ 	arch_spin_lock(&wakeup_lock);
+ 
+@@ -583,19 +580,17 @@ probe_wakeup(void *ignore, struct task_struct *p)
+ 
+ 	wakeup_task = get_task_struct(p);
+ 
+-	local_save_flags(flags);
+-
+ 	data = per_cpu_ptr(wakeup_trace->array_buffer.data, wakeup_cpu);
+ 	data->preempt_timestamp = ftrace_now(cpu);
+-	tracing_sched_wakeup_trace(wakeup_trace, p, current, flags, pc);
+-	__trace_stack(wakeup_trace, flags, 0, pc);
++	tracing_sched_wakeup_trace(wakeup_trace, p, current, trace_ctx);
++	__trace_stack(wakeup_trace, trace_ctx, 0);
+ 
+ 	/*
+ 	 * We must be careful in using CALLER_ADDR2. But since wake_up
+ 	 * is not called by an assembly function  (where as schedule is)
+ 	 * it should be safe to use it here.
+ 	 */
+-	__trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc);
++	__trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, trace_ctx);
+ 
+ out_locked:
+ 	arch_spin_unlock(&wakeup_lock);
+diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
+index d85a2f0f316b..8bfcd3b09422 100644
+--- a/kernel/trace/trace_syscalls.c
++++ b/kernel/trace/trace_syscalls.c
+@@ -298,9 +298,8 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
+ 	struct syscall_metadata *sys_data;
+ 	struct ring_buffer_event *event;
+ 	struct trace_buffer *buffer;
+-	unsigned long irq_flags;
++	unsigned int trace_ctx;
+ 	unsigned long args[6];
+-	int pc;
+ 	int syscall_nr;
+ 	int size;
+ 
+@@ -322,12 +321,11 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
+ 
+ 	size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
+ 
+-	local_save_flags(irq_flags);
+-	pc = preempt_count();
++	trace_ctx = tracing_gen_ctx();
+ 
+ 	buffer = tr->array_buffer.buffer;
+ 	event = trace_buffer_lock_reserve(buffer,
+-			sys_data->enter_event->event.type, size, irq_flags, pc);
++			sys_data->enter_event->event.type, size, trace_ctx);
+ 	if (!event)
+ 		return;
+ 
+@@ -337,7 +335,7 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
+ 	memcpy(entry->args, args, sizeof(unsigned long) * sys_data->nb_args);
+ 
+ 	event_trigger_unlock_commit(trace_file, buffer, event, entry,
+-				    irq_flags, pc);
++				    trace_ctx);
+ }
+ 
+ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
+@@ -348,8 +346,7 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
+ 	struct syscall_metadata *sys_data;
+ 	struct ring_buffer_event *event;
+ 	struct trace_buffer *buffer;
+-	unsigned long irq_flags;
+-	int pc;
++	unsigned int trace_ctx;
+ 	int syscall_nr;
+ 
+ 	syscall_nr = trace_get_syscall_nr(current, regs);
+@@ -368,13 +365,12 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
+ 	if (!sys_data)
+ 		return;
+ 
+-	local_save_flags(irq_flags);
+-	pc = preempt_count();
++	trace_ctx = tracing_gen_ctx();
+ 
+ 	buffer = tr->array_buffer.buffer;
+ 	event = trace_buffer_lock_reserve(buffer,
+ 			sys_data->exit_event->event.type, sizeof(*entry),
+-			irq_flags, pc);
++			trace_ctx);
+ 	if (!event)
+ 		return;
+ 
+@@ -383,7 +379,7 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
+ 	entry->ret = syscall_get_return_value(current, regs);
+ 
+ 	event_trigger_unlock_commit(trace_file, buffer, event, entry,
+-				    irq_flags, pc);
++				    trace_ctx);
+ }
+ 
+ static int reg_event_syscall_enter(struct trace_event_file *file,
+diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
+index 60ff36f5d7f9..0b07bb07127d 100644
+--- a/kernel/trace/trace_uprobe.c
++++ b/kernel/trace/trace_uprobe.c
+@@ -966,7 +966,7 @@ static void __uprobe_trace_func(struct trace_uprobe *tu,
+ 	esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
+ 	size = esize + tu->tp.size + dsize;
+ 	event = trace_event_buffer_lock_reserve(&buffer, trace_file,
+-						call->event.type, size, 0, 0);
++						call->event.type, size, 0);
+ 	if (!event)
+ 		return;
+ 
+@@ -982,7 +982,7 @@ static void __uprobe_trace_func(struct trace_uprobe *tu,
+ 
+ 	memcpy(data, ucb->buf, tu->tp.size + dsize);
+ 
+-	event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
++	event_trigger_unlock_commit(trace_file, buffer, event, entry, 0);
+ }
+ 
+ /* uprobe handler */
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0077-tracing-Inline-tracing_gen_ctx_flags.patch b/debian/patches-rt/0077-tracing-Inline-tracing_gen_ctx_flags.patch
new file mode 100644
index 000000000..38993b6b8
--- /dev/null
+++ b/debian/patches-rt/0077-tracing-Inline-tracing_gen_ctx_flags.patch
@@ -0,0 +1,184 @@
+From 49d76ea7e195eb08b5c73a3a11dba066afd40070 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 3 Feb 2021 11:05:24 -0500
+Subject: [PATCH 077/323] tracing: Inline tracing_gen_ctx_flags()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Inline tracing_gen_ctx_flags(). This allows to have one ifdef
+CONFIG_TRACE_IRQFLAGS_SUPPORT.
+
+This requires to move `trace_flag_type' so tracing_gen_ctx_flags() can
+use it.
+
+Link: https://lkml.kernel.org/r/20210125194511.3924915-3-bigeasy@linutronix.de
+
+Suggested-by: Steven Rostedt <rostedt@goodmis.org>
+Link: https://lkml.kernel.org/r/20210125140323.6b1ff20c@gandalf.local.home
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/trace_events.h | 54 ++++++++++++++++++++++++++++++++++--
+ kernel/trace/trace.c         | 38 ++-----------------------
+ kernel/trace/trace.h         | 19 -------------
+ 3 files changed, 53 insertions(+), 58 deletions(-)
+
+diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
+index 2a98c40526a0..c4b0524582d8 100644
+--- a/include/linux/trace_events.h
++++ b/include/linux/trace_events.h
+@@ -164,9 +164,57 @@ static inline void tracing_generic_entry_update(struct trace_entry *entry,
+ 	entry->flags =			trace_ctx >> 16;
+ }
+ 
+-unsigned int tracing_gen_ctx_flags(unsigned long irqflags);
+-unsigned int tracing_gen_ctx(void);
+-unsigned int tracing_gen_ctx_dec(void);
++unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status);
++
++enum trace_flag_type {
++	TRACE_FLAG_IRQS_OFF		= 0x01,
++	TRACE_FLAG_IRQS_NOSUPPORT	= 0x02,
++	TRACE_FLAG_NEED_RESCHED		= 0x04,
++	TRACE_FLAG_HARDIRQ		= 0x08,
++	TRACE_FLAG_SOFTIRQ		= 0x10,
++	TRACE_FLAG_PREEMPT_RESCHED	= 0x20,
++	TRACE_FLAG_NMI			= 0x40,
++};
++
++#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
++static inline unsigned int tracing_gen_ctx_flags(unsigned long irqflags)
++{
++	unsigned int irq_status = irqs_disabled_flags(irqflags) ?
++		TRACE_FLAG_IRQS_OFF : 0;
++	return tracing_gen_ctx_irq_test(irq_status);
++}
++static inline unsigned int tracing_gen_ctx(void)
++{
++	unsigned long irqflags;
++
++	local_save_flags(irqflags);
++	return tracing_gen_ctx_flags(irqflags);
++}
++#else
++
++static inline unsigned int tracing_gen_ctx_flags(unsigned long irqflags)
++{
++	return tracing_gen_ctx_irq_test(TRACE_FLAG_IRQS_NOSUPPORT);
++}
++static inline unsigned int tracing_gen_ctx(void)
++{
++	return tracing_gen_ctx_irq_test(TRACE_FLAG_IRQS_NOSUPPORT);
++}
++#endif
++
++static inline unsigned int tracing_gen_ctx_dec(void)
++{
++	unsigned int trace_ctx;
++
++	trace_ctx = tracing_gen_ctx();
++	/*
++	 * Subtract one from the preeption counter if preemption is enabled,
++	 * see trace_event_buffer_reserve()for details.
++	 */
++	if (IS_ENABLED(CONFIG_PREEMPTION))
++		trace_ctx--;
++	return trace_ctx;
++}
+ 
+ struct trace_event_file;
+ 
+diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
+index 376eb8a1c913..733ef9230c73 100644
+--- a/kernel/trace/trace.c
++++ b/kernel/trace/trace.c
+@@ -2575,20 +2575,13 @@ enum print_line_t trace_handle_return(struct trace_seq *s)
+ }
+ EXPORT_SYMBOL_GPL(trace_handle_return);
+ 
+-unsigned int tracing_gen_ctx_flags(unsigned long irqflags)
++unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
+ {
+-	unsigned int trace_flags = 0;
++	unsigned int trace_flags = irqs_status;
+ 	unsigned int pc;
+ 
+ 	pc = preempt_count();
+ 
+-#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
+-	if (irqs_disabled_flags(irqflags))
+-		trace_flags |= TRACE_FLAG_IRQS_OFF;
+-#else
+-	trace_flags |= TRACE_FLAG_IRQS_NOSUPPORT;
+-#endif
+-
+ 	if (pc & NMI_MASK)
+ 		trace_flags |= TRACE_FLAG_NMI;
+ 	if (pc & HARDIRQ_MASK)
+@@ -2604,33 +2597,6 @@ unsigned int tracing_gen_ctx_flags(unsigned long irqflags)
+ 	return (trace_flags << 16) | (pc & 0xff);
+ }
+ 
+-unsigned int tracing_gen_ctx(void)
+-{
+-	unsigned long irqflags;
+-
+-#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
+-	local_save_flags(irqflags);
+-#else
+-	irqflags = 0;
+-#endif
+-	return tracing_gen_ctx_flags(irqflags);
+-}
+-
+-unsigned int tracing_gen_ctx_dec(void)
+-{
+-	unsigned int trace_ctx;
+-
+-	trace_ctx = tracing_gen_ctx();
+-
+-	/*
+-	 * Subtract one from the preeption counter if preemption is enabled,
+-	 * see trace_event_buffer_reserve()for details.
+-	 */
+-	if (IS_ENABLED(CONFIG_PREEMPTION))
+-		trace_ctx--;
+-	return trace_ctx;
+-}
+-
+ struct ring_buffer_event *
+ trace_buffer_lock_reserve(struct trace_buffer *buffer,
+ 			  int type,
+diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
+index 27ed42bccd7f..40e5ee987578 100644
+--- a/kernel/trace/trace.h
++++ b/kernel/trace/trace.h
+@@ -136,25 +136,6 @@ struct kretprobe_trace_entry_head {
+ 	unsigned long		ret_ip;
+ };
+ 
+-/*
+- * trace_flag_type is an enumeration that holds different
+- * states when a trace occurs. These are:
+- *  IRQS_OFF		- interrupts were disabled
+- *  IRQS_NOSUPPORT	- arch does not support irqs_disabled_flags
+- *  NEED_RESCHED	- reschedule is requested
+- *  HARDIRQ		- inside an interrupt handler
+- *  SOFTIRQ		- inside a softirq handler
+- */
+-enum trace_flag_type {
+-	TRACE_FLAG_IRQS_OFF		= 0x01,
+-	TRACE_FLAG_IRQS_NOSUPPORT	= 0x02,
+-	TRACE_FLAG_NEED_RESCHED		= 0x04,
+-	TRACE_FLAG_HARDIRQ		= 0x08,
+-	TRACE_FLAG_SOFTIRQ		= 0x10,
+-	TRACE_FLAG_PREEMPT_RESCHED	= 0x20,
+-	TRACE_FLAG_NMI			= 0x40,
+-};
+-
+ #define TRACE_BUF_SIZE		1024
+ 
+ struct trace_array;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0078-tracing-Use-in_serving_softirq-to-deduct-softirq-sta.patch b/debian/patches-rt/0078-tracing-Use-in_serving_softirq-to-deduct-softirq-sta.patch
new file mode 100644
index 000000000..32411e1ff
--- /dev/null
+++ b/debian/patches-rt/0078-tracing-Use-in_serving_softirq-to-deduct-softirq-sta.patch
@@ -0,0 +1,48 @@
+From 1a49f21b61e919dbef7c948009870a1f1ba31270 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 3 Feb 2021 11:05:25 -0500
+Subject: [PATCH 078/323] tracing: Use in_serving_softirq() to deduct softirq
+ status.
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+PREEMPT_RT does not report "serving softirq" because the tracing core
+looks at the preemption counter while PREEMPT_RT does not update it
+while processing softirqs in order to remain preemptible. The
+information is stored somewhere else.
+The in_serving_softirq() macro and the SOFTIRQ_OFFSET define are still
+working but not on the preempt-counter.
+
+Use in_serving_softirq() macro which works on PREEMPT_RT. On !PREEMPT_RT
+the compiler (gcc-10 / clang-11) is smart enough to optimize the
+in_serving_softirq() related read of the preemption counter away.
+The only difference I noticed by using in_serving_softirq() on
+!PREEMPT_RT is that gcc-10 implemented tracing_gen_ctx_flags() as
+reading FLAG, jmp _tracing_gen_ctx_flags(). Without in_serving_softirq()
+it inlined _tracing_gen_ctx_flags() into tracing_gen_ctx_flags().
+
+Link: https://lkml.kernel.org/r/20210125194511.3924915-4-bigeasy@linutronix.de
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/trace/trace.c | 3 +--
+ 1 file changed, 1 insertion(+), 2 deletions(-)
+
+diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
+index 733ef9230c73..70ab6b46ef8f 100644
+--- a/kernel/trace/trace.c
++++ b/kernel/trace/trace.c
+@@ -2586,8 +2586,7 @@ unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
+ 		trace_flags |= TRACE_FLAG_NMI;
+ 	if (pc & HARDIRQ_MASK)
+ 		trace_flags |= TRACE_FLAG_HARDIRQ;
+-
+-	if (pc & SOFTIRQ_OFFSET)
++	if (in_serving_softirq())
+ 		trace_flags |= TRACE_FLAG_SOFTIRQ;
+ 
+ 	if (tif_need_resched())
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0079-tracing-Remove-NULL-check-from-current-in-tracing_ge.patch b/debian/patches-rt/0079-tracing-Remove-NULL-check-from-current-in-tracing_ge.patch
new file mode 100644
index 000000000..5853f5af4
--- /dev/null
+++ b/debian/patches-rt/0079-tracing-Remove-NULL-check-from-current-in-tracing_ge.patch
@@ -0,0 +1,43 @@
+From 76993b5cd21ad0898e6d940ea5fe0449dec94465 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 3 Feb 2021 11:05:26 -0500
+Subject: [PATCH 079/323] tracing: Remove NULL check from current in
+ tracing_generic_entry_update().
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+I can't imagine when or why `current' would return a NULL pointer. This
+check was added in commit
+      72829bc3d63cd ("ftrace: move enums to ftrace.h and make helper function global")
+
+but it doesn't give me hint why it was needed.
+
+Assume `current' never returns a NULL pointer and remove the check.
+
+Link: https://lkml.kernel.org/r/20210125194511.3924915-5-bigeasy@linutronix.de
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/trace_events.h | 4 +---
+ 1 file changed, 1 insertion(+), 3 deletions(-)
+
+diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
+index c4b0524582d8..2fea9fcd4d4e 100644
+--- a/include/linux/trace_events.h
++++ b/include/linux/trace_events.h
+@@ -156,10 +156,8 @@ static inline void tracing_generic_entry_update(struct trace_entry *entry,
+ 						unsigned short type,
+ 						unsigned int trace_ctx)
+ {
+-	struct task_struct *tsk = current;
+-
+ 	entry->preempt_count		= trace_ctx & 0xff;
+-	entry->pid			= (tsk) ? tsk->pid : 0;
++	entry->pid			= current->pid;
+ 	entry->type			= type;
+ 	entry->flags =			trace_ctx >> 16;
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0080-printk-inline-log_output-log_store-in-vprintk_store.patch b/debian/patches-rt/0080-printk-inline-log_output-log_store-in-vprintk_store.patch
new file mode 100644
index 000000000..3a67cf2f5
--- /dev/null
+++ b/debian/patches-rt/0080-printk-inline-log_output-log_store-in-vprintk_store.patch
@@ -0,0 +1,201 @@
+From fe124333809d2e0a0926d5609f78bafffc62f539 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Wed, 9 Dec 2020 01:50:52 +0106
+Subject: [PATCH 080/323] printk: inline log_output(),log_store() in
+ vprintk_store()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+In preparation for removing logbuf_lock, inline log_output()
+and log_store() into vprintk_store(). This will simplify dealing
+with the various code branches and fallbacks that are possible.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Reviewed-by: Petr Mladek <pmladek@suse.com>
+Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Signed-off-by: Petr Mladek <pmladek@suse.com>
+Link: https://lore.kernel.org/r/20201209004453.17720-2-john.ogness@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/printk/printk.c | 145 +++++++++++++++++++----------------------
+ 1 file changed, 67 insertions(+), 78 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 17a310dcb6d9..9a7c2b561e6d 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -493,52 +493,6 @@ static void truncate_msg(u16 *text_len, u16 *trunc_msg_len)
+ 		*trunc_msg_len = 0;
+ }
+ 
+-/* insert record into the buffer, discard old ones, update heads */
+-static int log_store(u32 caller_id, int facility, int level,
+-		     enum log_flags flags, u64 ts_nsec,
+-		     const struct dev_printk_info *dev_info,
+-		     const char *text, u16 text_len)
+-{
+-	struct prb_reserved_entry e;
+-	struct printk_record r;
+-	u16 trunc_msg_len = 0;
+-
+-	prb_rec_init_wr(&r, text_len);
+-
+-	if (!prb_reserve(&e, prb, &r)) {
+-		/* truncate the message if it is too long for empty buffer */
+-		truncate_msg(&text_len, &trunc_msg_len);
+-		prb_rec_init_wr(&r, text_len + trunc_msg_len);
+-		/* survive when the log buffer is too small for trunc_msg */
+-		if (!prb_reserve(&e, prb, &r))
+-			return 0;
+-	}
+-
+-	/* fill message */
+-	memcpy(&r.text_buf[0], text, text_len);
+-	if (trunc_msg_len)
+-		memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len);
+-	r.info->text_len = text_len + trunc_msg_len;
+-	r.info->facility = facility;
+-	r.info->level = level & 7;
+-	r.info->flags = flags & 0x1f;
+-	if (ts_nsec > 0)
+-		r.info->ts_nsec = ts_nsec;
+-	else
+-		r.info->ts_nsec = local_clock();
+-	r.info->caller_id = caller_id;
+-	if (dev_info)
+-		memcpy(&r.info->dev_info, dev_info, sizeof(r.info->dev_info));
+-
+-	/* A message without a trailing newline can be continued. */
+-	if (!(flags & LOG_NEWLINE))
+-		prb_commit(&e);
+-	else
+-		prb_final_commit(&e);
+-
+-	return (text_len + trunc_msg_len);
+-}
+-
+ int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT);
+ 
+ static int syslog_action_restricted(int type)
+@@ -1933,44 +1887,28 @@ static inline u32 printk_caller_id(void)
+ 		0x80000000 + raw_smp_processor_id();
+ }
+ 
+-static size_t log_output(int facility, int level, enum log_flags lflags,
+-			 const struct dev_printk_info *dev_info,
+-			 char *text, size_t text_len)
+-{
+-	const u32 caller_id = printk_caller_id();
+-
+-	if (lflags & LOG_CONT) {
+-		struct prb_reserved_entry e;
+-		struct printk_record r;
+-
+-		prb_rec_init_wr(&r, text_len);
+-		if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) {
+-			memcpy(&r.text_buf[r.info->text_len], text, text_len);
+-			r.info->text_len += text_len;
+-			if (lflags & LOG_NEWLINE) {
+-				r.info->flags |= LOG_NEWLINE;
+-				prb_final_commit(&e);
+-			} else {
+-				prb_commit(&e);
+-			}
+-			return text_len;
+-		}
+-	}
+-
+-	/* Store it in the record log */
+-	return log_store(caller_id, facility, level, lflags, 0,
+-			 dev_info, text, text_len);
+-}
+-
+ /* Must be called under logbuf_lock. */
+ int vprintk_store(int facility, int level,
+ 		  const struct dev_printk_info *dev_info,
+ 		  const char *fmt, va_list args)
+ {
++	const u32 caller_id = printk_caller_id();
+ 	static char textbuf[LOG_LINE_MAX];
+-	char *text = textbuf;
+-	size_t text_len;
++	struct prb_reserved_entry e;
+ 	enum log_flags lflags = 0;
++	struct printk_record r;
++	u16 trunc_msg_len = 0;
++	char *text = textbuf;
++	u16 text_len;
++	u64 ts_nsec;
++
++	/*
++	 * Since the duration of printk() can vary depending on the message
++	 * and state of the ringbuffer, grab the timestamp now so that it is
++	 * close to the call of printk(). This provides a more deterministic
++	 * timestamp with respect to the caller.
++	 */
++	ts_nsec = local_clock();
+ 
+ 	/*
+ 	 * The printf needs to come first; we need the syslog
+@@ -2009,7 +1947,58 @@ int vprintk_store(int facility, int level,
+ 	if (dev_info)
+ 		lflags |= LOG_NEWLINE;
+ 
+-	return log_output(facility, level, lflags, dev_info, text, text_len);
++	if (lflags & LOG_CONT) {
++		prb_rec_init_wr(&r, text_len);
++		if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) {
++			memcpy(&r.text_buf[r.info->text_len], text, text_len);
++			r.info->text_len += text_len;
++
++			if (lflags & LOG_NEWLINE) {
++				r.info->flags |= LOG_NEWLINE;
++				prb_final_commit(&e);
++			} else {
++				prb_commit(&e);
++			}
++
++			return text_len;
++		}
++	}
++
++	/*
++	 * Explicitly initialize the record before every prb_reserve() call.
++	 * prb_reserve_in_last() and prb_reserve() purposely invalidate the
++	 * structure when they fail.
++	 */
++	prb_rec_init_wr(&r, text_len);
++	if (!prb_reserve(&e, prb, &r)) {
++		/* truncate the message if it is too long for empty buffer */
++		truncate_msg(&text_len, &trunc_msg_len);
++
++		prb_rec_init_wr(&r, text_len + trunc_msg_len);
++		if (!prb_reserve(&e, prb, &r))
++			return 0;
++	}
++
++	/* fill message */
++	memcpy(&r.text_buf[0], text, text_len);
++	if (trunc_msg_len)
++		memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len);
++	r.info->text_len = text_len + trunc_msg_len;
++	r.info->facility = facility;
++	r.info->level = level & 7;
++	r.info->flags = lflags & 0x1f;
++	r.info->ts_nsec = ts_nsec;
++	r.info->caller_id = caller_id;
++	if (dev_info)
++		memcpy(&r.info->dev_info, dev_info, sizeof(r.info->dev_info));
++
++	/* A message without a trailing newline can be continued. */
++	if (!(lflags & LOG_NEWLINE))
++		prb_commit(&e);
++	else
++		prb_final_commit(&e);
++
++	return (text_len + trunc_msg_len);
+ }
+ 
+ asmlinkage int vprintk_emit(int facility, int level,
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0081-printk-remove-logbuf_lock-writer-protection-of-ringb.patch b/debian/patches-rt/0081-printk-remove-logbuf_lock-writer-protection-of-ringb.patch
new file mode 100644
index 000000000..15ea7d1b6
--- /dev/null
+++ b/debian/patches-rt/0081-printk-remove-logbuf_lock-writer-protection-of-ringb.patch
@@ -0,0 +1,251 @@
+From c2d6c379547a29aa25202641659917ecd9ae7712 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Wed, 9 Dec 2020 01:50:53 +0106
+Subject: [PATCH 081/323] printk: remove logbuf_lock writer-protection of
+ ringbuffer
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Since the ringbuffer is lockless, there is no need for it to be
+protected by @logbuf_lock. Remove @logbuf_lock writer-protection of
+the ringbuffer. The reader-protection is not removed because some
+variables, used by readers, are using @logbuf_lock for synchronization:
+@syslog_seq, @syslog_time, @syslog_partial, @console_seq,
+struct kmsg_dumper.
+
+For PRINTK_NMI_DIRECT_CONTEXT_MASK, @logbuf_lock usage is not removed
+because it may be used for dumper synchronization.
+
+Without @logbuf_lock synchronization of vprintk_store() it is no
+longer possible to use the single static buffer for temporarily
+sprint'ing the message. Instead, use vsnprintf() to determine the
+length and perform the real vscnprintf() using the area reserved from
+the ringbuffer. This leads to suboptimal packing of the message data,
+but will result in less wasted storage than multiple per-cpu buffers
+to support lockless temporary sprint'ing.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Reviewed-by: Petr Mladek <pmladek@suse.com>
+Signed-off-by: Petr Mladek <pmladek@suse.com>
+Link: https://lore.kernel.org/r/20201209004453.17720-3-john.ogness@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/printk/printk.c | 138 +++++++++++++++++++++++++++++------------
+ 1 file changed, 98 insertions(+), 40 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 9a7c2b561e6d..b0a3f7827819 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -1129,7 +1129,7 @@ void __init setup_log_buf(int early)
+ 		 new_descs, ilog2(new_descs_count),
+ 		 new_infos);
+ 
+-	logbuf_lock_irqsave(flags);
++	printk_safe_enter_irqsave(flags);
+ 
+ 	log_buf_len = new_log_buf_len;
+ 	log_buf = new_log_buf;
+@@ -1146,7 +1146,7 @@ void __init setup_log_buf(int early)
+ 	 */
+ 	prb = &printk_rb_dynamic;
+ 
+-	logbuf_unlock_irqrestore(flags);
++	printk_safe_exit_irqrestore(flags);
+ 
+ 	if (seq != prb_next_seq(&printk_rb_static)) {
+ 		pr_err("dropped %llu messages\n",
+@@ -1887,18 +1887,90 @@ static inline u32 printk_caller_id(void)
+ 		0x80000000 + raw_smp_processor_id();
+ }
+ 
+-/* Must be called under logbuf_lock. */
++/**
++ * parse_prefix - Parse level and control flags.
++ *
++ * @text:     The terminated text message.
++ * @level:    A pointer to the current level value, will be updated.
++ * @lflags:   A pointer to the current log flags, will be updated.
++ *
++ * @level may be NULL if the caller is not interested in the parsed value.
++ * Otherwise the variable pointed to by @level must be set to
++ * LOGLEVEL_DEFAULT in order to be updated with the parsed value.
++ *
++ * @lflags may be NULL if the caller is not interested in the parsed value.
++ * Otherwise the variable pointed to by @lflags will be OR'd with the parsed
++ * value.
++ *
++ * Return: The length of the parsed level and control flags.
++ */
++static u16 parse_prefix(char *text, int *level, enum log_flags *lflags)
++{
++	u16 prefix_len = 0;
++	int kern_level;
++
++	while (*text) {
++		kern_level = printk_get_level(text);
++		if (!kern_level)
++			break;
++
++		switch (kern_level) {
++		case '0' ... '7':
++			if (level && *level == LOGLEVEL_DEFAULT)
++				*level = kern_level - '0';
++			break;
++		case 'c':	/* KERN_CONT */
++			if (lflags)
++				*lflags |= LOG_CONT;
++		}
++
++		prefix_len += 2;
++		text += 2;
++	}
++
++	return prefix_len;
++}
++
++static u16 printk_sprint(char *text, u16 size, int facility, enum log_flags *lflags,
++			 const char *fmt, va_list args)
++{
++	u16 text_len;
++
++	text_len = vscnprintf(text, size, fmt, args);
++
++	/* Mark and strip a trailing newline. */
++	if (text_len && text[text_len - 1] == '\n') {
++		text_len--;
++		*lflags |= LOG_NEWLINE;
++	}
++
++	/* Strip log level and control flags. */
++	if (facility == 0) {
++		u16 prefix_len;
++
++		prefix_len = parse_prefix(text, NULL, NULL);
++		if (prefix_len) {
++			text_len -= prefix_len;
++			memmove(text, text + prefix_len, text_len);
++		}
++	}
++
++	return text_len;
++}
++
++__printf(4, 0)
+ int vprintk_store(int facility, int level,
+ 		  const struct dev_printk_info *dev_info,
+ 		  const char *fmt, va_list args)
+ {
+ 	const u32 caller_id = printk_caller_id();
+-	static char textbuf[LOG_LINE_MAX];
+ 	struct prb_reserved_entry e;
+ 	enum log_flags lflags = 0;
+ 	struct printk_record r;
+ 	u16 trunc_msg_len = 0;
+-	char *text = textbuf;
++	char prefix_buf[8];
++	u16 reserve_size;
++	va_list args2;
+ 	u16 text_len;
+ 	u64 ts_nsec;
+ 
+@@ -1911,35 +1983,21 @@ int vprintk_store(int facility, int level,
+ 	ts_nsec = local_clock();
+ 
+ 	/*
+-	 * The printf needs to come first; we need the syslog
+-	 * prefix which might be passed-in as a parameter.
++	 * The sprintf needs to come first since the syslog prefix might be
++	 * passed in as a parameter. An extra byte must be reserved so that
++	 * later the vscnprintf() into the reserved buffer has room for the
++	 * terminating '\0', which is not counted by vsnprintf().
+ 	 */
+-	text_len = vscnprintf(text, sizeof(textbuf), fmt, args);
+-
+-	/* mark and strip a trailing newline */
+-	if (text_len && text[text_len-1] == '\n') {
+-		text_len--;
+-		lflags |= LOG_NEWLINE;
+-	}
+-
+-	/* strip kernel syslog prefix and extract log level or control flags */
+-	if (facility == 0) {
+-		int kern_level;
++	va_copy(args2, args);
++	reserve_size = vsnprintf(&prefix_buf[0], sizeof(prefix_buf), fmt, args2) + 1;
++	va_end(args2);
+ 
+-		while ((kern_level = printk_get_level(text)) != 0) {
+-			switch (kern_level) {
+-			case '0' ... '7':
+-				if (level == LOGLEVEL_DEFAULT)
+-					level = kern_level - '0';
+-				break;
+-			case 'c':	/* KERN_CONT */
+-				lflags |= LOG_CONT;
+-			}
++	if (reserve_size > LOG_LINE_MAX)
++		reserve_size = LOG_LINE_MAX;
+ 
+-			text_len -= 2;
+-			text += 2;
+-		}
+-	}
++	/* Extract log level or control flags. */
++	if (facility == 0)
++		parse_prefix(&prefix_buf[0], &level, &lflags);
+ 
+ 	if (level == LOGLEVEL_DEFAULT)
+ 		level = default_message_loglevel;
+@@ -1948,9 +2006,10 @@ int vprintk_store(int facility, int level,
+ 		lflags |= LOG_NEWLINE;
+ 
+ 	if (lflags & LOG_CONT) {
+-		prb_rec_init_wr(&r, text_len);
++		prb_rec_init_wr(&r, reserve_size);
+ 		if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) {
+-			memcpy(&r.text_buf[r.info->text_len], text, text_len);
++			text_len = printk_sprint(&r.text_buf[r.info->text_len], reserve_size,
++						 facility, &lflags, fmt, args);
+ 			r.info->text_len += text_len;
+ 
+ 			if (lflags & LOG_NEWLINE) {
+@@ -1969,18 +2028,18 @@ int vprintk_store(int facility, int level,
+ 	 * prb_reserve_in_last() and prb_reserve() purposely invalidate the
+ 	 * structure when they fail.
+ 	 */
+-	prb_rec_init_wr(&r, text_len);
++	prb_rec_init_wr(&r, reserve_size);
+ 	if (!prb_reserve(&e, prb, &r)) {
+ 		/* truncate the message if it is too long for empty buffer */
+-		truncate_msg(&text_len, &trunc_msg_len);
++		truncate_msg(&reserve_size, &trunc_msg_len);
+ 
+-		prb_rec_init_wr(&r, text_len + trunc_msg_len);
++		prb_rec_init_wr(&r, reserve_size + trunc_msg_len);
+ 		if (!prb_reserve(&e, prb, &r))
+ 			return 0;
+ 	}
+ 
+ 	/* fill message */
+-	memcpy(&r.text_buf[0], text, text_len);
++	text_len = printk_sprint(&r.text_buf[0], reserve_size, facility, &lflags, fmt, args);
+ 	if (trunc_msg_len)
+ 		memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len);
+ 	r.info->text_len = text_len + trunc_msg_len;
+@@ -2021,10 +2080,9 @@ asmlinkage int vprintk_emit(int facility, int level,
+ 	boot_delay_msec(level);
+ 	printk_delay();
+ 
+-	/* This stops the holder of console_sem just where we want him */
+-	logbuf_lock_irqsave(flags);
++	printk_safe_enter_irqsave(flags);
+ 	printed_len = vprintk_store(facility, level, dev_info, fmt, args);
+-	logbuf_unlock_irqrestore(flags);
++	printk_safe_exit_irqrestore(flags);
+ 
+ 	/* If called from the scheduler, we can not call up(). */
+ 	if (!in_sched) {
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0082-printk-limit-second-loop-of-syslog_print_all.patch b/debian/patches-rt/0082-printk-limit-second-loop-of-syslog_print_all.patch
new file mode 100644
index 000000000..41d143e99
--- /dev/null
+++ b/debian/patches-rt/0082-printk-limit-second-loop-of-syslog_print_all.patch
@@ -0,0 +1,56 @@
+From 6769883ba30e543644f62ababe6910c6774f1885 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Wed, 17 Feb 2021 16:15:31 +0100
+Subject: [PATCH 082/323] printk: limit second loop of syslog_print_all
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The second loop of syslog_print_all() subtracts lengths that were
+added in the first loop. With commit b031a684bfd0 ("printk: remove
+logbuf_lock writer-protection of ringbuffer") it is possible that
+records are (over)written during syslog_print_all(). This allows the
+possibility of the second loop subtracting lengths that were never
+added in the first loop.
+
+This situation can result in syslog_print_all() filling the buffer
+starting from a later record, even though there may have been room
+to fit the earlier record(s) as well.
+
+Fixes: b031a684bfd0 ("printk: remove logbuf_lock writer-protection of ringbuffer")
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Reviewed-by: Petr Mladek <pmladek@suse.com>
+---
+ kernel/printk/printk.c | 9 ++++++++-
+ 1 file changed, 8 insertions(+), 1 deletion(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index b0a3f7827819..044bb3791896 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -1497,6 +1497,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 	struct printk_info info;
+ 	unsigned int line_count;
+ 	struct printk_record r;
++	u64 max_seq;
+ 	char *text;
+ 	int len = 0;
+ 	u64 seq;
+@@ -1515,9 +1516,15 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 	prb_for_each_info(clear_seq, prb, seq, &info, &line_count)
+ 		len += get_record_print_text_size(&info, line_count, true, time);
+ 
++	/*
++	 * Set an upper bound for the next loop to avoid subtracting lengths
++	 * that were never added.
++	 */
++	max_seq = seq;
++
+ 	/* move first record forward until length fits into the buffer */
+ 	prb_for_each_info(clear_seq, prb, seq, &info, &line_count) {
+-		if (len <= size)
++		if (len <= size || info.seq >= max_seq)
+ 			break;
+ 		len -= get_record_print_text_size(&info, line_count, true, time);
+ 	}
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0083-printk-kmsg_dump-remove-unused-fields.patch b/debian/patches-rt/0083-printk-kmsg_dump-remove-unused-fields.patch
new file mode 100644
index 000000000..8b219b627
--- /dev/null
+++ b/debian/patches-rt/0083-printk-kmsg_dump-remove-unused-fields.patch
@@ -0,0 +1,43 @@
+From dabfa71dd963396a46aee0066bb3eff206de08f7 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 21 Dec 2020 11:19:39 +0106
+Subject: [PATCH 083/323] printk: kmsg_dump: remove unused fields
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+struct kmsg_dumper still contains some fields that were used to
+iterate the old ringbuffer. They are no longer used. Remove them
+and update the struct documentation.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Reviewed-by: Petr Mladek <pmladek@suse.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/kmsg_dump.h | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
+index 3378bcbe585e..235c50982c2d 100644
+--- a/include/linux/kmsg_dump.h
++++ b/include/linux/kmsg_dump.h
+@@ -36,6 +36,9 @@ enum kmsg_dump_reason {
+  * 		through the record iterator
+  * @max_reason:	filter for highest reason number that should be dumped
+  * @registered:	Flag that specifies if this is already registered
++ * @active:	Flag that specifies if this is currently dumping
++ * @cur_seq:	Points to the oldest message to dump (private)
++ * @next_seq:	Points after the newest message to dump (private)
+  */
+ struct kmsg_dumper {
+ 	struct list_head list;
+@@ -45,8 +48,6 @@ struct kmsg_dumper {
+ 	bool registered;
+ 
+ 	/* private state of the kmsg iterator */
+-	u32 cur_idx;
+-	u32 next_idx;
+ 	u64 cur_seq;
+ 	u64 next_seq;
+ };
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0084-printk-refactor-kmsg_dump_get_buffer.patch b/debian/patches-rt/0084-printk-refactor-kmsg_dump_get_buffer.patch
new file mode 100644
index 000000000..dd1390103
--- /dev/null
+++ b/debian/patches-rt/0084-printk-refactor-kmsg_dump_get_buffer.patch
@@ -0,0 +1,145 @@
+From b6e17f3557ef5e32212483ca92910ea28eb21eeb Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 30 Nov 2020 01:41:56 +0106
+Subject: [PATCH 084/323] printk: refactor kmsg_dump_get_buffer()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+kmsg_dump_get_buffer() requires nearly the same logic as
+syslog_print_all(), but uses different variable names and
+does not make use of the ringbuffer loop macros. Modify
+kmsg_dump_get_buffer() so that the implementation is as similar
+to syslog_print_all() as possible.
+
+A follow-up commit will move this common logic into a
+separate helper function.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Reviewed-by: Petr Mladek <pmladek@suse.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/kmsg_dump.h |  2 +-
+ kernel/printk/printk.c    | 60 +++++++++++++++++++++------------------
+ 2 files changed, 33 insertions(+), 29 deletions(-)
+
+diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
+index 235c50982c2d..4095a34db0fa 100644
+--- a/include/linux/kmsg_dump.h
++++ b/include/linux/kmsg_dump.h
+@@ -62,7 +62,7 @@ bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
+ 			char *line, size_t size, size_t *len);
+ 
+ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+-			  char *buf, size_t size, size_t *len);
++			  char *buf, size_t size, size_t *len_out);
+ 
+ void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper);
+ 
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 044bb3791896..ad7edcb693d4 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -3429,7 +3429,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
+  * read.
+  */
+ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+-			  char *buf, size_t size, size_t *len)
++			  char *buf, size_t size, size_t *len_out)
+ {
+ 	struct printk_info info;
+ 	unsigned int line_count;
+@@ -3437,12 +3437,10 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+ 	unsigned long flags;
+ 	u64 seq;
+ 	u64 next_seq;
+-	size_t l = 0;
++	size_t len = 0;
+ 	bool ret = false;
+ 	bool time = printk_time;
+ 
+-	prb_rec_init_rd(&r, &info, buf, size);
+-
+ 	if (!dumper->active || !buf || !size)
+ 		goto out;
+ 
+@@ -3460,48 +3458,54 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+ 		goto out;
+ 	}
+ 
+-	/* calculate length of entire buffer */
+-	seq = dumper->cur_seq;
+-	while (prb_read_valid_info(prb, seq, &info, &line_count)) {
+-		if (r.info->seq >= dumper->next_seq)
++	/*
++	 * Find first record that fits, including all following records,
++	 * into the user-provided buffer for this dump.
++	 */
++
++	prb_for_each_info(dumper->cur_seq, prb, seq, &info, &line_count) {
++		if (info.seq >= dumper->next_seq)
+ 			break;
+-		l += get_record_print_text_size(&info, line_count, syslog, time);
+-		seq = r.info->seq + 1;
++		len += get_record_print_text_size(&info, line_count, syslog, time);
+ 	}
+ 
+-	/* move first record forward until length fits into the buffer */
+-	seq = dumper->cur_seq;
+-	while (l >= size && prb_read_valid_info(prb, seq,
+-						&info, &line_count)) {
+-		if (r.info->seq >= dumper->next_seq)
++	/*
++	 * Move first record forward until length fits into the buffer. Ignore
++	 * newest messages that were not counted in the above cycle. Messages
++	 * might appear and get lost in the meantime. This is the best effort
++	 * that prevents an infinite loop.
++	 */
++	prb_for_each_info(dumper->cur_seq, prb, seq, &info, &line_count) {
++		if (len < size || info.seq >= dumper->next_seq)
+ 			break;
+-		l -= get_record_print_text_size(&info, line_count, syslog, time);
+-		seq = r.info->seq + 1;
++		len -= get_record_print_text_size(&info, line_count, syslog, time);
+ 	}
+ 
+-	/* last message in next interation */
++	/*
++	 * Next kmsg_dump_get_buffer() invocation will dump block of
++	 * older records stored right before this one.
++	 */
+ 	next_seq = seq;
+ 
+-	/* actually read text into the buffer now */
+-	l = 0;
+-	while (prb_read_valid(prb, seq, &r)) {
++	prb_rec_init_rd(&r, &info, buf, size);
++
++	len = 0;
++	prb_for_each_record(seq, prb, seq, &r) {
+ 		if (r.info->seq >= dumper->next_seq)
+ 			break;
+ 
+-		l += record_print_text(&r, syslog, time);
+-
+-		/* adjust record to store to remaining buffer space */
+-		prb_rec_init_rd(&r, &info, buf + l, size - l);
++		len += record_print_text(&r, syslog, time);
+ 
+-		seq = r.info->seq + 1;
++		/* Adjust record to store to remaining buffer space. */
++		prb_rec_init_rd(&r, &info, buf + len, size - len);
+ 	}
+ 
+ 	dumper->next_seq = next_seq;
+ 	ret = true;
+ 	logbuf_unlock_irqrestore(flags);
+ out:
+-	if (len)
+-		*len = l;
++	if (len_out)
++		*len_out = len;
+ 	return ret;
+ }
+ EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0085-printk-consolidate-kmsg_dump_get_buffer-syslog_print.patch b/debian/patches-rt/0085-printk-consolidate-kmsg_dump_get_buffer-syslog_print.patch
new file mode 100644
index 000000000..acc8de768
--- /dev/null
+++ b/debian/patches-rt/0085-printk-consolidate-kmsg_dump_get_buffer-syslog_print.patch
@@ -0,0 +1,147 @@
+From 922cda1ee8d183c2e98429cdabf907a92df72465 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Wed, 13 Jan 2021 11:29:53 +0106
+Subject: [PATCH 085/323] printk: consolidate
+ kmsg_dump_get_buffer/syslog_print_all code
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The logic for finding records to fit into a buffer is the same for
+kmsg_dump_get_buffer() and syslog_print_all(). Introduce a helper
+function find_first_fitting_seq() to handle this logic.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+---
+ kernel/printk/printk.c | 87 ++++++++++++++++++++++++------------------
+ 1 file changed, 50 insertions(+), 37 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index ad7edcb693d4..1f710a2a40b6 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -1424,6 +1424,50 @@ static size_t get_record_print_text_size(struct printk_info *info,
+ 	return ((prefix_len * line_count) + info->text_len + 1);
+ }
+ 
++/*
++ * Beginning with @start_seq, find the first record where it and all following
++ * records up to (but not including) @max_seq fit into @size.
++ *
++ * @max_seq is simply an upper bound and does not need to exist. If the caller
++ * does not require an upper bound, -1 can be used for @max_seq.
++ */
++static u64 find_first_fitting_seq(u64 start_seq, u64 max_seq, size_t size,
++				  bool syslog, bool time)
++{
++	struct printk_info info;
++	unsigned int line_count;
++	size_t len = 0;
++	u64 seq;
++
++	/* Determine the size of the records up to @max_seq. */
++	prb_for_each_info(start_seq, prb, seq, &info, &line_count) {
++		if (info.seq >= max_seq)
++			break;
++		len += get_record_print_text_size(&info, line_count, syslog, time);
++	}
++
++	/*
++	 * Adjust the upper bound for the next loop to avoid subtracting
++	 * lengths that were never added.
++	 */
++	if (seq < max_seq)
++		max_seq = seq;
++
++	/*
++	 * Move first record forward until length fits into the buffer. Ignore
++	 * newest messages that were not counted in the above cycle. Messages
++	 * might appear and get lost in the meantime. This is a best effort
++	 * that prevents an infinite loop that could occur with a retry.
++	 */
++	prb_for_each_info(start_seq, prb, seq, &info, &line_count) {
++		if (len <= size || info.seq >= max_seq)
++			break;
++		len -= get_record_print_text_size(&info, line_count, syslog, time);
++	}
++
++	return seq;
++}
++
+ static int syslog_print(char __user *buf, int size)
+ {
+ 	struct printk_info info;
+@@ -1495,9 +1539,7 @@ static int syslog_print(char __user *buf, int size)
+ static int syslog_print_all(char __user *buf, int size, bool clear)
+ {
+ 	struct printk_info info;
+-	unsigned int line_count;
+ 	struct printk_record r;
+-	u64 max_seq;
+ 	char *text;
+ 	int len = 0;
+ 	u64 seq;
+@@ -1513,21 +1555,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 	 * Find first record that fits, including all following records,
+ 	 * into the user-provided buffer for this dump.
+ 	 */
+-	prb_for_each_info(clear_seq, prb, seq, &info, &line_count)
+-		len += get_record_print_text_size(&info, line_count, true, time);
+-
+-	/*
+-	 * Set an upper bound for the next loop to avoid subtracting lengths
+-	 * that were never added.
+-	 */
+-	max_seq = seq;
+-
+-	/* move first record forward until length fits into the buffer */
+-	prb_for_each_info(clear_seq, prb, seq, &info, &line_count) {
+-		if (len <= size || info.seq >= max_seq)
+-			break;
+-		len -= get_record_print_text_size(&info, line_count, true, time);
+-	}
++	seq = find_first_fitting_seq(clear_seq, -1, size, true, time);
+ 
+ 	prb_rec_init_rd(&r, &info, text, LOG_LINE_MAX + PREFIX_MAX);
+ 
+@@ -3432,7 +3460,6 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+ 			  char *buf, size_t size, size_t *len_out)
+ {
+ 	struct printk_info info;
+-	unsigned int line_count;
+ 	struct printk_record r;
+ 	unsigned long flags;
+ 	u64 seq;
+@@ -3460,26 +3487,12 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+ 
+ 	/*
+ 	 * Find first record that fits, including all following records,
+-	 * into the user-provided buffer for this dump.
++	 * into the user-provided buffer for this dump. Pass in size-1
++	 * because this function (by way of record_print_text()) will
++	 * not write more than size-1 bytes of text into @buf.
+ 	 */
+-
+-	prb_for_each_info(dumper->cur_seq, prb, seq, &info, &line_count) {
+-		if (info.seq >= dumper->next_seq)
+-			break;
+-		len += get_record_print_text_size(&info, line_count, syslog, time);
+-	}
+-
+-	/*
+-	 * Move first record forward until length fits into the buffer. Ignore
+-	 * newest messages that were not counted in the above cycle. Messages
+-	 * might appear and get lost in the meantime. This is the best effort
+-	 * that prevents an infinite loop.
+-	 */
+-	prb_for_each_info(dumper->cur_seq, prb, seq, &info, &line_count) {
+-		if (len < size || info.seq >= dumper->next_seq)
+-			break;
+-		len -= get_record_print_text_size(&info, line_count, syslog, time);
+-	}
++	seq = find_first_fitting_seq(dumper->cur_seq, dumper->next_seq,
++				     size - 1, syslog, time);
+ 
+ 	/*
+ 	 * Next kmsg_dump_get_buffer() invocation will dump block of
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0086-printk-introduce-CONSOLE_LOG_MAX-for-improved-multi-.patch b/debian/patches-rt/0086-printk-introduce-CONSOLE_LOG_MAX-for-improved-multi-.patch
new file mode 100644
index 000000000..876f0920e
--- /dev/null
+++ b/debian/patches-rt/0086-printk-introduce-CONSOLE_LOG_MAX-for-improved-multi-.patch
@@ -0,0 +1,95 @@
+From 2b148f755fdd9d276d191e982d525f330cffad0b Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Thu, 10 Dec 2020 12:48:01 +0106
+Subject: [PATCH 086/323] printk: introduce CONSOLE_LOG_MAX for improved
+ multi-line support
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Instead of using "LOG_LINE_MAX + PREFIX_MAX" for temporary buffer
+sizes, introduce CONSOLE_LOG_MAX. This represents the maximum size
+that is allowed to be printed to the console for a single record.
+
+Rather than setting CONSOLE_LOG_MAX to "LOG_LINE_MAX + PREFIX_MAX"
+(1024), increase it to 4096. With a larger buffer size, multi-line
+records that are nearly LOG_LINE_MAX in length will have a better
+chance of being fully printed. (When formatting a record for the
+console, each line of a multi-line record is prepended with a copy
+of the prefix.)
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+---
+ kernel/printk/printk.c | 18 +++++++++++-------
+ 1 file changed, 11 insertions(+), 7 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 1f710a2a40b6..1bc4ff19c0d2 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -412,8 +412,13 @@ static u64 clear_seq;
+ #else
+ #define PREFIX_MAX		32
+ #endif
++
++/* the maximum size allowed to be reserved for a record */
+ #define LOG_LINE_MAX		(1024 - PREFIX_MAX)
+ 
++/* the maximum size of a formatted record (i.e. with prefix added per line) */
++#define CONSOLE_LOG_MAX		4096
++
+ #define LOG_LEVEL(v)		((v) & 0x07)
+ #define LOG_FACILITY(v)		((v) >> 3 & 0xff)
+ 
+@@ -1475,11 +1480,11 @@ static int syslog_print(char __user *buf, int size)
+ 	char *text;
+ 	int len = 0;
+ 
+-	text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
++	text = kmalloc(CONSOLE_LOG_MAX, GFP_KERNEL);
+ 	if (!text)
+ 		return -ENOMEM;
+ 
+-	prb_rec_init_rd(&r, &info, text, LOG_LINE_MAX + PREFIX_MAX);
++	prb_rec_init_rd(&r, &info, text, CONSOLE_LOG_MAX);
+ 
+ 	while (size > 0) {
+ 		size_t n;
+@@ -1545,7 +1550,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 	u64 seq;
+ 	bool time;
+ 
+-	text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
++	text = kmalloc(CONSOLE_LOG_MAX, GFP_KERNEL);
+ 	if (!text)
+ 		return -ENOMEM;
+ 
+@@ -1557,7 +1562,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 	 */
+ 	seq = find_first_fitting_seq(clear_seq, -1, size, true, time);
+ 
+-	prb_rec_init_rd(&r, &info, text, LOG_LINE_MAX + PREFIX_MAX);
++	prb_rec_init_rd(&r, &info, text, CONSOLE_LOG_MAX);
+ 
+ 	len = 0;
+ 	prb_for_each_record(seq, prb, seq, &r) {
+@@ -2190,8 +2195,7 @@ EXPORT_SYMBOL(printk);
+ 
+ #else /* CONFIG_PRINTK */
+ 
+-#define LOG_LINE_MAX		0
+-#define PREFIX_MAX		0
++#define CONSOLE_LOG_MAX		0
+ #define printk_time		false
+ 
+ #define prb_read_valid(rb, seq, r)	false
+@@ -2509,7 +2513,7 @@ static inline int can_use_console(void)
+ void console_unlock(void)
+ {
+ 	static char ext_text[CONSOLE_EXT_LOG_MAX];
+-	static char text[LOG_LINE_MAX + PREFIX_MAX];
++	static char text[CONSOLE_LOG_MAX];
+ 	unsigned long flags;
+ 	bool do_cond_resched, retry;
+ 	struct printk_info info;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0087-printk-use-seqcount_latch-for-clear_seq.patch b/debian/patches-rt/0087-printk-use-seqcount_latch-for-clear_seq.patch
new file mode 100644
index 000000000..f34000021
--- /dev/null
+++ b/debian/patches-rt/0087-printk-use-seqcount_latch-for-clear_seq.patch
@@ -0,0 +1,147 @@
+From 0b877c3f36fc909dc2aec9f70e2e80ad0c69a60b Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 30 Nov 2020 01:41:58 +0106
+Subject: [PATCH 087/323] printk: use seqcount_latch for clear_seq
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+kmsg_dump_rewind_nolock() locklessly reads @clear_seq. However,
+this is not done atomically. Since @clear_seq is 64-bit, this
+cannot be an atomic operation for all platforms. Therefore, use
+a seqcount_latch to allow readers to always read a consistent
+value.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Reviewed-by: Petr Mladek <pmladek@suse.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/printk/printk.c | 58 ++++++++++++++++++++++++++++++++++++------
+ 1 file changed, 50 insertions(+), 8 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 1bc4ff19c0d2..4444b3e292d5 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -404,8 +404,21 @@ static u64 console_seq;
+ static u64 exclusive_console_stop_seq;
+ static unsigned long console_dropped;
+ 
+-/* the next printk record to read after the last 'clear' command */
+-static u64 clear_seq;
++struct latched_seq {
++	seqcount_latch_t	latch;
++	u64			val[2];
++};
++
++/*
++ * The next printk record to read after the last 'clear' command. There are
++ * two copies (updated with seqcount_latch) so that reads can locklessly
++ * access a valid value. Writers are synchronized by @logbuf_lock.
++ */
++static struct latched_seq clear_seq = {
++	.latch		= SEQCNT_LATCH_ZERO(clear_seq.latch),
++	.val[0]		= 0,
++	.val[1]		= 0,
++};
+ 
+ #ifdef CONFIG_PRINTK_CALLER
+ #define PREFIX_MAX		48
+@@ -459,6 +472,31 @@ bool printk_percpu_data_ready(void)
+ 	return __printk_percpu_data_ready;
+ }
+ 
++/* Must be called under logbuf_lock. */
++static void latched_seq_write(struct latched_seq *ls, u64 val)
++{
++	raw_write_seqcount_latch(&ls->latch);
++	ls->val[0] = val;
++	raw_write_seqcount_latch(&ls->latch);
++	ls->val[1] = val;
++}
++
++/* Can be called from any context. */
++static u64 latched_seq_read_nolock(struct latched_seq *ls)
++{
++	unsigned int seq;
++	unsigned int idx;
++	u64 val;
++
++	do {
++		seq = raw_read_seqcount_latch(&ls->latch);
++		idx = seq & 0x1;
++		val = ls->val[idx];
++	} while (read_seqcount_latch_retry(&ls->latch, seq));
++
++	return val;
++}
++
+ /* Return log buffer address */
+ char *log_buf_addr_get(void)
+ {
+@@ -804,7 +842,7 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
+ 		 * like issued by 'dmesg -c'. Reading /dev/kmsg itself
+ 		 * changes no global state, and does not clear anything.
+ 		 */
+-		user->seq = clear_seq;
++		user->seq = latched_seq_read_nolock(&clear_seq);
+ 		break;
+ 	case SEEK_END:
+ 		/* after the last record */
+@@ -963,6 +1001,9 @@ void log_buf_vmcoreinfo_setup(void)
+ 
+ 	VMCOREINFO_SIZE(atomic_long_t);
+ 	VMCOREINFO_TYPE_OFFSET(atomic_long_t, counter);
++
++	VMCOREINFO_STRUCT_SIZE(latched_seq);
++	VMCOREINFO_OFFSET(latched_seq, val);
+ }
+ #endif
+ 
+@@ -1560,7 +1601,8 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 	 * Find first record that fits, including all following records,
+ 	 * into the user-provided buffer for this dump.
+ 	 */
+-	seq = find_first_fitting_seq(clear_seq, -1, size, true, time);
++	seq = find_first_fitting_seq(latched_seq_read_nolock(&clear_seq), -1,
++				     size, true, time);
+ 
+ 	prb_rec_init_rd(&r, &info, text, CONSOLE_LOG_MAX);
+ 
+@@ -1587,7 +1629,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 	}
+ 
+ 	if (clear)
+-		clear_seq = seq;
++		latched_seq_write(&clear_seq, seq);
+ 	logbuf_unlock_irq();
+ 
+ 	kfree(text);
+@@ -1597,7 +1639,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ static void syslog_clear(void)
+ {
+ 	logbuf_lock_irq();
+-	clear_seq = prb_next_seq(prb);
++	latched_seq_write(&clear_seq, prb_next_seq(prb));
+ 	logbuf_unlock_irq();
+ }
+ 
+@@ -3341,7 +3383,7 @@ void kmsg_dump(enum kmsg_dump_reason reason)
+ 		dumper->active = true;
+ 
+ 		logbuf_lock_irqsave(flags);
+-		dumper->cur_seq = clear_seq;
++		dumper->cur_seq = latched_seq_read_nolock(&clear_seq);
+ 		dumper->next_seq = prb_next_seq(prb);
+ 		logbuf_unlock_irqrestore(flags);
+ 
+@@ -3539,7 +3581,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
+  */
+ void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
+ {
+-	dumper->cur_seq = clear_seq;
++	dumper->cur_seq = latched_seq_read_nolock(&clear_seq);
+ 	dumper->next_seq = prb_next_seq(prb);
+ }
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0088-printk-use-atomic64_t-for-devkmsg_user.seq.patch b/debian/patches-rt/0088-printk-use-atomic64_t-for-devkmsg_user.seq.patch
new file mode 100644
index 000000000..d5c3de71c
--- /dev/null
+++ b/debian/patches-rt/0088-printk-use-atomic64_t-for-devkmsg_user.seq.patch
@@ -0,0 +1,112 @@
+From ccc444abbce9df5f0747db8dd10bd39388d58836 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Thu, 10 Dec 2020 15:33:40 +0106
+Subject: [PATCH 088/323] printk: use atomic64_t for devkmsg_user.seq
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+@user->seq is indirectly protected by @logbuf_lock. Once @logbuf_lock
+is removed, @user->seq will be no longer safe from an atomicity point
+of view.
+
+In preparation for the removal of @logbuf_lock, change it to
+atomic64_t to provide this safety.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+---
+ kernel/printk/printk.c | 22 +++++++++++-----------
+ 1 file changed, 11 insertions(+), 11 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 4444b3e292d5..a351ed400c04 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -664,7 +664,7 @@ static ssize_t msg_print_ext_body(char *buf, size_t size,
+ 
+ /* /dev/kmsg - userspace message inject/listen interface */
+ struct devkmsg_user {
+-	u64 seq;
++	atomic64_t seq;
+ 	struct ratelimit_state rs;
+ 	struct mutex lock;
+ 	char buf[CONSOLE_EXT_LOG_MAX];
+@@ -766,7 +766,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
+ 		return ret;
+ 
+ 	logbuf_lock_irq();
+-	if (!prb_read_valid(prb, user->seq, r)) {
++	if (!prb_read_valid(prb, atomic64_read(&user->seq), r)) {
+ 		if (file->f_flags & O_NONBLOCK) {
+ 			ret = -EAGAIN;
+ 			logbuf_unlock_irq();
+@@ -775,15 +775,15 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
+ 
+ 		logbuf_unlock_irq();
+ 		ret = wait_event_interruptible(log_wait,
+-					prb_read_valid(prb, user->seq, r));
++				prb_read_valid(prb, atomic64_read(&user->seq), r));
+ 		if (ret)
+ 			goto out;
+ 		logbuf_lock_irq();
+ 	}
+ 
+-	if (r->info->seq != user->seq) {
++	if (r->info->seq != atomic64_read(&user->seq)) {
+ 		/* our last seen message is gone, return error and reset */
+-		user->seq = r->info->seq;
++		atomic64_set(&user->seq, r->info->seq);
+ 		ret = -EPIPE;
+ 		logbuf_unlock_irq();
+ 		goto out;
+@@ -794,7 +794,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
+ 				  &r->text_buf[0], r->info->text_len,
+ 				  &r->info->dev_info);
+ 
+-	user->seq = r->info->seq + 1;
++	atomic64_set(&user->seq, r->info->seq + 1);
+ 	logbuf_unlock_irq();
+ 
+ 	if (len > count) {
+@@ -834,7 +834,7 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
+ 	switch (whence) {
+ 	case SEEK_SET:
+ 		/* the first record */
+-		user->seq = prb_first_valid_seq(prb);
++		atomic64_set(&user->seq, prb_first_valid_seq(prb));
+ 		break;
+ 	case SEEK_DATA:
+ 		/*
+@@ -842,11 +842,11 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
+ 		 * like issued by 'dmesg -c'. Reading /dev/kmsg itself
+ 		 * changes no global state, and does not clear anything.
+ 		 */
+-		user->seq = latched_seq_read_nolock(&clear_seq);
++		atomic64_set(&user->seq, latched_seq_read_nolock(&clear_seq));
+ 		break;
+ 	case SEEK_END:
+ 		/* after the last record */
+-		user->seq = prb_next_seq(prb);
++		atomic64_set(&user->seq, prb_next_seq(prb));
+ 		break;
+ 	default:
+ 		ret = -EINVAL;
+@@ -869,7 +869,7 @@ static __poll_t devkmsg_poll(struct file *file, poll_table *wait)
+ 	logbuf_lock_irq();
+ 	if (prb_read_valid_info(prb, user->seq, &info, NULL)) {
+ 		/* return error when data has vanished underneath us */
+-		if (info.seq != user->seq)
++		if (info.seq != atomic64_read(&user->seq))
+ 			ret = EPOLLIN|EPOLLRDNORM|EPOLLERR|EPOLLPRI;
+ 		else
+ 			ret = EPOLLIN|EPOLLRDNORM;
+@@ -908,7 +908,7 @@ static int devkmsg_open(struct inode *inode, struct file *file)
+ 			&user->text_buf[0], sizeof(user->text_buf));
+ 
+ 	logbuf_lock_irq();
+-	user->seq = prb_first_valid_seq(prb);
++	atomic64_set(&user->seq, prb_first_valid_seq(prb));
+ 	logbuf_unlock_irq();
+ 
+ 	file->private_data = user;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0089-printk-add-syslog_lock.patch b/debian/patches-rt/0089-printk-add-syslog_lock.patch
new file mode 100644
index 000000000..42e77e5ab
--- /dev/null
+++ b/debian/patches-rt/0089-printk-add-syslog_lock.patch
@@ -0,0 +1,159 @@
+From 5521ed0e06ffc572d9f0ebf5421ab23288899804 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Thu, 10 Dec 2020 16:58:02 +0106
+Subject: [PATCH 089/323] printk: add syslog_lock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The global variables @syslog_seq, @syslog_partial, @syslog_time
+and write access to @clear_seq are protected by @logbuf_lock.
+Once @logbuf_lock is removed, these variables will need their
+own synchronization method. Introduce @syslog_lock for this
+purpose.
+
+@syslog_lock is a raw_spin_lock for now. This simplifies the
+transition to removing @logbuf_lock. Once @logbuf_lock and the
+safe buffers are removed, @syslog_lock can change to spin_lock.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/printk/printk.c | 41 +++++++++++++++++++++++++++++++++++++----
+ 1 file changed, 37 insertions(+), 4 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index a351ed400c04..986fc9fad210 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -392,8 +392,12 @@ DEFINE_RAW_SPINLOCK(logbuf_lock);
+ 		printk_safe_exit_irqrestore(flags);	\
+ 	} while (0)
+ 
++/* syslog_lock protects syslog_* variables and write access to clear_seq. */
++static DEFINE_RAW_SPINLOCK(syslog_lock);
++
+ #ifdef CONFIG_PRINTK
+ DECLARE_WAIT_QUEUE_HEAD(log_wait);
++/* All 3 protected by @syslog_lock. */
+ /* the next printk record to read by syslog(READ) or /proc/kmsg */
+ static u64 syslog_seq;
+ static size_t syslog_partial;
+@@ -412,7 +416,7 @@ struct latched_seq {
+ /*
+  * The next printk record to read after the last 'clear' command. There are
+  * two copies (updated with seqcount_latch) so that reads can locklessly
+- * access a valid value. Writers are synchronized by @logbuf_lock.
++ * access a valid value. Writers are synchronized by @syslog_lock.
+  */
+ static struct latched_seq clear_seq = {
+ 	.latch		= SEQCNT_LATCH_ZERO(clear_seq.latch),
+@@ -472,7 +476,7 @@ bool printk_percpu_data_ready(void)
+ 	return __printk_percpu_data_ready;
+ }
+ 
+-/* Must be called under logbuf_lock. */
++/* Must be called under syslog_lock. */
+ static void latched_seq_write(struct latched_seq *ls, u64 val)
+ {
+ 	raw_write_seqcount_latch(&ls->latch);
+@@ -1532,7 +1536,9 @@ static int syslog_print(char __user *buf, int size)
+ 		size_t skip;
+ 
+ 		logbuf_lock_irq();
++		raw_spin_lock(&syslog_lock);
+ 		if (!prb_read_valid(prb, syslog_seq, &r)) {
++			raw_spin_unlock(&syslog_lock);
+ 			logbuf_unlock_irq();
+ 			break;
+ 		}
+@@ -1562,6 +1568,7 @@ static int syslog_print(char __user *buf, int size)
+ 			syslog_partial += n;
+ 		} else
+ 			n = 0;
++		raw_spin_unlock(&syslog_lock);
+ 		logbuf_unlock_irq();
+ 
+ 		if (!n)
+@@ -1628,8 +1635,11 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 			break;
+ 	}
+ 
+-	if (clear)
++	if (clear) {
++		raw_spin_lock(&syslog_lock);
+ 		latched_seq_write(&clear_seq, seq);
++		raw_spin_unlock(&syslog_lock);
++	}
+ 	logbuf_unlock_irq();
+ 
+ 	kfree(text);
+@@ -1639,10 +1649,24 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ static void syslog_clear(void)
+ {
+ 	logbuf_lock_irq();
++	raw_spin_lock(&syslog_lock);
+ 	latched_seq_write(&clear_seq, prb_next_seq(prb));
++	raw_spin_unlock(&syslog_lock);
+ 	logbuf_unlock_irq();
+ }
+ 
++/* Return a consistent copy of @syslog_seq. */
++static u64 read_syslog_seq_irq(void)
++{
++	u64 seq;
++
++	raw_spin_lock_irq(&syslog_lock);
++	seq = syslog_seq;
++	raw_spin_unlock_irq(&syslog_lock);
++
++	return seq;
++}
++
+ int do_syslog(int type, char __user *buf, int len, int source)
+ {
+ 	struct printk_info info;
+@@ -1666,8 +1690,9 @@ int do_syslog(int type, char __user *buf, int len, int source)
+ 			return 0;
+ 		if (!access_ok(buf, len))
+ 			return -EFAULT;
++
+ 		error = wait_event_interruptible(log_wait,
+-				prb_read_valid(prb, syslog_seq, NULL));
++				prb_read_valid(prb, read_syslog_seq_irq(), NULL));
+ 		if (error)
+ 			return error;
+ 		error = syslog_print(buf, len);
+@@ -1716,8 +1741,10 @@ int do_syslog(int type, char __user *buf, int len, int source)
+ 	/* Number of chars in the log buffer */
+ 	case SYSLOG_ACTION_SIZE_UNREAD:
+ 		logbuf_lock_irq();
++		raw_spin_lock(&syslog_lock);
+ 		if (!prb_read_valid_info(prb, syslog_seq, &info, NULL)) {
+ 			/* No unread messages. */
++			raw_spin_unlock(&syslog_lock);
+ 			logbuf_unlock_irq();
+ 			return 0;
+ 		}
+@@ -1746,6 +1773,7 @@ int do_syslog(int type, char __user *buf, int len, int source)
+ 			}
+ 			error -= syslog_partial;
+ 		}
++		raw_spin_unlock(&syslog_lock);
+ 		logbuf_unlock_irq();
+ 		break;
+ 	/* Size of the log buffer */
+@@ -2995,7 +3023,12 @@ void register_console(struct console *newcon)
+ 		 */
+ 		exclusive_console = newcon;
+ 		exclusive_console_stop_seq = console_seq;
++
++		/* Get a consistent copy of @syslog_seq. */
++		raw_spin_lock(&syslog_lock);
+ 		console_seq = syslog_seq;
++		raw_spin_unlock(&syslog_lock);
++
+ 		logbuf_unlock_irqrestore(flags);
+ 	}
+ 	console_unlock();
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0090-printk-introduce-a-kmsg_dump-iterator.patch b/debian/patches-rt/0090-printk-introduce-a-kmsg_dump-iterator.patch
new file mode 100644
index 000000000..018c1949d
--- /dev/null
+++ b/debian/patches-rt/0090-printk-introduce-a-kmsg_dump-iterator.patch
@@ -0,0 +1,561 @@
+From 5bb123ebb8e508baa987e9bc17029e2eaa64575b Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Fri, 18 Dec 2020 11:40:08 +0000
+Subject: [PATCH 090/323] printk: introduce a kmsg_dump iterator
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Rather than store the iterator information into the registered
+kmsg_dump structure, create a separate iterator structure. The
+kmsg_dump_iter structure can reside on the stack of the caller,
+thus allowing lockless use of the kmsg_dump functions.
+
+This is in preparation for removal of @logbuf_lock.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/powerpc/kernel/nvram_64.c             | 12 ++--
+ arch/powerpc/platforms/powernv/opal-kmsg.c |  3 +-
+ arch/powerpc/xmon/xmon.c                   |  6 +-
+ arch/um/kernel/kmsg_dump.c                 |  5 +-
+ drivers/hv/vmbus_drv.c                     |  5 +-
+ drivers/mtd/mtdoops.c                      |  5 +-
+ fs/pstore/platform.c                       |  5 +-
+ include/linux/kmsg_dump.h                  | 43 +++++++-------
+ kernel/debug/kdb/kdb_main.c                | 10 ++--
+ kernel/printk/printk.c                     | 65 +++++++++++-----------
+ 10 files changed, 84 insertions(+), 75 deletions(-)
+
+diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c
+index 532f22637783..1ef55f4b389a 100644
+--- a/arch/powerpc/kernel/nvram_64.c
++++ b/arch/powerpc/kernel/nvram_64.c
+@@ -73,7 +73,8 @@ static const char *nvram_os_partitions[] = {
+ };
+ 
+ static void oops_to_nvram(struct kmsg_dumper *dumper,
+-			  enum kmsg_dump_reason reason);
++			  enum kmsg_dump_reason reason,
++			  struct kmsg_dumper_iter *iter);
+ 
+ static struct kmsg_dumper nvram_kmsg_dumper = {
+ 	.dump = oops_to_nvram
+@@ -643,7 +644,8 @@ void __init nvram_init_oops_partition(int rtas_partition_exists)
+  * partition.  If that's too much, go back and capture uncompressed text.
+  */
+ static void oops_to_nvram(struct kmsg_dumper *dumper,
+-			  enum kmsg_dump_reason reason)
++			  enum kmsg_dump_reason reason,
++			  struct kmsg_dumper_iter *iter)
+ {
+ 	struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
+ 	static unsigned int oops_count = 0;
+@@ -681,13 +683,13 @@ static void oops_to_nvram(struct kmsg_dumper *dumper,
+ 		return;
+ 
+ 	if (big_oops_buf) {
+-		kmsg_dump_get_buffer(dumper, false,
++		kmsg_dump_get_buffer(iter, false,
+ 				     big_oops_buf, big_oops_buf_sz, &text_len);
+ 		rc = zip_oops(text_len);
+ 	}
+ 	if (rc != 0) {
+-		kmsg_dump_rewind(dumper);
+-		kmsg_dump_get_buffer(dumper, false,
++		kmsg_dump_rewind(iter);
++		kmsg_dump_get_buffer(iter, false,
+ 				     oops_data, oops_data_sz, &text_len);
+ 		err_type = ERR_TYPE_KERNEL_PANIC;
+ 		oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
+diff --git a/arch/powerpc/platforms/powernv/opal-kmsg.c b/arch/powerpc/platforms/powernv/opal-kmsg.c
+index 6c3bc4b4da98..ec862846bc82 100644
+--- a/arch/powerpc/platforms/powernv/opal-kmsg.c
++++ b/arch/powerpc/platforms/powernv/opal-kmsg.c
+@@ -20,7 +20,8 @@
+  * message, it just ensures that OPAL completely flushes the console buffer.
+  */
+ static void kmsg_dump_opal_console_flush(struct kmsg_dumper *dumper,
+-				     enum kmsg_dump_reason reason)
++					 enum kmsg_dump_reason reason,
++					 struct kmsg_dumper_iter *iter)
+ {
+ 	/*
+ 	 * Outside of a panic context the pollers will continue to run,
+diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
+index 3de2adc0a807..9f62cca6c594 100644
+--- a/arch/powerpc/xmon/xmon.c
++++ b/arch/powerpc/xmon/xmon.c
+@@ -3003,7 +3003,7 @@ print_address(unsigned long addr)
+ static void
+ dump_log_buf(void)
+ {
+-	struct kmsg_dumper dumper = { .active = 1 };
++	struct kmsg_dumper_iter iter = { .active = 1 };
+ 	unsigned char buf[128];
+ 	size_t len;
+ 
+@@ -3015,9 +3015,9 @@ dump_log_buf(void)
+ 	catch_memory_errors = 1;
+ 	sync();
+ 
+-	kmsg_dump_rewind_nolock(&dumper);
++	kmsg_dump_rewind_nolock(&iter);
+ 	xmon_start_pagination();
+-	while (kmsg_dump_get_line_nolock(&dumper, false, buf, sizeof(buf), &len)) {
++	while (kmsg_dump_get_line_nolock(&iter, false, buf, sizeof(buf), &len)) {
+ 		buf[len] = '\0';
+ 		printf("%s", buf);
+ 	}
+diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c
+index e4abac6c9727..f38349ad00ea 100644
+--- a/arch/um/kernel/kmsg_dump.c
++++ b/arch/um/kernel/kmsg_dump.c
+@@ -6,7 +6,8 @@
+ #include <os.h>
+ 
+ static void kmsg_dumper_stdout(struct kmsg_dumper *dumper,
+-				enum kmsg_dump_reason reason)
++				enum kmsg_dump_reason reason,
++				struct kmsg_dumper_iter *iter)
+ {
+ 	static char line[1024];
+ 	struct console *con;
+@@ -25,7 +26,7 @@ static void kmsg_dumper_stdout(struct kmsg_dumper *dumper,
+ 		return;
+ 
+ 	printf("kmsg_dump:\n");
+-	while (kmsg_dump_get_line(dumper, true, line, sizeof(line), &len)) {
++	while (kmsg_dump_get_line(iter, true, line, sizeof(line), &len)) {
+ 		line[len] = '\0';
+ 		printf("%s", line);
+ 	}
+diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
+index e99400f3ae1d..db39c96bbf43 100644
+--- a/drivers/hv/vmbus_drv.c
++++ b/drivers/hv/vmbus_drv.c
+@@ -1359,7 +1359,8 @@ static void vmbus_isr(void)
+  * buffer and call into Hyper-V to transfer the data.
+  */
+ static void hv_kmsg_dump(struct kmsg_dumper *dumper,
+-			 enum kmsg_dump_reason reason)
++			 enum kmsg_dump_reason reason,
++			 struct kmsg_dumper_iter *iter)
+ {
+ 	size_t bytes_written;
+ 	phys_addr_t panic_pa;
+@@ -1374,7 +1375,7 @@ static void hv_kmsg_dump(struct kmsg_dumper *dumper,
+ 	 * Write dump contents to the page. No need to synchronize; panic should
+ 	 * be single-threaded.
+ 	 */
+-	kmsg_dump_get_buffer(dumper, false, hv_panic_page, HV_HYP_PAGE_SIZE,
++	kmsg_dump_get_buffer(iter, false, hv_panic_page, HV_HYP_PAGE_SIZE,
+ 			     &bytes_written);
+ 	if (bytes_written)
+ 		hyperv_report_panic_msg(panic_pa, bytes_written);
+diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c
+index 774970bfcf85..6bc2c728adb7 100644
+--- a/drivers/mtd/mtdoops.c
++++ b/drivers/mtd/mtdoops.c
+@@ -267,7 +267,8 @@ static void find_next_position(struct mtdoops_context *cxt)
+ }
+ 
+ static void mtdoops_do_dump(struct kmsg_dumper *dumper,
+-			    enum kmsg_dump_reason reason)
++			    enum kmsg_dump_reason reason,
++			    struct kmsg_dumper_iter *iter)
+ {
+ 	struct mtdoops_context *cxt = container_of(dumper,
+ 			struct mtdoops_context, dump);
+@@ -276,7 +277,7 @@ static void mtdoops_do_dump(struct kmsg_dumper *dumper,
+ 	if (reason == KMSG_DUMP_OOPS && !dump_oops)
+ 		return;
+ 
+-	kmsg_dump_get_buffer(dumper, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
++	kmsg_dump_get_buffer(iter, true, cxt->oops_buf + MTDOOPS_HEADER_SIZE,
+ 			     record_size - MTDOOPS_HEADER_SIZE, NULL);
+ 
+ 	if (reason != KMSG_DUMP_OOPS) {
+diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
+index d59f13b1fb96..64f3f85d2a5d 100644
+--- a/fs/pstore/platform.c
++++ b/fs/pstore/platform.c
+@@ -384,7 +384,8 @@ void pstore_record_init(struct pstore_record *record,
+  * end of the buffer.
+  */
+ static void pstore_dump(struct kmsg_dumper *dumper,
+-			enum kmsg_dump_reason reason)
++			enum kmsg_dump_reason reason,
++			struct kmsg_dumper_iter *iter)
+ {
+ 	unsigned long	total = 0;
+ 	const char	*why;
+@@ -434,7 +435,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
+ 		dst_size -= header_size;
+ 
+ 		/* Write dump contents. */
+-		if (!kmsg_dump_get_buffer(dumper, true, dst + header_size,
++		if (!kmsg_dump_get_buffer(iter, true, dst + header_size,
+ 					  dst_size, &dump_size))
+ 			break;
+ 
+diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
+index 4095a34db0fa..2fdb10ab1799 100644
+--- a/include/linux/kmsg_dump.h
++++ b/include/linux/kmsg_dump.h
+@@ -29,6 +29,18 @@ enum kmsg_dump_reason {
+ 	KMSG_DUMP_MAX
+ };
+ 
++/**
++ * struct kmsg_dumper_iter - iterator for kernel crash message dumper
++ * @active:	Flag that specifies if this is currently dumping
++ * @cur_seq:	Points to the oldest message to dump (private)
++ * @next_seq:	Points after the newest message to dump (private)
++ */
++struct kmsg_dumper_iter {
++	bool	active;
++	u64	cur_seq;
++	u64	next_seq;
++};
++
+ /**
+  * struct kmsg_dumper - kernel crash message dumper structure
+  * @list:	Entry in the dumper list (private)
+@@ -36,37 +48,30 @@ enum kmsg_dump_reason {
+  * 		through the record iterator
+  * @max_reason:	filter for highest reason number that should be dumped
+  * @registered:	Flag that specifies if this is already registered
+- * @active:	Flag that specifies if this is currently dumping
+- * @cur_seq:	Points to the oldest message to dump (private)
+- * @next_seq:	Points after the newest message to dump (private)
+  */
+ struct kmsg_dumper {
+ 	struct list_head list;
+-	void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason);
++	void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason,
++		     struct kmsg_dumper_iter *iter);
+ 	enum kmsg_dump_reason max_reason;
+-	bool active;
+ 	bool registered;
+-
+-	/* private state of the kmsg iterator */
+-	u64 cur_seq;
+-	u64 next_seq;
+ };
+ 
+ #ifdef CONFIG_PRINTK
+ void kmsg_dump(enum kmsg_dump_reason reason);
+ 
+-bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
++bool kmsg_dump_get_line_nolock(struct kmsg_dumper_iter *iter, bool syslog,
+ 			       char *line, size_t size, size_t *len);
+ 
+-bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
++bool kmsg_dump_get_line(struct kmsg_dumper_iter *iter, bool syslog,
+ 			char *line, size_t size, size_t *len);
+ 
+-bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
++bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog,
+ 			  char *buf, size_t size, size_t *len_out);
+ 
+-void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper);
++void kmsg_dump_rewind_nolock(struct kmsg_dumper_iter *iter);
+ 
+-void kmsg_dump_rewind(struct kmsg_dumper *dumper);
++void kmsg_dump_rewind(struct kmsg_dumper_iter *dumper_iter);
+ 
+ int kmsg_dump_register(struct kmsg_dumper *dumper);
+ 
+@@ -78,30 +83,30 @@ static inline void kmsg_dump(enum kmsg_dump_reason reason)
+ {
+ }
+ 
+-static inline bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper,
++static inline bool kmsg_dump_get_line_nolock(struct kmsg_dumper_iter *iter,
+ 					     bool syslog, const char *line,
+ 					     size_t size, size_t *len)
+ {
+ 	return false;
+ }
+ 
+-static inline bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
++static inline bool kmsg_dump_get_line(struct kmsg_dumper_iter *iter, bool syslog,
+ 				const char *line, size_t size, size_t *len)
+ {
+ 	return false;
+ }
+ 
+-static inline bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
++static inline bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog,
+ 					char *buf, size_t size, size_t *len)
+ {
+ 	return false;
+ }
+ 
+-static inline void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
++static inline void kmsg_dump_rewind_nolock(struct kmsg_dumper_iter *iter)
+ {
+ }
+ 
+-static inline void kmsg_dump_rewind(struct kmsg_dumper *dumper)
++static inline void kmsg_dump_rewind(struct kmsg_dumper_iter *iter)
+ {
+ }
+ 
+diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
+index 4e09fab52faf..048baadd7a41 100644
+--- a/kernel/debug/kdb/kdb_main.c
++++ b/kernel/debug/kdb/kdb_main.c
+@@ -2157,7 +2157,7 @@ static int kdb_dmesg(int argc, const char **argv)
+ 	int adjust = 0;
+ 	int n = 0;
+ 	int skip = 0;
+-	struct kmsg_dumper dumper = { .active = 1 };
++	struct kmsg_dumper_iter iter = { .active = 1 };
+ 	size_t len;
+ 	char buf[201];
+ 
+@@ -2182,8 +2182,8 @@ static int kdb_dmesg(int argc, const char **argv)
+ 		kdb_set(2, setargs);
+ 	}
+ 
+-	kmsg_dump_rewind_nolock(&dumper);
+-	while (kmsg_dump_get_line_nolock(&dumper, 1, NULL, 0, NULL))
++	kmsg_dump_rewind_nolock(&iter);
++	while (kmsg_dump_get_line_nolock(&iter, 1, NULL, 0, NULL))
+ 		n++;
+ 
+ 	if (lines < 0) {
+@@ -2215,8 +2215,8 @@ static int kdb_dmesg(int argc, const char **argv)
+ 	if (skip >= n || skip < 0)
+ 		return 0;
+ 
+-	kmsg_dump_rewind_nolock(&dumper);
+-	while (kmsg_dump_get_line_nolock(&dumper, 1, buf, sizeof(buf), &len)) {
++	kmsg_dump_rewind_nolock(&iter);
++	while (kmsg_dump_get_line_nolock(&iter, 1, buf, sizeof(buf), &len)) {
+ 		if (skip) {
+ 			skip--;
+ 			continue;
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 986fc9fad210..b992be31824f 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -3394,6 +3394,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_reason_str);
+  */
+ void kmsg_dump(enum kmsg_dump_reason reason)
+ {
++	struct kmsg_dumper_iter iter;
+ 	struct kmsg_dumper *dumper;
+ 	unsigned long flags;
+ 
+@@ -3413,25 +3414,21 @@ void kmsg_dump(enum kmsg_dump_reason reason)
+ 			continue;
+ 
+ 		/* initialize iterator with data about the stored records */
+-		dumper->active = true;
+-
++		iter.active = true;
+ 		logbuf_lock_irqsave(flags);
+-		dumper->cur_seq = latched_seq_read_nolock(&clear_seq);
+-		dumper->next_seq = prb_next_seq(prb);
++		iter.cur_seq = latched_seq_read_nolock(&clear_seq);
++		iter.next_seq = prb_next_seq(prb);
+ 		logbuf_unlock_irqrestore(flags);
+ 
+ 		/* invoke dumper which will iterate over records */
+-		dumper->dump(dumper, reason);
+-
+-		/* reset iterator */
+-		dumper->active = false;
++		dumper->dump(dumper, reason, &iter);
+ 	}
+ 	rcu_read_unlock();
+ }
+ 
+ /**
+  * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version)
+- * @dumper: registered kmsg dumper
++ * @iter: kmsg dumper iterator
+  * @syslog: include the "<4>" prefixes
+  * @line: buffer to copy the line to
+  * @size: maximum size of the buffer
+@@ -3448,7 +3445,7 @@ void kmsg_dump(enum kmsg_dump_reason reason)
+  *
+  * The function is similar to kmsg_dump_get_line(), but grabs no locks.
+  */
+-bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
++bool kmsg_dump_get_line_nolock(struct kmsg_dumper_iter *iter, bool syslog,
+ 			       char *line, size_t size, size_t *len)
+ {
+ 	struct printk_info info;
+@@ -3459,16 +3456,16 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
+ 
+ 	prb_rec_init_rd(&r, &info, line, size);
+ 
+-	if (!dumper->active)
++	if (!iter->active)
+ 		goto out;
+ 
+ 	/* Read text or count text lines? */
+ 	if (line) {
+-		if (!prb_read_valid(prb, dumper->cur_seq, &r))
++		if (!prb_read_valid(prb, iter->cur_seq, &r))
+ 			goto out;
+ 		l = record_print_text(&r, syslog, printk_time);
+ 	} else {
+-		if (!prb_read_valid_info(prb, dumper->cur_seq,
++		if (!prb_read_valid_info(prb, iter->cur_seq,
+ 					 &info, &line_count)) {
+ 			goto out;
+ 		}
+@@ -3477,7 +3474,7 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
+ 
+ 	}
+ 
+-	dumper->cur_seq = r.info->seq + 1;
++	iter->cur_seq = r.info->seq + 1;
+ 	ret = true;
+ out:
+ 	if (len)
+@@ -3487,7 +3484,7 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
+ 
+ /**
+  * kmsg_dump_get_line - retrieve one kmsg log line
+- * @dumper: registered kmsg dumper
++ * @iter: kmsg dumper iterator
+  * @syslog: include the "<4>" prefixes
+  * @line: buffer to copy the line to
+  * @size: maximum size of the buffer
+@@ -3502,14 +3499,14 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
+  * A return value of FALSE indicates that there are no more records to
+  * read.
+  */
+-bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
++bool kmsg_dump_get_line(struct kmsg_dumper_iter *iter, bool syslog,
+ 			char *line, size_t size, size_t *len)
+ {
+ 	unsigned long flags;
+ 	bool ret;
+ 
+ 	logbuf_lock_irqsave(flags);
+-	ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
++	ret = kmsg_dump_get_line_nolock(iter, syslog, line, size, len);
+ 	logbuf_unlock_irqrestore(flags);
+ 
+ 	return ret;
+@@ -3518,7 +3515,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
+ 
+ /**
+  * kmsg_dump_get_buffer - copy kmsg log lines
+- * @dumper: registered kmsg dumper
++ * @iter: kmsg dumper iterator
+  * @syslog: include the "<4>" prefixes
+  * @buf: buffer to copy the line to
+  * @size: maximum size of the buffer
+@@ -3535,7 +3532,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
+  * A return value of FALSE indicates that there are no more records to
+  * read.
+  */
+-bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
++bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog,
+ 			  char *buf, size_t size, size_t *len_out)
+ {
+ 	struct printk_info info;
+@@ -3547,19 +3544,19 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+ 	bool ret = false;
+ 	bool time = printk_time;
+ 
+-	if (!dumper->active || !buf || !size)
++	if (!iter->active || !buf || !size)
+ 		goto out;
+ 
+ 	logbuf_lock_irqsave(flags);
+-	if (prb_read_valid_info(prb, dumper->cur_seq, &info, NULL)) {
+-		if (info.seq != dumper->cur_seq) {
++	if (prb_read_valid_info(prb, iter->cur_seq, &info, NULL)) {
++		if (info.seq != iter->cur_seq) {
+ 			/* messages are gone, move to first available one */
+-			dumper->cur_seq = info.seq;
++			iter->cur_seq = info.seq;
+ 		}
+ 	}
+ 
+ 	/* last entry */
+-	if (dumper->cur_seq >= dumper->next_seq) {
++	if (iter->cur_seq >= iter->next_seq) {
+ 		logbuf_unlock_irqrestore(flags);
+ 		goto out;
+ 	}
+@@ -3570,7 +3567,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+ 	 * because this function (by way of record_print_text()) will
+ 	 * not write more than size-1 bytes of text into @buf.
+ 	 */
+-	seq = find_first_fitting_seq(dumper->cur_seq, dumper->next_seq,
++	seq = find_first_fitting_seq(iter->cur_seq, iter->next_seq,
+ 				     size - 1, syslog, time);
+ 
+ 	/*
+@@ -3583,7 +3580,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+ 
+ 	len = 0;
+ 	prb_for_each_record(seq, prb, seq, &r) {
+-		if (r.info->seq >= dumper->next_seq)
++		if (r.info->seq >= iter->next_seq)
+ 			break;
+ 
+ 		len += record_print_text(&r, syslog, time);
+@@ -3592,7 +3589,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+ 		prb_rec_init_rd(&r, &info, buf + len, size - len);
+ 	}
+ 
+-	dumper->next_seq = next_seq;
++	iter->next_seq = next_seq;
+ 	ret = true;
+ 	logbuf_unlock_irqrestore(flags);
+ out:
+@@ -3604,7 +3601,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
+ 
+ /**
+  * kmsg_dump_rewind_nolock - reset the iterator (unlocked version)
+- * @dumper: registered kmsg dumper
++ * @iter: kmsg dumper iterator
+  *
+  * Reset the dumper's iterator so that kmsg_dump_get_line() and
+  * kmsg_dump_get_buffer() can be called again and used multiple
+@@ -3612,26 +3609,26 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
+  *
+  * The function is similar to kmsg_dump_rewind(), but grabs no locks.
+  */
+-void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
++void kmsg_dump_rewind_nolock(struct kmsg_dumper_iter *iter)
+ {
+-	dumper->cur_seq = latched_seq_read_nolock(&clear_seq);
+-	dumper->next_seq = prb_next_seq(prb);
++	iter->cur_seq = latched_seq_read_nolock(&clear_seq);
++	iter->next_seq = prb_next_seq(prb);
+ }
+ 
+ /**
+  * kmsg_dump_rewind - reset the iterator
+- * @dumper: registered kmsg dumper
++ * @iter: kmsg dumper iterator
+  *
+  * Reset the dumper's iterator so that kmsg_dump_get_line() and
+  * kmsg_dump_get_buffer() can be called again and used multiple
+  * times within the same dumper.dump() callback.
+  */
+-void kmsg_dump_rewind(struct kmsg_dumper *dumper)
++void kmsg_dump_rewind(struct kmsg_dumper_iter *iter)
+ {
+ 	unsigned long flags;
+ 
+ 	logbuf_lock_irqsave(flags);
+-	kmsg_dump_rewind_nolock(dumper);
++	kmsg_dump_rewind_nolock(iter);
+ 	logbuf_unlock_irqrestore(flags);
+ }
+ EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0091-um-synchronize-kmsg_dumper.patch b/debian/patches-rt/0091-um-synchronize-kmsg_dumper.patch
new file mode 100644
index 000000000..88b6f08ca
--- /dev/null
+++ b/debian/patches-rt/0091-um-synchronize-kmsg_dumper.patch
@@ -0,0 +1,61 @@
+From 7790fa6baa700a285007a6e8ddf99393ba72acc2 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 21 Dec 2020 11:10:03 +0106
+Subject: [PATCH 091/323] um: synchronize kmsg_dumper
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The kmsg_dumper can be called from any context and CPU, possibly
+from multiple CPUs simultaneously. Since a static buffer is used
+to retrieve the kernel logs, this buffer must be protected against
+simultaneous dumping.
+
+Cc: Richard Weinberger <richard@nod.at>
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Reviewed-by: Petr Mladek <pmladek@suse.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/um/kernel/kmsg_dump.c | 8 ++++++++
+ 1 file changed, 8 insertions(+)
+
+diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c
+index f38349ad00ea..173999422ed8 100644
+--- a/arch/um/kernel/kmsg_dump.c
++++ b/arch/um/kernel/kmsg_dump.c
+@@ -1,5 +1,6 @@
+ // SPDX-License-Identifier: GPL-2.0
+ #include <linux/kmsg_dump.h>
++#include <linux/spinlock.h>
+ #include <linux/console.h>
+ #include <shared/init.h>
+ #include <shared/kern.h>
+@@ -9,8 +10,10 @@ static void kmsg_dumper_stdout(struct kmsg_dumper *dumper,
+ 				enum kmsg_dump_reason reason,
+ 				struct kmsg_dumper_iter *iter)
+ {
++	static DEFINE_SPINLOCK(lock);
+ 	static char line[1024];
+ 	struct console *con;
++	unsigned long flags;
+ 	size_t len = 0;
+ 
+ 	/* only dump kmsg when no console is available */
+@@ -25,11 +28,16 @@ static void kmsg_dumper_stdout(struct kmsg_dumper *dumper,
+ 	if (con)
+ 		return;
+ 
++	if (!spin_trylock_irqsave(&lock, flags))
++		return;
++
+ 	printf("kmsg_dump:\n");
+ 	while (kmsg_dump_get_line(iter, true, line, sizeof(line), &len)) {
+ 		line[len] = '\0';
+ 		printf("%s", line);
+ 	}
++
++	spin_unlock_irqrestore(&lock, flags);
+ }
+ 
+ static struct kmsg_dumper kmsg_dumper = {
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0092-printk-remove-logbuf_lock.patch b/debian/patches-rt/0092-printk-remove-logbuf_lock.patch
new file mode 100644
index 000000000..6f45ee8b3
--- /dev/null
+++ b/debian/patches-rt/0092-printk-remove-logbuf_lock.patch
@@ -0,0 +1,486 @@
+From 74a8c8a0d6b64df822c5946a582ca3adeec24e63 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Tue, 26 Jan 2021 17:43:19 +0106
+Subject: [PATCH 092/323] printk: remove logbuf_lock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Since the ringbuffer is lockless, there is no need for it to be
+protected by @logbuf_lock. Remove @logbuf_lock.
+
+This means that printk_nmi_direct and printk_safe_flush_on_panic()
+no longer need to acquire any lock to run.
+
+@console_seq, @exclusive_console_stop_seq, @console_dropped are
+protected by @console_lock.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/printk/internal.h    |   4 +-
+ kernel/printk/printk.c      | 118 ++++++++++++------------------------
+ kernel/printk/printk_safe.c |  29 +++------
+ 3 files changed, 48 insertions(+), 103 deletions(-)
+
+diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
+index 3a8fd491758c..e7acc2888c8e 100644
+--- a/kernel/printk/internal.h
++++ b/kernel/printk/internal.h
+@@ -12,8 +12,6 @@
+ 
+ #define PRINTK_NMI_CONTEXT_OFFSET	0x010000000
+ 
+-extern raw_spinlock_t logbuf_lock;
+-
+ __printf(4, 0)
+ int vprintk_store(int facility, int level,
+ 		  const struct dev_printk_info *dev_info,
+@@ -59,7 +57,7 @@ void defer_console_output(void);
+ __printf(1, 0) int vprintk_func(const char *fmt, va_list args) { return 0; }
+ 
+ /*
+- * In !PRINTK builds we still export logbuf_lock spin_lock, console_sem
++ * In !PRINTK builds we still export console_sem
+  * semaphore and some of console functions (console_unlock()/etc.), so
+  * printk-safe must preserve the existing local IRQ guarantees.
+  */
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index b992be31824f..dde1696d7564 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -357,41 +357,6 @@ enum log_flags {
+ 	LOG_CONT	= 8,	/* text is a fragment of a continuation line */
+ };
+ 
+-/*
+- * The logbuf_lock protects kmsg buffer, indices, counters.  This can be taken
+- * within the scheduler's rq lock. It must be released before calling
+- * console_unlock() or anything else that might wake up a process.
+- */
+-DEFINE_RAW_SPINLOCK(logbuf_lock);
+-
+-/*
+- * Helper macros to lock/unlock logbuf_lock and switch between
+- * printk-safe/unsafe modes.
+- */
+-#define logbuf_lock_irq()				\
+-	do {						\
+-		printk_safe_enter_irq();		\
+-		raw_spin_lock(&logbuf_lock);		\
+-	} while (0)
+-
+-#define logbuf_unlock_irq()				\
+-	do {						\
+-		raw_spin_unlock(&logbuf_lock);		\
+-		printk_safe_exit_irq();			\
+-	} while (0)
+-
+-#define logbuf_lock_irqsave(flags)			\
+-	do {						\
+-		printk_safe_enter_irqsave(flags);	\
+-		raw_spin_lock(&logbuf_lock);		\
+-	} while (0)
+-
+-#define logbuf_unlock_irqrestore(flags)		\
+-	do {						\
+-		raw_spin_unlock(&logbuf_lock);		\
+-		printk_safe_exit_irqrestore(flags);	\
+-	} while (0)
+-
+ /* syslog_lock protects syslog_* variables and write access to clear_seq. */
+ static DEFINE_RAW_SPINLOCK(syslog_lock);
+ 
+@@ -403,6 +368,7 @@ static u64 syslog_seq;
+ static size_t syslog_partial;
+ static bool syslog_time;
+ 
++/* All 3 protected by @console_sem. */
+ /* the next printk record to write to the console */
+ static u64 console_seq;
+ static u64 exclusive_console_stop_seq;
+@@ -769,27 +735,27 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
+ 	if (ret)
+ 		return ret;
+ 
+-	logbuf_lock_irq();
++	printk_safe_enter_irq();
+ 	if (!prb_read_valid(prb, atomic64_read(&user->seq), r)) {
+ 		if (file->f_flags & O_NONBLOCK) {
+ 			ret = -EAGAIN;
+-			logbuf_unlock_irq();
++			printk_safe_exit_irq();
+ 			goto out;
+ 		}
+ 
+-		logbuf_unlock_irq();
++		printk_safe_exit_irq();
+ 		ret = wait_event_interruptible(log_wait,
+ 				prb_read_valid(prb, atomic64_read(&user->seq), r));
+ 		if (ret)
+ 			goto out;
+-		logbuf_lock_irq();
++		printk_safe_enter_irq();
+ 	}
+ 
+ 	if (r->info->seq != atomic64_read(&user->seq)) {
+ 		/* our last seen message is gone, return error and reset */
+ 		atomic64_set(&user->seq, r->info->seq);
+ 		ret = -EPIPE;
+-		logbuf_unlock_irq();
++		printk_safe_exit_irq();
+ 		goto out;
+ 	}
+ 
+@@ -799,7 +765,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
+ 				  &r->info->dev_info);
+ 
+ 	atomic64_set(&user->seq, r->info->seq + 1);
+-	logbuf_unlock_irq();
++	printk_safe_exit_irq();
+ 
+ 	if (len > count) {
+ 		ret = -EINVAL;
+@@ -834,7 +800,7 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
+ 	if (offset)
+ 		return -ESPIPE;
+ 
+-	logbuf_lock_irq();
++	printk_safe_enter_irq();
+ 	switch (whence) {
+ 	case SEEK_SET:
+ 		/* the first record */
+@@ -855,7 +821,7 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
+ 	default:
+ 		ret = -EINVAL;
+ 	}
+-	logbuf_unlock_irq();
++	printk_safe_exit_irq();
+ 	return ret;
+ }
+ 
+@@ -870,15 +836,15 @@ static __poll_t devkmsg_poll(struct file *file, poll_table *wait)
+ 
+ 	poll_wait(file, &log_wait, wait);
+ 
+-	logbuf_lock_irq();
+-	if (prb_read_valid_info(prb, user->seq, &info, NULL)) {
++	printk_safe_enter_irq();
++	if (prb_read_valid_info(prb, atomic64_read(&user->seq), &info, NULL)) {
+ 		/* return error when data has vanished underneath us */
+ 		if (info.seq != atomic64_read(&user->seq))
+ 			ret = EPOLLIN|EPOLLRDNORM|EPOLLERR|EPOLLPRI;
+ 		else
+ 			ret = EPOLLIN|EPOLLRDNORM;
+ 	}
+-	logbuf_unlock_irq();
++	printk_safe_exit_irq();
+ 
+ 	return ret;
+ }
+@@ -911,9 +877,9 @@ static int devkmsg_open(struct inode *inode, struct file *file)
+ 	prb_rec_init_rd(&user->record, &user->info,
+ 			&user->text_buf[0], sizeof(user->text_buf));
+ 
+-	logbuf_lock_irq();
++	printk_safe_enter_irq();
+ 	atomic64_set(&user->seq, prb_first_valid_seq(prb));
+-	logbuf_unlock_irq();
++	printk_safe_exit_irq();
+ 
+ 	file->private_data = user;
+ 	return 0;
+@@ -1535,11 +1501,11 @@ static int syslog_print(char __user *buf, int size)
+ 		size_t n;
+ 		size_t skip;
+ 
+-		logbuf_lock_irq();
++		printk_safe_enter_irq();
+ 		raw_spin_lock(&syslog_lock);
+ 		if (!prb_read_valid(prb, syslog_seq, &r)) {
+ 			raw_spin_unlock(&syslog_lock);
+-			logbuf_unlock_irq();
++			printk_safe_exit_irq();
+ 			break;
+ 		}
+ 		if (r.info->seq != syslog_seq) {
+@@ -1569,7 +1535,7 @@ static int syslog_print(char __user *buf, int size)
+ 		} else
+ 			n = 0;
+ 		raw_spin_unlock(&syslog_lock);
+-		logbuf_unlock_irq();
++		printk_safe_exit_irq();
+ 
+ 		if (!n)
+ 			break;
+@@ -1603,7 +1569,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 		return -ENOMEM;
+ 
+ 	time = printk_time;
+-	logbuf_lock_irq();
++	printk_safe_enter_irq();
+ 	/*
+ 	 * Find first record that fits, including all following records,
+ 	 * into the user-provided buffer for this dump.
+@@ -1624,12 +1590,12 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 			break;
+ 		}
+ 
+-		logbuf_unlock_irq();
++		printk_safe_exit_irq();
+ 		if (copy_to_user(buf + len, text, textlen))
+ 			len = -EFAULT;
+ 		else
+ 			len += textlen;
+-		logbuf_lock_irq();
++		printk_safe_enter_irq();
+ 
+ 		if (len < 0)
+ 			break;
+@@ -1640,7 +1606,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 		latched_seq_write(&clear_seq, seq);
+ 		raw_spin_unlock(&syslog_lock);
+ 	}
+-	logbuf_unlock_irq();
++	printk_safe_exit_irq();
+ 
+ 	kfree(text);
+ 	return len;
+@@ -1648,11 +1614,11 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 
+ static void syslog_clear(void)
+ {
+-	logbuf_lock_irq();
++	printk_safe_enter_irq();
+ 	raw_spin_lock(&syslog_lock);
+ 	latched_seq_write(&clear_seq, prb_next_seq(prb));
+ 	raw_spin_unlock(&syslog_lock);
+-	logbuf_unlock_irq();
++	printk_safe_exit_irq();
+ }
+ 
+ /* Return a consistent copy of @syslog_seq. */
+@@ -1740,12 +1706,12 @@ int do_syslog(int type, char __user *buf, int len, int source)
+ 		break;
+ 	/* Number of chars in the log buffer */
+ 	case SYSLOG_ACTION_SIZE_UNREAD:
+-		logbuf_lock_irq();
++		printk_safe_enter_irq();
+ 		raw_spin_lock(&syslog_lock);
+ 		if (!prb_read_valid_info(prb, syslog_seq, &info, NULL)) {
+ 			/* No unread messages. */
+ 			raw_spin_unlock(&syslog_lock);
+-			logbuf_unlock_irq();
++			printk_safe_exit_irq();
+ 			return 0;
+ 		}
+ 		if (info.seq != syslog_seq) {
+@@ -1774,7 +1740,7 @@ int do_syslog(int type, char __user *buf, int len, int source)
+ 			error -= syslog_partial;
+ 		}
+ 		raw_spin_unlock(&syslog_lock);
+-		logbuf_unlock_irq();
++		printk_safe_exit_irq();
+ 		break;
+ 	/* Size of the log buffer */
+ 	case SYSLOG_ACTION_SIZE_BUFFER:
+@@ -2630,7 +2596,6 @@ void console_unlock(void)
+ 		size_t len;
+ 
+ 		printk_safe_enter_irqsave(flags);
+-		raw_spin_lock(&logbuf_lock);
+ skip:
+ 		if (!prb_read_valid(prb, console_seq, &r))
+ 			break;
+@@ -2674,7 +2639,6 @@ void console_unlock(void)
+ 				console_msg_format & MSG_FORMAT_SYSLOG,
+ 				printk_time);
+ 		console_seq++;
+-		raw_spin_unlock(&logbuf_lock);
+ 
+ 		/*
+ 		 * While actively printing out messages, if another printk()
+@@ -2701,8 +2665,6 @@ void console_unlock(void)
+ 
+ 	console_locked = 0;
+ 
+-	raw_spin_unlock(&logbuf_lock);
+-
+ 	up_console_sem();
+ 
+ 	/*
+@@ -2711,9 +2673,7 @@ void console_unlock(void)
+ 	 * there's a new owner and the console_unlock() from them will do the
+ 	 * flush, no worries.
+ 	 */
+-	raw_spin_lock(&logbuf_lock);
+ 	retry = prb_read_valid(prb, console_seq, NULL);
+-	raw_spin_unlock(&logbuf_lock);
+ 	printk_safe_exit_irqrestore(flags);
+ 
+ 	if (retry && console_trylock())
+@@ -2780,9 +2740,9 @@ void console_flush_on_panic(enum con_flush_mode mode)
+ 	if (mode == CONSOLE_REPLAY_ALL) {
+ 		unsigned long flags;
+ 
+-		logbuf_lock_irqsave(flags);
++		printk_safe_enter_irqsave(flags);
+ 		console_seq = prb_first_valid_seq(prb);
+-		logbuf_unlock_irqrestore(flags);
++		printk_safe_exit_irqrestore(flags);
+ 	}
+ 	console_unlock();
+ }
+@@ -3011,7 +2971,7 @@ void register_console(struct console *newcon)
+ 		 * console_unlock(); will print out the buffered messages
+ 		 * for us.
+ 		 */
+-		logbuf_lock_irqsave(flags);
++		printk_safe_enter_irqsave(flags);
+ 		/*
+ 		 * We're about to replay the log buffer.  Only do this to the
+ 		 * just-registered console to avoid excessive message spam to
+@@ -3029,7 +2989,7 @@ void register_console(struct console *newcon)
+ 		console_seq = syslog_seq;
+ 		raw_spin_unlock(&syslog_lock);
+ 
+-		logbuf_unlock_irqrestore(flags);
++		printk_safe_exit_irqrestore(flags);
+ 	}
+ 	console_unlock();
+ 	console_sysfs_notify();
+@@ -3415,10 +3375,10 @@ void kmsg_dump(enum kmsg_dump_reason reason)
+ 
+ 		/* initialize iterator with data about the stored records */
+ 		iter.active = true;
+-		logbuf_lock_irqsave(flags);
++		printk_safe_enter_irqsave(flags);
+ 		iter.cur_seq = latched_seq_read_nolock(&clear_seq);
+ 		iter.next_seq = prb_next_seq(prb);
+-		logbuf_unlock_irqrestore(flags);
++		printk_safe_exit_irqrestore(flags);
+ 
+ 		/* invoke dumper which will iterate over records */
+ 		dumper->dump(dumper, reason, &iter);
+@@ -3505,9 +3465,9 @@ bool kmsg_dump_get_line(struct kmsg_dumper_iter *iter, bool syslog,
+ 	unsigned long flags;
+ 	bool ret;
+ 
+-	logbuf_lock_irqsave(flags);
++	printk_safe_enter_irqsave(flags);
+ 	ret = kmsg_dump_get_line_nolock(iter, syslog, line, size, len);
+-	logbuf_unlock_irqrestore(flags);
++	printk_safe_exit_irqrestore(flags);
+ 
+ 	return ret;
+ }
+@@ -3547,7 +3507,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog,
+ 	if (!iter->active || !buf || !size)
+ 		goto out;
+ 
+-	logbuf_lock_irqsave(flags);
++	printk_safe_enter_irqsave(flags);
+ 	if (prb_read_valid_info(prb, iter->cur_seq, &info, NULL)) {
+ 		if (info.seq != iter->cur_seq) {
+ 			/* messages are gone, move to first available one */
+@@ -3557,7 +3517,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog,
+ 
+ 	/* last entry */
+ 	if (iter->cur_seq >= iter->next_seq) {
+-		logbuf_unlock_irqrestore(flags);
++		printk_safe_exit_irqrestore(flags);
+ 		goto out;
+ 	}
+ 
+@@ -3591,7 +3551,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog,
+ 
+ 	iter->next_seq = next_seq;
+ 	ret = true;
+-	logbuf_unlock_irqrestore(flags);
++	printk_safe_exit_irqrestore(flags);
+ out:
+ 	if (len_out)
+ 		*len_out = len;
+@@ -3627,9 +3587,9 @@ void kmsg_dump_rewind(struct kmsg_dumper_iter *iter)
+ {
+ 	unsigned long flags;
+ 
+-	logbuf_lock_irqsave(flags);
++	printk_safe_enter_irqsave(flags);
+ 	kmsg_dump_rewind_nolock(iter);
+-	logbuf_unlock_irqrestore(flags);
++	printk_safe_exit_irqrestore(flags);
+ }
+ EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
+ 
+diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
+index 2e9e3ed7d63e..7df8a88d4115 100644
+--- a/kernel/printk/printk_safe.c
++++ b/kernel/printk/printk_safe.c
+@@ -16,7 +16,7 @@
+ #include "internal.h"
+ 
+ /*
+- * printk() could not take logbuf_lock in NMI context. Instead,
++ * In NMI and safe mode, printk() avoids taking locks. Instead,
+  * it uses an alternative implementation that temporary stores
+  * the strings into a per-CPU buffer. The content of the buffer
+  * is later flushed into the main ring buffer via IRQ work.
+@@ -266,18 +266,6 @@ void printk_safe_flush(void)
+  */
+ void printk_safe_flush_on_panic(void)
+ {
+-	/*
+-	 * Make sure that we could access the main ring buffer.
+-	 * Do not risk a double release when more CPUs are up.
+-	 */
+-	if (raw_spin_is_locked(&logbuf_lock)) {
+-		if (num_online_cpus() > 1)
+-			return;
+-
+-		debug_locks_off();
+-		raw_spin_lock_init(&logbuf_lock);
+-	}
+-
+ 	if (raw_spin_is_locked(&safe_read_lock)) {
+ 		if (num_online_cpus() > 1)
+ 			return;
+@@ -319,9 +307,7 @@ void noinstr printk_nmi_exit(void)
+  * reordering.
+  *
+  * It has effect only when called in NMI context. Then printk()
+- * will try to store the messages into the main logbuf directly
+- * and use the per-CPU buffers only as a fallback when the lock
+- * is not available.
++ * will store the messages into the main logbuf directly.
+  */
+ void printk_nmi_direct_enter(void)
+ {
+@@ -376,20 +362,21 @@ __printf(1, 0) int vprintk_func(const char *fmt, va_list args)
+ #endif
+ 
+ 	/*
+-	 * Try to use the main logbuf even in NMI. But avoid calling console
++	 * Use the main logbuf even in NMI. But avoid calling console
+ 	 * drivers that might have their own locks.
+ 	 */
+-	if ((this_cpu_read(printk_context) & PRINTK_NMI_DIRECT_CONTEXT_MASK) &&
+-	    raw_spin_trylock(&logbuf_lock)) {
++	if ((this_cpu_read(printk_context) & PRINTK_NMI_DIRECT_CONTEXT_MASK)) {
++		unsigned long flags;
+ 		int len;
+ 
++		printk_safe_enter_irqsave(flags);
+ 		len = vprintk_store(0, LOGLEVEL_DEFAULT, NULL, fmt, args);
+-		raw_spin_unlock(&logbuf_lock);
++		printk_safe_exit_irqrestore(flags);
+ 		defer_console_output();
+ 		return len;
+ 	}
+ 
+-	/* Use extra buffer in NMI when logbuf_lock is taken or in safe mode. */
++	/* Use extra buffer in NMI. */
+ 	if (this_cpu_read(printk_context) & PRINTK_NMI_CONTEXT_MASK)
+ 		return vprintk_nmi(fmt, args);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0093-printk-kmsg_dump-remove-_nolock-variants.patch b/debian/patches-rt/0093-printk-kmsg_dump-remove-_nolock-variants.patch
new file mode 100644
index 000000000..6ad034c1a
--- /dev/null
+++ b/debian/patches-rt/0093-printk-kmsg_dump-remove-_nolock-variants.patch
@@ -0,0 +1,226 @@
+From 171ee108014d67150846f1b8f978921cefc7b1e3 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 21 Dec 2020 10:27:58 +0106
+Subject: [PATCH 093/323] printk: kmsg_dump: remove _nolock() variants
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+kmsg_dump_rewind() and kmsg_dump_get_line() are lockless, so there is
+no need for _nolock() variants. Remove these functions and switch all
+callers of the _nolock() variants.
+
+The functions without _nolock() were chosen because they are already
+exported to kernel modules.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+---
+ arch/powerpc/xmon/xmon.c    |  4 +--
+ include/linux/kmsg_dump.h   | 18 +----------
+ kernel/debug/kdb/kdb_main.c |  8 ++---
+ kernel/printk/printk.c      | 60 +++++--------------------------------
+ 4 files changed, 15 insertions(+), 75 deletions(-)
+
+diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
+index 9f62cca6c594..2eef587bf51d 100644
+--- a/arch/powerpc/xmon/xmon.c
++++ b/arch/powerpc/xmon/xmon.c
+@@ -3015,9 +3015,9 @@ dump_log_buf(void)
+ 	catch_memory_errors = 1;
+ 	sync();
+ 
+-	kmsg_dump_rewind_nolock(&iter);
++	kmsg_dump_rewind(&iter);
+ 	xmon_start_pagination();
+-	while (kmsg_dump_get_line_nolock(&iter, false, buf, sizeof(buf), &len)) {
++	while (kmsg_dump_get_line(&iter, false, buf, sizeof(buf), &len)) {
+ 		buf[len] = '\0';
+ 		printf("%s", buf);
+ 	}
+diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
+index 2fdb10ab1799..86673930c8ea 100644
+--- a/include/linux/kmsg_dump.h
++++ b/include/linux/kmsg_dump.h
+@@ -60,18 +60,13 @@ struct kmsg_dumper {
+ #ifdef CONFIG_PRINTK
+ void kmsg_dump(enum kmsg_dump_reason reason);
+ 
+-bool kmsg_dump_get_line_nolock(struct kmsg_dumper_iter *iter, bool syslog,
+-			       char *line, size_t size, size_t *len);
+-
+ bool kmsg_dump_get_line(struct kmsg_dumper_iter *iter, bool syslog,
+ 			char *line, size_t size, size_t *len);
+ 
+ bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog,
+ 			  char *buf, size_t size, size_t *len_out);
+ 
+-void kmsg_dump_rewind_nolock(struct kmsg_dumper_iter *iter);
+-
+-void kmsg_dump_rewind(struct kmsg_dumper_iter *dumper_iter);
++void kmsg_dump_rewind(struct kmsg_dumper_iter *iter);
+ 
+ int kmsg_dump_register(struct kmsg_dumper *dumper);
+ 
+@@ -83,13 +78,6 @@ static inline void kmsg_dump(enum kmsg_dump_reason reason)
+ {
+ }
+ 
+-static inline bool kmsg_dump_get_line_nolock(struct kmsg_dumper_iter *iter,
+-					     bool syslog, const char *line,
+-					     size_t size, size_t *len)
+-{
+-	return false;
+-}
+-
+ static inline bool kmsg_dump_get_line(struct kmsg_dumper_iter *iter, bool syslog,
+ 				const char *line, size_t size, size_t *len)
+ {
+@@ -102,10 +90,6 @@ static inline bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool sysl
+ 	return false;
+ }
+ 
+-static inline void kmsg_dump_rewind_nolock(struct kmsg_dumper_iter *iter)
+-{
+-}
+-
+ static inline void kmsg_dump_rewind(struct kmsg_dumper_iter *iter)
+ {
+ }
+diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
+index 048baadd7a41..1f5c577b926e 100644
+--- a/kernel/debug/kdb/kdb_main.c
++++ b/kernel/debug/kdb/kdb_main.c
+@@ -2182,8 +2182,8 @@ static int kdb_dmesg(int argc, const char **argv)
+ 		kdb_set(2, setargs);
+ 	}
+ 
+-	kmsg_dump_rewind_nolock(&iter);
+-	while (kmsg_dump_get_line_nolock(&iter, 1, NULL, 0, NULL))
++	kmsg_dump_rewind(&iter);
++	while (kmsg_dump_get_line(&iter, 1, NULL, 0, NULL))
+ 		n++;
+ 
+ 	if (lines < 0) {
+@@ -2215,8 +2215,8 @@ static int kdb_dmesg(int argc, const char **argv)
+ 	if (skip >= n || skip < 0)
+ 		return 0;
+ 
+-	kmsg_dump_rewind_nolock(&iter);
+-	while (kmsg_dump_get_line_nolock(&iter, 1, buf, sizeof(buf), &len)) {
++	kmsg_dump_rewind(&iter);
++	while (kmsg_dump_get_line(&iter, 1, buf, sizeof(buf), &len)) {
+ 		if (skip) {
+ 			skip--;
+ 			continue;
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index dde1696d7564..031ce3f00141 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -3387,7 +3387,7 @@ void kmsg_dump(enum kmsg_dump_reason reason)
+ }
+ 
+ /**
+- * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version)
++ * kmsg_dump_get_line - retrieve one kmsg log line
+  * @iter: kmsg dumper iterator
+  * @syslog: include the "<4>" prefixes
+  * @line: buffer to copy the line to
+@@ -3402,18 +3402,18 @@ void kmsg_dump(enum kmsg_dump_reason reason)
+  *
+  * A return value of FALSE indicates that there are no more records to
+  * read.
+- *
+- * The function is similar to kmsg_dump_get_line(), but grabs no locks.
+  */
+-bool kmsg_dump_get_line_nolock(struct kmsg_dumper_iter *iter, bool syslog,
+-			       char *line, size_t size, size_t *len)
++bool kmsg_dump_get_line(struct kmsg_dumper_iter *iter, bool syslog,
++			char *line, size_t size, size_t *len)
+ {
+ 	struct printk_info info;
+ 	unsigned int line_count;
+ 	struct printk_record r;
++	unsigned long flags;
+ 	size_t l = 0;
+ 	bool ret = false;
+ 
++	printk_safe_enter_irqsave(flags);
+ 	prb_rec_init_rd(&r, &info, line, size);
+ 
+ 	if (!iter->active)
+@@ -3437,40 +3437,11 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dumper_iter *iter, bool syslog,
+ 	iter->cur_seq = r.info->seq + 1;
+ 	ret = true;
+ out:
++	printk_safe_exit_irqrestore(flags);
+ 	if (len)
+ 		*len = l;
+ 	return ret;
+ }
+-
+-/**
+- * kmsg_dump_get_line - retrieve one kmsg log line
+- * @iter: kmsg dumper iterator
+- * @syslog: include the "<4>" prefixes
+- * @line: buffer to copy the line to
+- * @size: maximum size of the buffer
+- * @len: length of line placed into buffer
+- *
+- * Start at the beginning of the kmsg buffer, with the oldest kmsg
+- * record, and copy one record into the provided buffer.
+- *
+- * Consecutive calls will return the next available record moving
+- * towards the end of the buffer with the youngest messages.
+- *
+- * A return value of FALSE indicates that there are no more records to
+- * read.
+- */
+-bool kmsg_dump_get_line(struct kmsg_dumper_iter *iter, bool syslog,
+-			char *line, size_t size, size_t *len)
+-{
+-	unsigned long flags;
+-	bool ret;
+-
+-	printk_safe_enter_irqsave(flags);
+-	ret = kmsg_dump_get_line_nolock(iter, syslog, line, size, len);
+-	printk_safe_exit_irqrestore(flags);
+-
+-	return ret;
+-}
+ EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
+ 
+ /**
+@@ -3559,22 +3530,6 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog,
+ }
+ EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
+ 
+-/**
+- * kmsg_dump_rewind_nolock - reset the iterator (unlocked version)
+- * @iter: kmsg dumper iterator
+- *
+- * Reset the dumper's iterator so that kmsg_dump_get_line() and
+- * kmsg_dump_get_buffer() can be called again and used multiple
+- * times within the same dumper.dump() callback.
+- *
+- * The function is similar to kmsg_dump_rewind(), but grabs no locks.
+- */
+-void kmsg_dump_rewind_nolock(struct kmsg_dumper_iter *iter)
+-{
+-	iter->cur_seq = latched_seq_read_nolock(&clear_seq);
+-	iter->next_seq = prb_next_seq(prb);
+-}
+-
+ /**
+  * kmsg_dump_rewind - reset the iterator
+  * @iter: kmsg dumper iterator
+@@ -3588,7 +3543,8 @@ void kmsg_dump_rewind(struct kmsg_dumper_iter *iter)
+ 	unsigned long flags;
+ 
+ 	printk_safe_enter_irqsave(flags);
+-	kmsg_dump_rewind_nolock(iter);
++	iter->cur_seq = latched_seq_read_nolock(&clear_seq);
++	iter->next_seq = prb_next_seq(prb);
+ 	printk_safe_exit_irqrestore(flags);
+ }
+ EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0094-printk-kmsg_dump-use-kmsg_dump_rewind.patch b/debian/patches-rt/0094-printk-kmsg_dump-use-kmsg_dump_rewind.patch
new file mode 100644
index 000000000..7ff974d08
--- /dev/null
+++ b/debian/patches-rt/0094-printk-kmsg_dump-use-kmsg_dump_rewind.patch
@@ -0,0 +1,42 @@
+From 66a45e662dc7ecb7e9b519d3475c7893c0c1dc60 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Wed, 17 Feb 2021 18:23:16 +0100
+Subject: [PATCH 094/323] printk: kmsg_dump: use kmsg_dump_rewind
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+kmsg_dump() is open coding the kmsg_dump_rewind(). Call
+kmsg_dump_rewind() instead.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/printk/printk.c | 6 +-----
+ 1 file changed, 1 insertion(+), 5 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 031ce3f00141..c553b235d068 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -3356,7 +3356,6 @@ void kmsg_dump(enum kmsg_dump_reason reason)
+ {
+ 	struct kmsg_dumper_iter iter;
+ 	struct kmsg_dumper *dumper;
+-	unsigned long flags;
+ 
+ 	rcu_read_lock();
+ 	list_for_each_entry_rcu(dumper, &dump_list, list) {
+@@ -3375,10 +3374,7 @@ void kmsg_dump(enum kmsg_dump_reason reason)
+ 
+ 		/* initialize iterator with data about the stored records */
+ 		iter.active = true;
+-		printk_safe_enter_irqsave(flags);
+-		iter.cur_seq = latched_seq_read_nolock(&clear_seq);
+-		iter.next_seq = prb_next_seq(prb);
+-		printk_safe_exit_irqrestore(flags);
++		kmsg_dump_rewind(&iter);
+ 
+ 		/* invoke dumper which will iterate over records */
+ 		dumper->dump(dumper, reason, &iter);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0095-printk-console-remove-unnecessary-safe-buffer-usage.patch b/debian/patches-rt/0095-printk-console-remove-unnecessary-safe-buffer-usage.patch
new file mode 100644
index 000000000..2b93c47dd
--- /dev/null
+++ b/debian/patches-rt/0095-printk-console-remove-unnecessary-safe-buffer-usage.patch
@@ -0,0 +1,48 @@
+From 259c5c359d06d8bbbddebc6cc12fc2abc6bb2783 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Wed, 17 Feb 2021 18:28:05 +0100
+Subject: [PATCH 095/323] printk: console: remove unnecessary safe buffer usage
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Upon registering a console, safe buffers are activated when setting
+up the sequence number to replay the log. However, these are already
+protected by @console_sem and @syslog_lock. Remove the unnecessary
+safe buffer usage.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+---
+ kernel/printk/printk.c | 10 +++-------
+ 1 file changed, 3 insertions(+), 7 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index c553b235d068..aebc9e31b36a 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -2970,9 +2970,7 @@ void register_console(struct console *newcon)
+ 		/*
+ 		 * console_unlock(); will print out the buffered messages
+ 		 * for us.
+-		 */
+-		printk_safe_enter_irqsave(flags);
+-		/*
++		 *
+ 		 * We're about to replay the log buffer.  Only do this to the
+ 		 * just-registered console to avoid excessive message spam to
+ 		 * the already-registered consoles.
+@@ -2985,11 +2983,9 @@ void register_console(struct console *newcon)
+ 		exclusive_console_stop_seq = console_seq;
+ 
+ 		/* Get a consistent copy of @syslog_seq. */
+-		raw_spin_lock(&syslog_lock);
++		raw_spin_lock_irqsave(&syslog_lock, flags);
+ 		console_seq = syslog_seq;
+-		raw_spin_unlock(&syslog_lock);
+-
+-		printk_safe_exit_irqrestore(flags);
++		raw_spin_unlock_irqrestore(&syslog_lock, flags);
+ 	}
+ 	console_unlock();
+ 	console_sysfs_notify();
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0096-printk-track-limit-recursion.patch b/debian/patches-rt/0096-printk-track-limit-recursion.patch
new file mode 100644
index 000000000..ee26831be
--- /dev/null
+++ b/debian/patches-rt/0096-printk-track-limit-recursion.patch
@@ -0,0 +1,143 @@
+From 05db2b7a33a6aed0cb1ce99370c436dc2b72b521 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Fri, 11 Dec 2020 00:55:25 +0106
+Subject: [PATCH 096/323] printk: track/limit recursion
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Limit printk() recursion to 1 level. This is enough to print a
+stacktrace for the printk call, should a WARN or BUG occur.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/printk/printk.c | 74 ++++++++++++++++++++++++++++++++++++++++--
+ 1 file changed, 71 insertions(+), 3 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index aebc9e31b36a..31a2b7a116a7 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -1943,6 +1943,65 @@ static void call_console_drivers(const char *ext_text, size_t ext_len,
+ 	}
+ }
+ 
++#ifdef CONFIG_PRINTK_NMI
++#define NUM_RECURSION_CTX 2
++#else
++#define NUM_RECURSION_CTX 1
++#endif
++
++struct printk_recursion {
++	char	count[NUM_RECURSION_CTX];
++};
++
++static DEFINE_PER_CPU(struct printk_recursion, percpu_printk_recursion);
++static char printk_recursion_count[NUM_RECURSION_CTX];
++
++static char *printk_recursion_counter(void)
++{
++	struct printk_recursion *rec;
++	char *count;
++
++	if (!printk_percpu_data_ready()) {
++		count = &printk_recursion_count[0];
++	} else {
++		rec = this_cpu_ptr(&percpu_printk_recursion);
++
++		count = &rec->count[0];
++	}
++
++#ifdef CONFIG_PRINTK_NMI
++	if (in_nmi())
++		count++;
++#endif
++
++	return count;
++}
++
++static bool printk_enter_irqsave(unsigned long *flags)
++{
++	char *count;
++
++	local_irq_save(*flags);
++	count = printk_recursion_counter();
++	/* Only 1 level of recursion allowed. */
++	if (*count > 1) {
++		local_irq_restore(*flags);
++		return false;
++	}
++	(*count)++;
++
++	return true;
++}
++
++static void printk_exit_irqrestore(unsigned long flags)
++{
++	char *count;
++
++	count = printk_recursion_counter();
++	(*count)--;
++	local_irq_restore(flags);
++}
++
+ int printk_delay_msec __read_mostly;
+ 
+ static inline void printk_delay(void)
+@@ -2043,11 +2102,13 @@ int vprintk_store(int facility, int level,
+ 	struct prb_reserved_entry e;
+ 	enum log_flags lflags = 0;
+ 	struct printk_record r;
++	unsigned long irqflags;
+ 	u16 trunc_msg_len = 0;
+ 	char prefix_buf[8];
+ 	u16 reserve_size;
+ 	va_list args2;
+ 	u16 text_len;
++	int ret = 0;
+ 	u64 ts_nsec;
+ 
+ 	/*
+@@ -2058,6 +2119,9 @@ int vprintk_store(int facility, int level,
+ 	 */
+ 	ts_nsec = local_clock();
+ 
++	if (!printk_enter_irqsave(&irqflags))
++		return 0;
++
+ 	/*
+ 	 * The sprintf needs to come first since the syslog prefix might be
+ 	 * passed in as a parameter. An extra byte must be reserved so that
+@@ -2095,7 +2159,8 @@ int vprintk_store(int facility, int level,
+ 				prb_commit(&e);
+ 			}
+ 
+-			return text_len;
++			ret = text_len;
++			goto out;
+ 		}
+ 	}
+ 
+@@ -2111,7 +2176,7 @@ int vprintk_store(int facility, int level,
+ 
+ 		prb_rec_init_wr(&r, reserve_size + trunc_msg_len);
+ 		if (!prb_reserve(&e, prb, &r))
+-			return 0;
++			goto out;
+ 	}
+ 
+ 	/* fill message */
+@@ -2133,7 +2198,10 @@ int vprintk_store(int facility, int level,
+ 	else
+ 		prb_final_commit(&e);
+ 
+-	return (text_len + trunc_msg_len);
++	ret = text_len + trunc_msg_len;
++out:
++	printk_exit_irqrestore(irqflags);
++	return ret;
+ }
+ 
+ asmlinkage int vprintk_emit(int facility, int level,
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0097-printk-remove-safe-buffers.patch b/debian/patches-rt/0097-printk-remove-safe-buffers.patch
new file mode 100644
index 000000000..df3318972
--- /dev/null
+++ b/debian/patches-rt/0097-printk-remove-safe-buffers.patch
@@ -0,0 +1,877 @@
+From c0ee407b7db3b7ac5c24337a9d365a35450c233b Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 30 Nov 2020 01:42:00 +0106
+Subject: [PATCH 097/323] printk: remove safe buffers
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+With @logbuf_lock removed, the high level printk functions for
+storing messages are lockless. Messages can be stored from any
+context, so there is no need for the NMI and safe buffers anymore.
+
+Remove the NMI and safe buffers. In NMI or safe contexts, store
+the message immediately but still use irq_work to defer the console
+printing.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/powerpc/kernel/traps.c    |   1 -
+ arch/powerpc/kernel/watchdog.c |   5 -
+ include/linux/printk.h         |  10 -
+ kernel/kexec_core.c            |   1 -
+ kernel/panic.c                 |   3 -
+ kernel/printk/internal.h       |   2 -
+ kernel/printk/printk.c         |  85 ++-------
+ kernel/printk/printk_safe.c    | 329 +--------------------------------
+ lib/nmi_backtrace.c            |   6 -
+ 9 files changed, 17 insertions(+), 425 deletions(-)
+
+diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
+index 5e5a2448ae79..d39a4a6b4ddf 100644
+--- a/arch/powerpc/kernel/traps.c
++++ b/arch/powerpc/kernel/traps.c
+@@ -170,7 +170,6 @@ extern void panic_flush_kmsg_start(void)
+ 
+ extern void panic_flush_kmsg_end(void)
+ {
+-	printk_safe_flush_on_panic();
+ 	kmsg_dump(KMSG_DUMP_PANIC);
+ 	bust_spinlocks(0);
+ 	debug_locks_off();
+diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c
+index 75b2a6c4db5a..db40e20d0c54 100644
+--- a/arch/powerpc/kernel/watchdog.c
++++ b/arch/powerpc/kernel/watchdog.c
+@@ -185,11 +185,6 @@ static void watchdog_smp_panic(int cpu, u64 tb)
+ 
+ 	wd_smp_unlock(&flags);
+ 
+-	printk_safe_flush();
+-	/*
+-	 * printk_safe_flush() seems to require another print
+-	 * before anything actually goes out to console.
+-	 */
+ 	if (sysctl_hardlockup_all_cpu_backtrace)
+ 		trigger_allbutself_cpu_backtrace();
+ 
+diff --git a/include/linux/printk.h b/include/linux/printk.h
+index 344f6da3d4c3..c6bb48f0134c 100644
+--- a/include/linux/printk.h
++++ b/include/linux/printk.h
+@@ -207,8 +207,6 @@ __printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...);
+ void dump_stack_print_info(const char *log_lvl);
+ void show_regs_print_info(const char *log_lvl);
+ extern asmlinkage void dump_stack(void) __cold;
+-extern void printk_safe_flush(void);
+-extern void printk_safe_flush_on_panic(void);
+ #else
+ static inline __printf(1, 0)
+ int vprintk(const char *s, va_list args)
+@@ -272,14 +270,6 @@ static inline void show_regs_print_info(const char *log_lvl)
+ static inline void dump_stack(void)
+ {
+ }
+-
+-static inline void printk_safe_flush(void)
+-{
+-}
+-
+-static inline void printk_safe_flush_on_panic(void)
+-{
+-}
+ #endif
+ 
+ extern int kptr_restrict;
+diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
+index 3a37fc62dc95..78a1fd9c3c8a 100644
+--- a/kernel/kexec_core.c
++++ b/kernel/kexec_core.c
+@@ -978,7 +978,6 @@ void crash_kexec(struct pt_regs *regs)
+ 	old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
+ 	if (old_cpu == PANIC_CPU_INVALID) {
+ 		/* This is the 1st CPU which comes here, so go ahead. */
+-		printk_safe_flush_on_panic();
+ 		__crash_kexec(regs);
+ 
+ 		/*
+diff --git a/kernel/panic.c b/kernel/panic.c
+index bc39e2b27d31..7965f1e31224 100644
+--- a/kernel/panic.c
++++ b/kernel/panic.c
+@@ -324,7 +324,6 @@ void panic(const char *fmt, ...)
+ 	 * Bypass the panic_cpu check and call __crash_kexec directly.
+ 	 */
+ 	if (!_crash_kexec_post_notifiers) {
+-		printk_safe_flush_on_panic();
+ 		__crash_kexec(NULL);
+ 
+ 		/*
+@@ -348,8 +347,6 @@ void panic(const char *fmt, ...)
+ 	 */
+ 	atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
+ 
+-	/* Call flush even twice. It tries harder with a single online CPU */
+-	printk_safe_flush_on_panic();
+ 	kmsg_dump(KMSG_DUMP_PANIC);
+ 
+ 	/*
+diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
+index e7acc2888c8e..e108b2ece8c7 100644
+--- a/kernel/printk/internal.h
++++ b/kernel/printk/internal.h
+@@ -23,7 +23,6 @@ __printf(1, 0) int vprintk_func(const char *fmt, va_list args);
+ void __printk_safe_enter(void);
+ void __printk_safe_exit(void);
+ 
+-void printk_safe_init(void);
+ bool printk_percpu_data_ready(void);
+ 
+ #define printk_safe_enter_irqsave(flags)	\
+@@ -67,6 +66,5 @@ __printf(1, 0) int vprintk_func(const char *fmt, va_list args) { return 0; }
+ #define printk_safe_enter_irq() local_irq_disable()
+ #define printk_safe_exit_irq() local_irq_enable()
+ 
+-static inline void printk_safe_init(void) { }
+ static inline bool printk_percpu_data_ready(void) { return false; }
+ #endif /* CONFIG_PRINTK */
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 31a2b7a116a7..90a4cf4c23a4 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -735,27 +735,22 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
+ 	if (ret)
+ 		return ret;
+ 
+-	printk_safe_enter_irq();
+ 	if (!prb_read_valid(prb, atomic64_read(&user->seq), r)) {
+ 		if (file->f_flags & O_NONBLOCK) {
+ 			ret = -EAGAIN;
+-			printk_safe_exit_irq();
+ 			goto out;
+ 		}
+ 
+-		printk_safe_exit_irq();
+ 		ret = wait_event_interruptible(log_wait,
+ 				prb_read_valid(prb, atomic64_read(&user->seq), r));
+ 		if (ret)
+ 			goto out;
+-		printk_safe_enter_irq();
+ 	}
+ 
+ 	if (r->info->seq != atomic64_read(&user->seq)) {
+ 		/* our last seen message is gone, return error and reset */
+ 		atomic64_set(&user->seq, r->info->seq);
+ 		ret = -EPIPE;
+-		printk_safe_exit_irq();
+ 		goto out;
+ 	}
+ 
+@@ -765,7 +760,6 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
+ 				  &r->info->dev_info);
+ 
+ 	atomic64_set(&user->seq, r->info->seq + 1);
+-	printk_safe_exit_irq();
+ 
+ 	if (len > count) {
+ 		ret = -EINVAL;
+@@ -800,7 +794,6 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
+ 	if (offset)
+ 		return -ESPIPE;
+ 
+-	printk_safe_enter_irq();
+ 	switch (whence) {
+ 	case SEEK_SET:
+ 		/* the first record */
+@@ -821,7 +814,6 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
+ 	default:
+ 		ret = -EINVAL;
+ 	}
+-	printk_safe_exit_irq();
+ 	return ret;
+ }
+ 
+@@ -836,7 +828,6 @@ static __poll_t devkmsg_poll(struct file *file, poll_table *wait)
+ 
+ 	poll_wait(file, &log_wait, wait);
+ 
+-	printk_safe_enter_irq();
+ 	if (prb_read_valid_info(prb, atomic64_read(&user->seq), &info, NULL)) {
+ 		/* return error when data has vanished underneath us */
+ 		if (info.seq != atomic64_read(&user->seq))
+@@ -844,7 +835,6 @@ static __poll_t devkmsg_poll(struct file *file, poll_table *wait)
+ 		else
+ 			ret = EPOLLIN|EPOLLRDNORM;
+ 	}
+-	printk_safe_exit_irq();
+ 
+ 	return ret;
+ }
+@@ -877,9 +867,7 @@ static int devkmsg_open(struct inode *inode, struct file *file)
+ 	prb_rec_init_rd(&user->record, &user->info,
+ 			&user->text_buf[0], sizeof(user->text_buf));
+ 
+-	printk_safe_enter_irq();
+ 	atomic64_set(&user->seq, prb_first_valid_seq(prb));
+-	printk_safe_exit_irq();
+ 
+ 	file->private_data = user;
+ 	return 0;
+@@ -1045,9 +1033,6 @@ static inline void log_buf_add_cpu(void) {}
+ 
+ static void __init set_percpu_data_ready(void)
+ {
+-	printk_safe_init();
+-	/* Make sure we set this flag only after printk_safe() init is done */
+-	barrier();
+ 	__printk_percpu_data_ready = true;
+ }
+ 
+@@ -1145,8 +1130,6 @@ void __init setup_log_buf(int early)
+ 		 new_descs, ilog2(new_descs_count),
+ 		 new_infos);
+ 
+-	printk_safe_enter_irqsave(flags);
+-
+ 	log_buf_len = new_log_buf_len;
+ 	log_buf = new_log_buf;
+ 	new_log_buf_len = 0;
+@@ -1162,8 +1145,6 @@ void __init setup_log_buf(int early)
+ 	 */
+ 	prb = &printk_rb_dynamic;
+ 
+-	printk_safe_exit_irqrestore(flags);
+-
+ 	if (seq != prb_next_seq(&printk_rb_static)) {
+ 		pr_err("dropped %llu messages\n",
+ 		       prb_next_seq(&printk_rb_static) - seq);
+@@ -1501,11 +1482,9 @@ static int syslog_print(char __user *buf, int size)
+ 		size_t n;
+ 		size_t skip;
+ 
+-		printk_safe_enter_irq();
+-		raw_spin_lock(&syslog_lock);
++		raw_spin_lock_irq(&syslog_lock);
+ 		if (!prb_read_valid(prb, syslog_seq, &r)) {
+-			raw_spin_unlock(&syslog_lock);
+-			printk_safe_exit_irq();
++			raw_spin_unlock_irq(&syslog_lock);
+ 			break;
+ 		}
+ 		if (r.info->seq != syslog_seq) {
+@@ -1534,8 +1513,7 @@ static int syslog_print(char __user *buf, int size)
+ 			syslog_partial += n;
+ 		} else
+ 			n = 0;
+-		raw_spin_unlock(&syslog_lock);
+-		printk_safe_exit_irq();
++		raw_spin_unlock_irq(&syslog_lock);
+ 
+ 		if (!n)
+ 			break;
+@@ -1569,7 +1547,6 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 		return -ENOMEM;
+ 
+ 	time = printk_time;
+-	printk_safe_enter_irq();
+ 	/*
+ 	 * Find first record that fits, including all following records,
+ 	 * into the user-provided buffer for this dump.
+@@ -1590,23 +1567,20 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 			break;
+ 		}
+ 
+-		printk_safe_exit_irq();
+ 		if (copy_to_user(buf + len, text, textlen))
+ 			len = -EFAULT;
+ 		else
+ 			len += textlen;
+-		printk_safe_enter_irq();
+ 
+ 		if (len < 0)
+ 			break;
+ 	}
+ 
+ 	if (clear) {
+-		raw_spin_lock(&syslog_lock);
++		raw_spin_lock_irq(&syslog_lock);
+ 		latched_seq_write(&clear_seq, seq);
+-		raw_spin_unlock(&syslog_lock);
++		raw_spin_unlock_irq(&syslog_lock);
+ 	}
+-	printk_safe_exit_irq();
+ 
+ 	kfree(text);
+ 	return len;
+@@ -1614,11 +1588,9 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 
+ static void syslog_clear(void)
+ {
+-	printk_safe_enter_irq();
+-	raw_spin_lock(&syslog_lock);
++	raw_spin_lock_irq(&syslog_lock);
+ 	latched_seq_write(&clear_seq, prb_next_seq(prb));
+-	raw_spin_unlock(&syslog_lock);
+-	printk_safe_exit_irq();
++	raw_spin_unlock_irq(&syslog_lock);
+ }
+ 
+ /* Return a consistent copy of @syslog_seq. */
+@@ -1706,12 +1678,10 @@ int do_syslog(int type, char __user *buf, int len, int source)
+ 		break;
+ 	/* Number of chars in the log buffer */
+ 	case SYSLOG_ACTION_SIZE_UNREAD:
+-		printk_safe_enter_irq();
+-		raw_spin_lock(&syslog_lock);
++		raw_spin_lock_irq(&syslog_lock);
+ 		if (!prb_read_valid_info(prb, syslog_seq, &info, NULL)) {
+ 			/* No unread messages. */
+-			raw_spin_unlock(&syslog_lock);
+-			printk_safe_exit_irq();
++			raw_spin_unlock_irq(&syslog_lock);
+ 			return 0;
+ 		}
+ 		if (info.seq != syslog_seq) {
+@@ -1739,8 +1709,7 @@ int do_syslog(int type, char __user *buf, int len, int source)
+ 			}
+ 			error -= syslog_partial;
+ 		}
+-		raw_spin_unlock(&syslog_lock);
+-		printk_safe_exit_irq();
++		raw_spin_unlock_irq(&syslog_lock);
+ 		break;
+ 	/* Size of the log buffer */
+ 	case SYSLOG_ACTION_SIZE_BUFFER:
+@@ -2210,7 +2179,6 @@ asmlinkage int vprintk_emit(int facility, int level,
+ {
+ 	int printed_len;
+ 	bool in_sched = false;
+-	unsigned long flags;
+ 
+ 	/* Suppress unimportant messages after panic happens */
+ 	if (unlikely(suppress_printk))
+@@ -2224,9 +2192,7 @@ asmlinkage int vprintk_emit(int facility, int level,
+ 	boot_delay_msec(level);
+ 	printk_delay();
+ 
+-	printk_safe_enter_irqsave(flags);
+ 	printed_len = vprintk_store(facility, level, dev_info, fmt, args);
+-	printk_safe_exit_irqrestore(flags);
+ 
+ 	/* If called from the scheduler, we can not call up(). */
+ 	if (!in_sched) {
+@@ -2618,7 +2584,6 @@ void console_unlock(void)
+ {
+ 	static char ext_text[CONSOLE_EXT_LOG_MAX];
+ 	static char text[CONSOLE_LOG_MAX];
+-	unsigned long flags;
+ 	bool do_cond_resched, retry;
+ 	struct printk_info info;
+ 	struct printk_record r;
+@@ -2663,7 +2628,6 @@ void console_unlock(void)
+ 		size_t ext_len = 0;
+ 		size_t len;
+ 
+-		printk_safe_enter_irqsave(flags);
+ skip:
+ 		if (!prb_read_valid(prb, console_seq, &r))
+ 			break;
+@@ -2720,12 +2684,8 @@ void console_unlock(void)
+ 		call_console_drivers(ext_text, ext_len, text, len);
+ 		start_critical_timings();
+ 
+-		if (console_lock_spinning_disable_and_check()) {
+-			printk_safe_exit_irqrestore(flags);
++		if (console_lock_spinning_disable_and_check())
+ 			return;
+-		}
+-
+-		printk_safe_exit_irqrestore(flags);
+ 
+ 		if (do_cond_resched)
+ 			cond_resched();
+@@ -2742,8 +2702,6 @@ void console_unlock(void)
+ 	 * flush, no worries.
+ 	 */
+ 	retry = prb_read_valid(prb, console_seq, NULL);
+-	printk_safe_exit_irqrestore(flags);
+-
+ 	if (retry && console_trylock())
+ 		goto again;
+ }
+@@ -2805,13 +2763,8 @@ void console_flush_on_panic(enum con_flush_mode mode)
+ 	console_trylock();
+ 	console_may_schedule = 0;
+ 
+-	if (mode == CONSOLE_REPLAY_ALL) {
+-		unsigned long flags;
+-
+-		printk_safe_enter_irqsave(flags);
++	if (mode == CONSOLE_REPLAY_ALL)
+ 		console_seq = prb_first_valid_seq(prb);
+-		printk_safe_exit_irqrestore(flags);
+-	}
+ 	console_unlock();
+ }
+ 
+@@ -3469,11 +3422,9 @@ bool kmsg_dump_get_line(struct kmsg_dumper_iter *iter, bool syslog,
+ 	struct printk_info info;
+ 	unsigned int line_count;
+ 	struct printk_record r;
+-	unsigned long flags;
+ 	size_t l = 0;
+ 	bool ret = false;
+ 
+-	printk_safe_enter_irqsave(flags);
+ 	prb_rec_init_rd(&r, &info, line, size);
+ 
+ 	if (!iter->active)
+@@ -3497,7 +3448,6 @@ bool kmsg_dump_get_line(struct kmsg_dumper_iter *iter, bool syslog,
+ 	iter->cur_seq = r.info->seq + 1;
+ 	ret = true;
+ out:
+-	printk_safe_exit_irqrestore(flags);
+ 	if (len)
+ 		*len = l;
+ 	return ret;
+@@ -3528,7 +3478,6 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog,
+ {
+ 	struct printk_info info;
+ 	struct printk_record r;
+-	unsigned long flags;
+ 	u64 seq;
+ 	u64 next_seq;
+ 	size_t len = 0;
+@@ -3538,7 +3487,6 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog,
+ 	if (!iter->active || !buf || !size)
+ 		goto out;
+ 
+-	printk_safe_enter_irqsave(flags);
+ 	if (prb_read_valid_info(prb, iter->cur_seq, &info, NULL)) {
+ 		if (info.seq != iter->cur_seq) {
+ 			/* messages are gone, move to first available one */
+@@ -3547,10 +3495,8 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog,
+ 	}
+ 
+ 	/* last entry */
+-	if (iter->cur_seq >= iter->next_seq) {
+-		printk_safe_exit_irqrestore(flags);
++	if (iter->cur_seq >= iter->next_seq)
+ 		goto out;
+-	}
+ 
+ 	/*
+ 	 * Find first record that fits, including all following records,
+@@ -3582,7 +3528,6 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper_iter *iter, bool syslog,
+ 
+ 	iter->next_seq = next_seq;
+ 	ret = true;
+-	printk_safe_exit_irqrestore(flags);
+ out:
+ 	if (len_out)
+ 		*len_out = len;
+@@ -3600,12 +3545,8 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
+  */
+ void kmsg_dump_rewind(struct kmsg_dumper_iter *iter)
+ {
+-	unsigned long flags;
+-
+-	printk_safe_enter_irqsave(flags);
+ 	iter->cur_seq = latched_seq_read_nolock(&clear_seq);
+ 	iter->next_seq = prb_next_seq(prb);
+-	printk_safe_exit_irqrestore(flags);
+ }
+ EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
+ 
+diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
+index 7df8a88d4115..c23b127a6545 100644
+--- a/kernel/printk/printk_safe.c
++++ b/kernel/printk/printk_safe.c
+@@ -15,282 +15,9 @@
+ 
+ #include "internal.h"
+ 
+-/*
+- * In NMI and safe mode, printk() avoids taking locks. Instead,
+- * it uses an alternative implementation that temporary stores
+- * the strings into a per-CPU buffer. The content of the buffer
+- * is later flushed into the main ring buffer via IRQ work.
+- *
+- * The alternative implementation is chosen transparently
+- * by examining current printk() context mask stored in @printk_context
+- * per-CPU variable.
+- *
+- * The implementation allows to flush the strings also from another CPU.
+- * There are situations when we want to make sure that all buffers
+- * were handled or when IRQs are blocked.
+- */
+-
+-#define SAFE_LOG_BUF_LEN ((1 << CONFIG_PRINTK_SAFE_LOG_BUF_SHIFT) -	\
+-				sizeof(atomic_t) -			\
+-				sizeof(atomic_t) -			\
+-				sizeof(struct irq_work))
+-
+-struct printk_safe_seq_buf {
+-	atomic_t		len;	/* length of written data */
+-	atomic_t		message_lost;
+-	struct irq_work		work;	/* IRQ work that flushes the buffer */
+-	unsigned char		buffer[SAFE_LOG_BUF_LEN];
+-};
+-
+-static DEFINE_PER_CPU(struct printk_safe_seq_buf, safe_print_seq);
+ static DEFINE_PER_CPU(int, printk_context);
+ 
+-static DEFINE_RAW_SPINLOCK(safe_read_lock);
+-
+-#ifdef CONFIG_PRINTK_NMI
+-static DEFINE_PER_CPU(struct printk_safe_seq_buf, nmi_print_seq);
+-#endif
+-
+-/* Get flushed in a more safe context. */
+-static void queue_flush_work(struct printk_safe_seq_buf *s)
+-{
+-	if (printk_percpu_data_ready())
+-		irq_work_queue(&s->work);
+-}
+-
+-/*
+- * Add a message to per-CPU context-dependent buffer. NMI and printk-safe
+- * have dedicated buffers, because otherwise printk-safe preempted by
+- * NMI-printk would have overwritten the NMI messages.
+- *
+- * The messages are flushed from irq work (or from panic()), possibly,
+- * from other CPU, concurrently with printk_safe_log_store(). Should this
+- * happen, printk_safe_log_store() will notice the buffer->len mismatch
+- * and repeat the write.
+- */
+-static __printf(2, 0) int printk_safe_log_store(struct printk_safe_seq_buf *s,
+-						const char *fmt, va_list args)
+-{
+-	int add;
+-	size_t len;
+-	va_list ap;
+-
+-again:
+-	len = atomic_read(&s->len);
+-
+-	/* The trailing '\0' is not counted into len. */
+-	if (len >= sizeof(s->buffer) - 1) {
+-		atomic_inc(&s->message_lost);
+-		queue_flush_work(s);
+-		return 0;
+-	}
+-
+-	/*
+-	 * Make sure that all old data have been read before the buffer
+-	 * was reset. This is not needed when we just append data.
+-	 */
+-	if (!len)
+-		smp_rmb();
+-
+-	va_copy(ap, args);
+-	add = vscnprintf(s->buffer + len, sizeof(s->buffer) - len, fmt, ap);
+-	va_end(ap);
+-	if (!add)
+-		return 0;
+-
+-	/*
+-	 * Do it once again if the buffer has been flushed in the meantime.
+-	 * Note that atomic_cmpxchg() is an implicit memory barrier that
+-	 * makes sure that the data were written before updating s->len.
+-	 */
+-	if (atomic_cmpxchg(&s->len, len, len + add) != len)
+-		goto again;
+-
+-	queue_flush_work(s);
+-	return add;
+-}
+-
+-static inline void printk_safe_flush_line(const char *text, int len)
+-{
+-	/*
+-	 * Avoid any console drivers calls from here, because we may be
+-	 * in NMI or printk_safe context (when in panic). The messages
+-	 * must go only into the ring buffer at this stage.  Consoles will
+-	 * get explicitly called later when a crashdump is not generated.
+-	 */
+-	printk_deferred("%.*s", len, text);
+-}
+-
+-/* printk part of the temporary buffer line by line */
+-static int printk_safe_flush_buffer(const char *start, size_t len)
+-{
+-	const char *c, *end;
+-	bool header;
+-
+-	c = start;
+-	end = start + len;
+-	header = true;
+-
+-	/* Print line by line. */
+-	while (c < end) {
+-		if (*c == '\n') {
+-			printk_safe_flush_line(start, c - start + 1);
+-			start = ++c;
+-			header = true;
+-			continue;
+-		}
+-
+-		/* Handle continuous lines or missing new line. */
+-		if ((c + 1 < end) && printk_get_level(c)) {
+-			if (header) {
+-				c = printk_skip_level(c);
+-				continue;
+-			}
+-
+-			printk_safe_flush_line(start, c - start);
+-			start = c++;
+-			header = true;
+-			continue;
+-		}
+-
+-		header = false;
+-		c++;
+-	}
+-
+-	/* Check if there was a partial line. Ignore pure header. */
+-	if (start < end && !header) {
+-		static const char newline[] = KERN_CONT "\n";
+-
+-		printk_safe_flush_line(start, end - start);
+-		printk_safe_flush_line(newline, strlen(newline));
+-	}
+-
+-	return len;
+-}
+-
+-static void report_message_lost(struct printk_safe_seq_buf *s)
+-{
+-	int lost = atomic_xchg(&s->message_lost, 0);
+-
+-	if (lost)
+-		printk_deferred("Lost %d message(s)!\n", lost);
+-}
+-
+-/*
+- * Flush data from the associated per-CPU buffer. The function
+- * can be called either via IRQ work or independently.
+- */
+-static void __printk_safe_flush(struct irq_work *work)
+-{
+-	struct printk_safe_seq_buf *s =
+-		container_of(work, struct printk_safe_seq_buf, work);
+-	unsigned long flags;
+-	size_t len;
+-	int i;
+-
+-	/*
+-	 * The lock has two functions. First, one reader has to flush all
+-	 * available message to make the lockless synchronization with
+-	 * writers easier. Second, we do not want to mix messages from
+-	 * different CPUs. This is especially important when printing
+-	 * a backtrace.
+-	 */
+-	raw_spin_lock_irqsave(&safe_read_lock, flags);
+-
+-	i = 0;
+-more:
+-	len = atomic_read(&s->len);
+-
+-	/*
+-	 * This is just a paranoid check that nobody has manipulated
+-	 * the buffer an unexpected way. If we printed something then
+-	 * @len must only increase. Also it should never overflow the
+-	 * buffer size.
+-	 */
+-	if ((i && i >= len) || len > sizeof(s->buffer)) {
+-		const char *msg = "printk_safe_flush: internal error\n";
+-
+-		printk_safe_flush_line(msg, strlen(msg));
+-		len = 0;
+-	}
+-
+-	if (!len)
+-		goto out; /* Someone else has already flushed the buffer. */
+-
+-	/* Make sure that data has been written up to the @len */
+-	smp_rmb();
+-	i += printk_safe_flush_buffer(s->buffer + i, len - i);
+-
+-	/*
+-	 * Check that nothing has got added in the meantime and truncate
+-	 * the buffer. Note that atomic_cmpxchg() is an implicit memory
+-	 * barrier that makes sure that the data were copied before
+-	 * updating s->len.
+-	 */
+-	if (atomic_cmpxchg(&s->len, len, 0) != len)
+-		goto more;
+-
+-out:
+-	report_message_lost(s);
+-	raw_spin_unlock_irqrestore(&safe_read_lock, flags);
+-}
+-
+-/**
+- * printk_safe_flush - flush all per-cpu nmi buffers.
+- *
+- * The buffers are flushed automatically via IRQ work. This function
+- * is useful only when someone wants to be sure that all buffers have
+- * been flushed at some point.
+- */
+-void printk_safe_flush(void)
+-{
+-	int cpu;
+-
+-	for_each_possible_cpu(cpu) {
+-#ifdef CONFIG_PRINTK_NMI
+-		__printk_safe_flush(&per_cpu(nmi_print_seq, cpu).work);
+-#endif
+-		__printk_safe_flush(&per_cpu(safe_print_seq, cpu).work);
+-	}
+-}
+-
+-/**
+- * printk_safe_flush_on_panic - flush all per-cpu nmi buffers when the system
+- *	goes down.
+- *
+- * Similar to printk_safe_flush() but it can be called even in NMI context when
+- * the system goes down. It does the best effort to get NMI messages into
+- * the main ring buffer.
+- *
+- * Note that it could try harder when there is only one CPU online.
+- */
+-void printk_safe_flush_on_panic(void)
+-{
+-	if (raw_spin_is_locked(&safe_read_lock)) {
+-		if (num_online_cpus() > 1)
+-			return;
+-
+-		debug_locks_off();
+-		raw_spin_lock_init(&safe_read_lock);
+-	}
+-
+-	printk_safe_flush();
+-}
+-
+ #ifdef CONFIG_PRINTK_NMI
+-/*
+- * Safe printk() for NMI context. It uses a per-CPU buffer to
+- * store the message. NMIs are not nested, so there is always only
+- * one writer running. But the buffer might get flushed from another
+- * CPU, so we need to be careful.
+- */
+-static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args)
+-{
+-	struct printk_safe_seq_buf *s = this_cpu_ptr(&nmi_print_seq);
+-
+-	return printk_safe_log_store(s, fmt, args);
+-}
+-
+ void noinstr printk_nmi_enter(void)
+ {
+ 	this_cpu_add(printk_context, PRINTK_NMI_CONTEXT_OFFSET);
+@@ -305,9 +32,6 @@ void noinstr printk_nmi_exit(void)
+  * Marks a code that might produce many messages in NMI context
+  * and the risk of losing them is more critical than eventual
+  * reordering.
+- *
+- * It has effect only when called in NMI context. Then printk()
+- * will store the messages into the main logbuf directly.
+  */
+ void printk_nmi_direct_enter(void)
+ {
+@@ -320,27 +44,8 @@ void printk_nmi_direct_exit(void)
+ 	this_cpu_and(printk_context, ~PRINTK_NMI_DIRECT_CONTEXT_MASK);
+ }
+ 
+-#else
+-
+-static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args)
+-{
+-	return 0;
+-}
+-
+ #endif /* CONFIG_PRINTK_NMI */
+ 
+-/*
+- * Lock-less printk(), to avoid deadlocks should the printk() recurse
+- * into itself. It uses a per-CPU buffer to store the message, just like
+- * NMI.
+- */
+-static __printf(1, 0) int vprintk_safe(const char *fmt, va_list args)
+-{
+-	struct printk_safe_seq_buf *s = this_cpu_ptr(&safe_print_seq);
+-
+-	return printk_safe_log_store(s, fmt, args);
+-}
+-
+ /* Can be preempted by NMI. */
+ void __printk_safe_enter(void)
+ {
+@@ -365,8 +70,10 @@ __printf(1, 0) int vprintk_func(const char *fmt, va_list args)
+ 	 * Use the main logbuf even in NMI. But avoid calling console
+ 	 * drivers that might have their own locks.
+ 	 */
+-	if ((this_cpu_read(printk_context) & PRINTK_NMI_DIRECT_CONTEXT_MASK)) {
+-		unsigned long flags;
++	if (this_cpu_read(printk_context) &
++	    (PRINTK_NMI_DIRECT_CONTEXT_MASK |
++	     PRINTK_NMI_CONTEXT_MASK |
++	     PRINTK_SAFE_CONTEXT_MASK)) {
+ 		int len;
+ 
+ 		printk_safe_enter_irqsave(flags);
+@@ -376,34 +83,6 @@ __printf(1, 0) int vprintk_func(const char *fmt, va_list args)
+ 		return len;
+ 	}
+ 
+-	/* Use extra buffer in NMI. */
+-	if (this_cpu_read(printk_context) & PRINTK_NMI_CONTEXT_MASK)
+-		return vprintk_nmi(fmt, args);
+-
+-	/* Use extra buffer to prevent a recursion deadlock in safe mode. */
+-	if (this_cpu_read(printk_context) & PRINTK_SAFE_CONTEXT_MASK)
+-		return vprintk_safe(fmt, args);
+-
+ 	/* No obstacles. */
+ 	return vprintk_default(fmt, args);
+ }
+-
+-void __init printk_safe_init(void)
+-{
+-	int cpu;
+-
+-	for_each_possible_cpu(cpu) {
+-		struct printk_safe_seq_buf *s;
+-
+-		s = &per_cpu(safe_print_seq, cpu);
+-		init_irq_work(&s->work, __printk_safe_flush);
+-
+-#ifdef CONFIG_PRINTK_NMI
+-		s = &per_cpu(nmi_print_seq, cpu);
+-		init_irq_work(&s->work, __printk_safe_flush);
+-#endif
+-	}
+-
+-	/* Flush pending messages that did not have scheduled IRQ works. */
+-	printk_safe_flush();
+-}
+diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c
+index 8abe1870dba4..b09a490f5f70 100644
+--- a/lib/nmi_backtrace.c
++++ b/lib/nmi_backtrace.c
+@@ -75,12 +75,6 @@ void nmi_trigger_cpumask_backtrace(const cpumask_t *mask,
+ 		touch_softlockup_watchdog();
+ 	}
+ 
+-	/*
+-	 * Force flush any remote buffers that might be stuck in IRQ context
+-	 * and therefore could not run their irq_work.
+-	 */
+-	printk_safe_flush();
+-
+ 	clear_bit_unlock(0, &backtrace_flag);
+ 	put_cpu();
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0098-printk-convert-syslog_lock-to-spin_lock.patch b/debian/patches-rt/0098-printk-convert-syslog_lock-to-spin_lock.patch
new file mode 100644
index 000000000..639c0cf84
--- /dev/null
+++ b/debian/patches-rt/0098-printk-convert-syslog_lock-to-spin_lock.patch
@@ -0,0 +1,119 @@
+From 8e6eb9e51cf4c4efeeb61910c35b01dcce2ec502 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Thu, 18 Feb 2021 17:37:41 +0100
+Subject: [PATCH 098/323] printk: convert @syslog_lock to spin_lock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/printk/printk.c | 30 +++++++++++++++---------------
+ 1 file changed, 15 insertions(+), 15 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 90a4cf4c23a4..57f3b8d7f35c 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -358,7 +358,7 @@ enum log_flags {
+ };
+ 
+ /* syslog_lock protects syslog_* variables and write access to clear_seq. */
+-static DEFINE_RAW_SPINLOCK(syslog_lock);
++static DEFINE_SPINLOCK(syslog_lock);
+ 
+ #ifdef CONFIG_PRINTK
+ DECLARE_WAIT_QUEUE_HEAD(log_wait);
+@@ -1482,9 +1482,9 @@ static int syslog_print(char __user *buf, int size)
+ 		size_t n;
+ 		size_t skip;
+ 
+-		raw_spin_lock_irq(&syslog_lock);
++		spin_lock_irq(&syslog_lock);
+ 		if (!prb_read_valid(prb, syslog_seq, &r)) {
+-			raw_spin_unlock_irq(&syslog_lock);
++			spin_unlock_irq(&syslog_lock);
+ 			break;
+ 		}
+ 		if (r.info->seq != syslog_seq) {
+@@ -1513,7 +1513,7 @@ static int syslog_print(char __user *buf, int size)
+ 			syslog_partial += n;
+ 		} else
+ 			n = 0;
+-		raw_spin_unlock_irq(&syslog_lock);
++		spin_unlock_irq(&syslog_lock);
+ 
+ 		if (!n)
+ 			break;
+@@ -1577,9 +1577,9 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 	}
+ 
+ 	if (clear) {
+-		raw_spin_lock_irq(&syslog_lock);
++		spin_lock_irq(&syslog_lock);
+ 		latched_seq_write(&clear_seq, seq);
+-		raw_spin_unlock_irq(&syslog_lock);
++		spin_unlock_irq(&syslog_lock);
+ 	}
+ 
+ 	kfree(text);
+@@ -1588,9 +1588,9 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
+ 
+ static void syslog_clear(void)
+ {
+-	raw_spin_lock_irq(&syslog_lock);
++	spin_lock_irq(&syslog_lock);
+ 	latched_seq_write(&clear_seq, prb_next_seq(prb));
+-	raw_spin_unlock_irq(&syslog_lock);
++	spin_unlock_irq(&syslog_lock);
+ }
+ 
+ /* Return a consistent copy of @syslog_seq. */
+@@ -1598,9 +1598,9 @@ static u64 read_syslog_seq_irq(void)
+ {
+ 	u64 seq;
+ 
+-	raw_spin_lock_irq(&syslog_lock);
++	spin_lock_irq(&syslog_lock);
+ 	seq = syslog_seq;
+-	raw_spin_unlock_irq(&syslog_lock);
++	spin_unlock_irq(&syslog_lock);
+ 
+ 	return seq;
+ }
+@@ -1678,10 +1678,10 @@ int do_syslog(int type, char __user *buf, int len, int source)
+ 		break;
+ 	/* Number of chars in the log buffer */
+ 	case SYSLOG_ACTION_SIZE_UNREAD:
+-		raw_spin_lock_irq(&syslog_lock);
++		spin_lock_irq(&syslog_lock);
+ 		if (!prb_read_valid_info(prb, syslog_seq, &info, NULL)) {
+ 			/* No unread messages. */
+-			raw_spin_unlock_irq(&syslog_lock);
++			spin_unlock_irq(&syslog_lock);
+ 			return 0;
+ 		}
+ 		if (info.seq != syslog_seq) {
+@@ -1709,7 +1709,7 @@ int do_syslog(int type, char __user *buf, int len, int source)
+ 			}
+ 			error -= syslog_partial;
+ 		}
+-		raw_spin_unlock_irq(&syslog_lock);
++		spin_unlock_irq(&syslog_lock);
+ 		break;
+ 	/* Size of the log buffer */
+ 	case SYSLOG_ACTION_SIZE_BUFFER:
+@@ -3004,9 +3004,9 @@ void register_console(struct console *newcon)
+ 		exclusive_console_stop_seq = console_seq;
+ 
+ 		/* Get a consistent copy of @syslog_seq. */
+-		raw_spin_lock_irqsave(&syslog_lock, flags);
++		spin_lock_irqsave(&syslog_lock, flags);
+ 		console_seq = syslog_seq;
+-		raw_spin_unlock_irqrestore(&syslog_lock, flags);
++		spin_unlock_irqrestore(&syslog_lock, flags);
+ 	}
+ 	console_unlock();
+ 	console_sysfs_notify();
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0099-console-add-write_atomic-interface.patch b/debian/patches-rt/0099-console-add-write_atomic-interface.patch
new file mode 100644
index 000000000..86f553013
--- /dev/null
+++ b/debian/patches-rt/0099-console-add-write_atomic-interface.patch
@@ -0,0 +1,163 @@
+From a021f069828ba9181d19f5ee9a977cf305ddaf19 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 30 Nov 2020 01:42:01 +0106
+Subject: [PATCH 099/323] console: add write_atomic interface
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Add a write_atomic() callback to the console. This is an optional
+function for console drivers. The function must be atomic (including
+NMI safe) for writing to the console.
+
+Console drivers must still implement the write() callback. The
+write_atomic() callback will only be used in special situations,
+such as when the kernel panics.
+
+Creating an NMI safe write_atomic() that must synchronize with
+write() requires a careful implementation of the console driver. To
+aid with the implementation, a set of console_atomic_*() functions
+are provided:
+
+    void console_atomic_lock(unsigned int *flags);
+    void console_atomic_unlock(unsigned int flags);
+
+These functions synchronize using a processor-reentrant spinlock
+(called a cpulock).
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/console.h |   4 ++
+ kernel/printk/printk.c  | 100 ++++++++++++++++++++++++++++++++++++++++
+ 2 files changed, 104 insertions(+)
+
+diff --git a/include/linux/console.h b/include/linux/console.h
+index bc2a749e6f0d..613df76903f5 100644
+--- a/include/linux/console.h
++++ b/include/linux/console.h
+@@ -141,6 +141,7 @@ static inline int con_debug_leave(void)
+ struct console {
+ 	char	name[16];
+ 	void	(*write)(struct console *, const char *, unsigned);
++	void	(*write_atomic)(struct console *co, const char *s, unsigned int count);
+ 	int	(*read)(struct console *, char *, unsigned);
+ 	struct tty_driver *(*device)(struct console *, int *);
+ 	void	(*unblank)(void);
+@@ -232,4 +233,7 @@ extern void console_init(void);
+ void dummycon_register_output_notifier(struct notifier_block *nb);
+ void dummycon_unregister_output_notifier(struct notifier_block *nb);
+ 
++extern void console_atomic_lock(unsigned int *flags);
++extern void console_atomic_unlock(unsigned int flags);
++
+ #endif /* _LINUX_CONSOLE_H */
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 57f3b8d7f35c..8768473712b2 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -3551,3 +3551,103 @@ void kmsg_dump_rewind(struct kmsg_dumper_iter *iter)
+ EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
+ 
+ #endif
++
++struct prb_cpulock {
++	atomic_t owner;
++	unsigned long __percpu *irqflags;
++};
++
++#define DECLARE_STATIC_PRINTKRB_CPULOCK(name)				\
++static DEFINE_PER_CPU(unsigned long, _##name##_percpu_irqflags);	\
++static struct prb_cpulock name = {					\
++	.owner = ATOMIC_INIT(-1),					\
++	.irqflags = &_##name##_percpu_irqflags,				\
++}
++
++static bool __prb_trylock(struct prb_cpulock *cpu_lock,
++			  unsigned int *cpu_store)
++{
++	unsigned long *flags;
++	unsigned int cpu;
++
++	cpu = get_cpu();
++
++	*cpu_store = atomic_read(&cpu_lock->owner);
++	/* memory barrier to ensure the current lock owner is visible */
++	smp_rmb();
++	if (*cpu_store == -1) {
++		flags = per_cpu_ptr(cpu_lock->irqflags, cpu);
++		local_irq_save(*flags);
++		if (atomic_try_cmpxchg_acquire(&cpu_lock->owner,
++					       cpu_store, cpu)) {
++			return true;
++		}
++		local_irq_restore(*flags);
++	} else if (*cpu_store == cpu) {
++		return true;
++	}
++
++	put_cpu();
++	return false;
++}
++
++/*
++ * prb_lock: Perform a processor-reentrant spin lock.
++ * @cpu_lock: A pointer to the lock object.
++ * @cpu_store: A "flags" pointer to store lock status information.
++ *
++ * If no processor has the lock, the calling processor takes the lock and
++ * becomes the owner. If the calling processor is already the owner of the
++ * lock, this function succeeds immediately. If lock is locked by another
++ * processor, this function spins until the calling processor becomes the
++ * owner.
++ *
++ * It is safe to call this function from any context and state.
++ */
++static void prb_lock(struct prb_cpulock *cpu_lock, unsigned int *cpu_store)
++{
++	for (;;) {
++		if (__prb_trylock(cpu_lock, cpu_store))
++			break;
++		cpu_relax();
++	}
++}
++
++/*
++ * prb_unlock: Perform a processor-reentrant spin unlock.
++ * @cpu_lock: A pointer to the lock object.
++ * @cpu_store: A "flags" object storing lock status information.
++ *
++ * Release the lock. The calling processor must be the owner of the lock.
++ *
++ * It is safe to call this function from any context and state.
++ */
++static void prb_unlock(struct prb_cpulock *cpu_lock, unsigned int cpu_store)
++{
++	unsigned long *flags;
++	unsigned int cpu;
++
++	cpu = atomic_read(&cpu_lock->owner);
++	atomic_set_release(&cpu_lock->owner, cpu_store);
++
++	if (cpu_store == -1) {
++		flags = per_cpu_ptr(cpu_lock->irqflags, cpu);
++		local_irq_restore(*flags);
++	}
++
++	put_cpu();
++}
++
++DECLARE_STATIC_PRINTKRB_CPULOCK(printk_cpulock);
++
++void console_atomic_lock(unsigned int *flags)
++{
++	prb_lock(&printk_cpulock, flags);
++}
++EXPORT_SYMBOL(console_atomic_lock);
++
++void console_atomic_unlock(unsigned int flags)
++{
++	prb_unlock(&printk_cpulock, flags);
++}
++EXPORT_SYMBOL(console_atomic_unlock);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0100-serial-8250-implement-write_atomic.patch b/debian/patches-rt/0100-serial-8250-implement-write_atomic.patch
new file mode 100644
index 000000000..ad692ff78
--- /dev/null
+++ b/debian/patches-rt/0100-serial-8250-implement-write_atomic.patch
@@ -0,0 +1,500 @@
+From 713182575337acb0891fcfaef75c3a36408d1766 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 30 Nov 2020 01:42:02 +0106
+Subject: [PATCH 100/323] serial: 8250: implement write_atomic
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Implement a non-sleeping NMI-safe write_atomic() console function in
+order to support emergency console printing.
+
+Since interrupts need to be disabled during transmit, all usage of
+the IER register is wrapped with access functions that use the
+console_atomic_lock() function to synchronize register access while
+tracking the state of the interrupts. This is necessary because
+write_atomic() can be called from an NMI context that has preempted
+write_atomic().
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/tty/serial/8250/8250.h         | 47 ++++++++++++-
+ drivers/tty/serial/8250/8250_core.c    | 17 +++--
+ drivers/tty/serial/8250/8250_fsl.c     |  9 +++
+ drivers/tty/serial/8250/8250_ingenic.c |  7 ++
+ drivers/tty/serial/8250/8250_mtk.c     | 29 +++++++-
+ drivers/tty/serial/8250/8250_port.c    | 92 ++++++++++++++++----------
+ include/linux/serial_8250.h            |  5 ++
+ 7 files changed, 162 insertions(+), 44 deletions(-)
+
+diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
+index 61b11490ae5b..32c534b87397 100644
+--- a/drivers/tty/serial/8250/8250.h
++++ b/drivers/tty/serial/8250/8250.h
+@@ -152,12 +152,55 @@ static inline void serial_dl_write(struct uart_8250_port *up, int value)
+ 	up->dl_write(up, value);
+ }
+ 
++static inline void serial8250_set_IER(struct uart_8250_port *up,
++				      unsigned char ier)
++{
++	struct uart_port *port = &up->port;
++	unsigned int flags;
++	bool is_console;
++
++	is_console = uart_console(port);
++
++	if (is_console)
++		console_atomic_lock(&flags);
++
++	serial_out(up, UART_IER, ier);
++
++	if (is_console)
++		console_atomic_unlock(flags);
++}
++
++static inline unsigned char serial8250_clear_IER(struct uart_8250_port *up)
++{
++	struct uart_port *port = &up->port;
++	unsigned int clearval = 0;
++	unsigned int prior;
++	unsigned int flags;
++	bool is_console;
++
++	is_console = uart_console(port);
++
++	if (up->capabilities & UART_CAP_UUE)
++		clearval = UART_IER_UUE;
++
++	if (is_console)
++		console_atomic_lock(&flags);
++
++	prior = serial_port_in(port, UART_IER);
++	serial_port_out(port, UART_IER, clearval);
++
++	if (is_console)
++		console_atomic_unlock(flags);
++
++	return prior;
++}
++
+ static inline bool serial8250_set_THRI(struct uart_8250_port *up)
+ {
+ 	if (up->ier & UART_IER_THRI)
+ 		return false;
+ 	up->ier |= UART_IER_THRI;
+-	serial_out(up, UART_IER, up->ier);
++	serial8250_set_IER(up, up->ier);
+ 	return true;
+ }
+ 
+@@ -166,7 +209,7 @@ static inline bool serial8250_clear_THRI(struct uart_8250_port *up)
+ 	if (!(up->ier & UART_IER_THRI))
+ 		return false;
+ 	up->ier &= ~UART_IER_THRI;
+-	serial_out(up, UART_IER, up->ier);
++	serial8250_set_IER(up, up->ier);
+ 	return true;
+ }
+ 
+diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
+index 43f2eed6df78..687119fe2f8c 100644
+--- a/drivers/tty/serial/8250/8250_core.c
++++ b/drivers/tty/serial/8250/8250_core.c
+@@ -275,10 +275,8 @@ static void serial8250_backup_timeout(struct timer_list *t)
+ 	 * Must disable interrupts or else we risk racing with the interrupt
+ 	 * based handler.
+ 	 */
+-	if (up->port.irq) {
+-		ier = serial_in(up, UART_IER);
+-		serial_out(up, UART_IER, 0);
+-	}
++	if (up->port.irq)
++		ier = serial8250_clear_IER(up);
+ 
+ 	iir = serial_in(up, UART_IIR);
+ 
+@@ -301,7 +299,7 @@ static void serial8250_backup_timeout(struct timer_list *t)
+ 		serial8250_tx_chars(up);
+ 
+ 	if (up->port.irq)
+-		serial_out(up, UART_IER, ier);
++		serial8250_set_IER(up, ier);
+ 
+ 	spin_unlock_irqrestore(&up->port.lock, flags);
+ 
+@@ -588,6 +586,14 @@ serial8250_register_ports(struct uart_driver *drv, struct device *dev)
+ 
+ #ifdef CONFIG_SERIAL_8250_CONSOLE
+ 
++static void univ8250_console_write_atomic(struct console *co, const char *s,
++					  unsigned int count)
++{
++	struct uart_8250_port *up = &serial8250_ports[co->index];
++
++	serial8250_console_write_atomic(up, s, count);
++}
++
+ static void univ8250_console_write(struct console *co, const char *s,
+ 				   unsigned int count)
+ {
+@@ -681,6 +687,7 @@ static int univ8250_console_match(struct console *co, char *name, int idx,
+ 
+ static struct console univ8250_console = {
+ 	.name		= "ttyS",
++	.write_atomic	= univ8250_console_write_atomic,
+ 	.write		= univ8250_console_write,
+ 	.device		= uart_console_device,
+ 	.setup		= univ8250_console_setup,
+diff --git a/drivers/tty/serial/8250/8250_fsl.c b/drivers/tty/serial/8250/8250_fsl.c
+index fbcc90c31ca1..b33cb454ce03 100644
+--- a/drivers/tty/serial/8250/8250_fsl.c
++++ b/drivers/tty/serial/8250/8250_fsl.c
+@@ -60,9 +60,18 @@ int fsl8250_handle_irq(struct uart_port *port)
+ 
+ 	/* Stop processing interrupts on input overrun */
+ 	if ((orig_lsr & UART_LSR_OE) && (up->overrun_backoff_time_ms > 0)) {
++		unsigned int ca_flags;
+ 		unsigned long delay;
++		bool is_console;
+ 
++		is_console = uart_console(port);
++
++		if (is_console)
++			console_atomic_lock(&ca_flags);
+ 		up->ier = port->serial_in(port, UART_IER);
++		if (is_console)
++			console_atomic_unlock(ca_flags);
++
+ 		if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) {
+ 			port->ops->stop_rx(port);
+ 		} else {
+diff --git a/drivers/tty/serial/8250/8250_ingenic.c b/drivers/tty/serial/8250/8250_ingenic.c
+index 988bf6bcce42..bcd26d672539 100644
+--- a/drivers/tty/serial/8250/8250_ingenic.c
++++ b/drivers/tty/serial/8250/8250_ingenic.c
+@@ -146,6 +146,8 @@ OF_EARLYCON_DECLARE(x1000_uart, "ingenic,x1000-uart",
+ 
+ static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value)
+ {
++	unsigned int flags;
++	bool is_console;
+ 	int ier;
+ 
+ 	switch (offset) {
+@@ -167,7 +169,12 @@ static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value)
+ 		 * If we have enabled modem status IRQs we should enable
+ 		 * modem mode.
+ 		 */
++		is_console = uart_console(p);
++		if (is_console)
++			console_atomic_lock(&flags);
+ 		ier = p->serial_in(p, UART_IER);
++		if (is_console)
++			console_atomic_unlock(flags);
+ 
+ 		if (ier & UART_IER_MSI)
+ 			value |= UART_MCR_MDCE | UART_MCR_FCM;
+diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
+index de48a58460f4..d246f2755fed 100644
+--- a/drivers/tty/serial/8250/8250_mtk.c
++++ b/drivers/tty/serial/8250/8250_mtk.c
+@@ -222,12 +222,37 @@ static void mtk8250_shutdown(struct uart_port *port)
+ 
+ static void mtk8250_disable_intrs(struct uart_8250_port *up, int mask)
+ {
+-	serial_out(up, UART_IER, serial_in(up, UART_IER) & (~mask));
++	struct uart_port *port = &up->port;
++	unsigned int flags;
++	unsigned int ier;
++	bool is_console;
++
++	is_console = uart_console(port);
++
++	if (is_console)
++		console_atomic_lock(&flags);
++
++	ier = serial_in(up, UART_IER);
++	serial_out(up, UART_IER, ier & (~mask));
++
++	if (is_console)
++		console_atomic_unlock(flags);
+ }
+ 
+ static void mtk8250_enable_intrs(struct uart_8250_port *up, int mask)
+ {
+-	serial_out(up, UART_IER, serial_in(up, UART_IER) | mask);
++	struct uart_port *port = &up->port;
++	unsigned int flags;
++	unsigned int ier;
++
++	if (uart_console(port))
++		console_atomic_lock(&flags);
++
++	ier = serial_in(up, UART_IER);
++	serial_out(up, UART_IER, ier | mask);
++
++	if (uart_console(port))
++		console_atomic_unlock(flags);
+ }
+ 
+ static void mtk8250_set_flow_ctrl(struct uart_8250_port *up, int mode)
+diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
+index 8b49ac4856d2..947737d0e46b 100644
+--- a/drivers/tty/serial/8250/8250_port.c
++++ b/drivers/tty/serial/8250/8250_port.c
+@@ -730,7 +730,7 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
+ 			serial_out(p, UART_EFR, UART_EFR_ECB);
+ 			serial_out(p, UART_LCR, 0);
+ 		}
+-		serial_out(p, UART_IER, sleep ? UART_IERX_SLEEP : 0);
++		serial8250_set_IER(p, sleep ? UART_IERX_SLEEP : 0);
+ 		if (p->capabilities & UART_CAP_EFR) {
+ 			serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
+ 			serial_out(p, UART_EFR, efr);
+@@ -1405,7 +1405,7 @@ static void serial8250_stop_rx(struct uart_port *port)
+ 
+ 	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
+ 	up->port.read_status_mask &= ~UART_LSR_DR;
+-	serial_port_out(port, UART_IER, up->ier);
++	serial8250_set_IER(up, up->ier);
+ 
+ 	serial8250_rpm_put(up);
+ }
+@@ -1435,7 +1435,7 @@ void serial8250_em485_stop_tx(struct uart_8250_port *p)
+ 		serial8250_clear_and_reinit_fifos(p);
+ 
+ 		p->ier |= UART_IER_RLSI | UART_IER_RDI;
+-		serial_port_out(&p->port, UART_IER, p->ier);
++		serial8250_set_IER(p, p->ier);
+ 	}
+ }
+ EXPORT_SYMBOL_GPL(serial8250_em485_stop_tx);
+@@ -1677,7 +1677,7 @@ static void serial8250_disable_ms(struct uart_port *port)
+ 	mctrl_gpio_disable_ms(up->gpios);
+ 
+ 	up->ier &= ~UART_IER_MSI;
+-	serial_port_out(port, UART_IER, up->ier);
++	serial8250_set_IER(up, up->ier);
+ }
+ 
+ static void serial8250_enable_ms(struct uart_port *port)
+@@ -1693,7 +1693,7 @@ static void serial8250_enable_ms(struct uart_port *port)
+ 	up->ier |= UART_IER_MSI;
+ 
+ 	serial8250_rpm_get(up);
+-	serial_port_out(port, UART_IER, up->ier);
++	serial8250_set_IER(up, up->ier);
+ 	serial8250_rpm_put(up);
+ }
+ 
+@@ -2129,14 +2129,7 @@ static void serial8250_put_poll_char(struct uart_port *port,
+ 	struct uart_8250_port *up = up_to_u8250p(port);
+ 
+ 	serial8250_rpm_get(up);
+-	/*
+-	 *	First save the IER then disable the interrupts
+-	 */
+-	ier = serial_port_in(port, UART_IER);
+-	if (up->capabilities & UART_CAP_UUE)
+-		serial_port_out(port, UART_IER, UART_IER_UUE);
+-	else
+-		serial_port_out(port, UART_IER, 0);
++	ier = serial8250_clear_IER(up);
+ 
+ 	wait_for_xmitr(up, BOTH_EMPTY);
+ 	/*
+@@ -2149,7 +2142,7 @@ static void serial8250_put_poll_char(struct uart_port *port,
+ 	 *	and restore the IER
+ 	 */
+ 	wait_for_xmitr(up, BOTH_EMPTY);
+-	serial_port_out(port, UART_IER, ier);
++	serial8250_set_IER(up, ier);
+ 	serial8250_rpm_put(up);
+ }
+ 
+@@ -2454,7 +2447,7 @@ void serial8250_do_shutdown(struct uart_port *port)
+ 	 */
+ 	spin_lock_irqsave(&port->lock, flags);
+ 	up->ier = 0;
+-	serial_port_out(port, UART_IER, 0);
++	serial8250_set_IER(up, 0);
+ 	spin_unlock_irqrestore(&port->lock, flags);
+ 
+ 	synchronize_irq(port->irq);
+@@ -2806,7 +2799,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
+ 	if (up->capabilities & UART_CAP_RTOIE)
+ 		up->ier |= UART_IER_RTOIE;
+ 
+-	serial_port_out(port, UART_IER, up->ier);
++	serial8250_set_IER(up, up->ier);
+ 
+ 	if (up->capabilities & UART_CAP_EFR) {
+ 		unsigned char efr = 0;
+@@ -3271,7 +3264,7 @@ EXPORT_SYMBOL_GPL(serial8250_set_defaults);
+ 
+ #ifdef CONFIG_SERIAL_8250_CONSOLE
+ 
+-static void serial8250_console_putchar(struct uart_port *port, int ch)
++static void serial8250_console_putchar_locked(struct uart_port *port, int ch)
+ {
+ 	struct uart_8250_port *up = up_to_u8250p(port);
+ 
+@@ -3279,6 +3272,18 @@ static void serial8250_console_putchar(struct uart_port *port, int ch)
+ 	serial_port_out(port, UART_TX, ch);
+ }
+ 
++static void serial8250_console_putchar(struct uart_port *port, int ch)
++{
++	struct uart_8250_port *up = up_to_u8250p(port);
++	unsigned int flags;
++
++	wait_for_xmitr(up, UART_LSR_THRE);
++
++	console_atomic_lock(&flags);
++	serial8250_console_putchar_locked(port, ch);
++	console_atomic_unlock(flags);
++}
++
+ /*
+  *	Restore serial console when h/w power-off detected
+  */
+@@ -3305,6 +3310,32 @@ static void serial8250_console_restore(struct uart_8250_port *up)
+ 	serial8250_out_MCR(up, up->mcr | UART_MCR_DTR | UART_MCR_RTS);
+ }
+ 
++void serial8250_console_write_atomic(struct uart_8250_port *up,
++				     const char *s, unsigned int count)
++{
++	struct uart_port *port = &up->port;
++	unsigned int flags;
++	unsigned int ier;
++
++	console_atomic_lock(&flags);
++
++	touch_nmi_watchdog();
++
++	ier = serial8250_clear_IER(up);
++
++	if (atomic_fetch_inc(&up->console_printing)) {
++		uart_console_write(port, "\n", 1,
++				   serial8250_console_putchar_locked);
++	}
++	uart_console_write(port, s, count, serial8250_console_putchar_locked);
++	atomic_dec(&up->console_printing);
++
++	wait_for_xmitr(up, BOTH_EMPTY);
++	serial8250_set_IER(up, ier);
++
++	console_atomic_unlock(flags);
++}
++
+ /*
+  *	Print a string to the serial port trying not to disturb
+  *	any possible real use of the port...
+@@ -3321,24 +3352,12 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
+ 	struct uart_port *port = &up->port;
+ 	unsigned long flags;
+ 	unsigned int ier;
+-	int locked = 1;
+ 
+ 	touch_nmi_watchdog();
+ 
+-	if (oops_in_progress)
+-		locked = spin_trylock_irqsave(&port->lock, flags);
+-	else
+-		spin_lock_irqsave(&port->lock, flags);
+-
+-	/*
+-	 *	First save the IER then disable the interrupts
+-	 */
+-	ier = serial_port_in(port, UART_IER);
++	spin_lock_irqsave(&port->lock, flags);
+ 
+-	if (up->capabilities & UART_CAP_UUE)
+-		serial_port_out(port, UART_IER, UART_IER_UUE);
+-	else
+-		serial_port_out(port, UART_IER, 0);
++	ier = serial8250_clear_IER(up);
+ 
+ 	/* check scratch reg to see if port powered off during system sleep */
+ 	if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) {
+@@ -3352,7 +3371,9 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
+ 		mdelay(port->rs485.delay_rts_before_send);
+ 	}
+ 
++	atomic_inc(&up->console_printing);
+ 	uart_console_write(port, s, count, serial8250_console_putchar);
++	atomic_dec(&up->console_printing);
+ 
+ 	/*
+ 	 *	Finally, wait for transmitter to become empty
+@@ -3365,8 +3386,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
+ 		if (em485->tx_stopped)
+ 			up->rs485_stop_tx(up);
+ 	}
+-
+-	serial_port_out(port, UART_IER, ier);
++	serial8250_set_IER(up, ier);
+ 
+ 	/*
+ 	 *	The receive handling will happen properly because the
+@@ -3378,8 +3398,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
+ 	if (up->msr_saved_flags)
+ 		serial8250_modem_status(up);
+ 
+-	if (locked)
+-		spin_unlock_irqrestore(&port->lock, flags);
++	spin_unlock_irqrestore(&port->lock, flags);
+ }
+ 
+ static unsigned int probe_baud(struct uart_port *port)
+@@ -3399,6 +3418,7 @@ static unsigned int probe_baud(struct uart_port *port)
+ 
+ int serial8250_console_setup(struct uart_port *port, char *options, bool probe)
+ {
++	struct uart_8250_port *up = up_to_u8250p(port);
+ 	int baud = 9600;
+ 	int bits = 8;
+ 	int parity = 'n';
+@@ -3408,6 +3428,8 @@ int serial8250_console_setup(struct uart_port *port, char *options, bool probe)
+ 	if (!port->iobase && !port->membase)
+ 		return -ENODEV;
+ 
++	atomic_set(&up->console_printing, 0);
++
+ 	if (options)
+ 		uart_parse_options(options, &baud, &parity, &bits, &flow);
+ 	else if (probe)
+diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
+index abb928361270..77de68ed2d60 100644
+--- a/include/linux/serial_8250.h
++++ b/include/linux/serial_8250.h
+@@ -7,6 +7,7 @@
+ #ifndef _LINUX_SERIAL_8250_H
+ #define _LINUX_SERIAL_8250_H
+ 
++#include <linux/atomic.h>
+ #include <linux/serial_core.h>
+ #include <linux/serial_reg.h>
+ #include <linux/platform_device.h>
+@@ -125,6 +126,8 @@ struct uart_8250_port {
+ #define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
+ 	unsigned char		msr_saved_flags;
+ 
++	atomic_t		console_printing;
++
+ 	struct uart_8250_dma	*dma;
+ 	const struct uart_8250_ops *ops;
+ 
+@@ -180,6 +183,8 @@ void serial8250_init_port(struct uart_8250_port *up);
+ void serial8250_set_defaults(struct uart_8250_port *up);
+ void serial8250_console_write(struct uart_8250_port *up, const char *s,
+ 			      unsigned int count);
++void serial8250_console_write_atomic(struct uart_8250_port *up, const char *s,
++				     unsigned int count);
+ int serial8250_console_setup(struct uart_port *port, char *options, bool probe);
+ int serial8250_console_exit(struct uart_port *port);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0101-printk-relocate-printk_delay-and-vprintk_default.patch b/debian/patches-rt/0101-printk-relocate-printk_delay-and-vprintk_default.patch
new file mode 100644
index 000000000..27a3bd9d4
--- /dev/null
+++ b/debian/patches-rt/0101-printk-relocate-printk_delay-and-vprintk_default.patch
@@ -0,0 +1,89 @@
+From 598543b96b715ed360718ca3597ad4a2eda53241 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 30 Nov 2020 01:42:03 +0106
+Subject: [PATCH 101/323] printk: relocate printk_delay() and vprintk_default()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Move printk_delay() and vprintk_default() "as is" further up so that
+they can be used by new functions in an upcoming commit.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/printk/printk.c | 40 ++++++++++++++++++++--------------------
+ 1 file changed, 20 insertions(+), 20 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 8768473712b2..c3fc6706a118 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -1728,6 +1728,20 @@ SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
+ 	return do_syslog(type, buf, len, SYSLOG_FROM_READER);
+ }
+ 
++int printk_delay_msec __read_mostly;
++
++static inline void printk_delay(void)
++{
++	if (unlikely(printk_delay_msec)) {
++		int m = printk_delay_msec;
++
++		while (m--) {
++			mdelay(1);
++			touch_nmi_watchdog();
++		}
++	}
++}
++
+ /*
+  * Special console_lock variants that help to reduce the risk of soft-lockups.
+  * They allow to pass console_lock to another printk() call using a busy wait.
+@@ -1971,20 +1985,6 @@ static void printk_exit_irqrestore(unsigned long flags)
+ 	local_irq_restore(flags);
+ }
+ 
+-int printk_delay_msec __read_mostly;
+-
+-static inline void printk_delay(void)
+-{
+-	if (unlikely(printk_delay_msec)) {
+-		int m = printk_delay_msec;
+-
+-		while (m--) {
+-			mdelay(1);
+-			touch_nmi_watchdog();
+-		}
+-	}
+-}
+-
+ static inline u32 printk_caller_id(void)
+ {
+ 	return in_task() ? task_pid_nr(current) :
+@@ -2217,18 +2217,18 @@ asmlinkage int vprintk_emit(int facility, int level,
+ }
+ EXPORT_SYMBOL(vprintk_emit);
+ 
+-asmlinkage int vprintk(const char *fmt, va_list args)
+-{
+-	return vprintk_func(fmt, args);
+-}
+-EXPORT_SYMBOL(vprintk);
+-
+ int vprintk_default(const char *fmt, va_list args)
+ {
+ 	return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, fmt, args);
+ }
+ EXPORT_SYMBOL_GPL(vprintk_default);
+ 
++asmlinkage int vprintk(const char *fmt, va_list args)
++{
++	return vprintk_func(fmt, args);
++}
++EXPORT_SYMBOL(vprintk);
++
+ /**
+  * printk - print a kernel message
+  * @fmt: format string
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0102-printk-combine-boot_delay_msec-into-printk_delay.patch b/debian/patches-rt/0102-printk-combine-boot_delay_msec-into-printk_delay.patch
new file mode 100644
index 000000000..64dda79fa
--- /dev/null
+++ b/debian/patches-rt/0102-printk-combine-boot_delay_msec-into-printk_delay.patch
@@ -0,0 +1,44 @@
+From 17a9ff9877863dc267a2b0ead2ab3f792b5e405c Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 30 Nov 2020 01:42:04 +0106
+Subject: [PATCH 102/323] printk: combine boot_delay_msec() into printk_delay()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+boot_delay_msec() is always called immediately before printk_delay()
+so just combine the two.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/printk/printk.c | 7 ++++---
+ 1 file changed, 4 insertions(+), 3 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index c3fc6706a118..0ae184675e86 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -1730,8 +1730,10 @@ SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
+ 
+ int printk_delay_msec __read_mostly;
+ 
+-static inline void printk_delay(void)
++static inline void printk_delay(int level)
+ {
++	boot_delay_msec(level);
++
+ 	if (unlikely(printk_delay_msec)) {
+ 		int m = printk_delay_msec;
+ 
+@@ -2189,8 +2191,7 @@ asmlinkage int vprintk_emit(int facility, int level,
+ 		in_sched = true;
+ 	}
+ 
+-	boot_delay_msec(level);
+-	printk_delay();
++	printk_delay(level);
+ 
+ 	printed_len = vprintk_store(facility, level, dev_info, fmt, args);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0103-printk-change-console_seq-to-atomic64_t.patch b/debian/patches-rt/0103-printk-change-console_seq-to-atomic64_t.patch
new file mode 100644
index 000000000..6647ecd6c
--- /dev/null
+++ b/debian/patches-rt/0103-printk-change-console_seq-to-atomic64_t.patch
@@ -0,0 +1,132 @@
+From ebdec06c58c4330925d5603649542827bf7bff25 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 30 Nov 2020 01:42:05 +0106
+Subject: [PATCH 103/323] printk: change @console_seq to atomic64_t
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+In preparation for atomic printing, change @console_seq to atomic
+so that it can be accessed without requiring @console_sem.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/printk/printk.c | 34 +++++++++++++++++++---------------
+ 1 file changed, 19 insertions(+), 15 deletions(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 0ae184675e86..2bc9904fd8ab 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -368,12 +368,13 @@ static u64 syslog_seq;
+ static size_t syslog_partial;
+ static bool syslog_time;
+ 
+-/* All 3 protected by @console_sem. */
+-/* the next printk record to write to the console */
+-static u64 console_seq;
++/* Both protected by @console_sem. */
+ static u64 exclusive_console_stop_seq;
+ static unsigned long console_dropped;
+ 
++/* the next printk record to write to the console */
++static atomic64_t console_seq = ATOMIC64_INIT(0);
++
+ struct latched_seq {
+ 	seqcount_latch_t	latch;
+ 	u64			val[2];
+@@ -2273,7 +2274,7 @@ EXPORT_SYMBOL(printk);
+ #define prb_first_valid_seq(rb)		0
+ 
+ static u64 syslog_seq;
+-static u64 console_seq;
++static atomic64_t console_seq = ATOMIC64_INIT(0);
+ static u64 exclusive_console_stop_seq;
+ static unsigned long console_dropped;
+ 
+@@ -2588,6 +2589,7 @@ void console_unlock(void)
+ 	bool do_cond_resched, retry;
+ 	struct printk_info info;
+ 	struct printk_record r;
++	u64 seq;
+ 
+ 	if (console_suspended) {
+ 		up_console_sem();
+@@ -2630,12 +2632,14 @@ void console_unlock(void)
+ 		size_t len;
+ 
+ skip:
+-		if (!prb_read_valid(prb, console_seq, &r))
++		seq = atomic64_read(&console_seq);
++		if (!prb_read_valid(prb, seq, &r))
+ 			break;
+ 
+-		if (console_seq != r.info->seq) {
+-			console_dropped += r.info->seq - console_seq;
+-			console_seq = r.info->seq;
++		if (seq != r.info->seq) {
++			console_dropped += r.info->seq - seq;
++			atomic64_set(&console_seq, r.info->seq);
++			seq = r.info->seq;
+ 		}
+ 
+ 		if (suppress_message_printing(r.info->level)) {
+@@ -2644,13 +2648,13 @@ void console_unlock(void)
+ 			 * directly to the console when we received it, and
+ 			 * record that has level above the console loglevel.
+ 			 */
+-			console_seq++;
++			atomic64_set(&console_seq, seq + 1);
+ 			goto skip;
+ 		}
+ 
+ 		/* Output to all consoles once old messages replayed. */
+ 		if (unlikely(exclusive_console &&
+-			     console_seq >= exclusive_console_stop_seq)) {
++			     seq >= exclusive_console_stop_seq)) {
+ 			exclusive_console = NULL;
+ 		}
+ 
+@@ -2671,7 +2675,7 @@ void console_unlock(void)
+ 		len = record_print_text(&r,
+ 				console_msg_format & MSG_FORMAT_SYSLOG,
+ 				printk_time);
+-		console_seq++;
++		atomic64_set(&console_seq, seq + 1);
+ 
+ 		/*
+ 		 * While actively printing out messages, if another printk()
+@@ -2702,7 +2706,7 @@ void console_unlock(void)
+ 	 * there's a new owner and the console_unlock() from them will do the
+ 	 * flush, no worries.
+ 	 */
+-	retry = prb_read_valid(prb, console_seq, NULL);
++	retry = prb_read_valid(prb, atomic64_read(&console_seq), NULL);
+ 	if (retry && console_trylock())
+ 		goto again;
+ }
+@@ -2765,7 +2769,7 @@ void console_flush_on_panic(enum con_flush_mode mode)
+ 	console_may_schedule = 0;
+ 
+ 	if (mode == CONSOLE_REPLAY_ALL)
+-		console_seq = prb_first_valid_seq(prb);
++		atomic64_set(&console_seq, prb_first_valid_seq(prb));
+ 	console_unlock();
+ }
+ 
+@@ -3002,11 +3006,11 @@ void register_console(struct console *newcon)
+ 		 * ignores console_lock.
+ 		 */
+ 		exclusive_console = newcon;
+-		exclusive_console_stop_seq = console_seq;
++		exclusive_console_stop_seq = atomic64_read(&console_seq);
+ 
+ 		/* Get a consistent copy of @syslog_seq. */
+ 		spin_lock_irqsave(&syslog_lock, flags);
+-		console_seq = syslog_seq;
++		atomic64_set(&console_seq, syslog_seq);
+ 		spin_unlock_irqrestore(&syslog_lock, flags);
+ 	}
+ 	console_unlock();
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0104-printk-introduce-kernel-sync-mode.patch b/debian/patches-rt/0104-printk-introduce-kernel-sync-mode.patch
new file mode 100644
index 000000000..3dfd1b707
--- /dev/null
+++ b/debian/patches-rt/0104-printk-introduce-kernel-sync-mode.patch
@@ -0,0 +1,310 @@
+From fcf68eb3d589c57f73e4a79b7df2f6ec8080b1ce Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 30 Nov 2020 01:42:06 +0106
+Subject: [PATCH 104/323] printk: introduce kernel sync mode
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+When the kernel performs an OOPS, enter into "sync mode":
+
+- only atomic consoles (write_atomic() callback) will print
+- printing occurs within vprintk_store() instead of console_unlock()
+
+CONSOLE_LOG_MAX is moved to printk.h to support the per-console
+buffer used in sync mode.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ include/linux/console.h |   4 ++
+ include/linux/printk.h  |   6 ++
+ kernel/printk/printk.c  | 133 ++++++++++++++++++++++++++++++++++++++--
+ 3 files changed, 137 insertions(+), 6 deletions(-)
+
+diff --git a/include/linux/console.h b/include/linux/console.h
+index 613df76903f5..fcc98354f733 100644
+--- a/include/linux/console.h
++++ b/include/linux/console.h
+@@ -16,6 +16,7 @@
+ 
+ #include <linux/atomic.h>
+ #include <linux/types.h>
++#include <linux/printk.h>
+ 
+ struct vc_data;
+ struct console_font_op;
+@@ -151,6 +152,9 @@ struct console {
+ 	short	flags;
+ 	short	index;
+ 	int	cflag;
++#ifdef CONFIG_PRINTK
++	char	sync_buf[CONSOLE_LOG_MAX];
++#endif
+ 	uint	ispeed;
+ 	uint	ospeed;
+ 	void	*data;
+diff --git a/include/linux/printk.h b/include/linux/printk.h
+index c6bb48f0134c..3738374e2b3b 100644
+--- a/include/linux/printk.h
++++ b/include/linux/printk.h
+@@ -46,6 +46,12 @@ static inline const char *printk_skip_headers(const char *buffer)
+ 
+ #define CONSOLE_EXT_LOG_MAX	8192
+ 
++/*
++ * The maximum size of a record formatted for console printing
++ * (i.e. with the prefix prepended to every line).
++ */
++#define CONSOLE_LOG_MAX		4096
++
+ /* printk's without a loglevel use this.. */
+ #define MESSAGE_LOGLEVEL_DEFAULT CONFIG_MESSAGE_LOGLEVEL_DEFAULT
+ 
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 2bc9904fd8ab..8a0af76b6f69 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -44,6 +44,7 @@
+ #include <linux/irq_work.h>
+ #include <linux/ctype.h>
+ #include <linux/uio.h>
++#include <linux/clocksource.h>
+ #include <linux/sched/clock.h>
+ #include <linux/sched/debug.h>
+ #include <linux/sched/task_stack.h>
+@@ -361,6 +362,9 @@ enum log_flags {
+ static DEFINE_SPINLOCK(syslog_lock);
+ 
+ #ifdef CONFIG_PRINTK
++/* Set to enable sync mode. Once set, it is never cleared. */
++static bool sync_mode;
++
+ DECLARE_WAIT_QUEUE_HEAD(log_wait);
+ /* All 3 protected by @syslog_lock. */
+ /* the next printk record to read by syslog(READ) or /proc/kmsg */
+@@ -400,9 +404,6 @@ static struct latched_seq clear_seq = {
+ /* the maximum size allowed to be reserved for a record */
+ #define LOG_LINE_MAX		(1024 - PREFIX_MAX)
+ 
+-/* the maximum size of a formatted record (i.e. with prefix added per line) */
+-#define CONSOLE_LOG_MAX		4096
+-
+ #define LOG_LEVEL(v)		((v) & 0x07)
+ #define LOG_FACILITY(v)		((v) >> 3 & 0xff)
+ 
+@@ -1745,6 +1746,91 @@ static inline void printk_delay(int level)
+ 	}
+ }
+ 
++static bool kernel_sync_mode(void)
++{
++	return (oops_in_progress || sync_mode);
++}
++
++static bool console_can_sync(struct console *con)
++{
++	if (!(con->flags & CON_ENABLED))
++		return false;
++	if (con->write_atomic && kernel_sync_mode())
++		return true;
++	return false;
++}
++
++static bool call_sync_console_driver(struct console *con, const char *text, size_t text_len)
++{
++	if (!(con->flags & CON_ENABLED))
++		return false;
++	if (con->write_atomic && kernel_sync_mode())
++		con->write_atomic(con, text, text_len);
++	else
++		return false;
++
++	return true;
++}
++
++static bool have_atomic_console(void)
++{
++	struct console *con;
++
++	for_each_console(con) {
++		if (!(con->flags & CON_ENABLED))
++			continue;
++		if (con->write_atomic)
++			return true;
++	}
++	return false;
++}
++
++static bool print_sync(struct console *con, u64 *seq)
++{
++	struct printk_info info;
++	struct printk_record r;
++	size_t text_len;
++
++	prb_rec_init_rd(&r, &info, &con->sync_buf[0], sizeof(con->sync_buf));
++
++	if (!prb_read_valid(prb, *seq, &r))
++		return false;
++
++	text_len = record_print_text(&r, console_msg_format & MSG_FORMAT_SYSLOG, printk_time);
++
++	if (!call_sync_console_driver(con, &con->sync_buf[0], text_len))
++		return false;
++
++	*seq = r.info->seq;
++
++	touch_softlockup_watchdog_sync();
++	clocksource_touch_watchdog();
++	rcu_cpu_stall_reset();
++	touch_nmi_watchdog();
++
++	if (text_len)
++		printk_delay(r.info->level);
++
++	return true;
++}
++
++static void print_sync_until(struct console *con, u64 seq)
++{
++	unsigned int flags;
++	u64 printk_seq;
++
++	console_atomic_lock(&flags);
++	for (;;) {
++		printk_seq = atomic64_read(&console_seq);
++		if (printk_seq >= seq)
++			break;
++		if (!print_sync(con, &printk_seq))
++			break;
++		atomic64_set(&console_seq, printk_seq + 1);
++	}
++	console_atomic_unlock(flags);
++}
++
+ /*
+  * Special console_lock variants that help to reduce the risk of soft-lockups.
+  * They allow to pass console_lock to another printk() call using a busy wait.
+@@ -1919,6 +2005,8 @@ static void call_console_drivers(const char *ext_text, size_t ext_len,
+ 		if (!cpu_online(smp_processor_id()) &&
+ 		    !(con->flags & CON_ANYTIME))
+ 			continue;
++		if (kernel_sync_mode())
++			continue;
+ 		if (con->flags & CON_EXTENDED)
+ 			con->write(con, ext_text, ext_len);
+ 		else {
+@@ -2073,6 +2161,7 @@ int vprintk_store(int facility, int level,
+ 	const u32 caller_id = printk_caller_id();
+ 	struct prb_reserved_entry e;
+ 	enum log_flags lflags = 0;
++	bool final_commit = false;
+ 	struct printk_record r;
+ 	unsigned long irqflags;
+ 	u16 trunc_msg_len = 0;
+@@ -2082,6 +2171,7 @@ int vprintk_store(int facility, int level,
+ 	u16 text_len;
+ 	int ret = 0;
+ 	u64 ts_nsec;
++	u64 seq;
+ 
+ 	/*
+ 	 * Since the duration of printk() can vary depending on the message
+@@ -2120,6 +2210,7 @@ int vprintk_store(int facility, int level,
+ 	if (lflags & LOG_CONT) {
+ 		prb_rec_init_wr(&r, reserve_size);
+ 		if (prb_reserve_in_last(&e, prb, &r, caller_id, LOG_LINE_MAX)) {
++			seq = r.info->seq;
+ 			text_len = printk_sprint(&r.text_buf[r.info->text_len], reserve_size,
+ 						 facility, &lflags, fmt, args);
+ 			r.info->text_len += text_len;
+@@ -2127,6 +2218,7 @@ int vprintk_store(int facility, int level,
+ 			if (lflags & LOG_NEWLINE) {
+ 				r.info->flags |= LOG_NEWLINE;
+ 				prb_final_commit(&e);
++				final_commit = true;
+ 			} else {
+ 				prb_commit(&e);
+ 			}
+@@ -2151,6 +2243,8 @@ int vprintk_store(int facility, int level,
+ 			goto out;
+ 	}
+ 
++	seq = r.info->seq;
++
+ 	/* fill message */
+ 	text_len = printk_sprint(&r.text_buf[0], reserve_size, facility, &lflags, fmt, args);
+ 	if (trunc_msg_len)
+@@ -2165,13 +2259,25 @@ int vprintk_store(int facility, int level,
+ 		memcpy(&r.info->dev_info, dev_info, sizeof(r.info->dev_info));
+ 
+ 	/* A message without a trailing newline can be continued. */
+-	if (!(lflags & LOG_NEWLINE))
++	if (!(lflags & LOG_NEWLINE)) {
+ 		prb_commit(&e);
+-	else
++	} else {
+ 		prb_final_commit(&e);
++		final_commit = true;
++	}
+ 
+ 	ret = text_len + trunc_msg_len;
+ out:
++	/* only the kernel may perform synchronous printing */
++	if (facility == 0 && final_commit) {
++		struct console *con;
++
++		for_each_console(con) {
++			if (console_can_sync(con))
++				print_sync_until(con, seq + 1);
++		}
++	}
++
+ 	printk_exit_irqrestore(irqflags);
+ 	return ret;
+ }
+@@ -2267,12 +2373,13 @@ EXPORT_SYMBOL(printk);
+ 
+ #else /* CONFIG_PRINTK */
+ 
+-#define CONSOLE_LOG_MAX		0
+ #define printk_time		false
+ 
+ #define prb_read_valid(rb, seq, r)	false
+ #define prb_first_valid_seq(rb)		0
+ 
++#define kernel_sync_mode()	false
++
+ static u64 syslog_seq;
+ static atomic64_t console_seq = ATOMIC64_INIT(0);
+ static u64 exclusive_console_stop_seq;
+@@ -2565,6 +2672,8 @@ static int have_callable_console(void)
+  */
+ static inline int can_use_console(void)
+ {
++	if (kernel_sync_mode())
++		return false;
+ 	return cpu_online(raw_smp_processor_id()) || have_callable_console();
+ }
+ 
+@@ -3379,6 +3488,18 @@ void kmsg_dump(enum kmsg_dump_reason reason)
+ 	struct kmsg_dumper_iter iter;
+ 	struct kmsg_dumper *dumper;
+ 
++	if (!oops_in_progress) {
++		/*
++		 * If atomic consoles are available, activate kernel sync mode
++		 * to make sure any final messages are visible. The trailing
++		 * printk message is important to flush any pending messages.
++		 */
++		if (have_atomic_console()) {
++			sync_mode = true;
++			pr_info("enabled sync mode\n");
++		}
++	}
++
+ 	rcu_read_lock();
+ 	list_for_each_entry_rcu(dumper, &dump_list, list) {
+ 		enum kmsg_dump_reason max_reason = dumper->max_reason;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0105-printk-move-console-printing-to-kthreads.patch b/debian/patches-rt/0105-printk-move-console-printing-to-kthreads.patch
new file mode 100644
index 000000000..5f6075baf
--- /dev/null
+++ b/debian/patches-rt/0105-printk-move-console-printing-to-kthreads.patch
@@ -0,0 +1,848 @@
+From 24c419661c9c605b6f1ddccf1683c2c0f8c5dcf4 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 30 Nov 2020 01:42:07 +0106
+Subject: [PATCH 105/323] printk: move console printing to kthreads
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Create a kthread for each console to perform console printing. Now
+all console printing is fully asynchronous except for the boot
+console and when the kernel enters sync mode (and there are atomic
+consoles available).
+
+The console_lock() and console_unlock() functions now only do what
+their name says... locking and unlocking of the console.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ include/linux/console.h |   2 +
+ kernel/printk/printk.c  | 625 ++++++++++++----------------------------
+ 2 files changed, 186 insertions(+), 441 deletions(-)
+
+diff --git a/include/linux/console.h b/include/linux/console.h
+index fcc98354f733..3e99359e0660 100644
+--- a/include/linux/console.h
++++ b/include/linux/console.h
+@@ -155,6 +155,8 @@ struct console {
+ #ifdef CONFIG_PRINTK
+ 	char	sync_buf[CONSOLE_LOG_MAX];
+ #endif
++	atomic64_t printk_seq;
++	struct task_struct *thread;
+ 	uint	ispeed;
+ 	uint	ospeed;
+ 	void	*data;
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 8a0af76b6f69..232ce58e94c2 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -44,6 +44,7 @@
+ #include <linux/irq_work.h>
+ #include <linux/ctype.h>
+ #include <linux/uio.h>
++#include <linux/kthread.h>
+ #include <linux/clocksource.h>
+ #include <linux/sched/clock.h>
+ #include <linux/sched/debug.h>
+@@ -269,11 +270,6 @@ static void __up_console_sem(unsigned long ip)
+  */
+ static int console_locked, console_suspended;
+ 
+-/*
+- * If exclusive_console is non-NULL then only this console is to be printed to.
+- */
+-static struct console *exclusive_console;
+-
+ /*
+  *	Array of consoles built from command line options (console=)
+  */
+@@ -358,10 +354,10 @@ enum log_flags {
+ 	LOG_CONT	= 8,	/* text is a fragment of a continuation line */
+ };
+ 
++#ifdef CONFIG_PRINTK
+ /* syslog_lock protects syslog_* variables and write access to clear_seq. */
+ static DEFINE_SPINLOCK(syslog_lock);
+ 
+-#ifdef CONFIG_PRINTK
+ /* Set to enable sync mode. Once set, it is never cleared. */
+ static bool sync_mode;
+ 
+@@ -372,13 +368,6 @@ static u64 syslog_seq;
+ static size_t syslog_partial;
+ static bool syslog_time;
+ 
+-/* Both protected by @console_sem. */
+-static u64 exclusive_console_stop_seq;
+-static unsigned long console_dropped;
+-
+-/* the next printk record to write to the console */
+-static atomic64_t console_seq = ATOMIC64_INIT(0);
+-
+ struct latched_seq {
+ 	seqcount_latch_t	latch;
+ 	u64			val[2];
+@@ -1757,6 +1746,8 @@ static bool console_can_sync(struct console *con)
+ 		return false;
+ 	if (con->write_atomic && kernel_sync_mode())
+ 		return true;
++	if (con->write && (con->flags & CON_BOOT) && !con->thread)
++		return true;
+ 	return false;
+ }
+ 
+@@ -1766,6 +1757,8 @@ static bool call_sync_console_driver(struct console *con, const char *text, size
+ 		return false;
+ 	if (con->write_atomic && kernel_sync_mode())
+ 		con->write_atomic(con, text, text_len);
++	else if (con->write && (con->flags & CON_BOOT) && !con->thread)
++		con->write(con, text, text_len);
+ 	else
+ 		return false;
+ 
+@@ -1821,202 +1814,16 @@ static void print_sync_until(struct console *con, u64 seq)
+ 
+ 	console_atomic_lock(&flags);
+ 	for (;;) {
+-		printk_seq = atomic64_read(&console_seq);
++		printk_seq = atomic64_read(&con->printk_seq);
+ 		if (printk_seq >= seq)
+ 			break;
+ 		if (!print_sync(con, &printk_seq))
+ 			break;
+-		atomic64_set(&console_seq, printk_seq + 1);
++		atomic64_set(&con->printk_seq, printk_seq + 1);
+ 	}
+ 	console_atomic_unlock(flags);
+ }
+ 
+-/*
+- * Special console_lock variants that help to reduce the risk of soft-lockups.
+- * They allow to pass console_lock to another printk() call using a busy wait.
+- */
+-
+-#ifdef CONFIG_LOCKDEP
+-static struct lockdep_map console_owner_dep_map = {
+-	.name = "console_owner"
+-};
+-#endif
+-
+-static DEFINE_RAW_SPINLOCK(console_owner_lock);
+-static struct task_struct *console_owner;
+-static bool console_waiter;
+-
+-/**
+- * console_lock_spinning_enable - mark beginning of code where another
+- *	thread might safely busy wait
+- *
+- * This basically converts console_lock into a spinlock. This marks
+- * the section where the console_lock owner can not sleep, because
+- * there may be a waiter spinning (like a spinlock). Also it must be
+- * ready to hand over the lock at the end of the section.
+- */
+-static void console_lock_spinning_enable(void)
+-{
+-	raw_spin_lock(&console_owner_lock);
+-	console_owner = current;
+-	raw_spin_unlock(&console_owner_lock);
+-
+-	/* The waiter may spin on us after setting console_owner */
+-	spin_acquire(&console_owner_dep_map, 0, 0, _THIS_IP_);
+-}
+-
+-/**
+- * console_lock_spinning_disable_and_check - mark end of code where another
+- *	thread was able to busy wait and check if there is a waiter
+- *
+- * This is called at the end of the section where spinning is allowed.
+- * It has two functions. First, it is a signal that it is no longer
+- * safe to start busy waiting for the lock. Second, it checks if
+- * there is a busy waiter and passes the lock rights to her.
+- *
+- * Important: Callers lose the lock if there was a busy waiter.
+- *	They must not touch items synchronized by console_lock
+- *	in this case.
+- *
+- * Return: 1 if the lock rights were passed, 0 otherwise.
+- */
+-static int console_lock_spinning_disable_and_check(void)
+-{
+-	int waiter;
+-
+-	raw_spin_lock(&console_owner_lock);
+-	waiter = READ_ONCE(console_waiter);
+-	console_owner = NULL;
+-	raw_spin_unlock(&console_owner_lock);
+-
+-	if (!waiter) {
+-		spin_release(&console_owner_dep_map, _THIS_IP_);
+-		return 0;
+-	}
+-
+-	/* The waiter is now free to continue */
+-	WRITE_ONCE(console_waiter, false);
+-
+-	spin_release(&console_owner_dep_map, _THIS_IP_);
+-
+-	/*
+-	 * Hand off console_lock to waiter. The waiter will perform
+-	 * the up(). After this, the waiter is the console_lock owner.
+-	 */
+-	mutex_release(&console_lock_dep_map, _THIS_IP_);
+-	return 1;
+-}
+-
+-/**
+- * console_trylock_spinning - try to get console_lock by busy waiting
+- *
+- * This allows to busy wait for the console_lock when the current
+- * owner is running in specially marked sections. It means that
+- * the current owner is running and cannot reschedule until it
+- * is ready to lose the lock.
+- *
+- * Return: 1 if we got the lock, 0 othrewise
+- */
+-static int console_trylock_spinning(void)
+-{
+-	struct task_struct *owner = NULL;
+-	bool waiter;
+-	bool spin = false;
+-	unsigned long flags;
+-
+-	if (console_trylock())
+-		return 1;
+-
+-	printk_safe_enter_irqsave(flags);
+-
+-	raw_spin_lock(&console_owner_lock);
+-	owner = READ_ONCE(console_owner);
+-	waiter = READ_ONCE(console_waiter);
+-	if (!waiter && owner && owner != current) {
+-		WRITE_ONCE(console_waiter, true);
+-		spin = true;
+-	}
+-	raw_spin_unlock(&console_owner_lock);
+-
+-	/*
+-	 * If there is an active printk() writing to the
+-	 * consoles, instead of having it write our data too,
+-	 * see if we can offload that load from the active
+-	 * printer, and do some printing ourselves.
+-	 * Go into a spin only if there isn't already a waiter
+-	 * spinning, and there is an active printer, and
+-	 * that active printer isn't us (recursive printk?).
+-	 */
+-	if (!spin) {
+-		printk_safe_exit_irqrestore(flags);
+-		return 0;
+-	}
+-
+-	/* We spin waiting for the owner to release us */
+-	spin_acquire(&console_owner_dep_map, 0, 0, _THIS_IP_);
+-	/* Owner will clear console_waiter on hand off */
+-	while (READ_ONCE(console_waiter))
+-		cpu_relax();
+-	spin_release(&console_owner_dep_map, _THIS_IP_);
+-
+-	printk_safe_exit_irqrestore(flags);
+-	/*
+-	 * The owner passed the console lock to us.
+-	 * Since we did not spin on console lock, annotate
+-	 * this as a trylock. Otherwise lockdep will
+-	 * complain.
+-	 */
+-	mutex_acquire(&console_lock_dep_map, 0, 1, _THIS_IP_);
+-
+-	return 1;
+-}
+-
+-/*
+- * Call the console drivers, asking them to write out
+- * log_buf[start] to log_buf[end - 1].
+- * The console_lock must be held.
+- */
+-static void call_console_drivers(const char *ext_text, size_t ext_len,
+-				 const char *text, size_t len)
+-{
+-	static char dropped_text[64];
+-	size_t dropped_len = 0;
+-	struct console *con;
+-
+-	trace_console_rcuidle(text, len);
+-
+-	if (!console_drivers)
+-		return;
+-
+-	if (console_dropped) {
+-		dropped_len = snprintf(dropped_text, sizeof(dropped_text),
+-				       "** %lu printk messages dropped **\n",
+-				       console_dropped);
+-		console_dropped = 0;
+-	}
+-
+-	for_each_console(con) {
+-		if (exclusive_console && con != exclusive_console)
+-			continue;
+-		if (!(con->flags & CON_ENABLED))
+-			continue;
+-		if (!con->write)
+-			continue;
+-		if (!cpu_online(smp_processor_id()) &&
+-		    !(con->flags & CON_ANYTIME))
+-			continue;
+-		if (kernel_sync_mode())
+-			continue;
+-		if (con->flags & CON_EXTENDED)
+-			con->write(con, ext_text, ext_len);
+-		else {
+-			if (dropped_len)
+-				con->write(con, dropped_text, dropped_len);
+-			con->write(con, text, len);
+-		}
+-	}
+-}
+-
+ #ifdef CONFIG_PRINTK_NMI
+ #define NUM_RECURSION_CTX 2
+ #else
+@@ -2287,39 +2094,16 @@ asmlinkage int vprintk_emit(int facility, int level,
+ 			    const char *fmt, va_list args)
+ {
+ 	int printed_len;
+-	bool in_sched = false;
+ 
+ 	/* Suppress unimportant messages after panic happens */
+ 	if (unlikely(suppress_printk))
+ 		return 0;
+ 
+-	if (level == LOGLEVEL_SCHED) {
++	if (level == LOGLEVEL_SCHED)
+ 		level = LOGLEVEL_DEFAULT;
+-		in_sched = true;
+-	}
+-
+-	printk_delay(level);
+ 
+ 	printed_len = vprintk_store(facility, level, dev_info, fmt, args);
+ 
+-	/* If called from the scheduler, we can not call up(). */
+-	if (!in_sched) {
+-		/*
+-		 * Disable preemption to avoid being preempted while holding
+-		 * console_sem which would prevent anyone from printing to
+-		 * console
+-		 */
+-		preempt_disable();
+-		/*
+-		 * Try to acquire and then immediately release the console
+-		 * semaphore.  The release will print out buffers and wake up
+-		 * /dev/kmsg and syslog() users.
+-		 */
+-		if (console_trylock_spinning())
+-			console_unlock();
+-		preempt_enable();
+-	}
+-
+ 	wake_up_klogd();
+ 	return printed_len;
+ }
+@@ -2371,38 +2155,158 @@ asmlinkage __visible int printk(const char *fmt, ...)
+ }
+ EXPORT_SYMBOL(printk);
+ 
+-#else /* CONFIG_PRINTK */
++static int printk_kthread_func(void *data)
++{
++	struct console *con = data;
++	unsigned long dropped = 0;
++	char *dropped_text = NULL;
++	struct printk_info info;
++	struct printk_record r;
++	char *ext_text = NULL;
++	size_t dropped_len;
++	int ret = -ENOMEM;
++	char *text = NULL;
++	char *write_text;
++	u64 printk_seq;
++	size_t len;
++	int error;
++	u64 seq;
+ 
+-#define printk_time		false
++	if (con->flags & CON_EXTENDED) {
++		ext_text = kmalloc(CONSOLE_EXT_LOG_MAX, GFP_KERNEL);
++		if (!ext_text)
++			goto out;
++	}
++	text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
++	dropped_text = kmalloc(64, GFP_KERNEL);
++	if (!text || !dropped_text)
++		goto out;
+ 
+-#define prb_read_valid(rb, seq, r)	false
+-#define prb_first_valid_seq(rb)		0
++	if (con->flags & CON_EXTENDED)
++		write_text = ext_text;
++	else
++		write_text = text;
+ 
+-#define kernel_sync_mode()	false
++	seq = atomic64_read(&con->printk_seq);
+ 
+-static u64 syslog_seq;
+-static atomic64_t console_seq = ATOMIC64_INIT(0);
+-static u64 exclusive_console_stop_seq;
+-static unsigned long console_dropped;
++	prb_rec_init_rd(&r, &info, text, LOG_LINE_MAX + PREFIX_MAX);
++
++	for (;;) {
++		error = wait_event_interruptible(log_wait,
++				prb_read_valid(prb, seq, &r) || kthread_should_stop());
++
++		if (kthread_should_stop())
++			break;
++
++		if (error)
++			continue;
++
++		if (seq != r.info->seq) {
++			dropped += r.info->seq - seq;
++			seq = r.info->seq;
++		}
++
++		seq++;
++
++		if (!(con->flags & CON_ENABLED))
++			continue;
++
++		if (suppress_message_printing(r.info->level))
++			continue;
++
++		if (con->flags & CON_EXTENDED) {
++			len = info_print_ext_header(ext_text,
++				CONSOLE_EXT_LOG_MAX,
++				r.info);
++			len += msg_print_ext_body(ext_text + len,
++				CONSOLE_EXT_LOG_MAX - len,
++				&r.text_buf[0], r.info->text_len,
++				&r.info->dev_info);
++		} else {
++			len = record_print_text(&r,
++				console_msg_format & MSG_FORMAT_SYSLOG,
++				printk_time);
++		}
++
++		printk_seq = atomic64_read(&con->printk_seq);
+ 
+-static size_t record_print_text(const struct printk_record *r,
+-				bool syslog, bool time)
++		console_lock();
++		console_may_schedule = 0;
++
++		if (kernel_sync_mode() && con->write_atomic) {
++			console_unlock();
++			break;
++		}
++
++		if (!(con->flags & CON_EXTENDED) && dropped) {
++			dropped_len = snprintf(dropped_text, 64,
++					       "** %lu printk messages dropped **\n",
++					       dropped);
++			dropped = 0;
++
++			con->write(con, dropped_text, dropped_len);
++			printk_delay(r.info->level);
++		}
++
++		con->write(con, write_text, len);
++		if (len)
++			printk_delay(r.info->level);
++
++		atomic64_cmpxchg_relaxed(&con->printk_seq, printk_seq, seq);
++
++		console_unlock();
++	}
++out:
++	kfree(dropped_text);
++	kfree(text);
++	kfree(ext_text);
++	pr_info("%sconsole [%s%d]: printing thread stopped\n",
++		(con->flags & CON_BOOT) ? "boot" : "",
++		con->name, con->index);
++	return ret;
++}
++
++/* Must be called within console_lock(). */
++static void start_printk_kthread(struct console *con)
+ {
+-	return 0;
++	con->thread = kthread_run(printk_kthread_func, con,
++				  "pr/%s%d", con->name, con->index);
++	if (IS_ERR(con->thread)) {
++		pr_err("%sconsole [%s%d]: unable to start printing thread\n",
++			(con->flags & CON_BOOT) ? "boot" : "",
++			con->name, con->index);
++		return;
++	}
++	pr_info("%sconsole [%s%d]: printing thread started\n",
++		(con->flags & CON_BOOT) ? "boot" : "",
++		con->name, con->index);
+ }
+-static ssize_t info_print_ext_header(char *buf, size_t size,
+-				     struct printk_info *info)
++
++/* protected by console_lock */
++static bool kthreads_started;
++
++/* Must be called within console_lock(). */
++static void console_try_thread(struct console *con)
+ {
+-	return 0;
++	if (kthreads_started) {
++		start_printk_kthread(con);
++		return;
++	}
++
++	/*
++	 * The printing threads have not been started yet. If this console
++	 * can print synchronously, print all unprinted messages.
++	 */
++	if (console_can_sync(con))
++		print_sync_until(con, prb_next_seq(prb));
+ }
+-static ssize_t msg_print_ext_body(char *buf, size_t size,
+-				  char *text, size_t text_len,
+-				  struct dev_printk_info *dev_info) { return 0; }
+-static void console_lock_spinning_enable(void) { }
+-static int console_lock_spinning_disable_and_check(void) { return 0; }
+-static void call_console_drivers(const char *ext_text, size_t ext_len,
+-				 const char *text, size_t len) {}
+-static bool suppress_message_printing(int level) { return false; }
++
++#else /* CONFIG_PRINTK */
++
++#define prb_first_valid_seq(rb)		0
++#define prb_next_seq(rb)		0
++
++#define console_try_thread(con)
+ 
+ #endif /* CONFIG_PRINTK */
+ 
+@@ -2647,36 +2551,6 @@ int is_console_locked(void)
+ }
+ EXPORT_SYMBOL(is_console_locked);
+ 
+-/*
+- * Check if we have any console that is capable of printing while cpu is
+- * booting or shutting down. Requires console_sem.
+- */
+-static int have_callable_console(void)
+-{
+-	struct console *con;
+-
+-	for_each_console(con)
+-		if ((con->flags & CON_ENABLED) &&
+-				(con->flags & CON_ANYTIME))
+-			return 1;
+-
+-	return 0;
+-}
+-
+-/*
+- * Can we actually use the console at this time on this cpu?
+- *
+- * Console drivers may assume that per-cpu resources have been allocated. So
+- * unless they're explicitly marked as being able to cope (CON_ANYTIME) don't
+- * call them until this CPU is officially up.
+- */
+-static inline int can_use_console(void)
+-{
+-	if (kernel_sync_mode())
+-		return false;
+-	return cpu_online(raw_smp_processor_id()) || have_callable_console();
+-}
+-
+ /**
+  * console_unlock - unlock the console system
+  *
+@@ -2693,131 +2567,14 @@ static inline int can_use_console(void)
+  */
+ void console_unlock(void)
+ {
+-	static char ext_text[CONSOLE_EXT_LOG_MAX];
+-	static char text[CONSOLE_LOG_MAX];
+-	bool do_cond_resched, retry;
+-	struct printk_info info;
+-	struct printk_record r;
+-	u64 seq;
+-
+ 	if (console_suspended) {
+ 		up_console_sem();
+ 		return;
+ 	}
+ 
+-	prb_rec_init_rd(&r, &info, text, sizeof(text));
+-
+-	/*
+-	 * Console drivers are called with interrupts disabled, so
+-	 * @console_may_schedule should be cleared before; however, we may
+-	 * end up dumping a lot of lines, for example, if called from
+-	 * console registration path, and should invoke cond_resched()
+-	 * between lines if allowable.  Not doing so can cause a very long
+-	 * scheduling stall on a slow console leading to RCU stall and
+-	 * softlockup warnings which exacerbate the issue with more
+-	 * messages practically incapacitating the system.
+-	 *
+-	 * console_trylock() is not able to detect the preemptive
+-	 * context reliably. Therefore the value must be stored before
+-	 * and cleared after the "again" goto label.
+-	 */
+-	do_cond_resched = console_may_schedule;
+-again:
+-	console_may_schedule = 0;
+-
+-	/*
+-	 * We released the console_sem lock, so we need to recheck if
+-	 * cpu is online and (if not) is there at least one CON_ANYTIME
+-	 * console.
+-	 */
+-	if (!can_use_console()) {
+-		console_locked = 0;
+-		up_console_sem();
+-		return;
+-	}
+-
+-	for (;;) {
+-		size_t ext_len = 0;
+-		size_t len;
+-
+-skip:
+-		seq = atomic64_read(&console_seq);
+-		if (!prb_read_valid(prb, seq, &r))
+-			break;
+-
+-		if (seq != r.info->seq) {
+-			console_dropped += r.info->seq - seq;
+-			atomic64_set(&console_seq, r.info->seq);
+-			seq = r.info->seq;
+-		}
+-
+-		if (suppress_message_printing(r.info->level)) {
+-			/*
+-			 * Skip record we have buffered and already printed
+-			 * directly to the console when we received it, and
+-			 * record that has level above the console loglevel.
+-			 */
+-			atomic64_set(&console_seq, seq + 1);
+-			goto skip;
+-		}
+-
+-		/* Output to all consoles once old messages replayed. */
+-		if (unlikely(exclusive_console &&
+-			     seq >= exclusive_console_stop_seq)) {
+-			exclusive_console = NULL;
+-		}
+-
+-		/*
+-		 * Handle extended console text first because later
+-		 * record_print_text() will modify the record buffer in-place.
+-		 */
+-		if (nr_ext_console_drivers) {
+-			ext_len = info_print_ext_header(ext_text,
+-						sizeof(ext_text),
+-						r.info);
+-			ext_len += msg_print_ext_body(ext_text + ext_len,
+-						sizeof(ext_text) - ext_len,
+-						&r.text_buf[0],
+-						r.info->text_len,
+-						&r.info->dev_info);
+-		}
+-		len = record_print_text(&r,
+-				console_msg_format & MSG_FORMAT_SYSLOG,
+-				printk_time);
+-		atomic64_set(&console_seq, seq + 1);
+-
+-		/*
+-		 * While actively printing out messages, if another printk()
+-		 * were to occur on another CPU, it may wait for this one to
+-		 * finish. This task can not be preempted if there is a
+-		 * waiter waiting to take over.
+-		 */
+-		console_lock_spinning_enable();
+-
+-		stop_critical_timings();	/* don't trace print latency */
+-		call_console_drivers(ext_text, ext_len, text, len);
+-		start_critical_timings();
+-
+-		if (console_lock_spinning_disable_and_check())
+-			return;
+-
+-		if (do_cond_resched)
+-			cond_resched();
+-	}
+-
+ 	console_locked = 0;
+ 
+ 	up_console_sem();
+-
+-	/*
+-	 * Someone could have filled up the buffer again, so re-check if there's
+-	 * something to flush. In case we cannot trylock the console_sem again,
+-	 * there's a new owner and the console_unlock() from them will do the
+-	 * flush, no worries.
+-	 */
+-	retry = prb_read_valid(prb, atomic64_read(&console_seq), NULL);
+-	if (retry && console_trylock())
+-		goto again;
+ }
+ EXPORT_SYMBOL(console_unlock);
+ 
+@@ -2867,18 +2624,20 @@ void console_unblank(void)
+  */
+ void console_flush_on_panic(enum con_flush_mode mode)
+ {
+-	/*
+-	 * If someone else is holding the console lock, trylock will fail
+-	 * and may_schedule may be set.  Ignore and proceed to unlock so
+-	 * that messages are flushed out.  As this can be called from any
+-	 * context and we don't want to get preempted while flushing,
+-	 * ensure may_schedule is cleared.
+-	 */
+-	console_trylock();
++	struct console *c;
++	u64 seq;
++
++	if (!console_trylock())
++		return;
++
+ 	console_may_schedule = 0;
+ 
+-	if (mode == CONSOLE_REPLAY_ALL)
+-		atomic64_set(&console_seq, prb_first_valid_seq(prb));
++	if (mode == CONSOLE_REPLAY_ALL) {
++		seq = prb_first_valid_seq(prb);
++		for_each_console(c)
++			atomic64_set(&c->printk_seq, seq);
++	}
++
+ 	console_unlock();
+ }
+ 
+@@ -3013,7 +2772,6 @@ static int try_enable_new_console(struct console *newcon, bool user_specified)
+  */
+ void register_console(struct console *newcon)
+ {
+-	unsigned long flags;
+ 	struct console *bcon = NULL;
+ 	int err;
+ 
+@@ -3037,6 +2795,8 @@ void register_console(struct console *newcon)
+ 		}
+ 	}
+ 
++	newcon->thread = NULL;
++
+ 	if (console_drivers && console_drivers->flags & CON_BOOT)
+ 		bcon = console_drivers;
+ 
+@@ -3101,27 +2861,12 @@ void register_console(struct console *newcon)
+ 	if (newcon->flags & CON_EXTENDED)
+ 		nr_ext_console_drivers++;
+ 
+-	if (newcon->flags & CON_PRINTBUFFER) {
+-		/*
+-		 * console_unlock(); will print out the buffered messages
+-		 * for us.
+-		 *
+-		 * We're about to replay the log buffer.  Only do this to the
+-		 * just-registered console to avoid excessive message spam to
+-		 * the already-registered consoles.
+-		 *
+-		 * Set exclusive_console with disabled interrupts to reduce
+-		 * race window with eventual console_flush_on_panic() that
+-		 * ignores console_lock.
+-		 */
+-		exclusive_console = newcon;
+-		exclusive_console_stop_seq = atomic64_read(&console_seq);
++	if (newcon->flags & CON_PRINTBUFFER)
++		atomic64_set(&newcon->printk_seq, 0);
++	else
++		atomic64_set(&newcon->printk_seq, prb_next_seq(prb));
+ 
+-		/* Get a consistent copy of @syslog_seq. */
+-		spin_lock_irqsave(&syslog_lock, flags);
+-		atomic64_set(&console_seq, syslog_seq);
+-		spin_unlock_irqrestore(&syslog_lock, flags);
+-	}
++	console_try_thread(newcon);
+ 	console_unlock();
+ 	console_sysfs_notify();
+ 
+@@ -3195,6 +2940,9 @@ int unregister_console(struct console *console)
+ 	console_unlock();
+ 	console_sysfs_notify();
+ 
++	if (console->thread && !IS_ERR(console->thread))
++		kthread_stop(console->thread);
++
+ 	if (console->exit)
+ 		res = console->exit(console);
+ 
+@@ -3277,6 +3025,15 @@ static int __init printk_late_init(void)
+ 			unregister_console(con);
+ 		}
+ 	}
++
++#ifdef CONFIG_PRINTK
++	console_lock();
++	for_each_console(con)
++		start_printk_kthread(con);
++	kthreads_started = true;
++	console_unlock();
++#endif
++
+ 	ret = cpuhp_setup_state_nocalls(CPUHP_PRINTK_DEAD, "printk:dead", NULL,
+ 					console_cpu_notify);
+ 	WARN_ON(ret < 0);
+@@ -3292,7 +3049,6 @@ late_initcall(printk_late_init);
+  * Delayed printk version, for scheduler-internal messages:
+  */
+ #define PRINTK_PENDING_WAKEUP	0x01
+-#define PRINTK_PENDING_OUTPUT	0x02
+ 
+ static DEFINE_PER_CPU(int, printk_pending);
+ 
+@@ -3300,14 +3056,8 @@ static void wake_up_klogd_work_func(struct irq_work *irq_work)
+ {
+ 	int pending = __this_cpu_xchg(printk_pending, 0);
+ 
+-	if (pending & PRINTK_PENDING_OUTPUT) {
+-		/* If trylock fails, someone else is doing the printing */
+-		if (console_trylock())
+-			console_unlock();
+-	}
+-
+ 	if (pending & PRINTK_PENDING_WAKEUP)
+-		wake_up_interruptible(&log_wait);
++		wake_up_interruptible_all(&log_wait);
+ }
+ 
+ static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
+@@ -3330,13 +3080,6 @@ void wake_up_klogd(void)
+ 
+ void defer_console_output(void)
+ {
+-	if (!printk_percpu_data_ready())
+-		return;
+-
+-	preempt_disable();
+-	__this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
+-	irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
+-	preempt_enable();
+ }
+ 
+ int vprintk_deferred(const char *fmt, va_list args)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0106-printk-remove-deferred-printing.patch b/debian/patches-rt/0106-printk-remove-deferred-printing.patch
new file mode 100644
index 000000000..b65397f57
--- /dev/null
+++ b/debian/patches-rt/0106-printk-remove-deferred-printing.patch
@@ -0,0 +1,432 @@
+From f1e8f72e9d5c1df1ddaac09999645f7255219d77 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 30 Nov 2020 01:42:08 +0106
+Subject: [PATCH 106/323] printk: remove deferred printing
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Since printing occurs either atomically or from the printing
+kthread, there is no need for any deferring or tracking possible
+recursion paths. Remove all printk context tracking.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/arm/kernel/smp.c       |  2 -
+ arch/powerpc/kexec/crash.c  |  3 --
+ include/linux/hardirq.h     |  2 -
+ include/linux/printk.h      | 12 -----
+ kernel/printk/Makefile      |  1 -
+ kernel/printk/internal.h    | 70 -----------------------------
+ kernel/printk/printk.c      | 58 ++++++++++--------------
+ kernel/printk/printk_safe.c | 88 -------------------------------------
+ kernel/trace/trace.c        |  2 -
+ 9 files changed, 22 insertions(+), 216 deletions(-)
+ delete mode 100644 kernel/printk/internal.h
+ delete mode 100644 kernel/printk/printk_safe.c
+
+diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
+index 8aa7fa949c23..3693706ba0a1 100644
+--- a/arch/arm/kernel/smp.c
++++ b/arch/arm/kernel/smp.c
+@@ -671,9 +671,7 @@ static void do_handle_IPI(int ipinr)
+ 		break;
+ 
+ 	case IPI_CPU_BACKTRACE:
+-		printk_nmi_enter();
+ 		nmi_cpu_backtrace(get_irq_regs());
+-		printk_nmi_exit();
+ 		break;
+ 
+ 	default:
+diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c
+index c9a889880214..d488311efab1 100644
+--- a/arch/powerpc/kexec/crash.c
++++ b/arch/powerpc/kexec/crash.c
+@@ -311,9 +311,6 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
+ 	unsigned int i;
+ 	int (*old_handler)(struct pt_regs *regs);
+ 
+-	/* Avoid hardlocking with irresponsive CPU holding logbuf_lock */
+-	printk_nmi_enter();
+-
+ 	/*
+ 	 * This function is only called after the system
+ 	 * has panicked or is otherwise in a critical state.
+diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
+index 754f67ac4326..c35b71f8644a 100644
+--- a/include/linux/hardirq.h
++++ b/include/linux/hardirq.h
+@@ -115,7 +115,6 @@ extern void rcu_nmi_exit(void);
+ 	do {							\
+ 		lockdep_off();					\
+ 		arch_nmi_enter();				\
+-		printk_nmi_enter();				\
+ 		BUG_ON(in_nmi() == NMI_MASK);			\
+ 		__preempt_count_add(NMI_OFFSET + HARDIRQ_OFFSET);	\
+ 	} while (0)
+@@ -134,7 +133,6 @@ extern void rcu_nmi_exit(void);
+ 	do {							\
+ 		BUG_ON(!in_nmi());				\
+ 		__preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET);	\
+-		printk_nmi_exit();				\
+ 		arch_nmi_exit();				\
+ 		lockdep_on();					\
+ 	} while (0)
+diff --git a/include/linux/printk.h b/include/linux/printk.h
+index 3738374e2b3b..410435ac15ea 100644
+--- a/include/linux/printk.h
++++ b/include/linux/printk.h
+@@ -155,18 +155,6 @@ static inline __printf(1, 2) __cold
+ void early_printk(const char *s, ...) { }
+ #endif
+ 
+-#ifdef CONFIG_PRINTK_NMI
+-extern void printk_nmi_enter(void);
+-extern void printk_nmi_exit(void);
+-extern void printk_nmi_direct_enter(void);
+-extern void printk_nmi_direct_exit(void);
+-#else
+-static inline void printk_nmi_enter(void) { }
+-static inline void printk_nmi_exit(void) { }
+-static inline void printk_nmi_direct_enter(void) { }
+-static inline void printk_nmi_direct_exit(void) { }
+-#endif /* PRINTK_NMI */
+-
+ struct dev_printk_info;
+ 
+ #ifdef CONFIG_PRINTK
+diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile
+index eee3dc9b60a9..59cb24e25f00 100644
+--- a/kernel/printk/Makefile
++++ b/kernel/printk/Makefile
+@@ -1,5 +1,4 @@
+ # SPDX-License-Identifier: GPL-2.0-only
+ obj-y	= printk.o
+-obj-$(CONFIG_PRINTK)	+= printk_safe.o
+ obj-$(CONFIG_A11Y_BRAILLE_CONSOLE)	+= braille.o
+ obj-$(CONFIG_PRINTK)	+= printk_ringbuffer.o
+diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
+deleted file mode 100644
+index e108b2ece8c7..000000000000
+--- a/kernel/printk/internal.h
++++ /dev/null
+@@ -1,70 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0-or-later */
+-/*
+- * internal.h - printk internal definitions
+- */
+-#include <linux/percpu.h>
+-
+-#ifdef CONFIG_PRINTK
+-
+-#define PRINTK_SAFE_CONTEXT_MASK	0x007ffffff
+-#define PRINTK_NMI_DIRECT_CONTEXT_MASK	0x008000000
+-#define PRINTK_NMI_CONTEXT_MASK		0xff0000000
+-
+-#define PRINTK_NMI_CONTEXT_OFFSET	0x010000000
+-
+-__printf(4, 0)
+-int vprintk_store(int facility, int level,
+-		  const struct dev_printk_info *dev_info,
+-		  const char *fmt, va_list args);
+-
+-__printf(1, 0) int vprintk_default(const char *fmt, va_list args);
+-__printf(1, 0) int vprintk_deferred(const char *fmt, va_list args);
+-__printf(1, 0) int vprintk_func(const char *fmt, va_list args);
+-void __printk_safe_enter(void);
+-void __printk_safe_exit(void);
+-
+-bool printk_percpu_data_ready(void);
+-
+-#define printk_safe_enter_irqsave(flags)	\
+-	do {					\
+-		local_irq_save(flags);		\
+-		__printk_safe_enter();		\
+-	} while (0)
+-
+-#define printk_safe_exit_irqrestore(flags)	\
+-	do {					\
+-		__printk_safe_exit();		\
+-		local_irq_restore(flags);	\
+-	} while (0)
+-
+-#define printk_safe_enter_irq()		\
+-	do {					\
+-		local_irq_disable();		\
+-		__printk_safe_enter();		\
+-	} while (0)
+-
+-#define printk_safe_exit_irq()			\
+-	do {					\
+-		__printk_safe_exit();		\
+-		local_irq_enable();		\
+-	} while (0)
+-
+-void defer_console_output(void);
+-
+-#else
+-
+-__printf(1, 0) int vprintk_func(const char *fmt, va_list args) { return 0; }
+-
+-/*
+- * In !PRINTK builds we still export console_sem
+- * semaphore and some of console functions (console_unlock()/etc.), so
+- * printk-safe must preserve the existing local IRQ guarantees.
+- */
+-#define printk_safe_enter_irqsave(flags) local_irq_save(flags)
+-#define printk_safe_exit_irqrestore(flags) local_irq_restore(flags)
+-
+-#define printk_safe_enter_irq() local_irq_disable()
+-#define printk_safe_exit_irq() local_irq_enable()
+-
+-static inline bool printk_percpu_data_ready(void) { return false; }
+-#endif /* CONFIG_PRINTK */
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 232ce58e94c2..2b110b9ae34a 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -45,6 +45,7 @@
+ #include <linux/ctype.h>
+ #include <linux/uio.h>
+ #include <linux/kthread.h>
++#include <linux/kdb.h>
+ #include <linux/clocksource.h>
+ #include <linux/sched/clock.h>
+ #include <linux/sched/debug.h>
+@@ -60,7 +61,6 @@
+ #include "printk_ringbuffer.h"
+ #include "console_cmdline.h"
+ #include "braille.h"
+-#include "internal.h"
+ 
+ int console_printk[4] = {
+ 	CONSOLE_LOGLEVEL_DEFAULT,	/* console_loglevel */
+@@ -229,19 +229,7 @@ static int nr_ext_console_drivers;
+ 
+ static int __down_trylock_console_sem(unsigned long ip)
+ {
+-	int lock_failed;
+-	unsigned long flags;
+-
+-	/*
+-	 * Here and in __up_console_sem() we need to be in safe mode,
+-	 * because spindump/WARN/etc from under console ->lock will
+-	 * deadlock in printk()->down_trylock_console_sem() otherwise.
+-	 */
+-	printk_safe_enter_irqsave(flags);
+-	lock_failed = down_trylock(&console_sem);
+-	printk_safe_exit_irqrestore(flags);
+-
+-	if (lock_failed)
++	if (down_trylock(&console_sem))
+ 		return 1;
+ 	mutex_acquire(&console_lock_dep_map, 0, 1, ip);
+ 	return 0;
+@@ -250,13 +238,9 @@ static int __down_trylock_console_sem(unsigned long ip)
+ 
+ static void __up_console_sem(unsigned long ip)
+ {
+-	unsigned long flags;
+-
+ 	mutex_release(&console_lock_dep_map, ip);
+ 
+-	printk_safe_enter_irqsave(flags);
+ 	up(&console_sem);
+-	printk_safe_exit_irqrestore(flags);
+ }
+ #define up_console_sem() __up_console_sem(_RET_IP_)
+ 
+@@ -428,7 +412,7 @@ static struct printk_ringbuffer *prb = &printk_rb_static;
+  */
+ static bool __printk_percpu_data_ready __read_mostly;
+ 
+-bool printk_percpu_data_ready(void)
++static bool printk_percpu_data_ready(void)
+ {
+ 	return __printk_percpu_data_ready;
+ }
+@@ -1063,7 +1047,6 @@ void __init setup_log_buf(int early)
+ 	struct printk_record r;
+ 	size_t new_descs_size;
+ 	size_t new_infos_size;
+-	unsigned long flags;
+ 	char *new_log_buf;
+ 	unsigned int free;
+ 	u64 seq;
+@@ -1961,9 +1944,9 @@ static u16 printk_sprint(char *text, u16 size, int facility, enum log_flags *lfl
+ }
+ 
+ __printf(4, 0)
+-int vprintk_store(int facility, int level,
+-		  const struct dev_printk_info *dev_info,
+-		  const char *fmt, va_list args)
++static int vprintk_store(int facility, int level,
++			 const struct dev_printk_info *dev_info,
++			 const char *fmt, va_list args)
+ {
+ 	const u32 caller_id = printk_caller_id();
+ 	struct prb_reserved_entry e;
+@@ -2109,11 +2092,22 @@ asmlinkage int vprintk_emit(int facility, int level,
+ }
+ EXPORT_SYMBOL(vprintk_emit);
+ 
+-int vprintk_default(const char *fmt, va_list args)
++__printf(1, 0)
++static int vprintk_default(const char *fmt, va_list args)
+ {
+ 	return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, fmt, args);
+ }
+-EXPORT_SYMBOL_GPL(vprintk_default);
++
++__printf(1, 0)
++static int vprintk_func(const char *fmt, va_list args)
++{
++#ifdef CONFIG_KGDB_KDB
++	/* Allow to pass printk() to kdb but avoid a recursion. */
++	if (unlikely(kdb_trap_printk && kdb_printf_cpu < 0))
++		return vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args);
++#endif
++	return vprintk_default(fmt, args);
++}
+ 
+ asmlinkage int vprintk(const char *fmt, va_list args)
+ {
+@@ -3078,18 +3072,10 @@ void wake_up_klogd(void)
+ 	preempt_enable();
+ }
+ 
+-void defer_console_output(void)
+-{
+-}
+-
+-int vprintk_deferred(const char *fmt, va_list args)
++__printf(1, 0)
++static int vprintk_deferred(const char *fmt, va_list args)
+ {
+-	int r;
+-
+-	r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, fmt, args);
+-	defer_console_output();
+-
+-	return r;
++	return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, fmt, args);
+ }
+ 
+ int printk_deferred(const char *fmt, ...)
+diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
+deleted file mode 100644
+index c23b127a6545..000000000000
+--- a/kernel/printk/printk_safe.c
++++ /dev/null
+@@ -1,88 +0,0 @@
+-// SPDX-License-Identifier: GPL-2.0-or-later
+-/*
+- * printk_safe.c - Safe printk for printk-deadlock-prone contexts
+- */
+-
+-#include <linux/preempt.h>
+-#include <linux/spinlock.h>
+-#include <linux/debug_locks.h>
+-#include <linux/kdb.h>
+-#include <linux/smp.h>
+-#include <linux/cpumask.h>
+-#include <linux/irq_work.h>
+-#include <linux/printk.h>
+-#include <linux/kprobes.h>
+-
+-#include "internal.h"
+-
+-static DEFINE_PER_CPU(int, printk_context);
+-
+-#ifdef CONFIG_PRINTK_NMI
+-void noinstr printk_nmi_enter(void)
+-{
+-	this_cpu_add(printk_context, PRINTK_NMI_CONTEXT_OFFSET);
+-}
+-
+-void noinstr printk_nmi_exit(void)
+-{
+-	this_cpu_sub(printk_context, PRINTK_NMI_CONTEXT_OFFSET);
+-}
+-
+-/*
+- * Marks a code that might produce many messages in NMI context
+- * and the risk of losing them is more critical than eventual
+- * reordering.
+- */
+-void printk_nmi_direct_enter(void)
+-{
+-	if (this_cpu_read(printk_context) & PRINTK_NMI_CONTEXT_MASK)
+-		this_cpu_or(printk_context, PRINTK_NMI_DIRECT_CONTEXT_MASK);
+-}
+-
+-void printk_nmi_direct_exit(void)
+-{
+-	this_cpu_and(printk_context, ~PRINTK_NMI_DIRECT_CONTEXT_MASK);
+-}
+-
+-#endif /* CONFIG_PRINTK_NMI */
+-
+-/* Can be preempted by NMI. */
+-void __printk_safe_enter(void)
+-{
+-	this_cpu_inc(printk_context);
+-}
+-
+-/* Can be preempted by NMI. */
+-void __printk_safe_exit(void)
+-{
+-	this_cpu_dec(printk_context);
+-}
+-
+-__printf(1, 0) int vprintk_func(const char *fmt, va_list args)
+-{
+-#ifdef CONFIG_KGDB_KDB
+-	/* Allow to pass printk() to kdb but avoid a recursion. */
+-	if (unlikely(kdb_trap_printk && kdb_printf_cpu < 0))
+-		return vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args);
+-#endif
+-
+-	/*
+-	 * Use the main logbuf even in NMI. But avoid calling console
+-	 * drivers that might have their own locks.
+-	 */
+-	if (this_cpu_read(printk_context) &
+-	    (PRINTK_NMI_DIRECT_CONTEXT_MASK |
+-	     PRINTK_NMI_CONTEXT_MASK |
+-	     PRINTK_SAFE_CONTEXT_MASK)) {
+-		int len;
+-
+-		printk_safe_enter_irqsave(flags);
+-		len = vprintk_store(0, LOGLEVEL_DEFAULT, NULL, fmt, args);
+-		printk_safe_exit_irqrestore(flags);
+-		defer_console_output();
+-		return len;
+-	}
+-
+-	/* No obstacles. */
+-	return vprintk_default(fmt, args);
+-}
+diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
+index 70ab6b46ef8f..5d6730589823 100644
+--- a/kernel/trace/trace.c
++++ b/kernel/trace/trace.c
+@@ -9517,7 +9517,6 @@ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
+ 	tracing_off();
+ 
+ 	local_irq_save(flags);
+-	printk_nmi_direct_enter();
+ 
+ 	/* Simulate the iterator */
+ 	trace_init_global_iter(&iter);
+@@ -9594,7 +9593,6 @@ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
+ 		atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
+ 	}
+ 	atomic_dec(&dump_running);
+-	printk_nmi_direct_exit();
+ 	local_irq_restore(flags);
+ }
+ EXPORT_SYMBOL_GPL(ftrace_dump);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0107-printk-add-console-handover.patch b/debian/patches-rt/0107-printk-add-console-handover.patch
new file mode 100644
index 000000000..9abc4efd5
--- /dev/null
+++ b/debian/patches-rt/0107-printk-add-console-handover.patch
@@ -0,0 +1,76 @@
+From ead093d95a7917fa12f9d4653032eac383d21c1d Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 30 Nov 2020 01:42:09 +0106
+Subject: [PATCH 107/323] printk: add console handover
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+If earlyprintk is used, a boot console will print directly to the
+console immediately. The boot console will unregister itself as soon
+as a non-boot console registers. However, the non-boot console does
+not begin printing until its kthread has started. Since this happens
+much later, there is a long pause in the console output. If the
+ringbuffer is small, messages could even be dropped during the
+pause.
+
+Add a new CON_HANDOVER console flag to be used internally by printk
+in order to track which non-boot console took over from a boot
+console. If handover consoles have implemented write_atomic(), they
+are allowed to print directly to the console until their kthread can
+take over.
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/console.h | 1 +
+ kernel/printk/printk.c  | 8 +++++++-
+ 2 files changed, 8 insertions(+), 1 deletion(-)
+
+diff --git a/include/linux/console.h b/include/linux/console.h
+index 3e99359e0660..027278792eea 100644
+--- a/include/linux/console.h
++++ b/include/linux/console.h
+@@ -138,6 +138,7 @@ static inline int con_debug_leave(void)
+ #define CON_ANYTIME	(16) /* Safe to call when cpu is offline */
+ #define CON_BRL		(32) /* Used for a braille device */
+ #define CON_EXTENDED	(64) /* Use the extended output format a la /dev/kmsg */
++#define CON_HANDOVER	(128) /* Device was previously a boot console. */
+ 
+ struct console {
+ 	char	name[16];
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 2b110b9ae34a..58da007d7c99 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -1729,6 +1729,8 @@ static bool console_can_sync(struct console *con)
+ 		return false;
+ 	if (con->write_atomic && kernel_sync_mode())
+ 		return true;
++	if (con->write_atomic && (con->flags & CON_HANDOVER) && !con->thread)
++		return true;
+ 	if (con->write && (con->flags & CON_BOOT) && !con->thread)
+ 		return true;
+ 	return false;
+@@ -1740,6 +1742,8 @@ static bool call_sync_console_driver(struct console *con, const char *text, size
+ 		return false;
+ 	if (con->write_atomic && kernel_sync_mode())
+ 		con->write_atomic(con, text, text_len);
++	else if (con->write_atomic && (con->flags & CON_HANDOVER) && !con->thread)
++		con->write_atomic(con, text, text_len);
+ 	else if (con->write && (con->flags & CON_BOOT) && !con->thread)
+ 		con->write(con, text, text_len);
+ 	else
+@@ -2832,8 +2836,10 @@ void register_console(struct console *newcon)
+ 	 * the real console are the same physical device, it's annoying to
+ 	 * see the beginning boot messages twice
+ 	 */
+-	if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV))
++	if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) {
+ 		newcon->flags &= ~CON_PRINTBUFFER;
++		newcon->flags |= CON_HANDOVER;
++	}
+ 
+ 	/*
+ 	 *	Put this console in the list - keep the
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0108-printk-add-pr_flush.patch b/debian/patches-rt/0108-printk-add-pr_flush.patch
new file mode 100644
index 000000000..013525f54
--- /dev/null
+++ b/debian/patches-rt/0108-printk-add-pr_flush.patch
@@ -0,0 +1,213 @@
+From cf83f550753a28a3f2a5a7ddd45456fb3ccd03ed Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Mon, 30 Nov 2020 01:42:10 +0106
+Subject: [PATCH 108/323] printk: add pr_flush()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Provide a function to allow waiting for console printers to catch
+up to the latest logged message.
+
+Use pr_flush() to give console printers a chance to finish in
+critical situations if no atomic console is available. For now
+pr_flush() is only used in the most common error paths:
+panic(), print_oops_end_marker(), report_bug(), kmsg_dump().
+
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ include/linux/printk.h |  2 ++
+ kernel/panic.c         | 28 +++++++++------
+ kernel/printk/printk.c | 79 ++++++++++++++++++++++++++++++++++++++++++
+ lib/bug.c              |  1 +
+ 4 files changed, 99 insertions(+), 11 deletions(-)
+
+diff --git a/include/linux/printk.h b/include/linux/printk.h
+index 410435ac15ea..83c7734e9802 100644
+--- a/include/linux/printk.h
++++ b/include/linux/printk.h
+@@ -481,6 +481,8 @@ extern int kptr_restrict;
+ 	no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
+ #endif
+ 
++bool pr_flush(int timeout_ms, bool reset_on_progress);
++
+ /*
+  * ratelimited messages with local ratelimit_state,
+  * no local ratelimit_state used in the !PRINTK case
+diff --git a/kernel/panic.c b/kernel/panic.c
+index 7965f1e31224..5a1a4bf2feb3 100644
+--- a/kernel/panic.c
++++ b/kernel/panic.c
+@@ -244,6 +244,7 @@ void check_panic_on_warn(const char *origin)
+ void panic(const char *fmt, ...)
+ {
+ 	static char buf[1024];
++	va_list args2;
+ 	va_list args;
+ 	long i, i_next = 0, len;
+ 	int state = 0;
+@@ -260,6 +261,21 @@ void panic(const char *fmt, ...)
+ 		panic_on_warn = 0;
+ 	}
+ 
++	console_verbose();
++	pr_emerg("Kernel panic - not syncing:\n");
++	va_start(args2, fmt);
++	va_copy(args, args2);
++	vprintk(fmt, args2);
++	va_end(args2);
++#ifdef CONFIG_DEBUG_BUGVERBOSE
++	/*
++	 * Avoid nested stack-dumping if a panic occurs during oops processing
++	 */
++	if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
++		dump_stack();
++#endif
++	pr_flush(1000, true);
++
+ 	/*
+ 	 * Disable local interrupts. This will prevent panic_smp_self_stop
+ 	 * from deadlocking the first cpu that invokes the panic, since
+@@ -290,24 +306,13 @@ void panic(const char *fmt, ...)
+ 	if (old_cpu != PANIC_CPU_INVALID && old_cpu != this_cpu)
+ 		panic_smp_self_stop();
+ 
+-	console_verbose();
+ 	bust_spinlocks(1);
+-	va_start(args, fmt);
+ 	len = vscnprintf(buf, sizeof(buf), fmt, args);
+ 	va_end(args);
+ 
+ 	if (len && buf[len - 1] == '\n')
+ 		buf[len - 1] = '\0';
+ 
+-	pr_emerg("Kernel panic - not syncing: %s\n", buf);
+-#ifdef CONFIG_DEBUG_BUGVERBOSE
+-	/*
+-	 * Avoid nested stack-dumping if a panic occurs during oops processing
+-	 */
+-	if (!test_taint(TAINT_DIE) && oops_in_progress <= 1)
+-		dump_stack();
+-#endif
+-
+ 	/*
+ 	 * If kgdb is enabled, give it a chance to run before we stop all
+ 	 * the other CPUs or else we won't be able to debug processes left
+@@ -629,6 +634,7 @@ static void print_oops_end_marker(void)
+ {
+ 	init_oops_id();
+ 	pr_warn("---[ end trace %016llx ]---\n", (unsigned long long)oops_id);
++	pr_flush(1000, true);
+ }
+ 
+ /*
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 58da007d7c99..14cb111fe9f0 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -3233,6 +3233,12 @@ void kmsg_dump(enum kmsg_dump_reason reason)
+ 			sync_mode = true;
+ 			pr_info("enabled sync mode\n");
+ 		}
++
++		/*
++		 * Give the printing threads time to flush, allowing up to
++		 * 1s of no printing forward progress before giving up.
++		 */
++		pr_flush(1000, true);
+ 	}
+ 
+ 	rcu_read_lock();
+@@ -3512,3 +3518,76 @@ void console_atomic_unlock(unsigned int flags)
+ 	prb_unlock(&printk_cpulock, flags);
+ }
+ EXPORT_SYMBOL(console_atomic_unlock);
++
++static void pr_msleep(bool may_sleep, int ms)
++{
++	if (may_sleep) {
++		msleep(ms);
++	} else {
++		while (ms--)
++			udelay(1000);
++	}
++}
++
++/**
++ * pr_flush() - Wait for printing threads to catch up.
++ *
++ * @timeout_ms:        The maximum time (in ms) to wait.
++ * @reset_on_progress: Reset the timeout if forward progress is seen.
++ *
++ * A value of 0 for @timeout_ms means no waiting will occur. A value of -1
++ * represents infinite waiting.
++ *
++ * If @reset_on_progress is true, the timeout will be reset whenever any
++ * printer has been seen to make some forward progress.
++ *
++ * Context: Any context.
++ * Return: true if all enabled printers are caught up.
++ */
++bool pr_flush(int timeout_ms, bool reset_on_progress)
++{
++	int remaining = timeout_ms;
++	struct console *con;
++	u64 last_diff = 0;
++	bool may_sleep;
++	u64 printk_seq;
++	u64 diff;
++	u64 seq;
++
++	may_sleep = (preemptible() && !in_softirq());
++
++	seq = prb_next_seq(prb);
++
++	for (;;) {
++		diff = 0;
++
++		for_each_console(con) {
++			if (!(con->flags & CON_ENABLED))
++				continue;
++			printk_seq = atomic64_read(&con->printk_seq);
++			if (printk_seq < seq)
++				diff += seq - printk_seq;
++		}
++
++		if (diff != last_diff && reset_on_progress)
++			remaining = timeout_ms;
++
++		if (!diff || remaining == 0)
++			break;
++
++		if (remaining < 0) {
++			pr_msleep(may_sleep, 100);
++		} else if (remaining < 100) {
++			pr_msleep(may_sleep, remaining);
++			remaining = 0;
++		} else {
++			pr_msleep(may_sleep, 100);
++			remaining -= 100;
++		}
++
++		last_diff = diff;
++	}
++
++	return (diff == 0);
++}
++EXPORT_SYMBOL(pr_flush);
+diff --git a/lib/bug.c b/lib/bug.c
+index 4ab398a2de93..9c681f29e61e 100644
+--- a/lib/bug.c
++++ b/lib/bug.c
+@@ -202,6 +202,7 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
+ 	else
+ 		pr_crit("Kernel BUG at %pB [verbose debug info unavailable]\n",
+ 			(void *)bugaddr);
++	pr_flush(1000, true);
+ 
+ 	return BUG_TRAP_TYPE_BUG;
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0109-cgroup-use-irqsave-in-cgroup_rstat_flush_locked.patch b/debian/patches-rt/0109-cgroup-use-irqsave-in-cgroup_rstat_flush_locked.patch
new file mode 100644
index 000000000..3fad12a67
--- /dev/null
+++ b/debian/patches-rt/0109-cgroup-use-irqsave-in-cgroup_rstat_flush_locked.patch
@@ -0,0 +1,50 @@
+From 5c99ffb2025e5ae87404c3b9641b9dafaec9336e Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 3 Jul 2018 18:19:48 +0200
+Subject: [PATCH 109/323] cgroup: use irqsave in cgroup_rstat_flush_locked()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+All callers of cgroup_rstat_flush_locked() acquire cgroup_rstat_lock
+either with spin_lock_irq() or spin_lock_irqsave().
+cgroup_rstat_flush_locked() itself acquires cgroup_rstat_cpu_lock which
+is a raw_spin_lock. This lock is also acquired in cgroup_rstat_updated()
+in IRQ context and therefore requires _irqsave() locking suffix in
+cgroup_rstat_flush_locked().
+Since there is no difference between spin_lock_t and raw_spin_lock_t
+on !RT lockdep does not complain here. On RT lockdep complains because
+the interrupts were not disabled here and a deadlock is possible.
+
+Acquire the raw_spin_lock_t with disabled interrupts.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/cgroup/rstat.c | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c
+index 89ca9b61aa0d..753dc346520a 100644
+--- a/kernel/cgroup/rstat.c
++++ b/kernel/cgroup/rstat.c
+@@ -149,8 +149,9 @@ static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep)
+ 		raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock,
+ 						       cpu);
+ 		struct cgroup *pos = NULL;
++		unsigned long flags;
+ 
+-		raw_spin_lock(cpu_lock);
++		raw_spin_lock_irqsave(cpu_lock, flags);
+ 		while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu))) {
+ 			struct cgroup_subsys_state *css;
+ 
+@@ -162,7 +163,7 @@ static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep)
+ 				css->ss->css_rstat_flush(css, cpu);
+ 			rcu_read_unlock();
+ 		}
+-		raw_spin_unlock(cpu_lock);
++		raw_spin_unlock_irqrestore(cpu_lock, flags);
+ 
+ 		/* if @may_sleep, play nice and yield if necessary */
+ 		if (may_sleep && (need_resched() ||
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0110-mm-workingset-replace-IRQ-off-check-with-a-lockdep-a.patch b/debian/patches-rt/0110-mm-workingset-replace-IRQ-off-check-with-a-lockdep-a.patch
new file mode 100644
index 000000000..e9c3583b7
--- /dev/null
+++ b/debian/patches-rt/0110-mm-workingset-replace-IRQ-off-check-with-a-lockdep-a.patch
@@ -0,0 +1,49 @@
+From e215644e77fc149727b2ed1c3412c2e7668ff5aa Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 11 Feb 2019 10:40:46 +0100
+Subject: [PATCH 110/323] mm: workingset: replace IRQ-off check with a lockdep
+ assert.
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Commit
+
+  68d48e6a2df57 ("mm: workingset: add vmstat counter for shadow nodes")
+
+introduced an IRQ-off check to ensure that a lock is held which also
+disabled interrupts. This does not work the same way on -RT because none
+of the locks, that are held, disable interrupts.
+Replace this check with a lockdep assert which ensures that the lock is
+held.
+
+Cc: Peter Zijlstra <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/workingset.c | 5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+diff --git a/mm/workingset.c b/mm/workingset.c
+index 975a4d2dd02e..c3d098c01052 100644
+--- a/mm/workingset.c
++++ b/mm/workingset.c
+@@ -432,6 +432,8 @@ static struct list_lru shadow_nodes;
+ 
+ void workingset_update_node(struct xa_node *node)
+ {
++	struct address_space *mapping;
++
+ 	/*
+ 	 * Track non-empty nodes that contain only shadow entries;
+ 	 * unlink those that contain pages or are being freed.
+@@ -440,7 +442,8 @@ void workingset_update_node(struct xa_node *node)
+ 	 * already where they should be. The list_empty() test is safe
+ 	 * as node->private_list is protected by the i_pages lock.
+ 	 */
+-	VM_WARN_ON_ONCE(!irqs_disabled());  /* For __inc_lruvec_page_state */
++	mapping = container_of(node->array, struct address_space, i_pages);
++	lockdep_assert_held(&mapping->i_pages.xa_lock);
+ 
+ 	if (node->count && node->count == node->nr_values) {
+ 		if (list_empty(&node->private_list)) {
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0111-tpm-remove-tpm_dev_wq_lock.patch b/debian/patches-rt/0111-tpm-remove-tpm_dev_wq_lock.patch
new file mode 100644
index 000000000..f69a126e3
--- /dev/null
+++ b/debian/patches-rt/0111-tpm-remove-tpm_dev_wq_lock.patch
@@ -0,0 +1,35 @@
+From 74373c599ec7fa9991304d680c34ec5b591d4cad Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 11 Feb 2019 11:33:11 +0100
+Subject: [PATCH 111/323] tpm: remove tpm_dev_wq_lock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Added in commit
+
+  9e1b74a63f776 ("tpm: add support for nonblocking operation")
+
+but never actually used it.
+
+Cc: Philip Tricca <philip.b.tricca@intel.com>
+Cc: Tadeusz Struk <tadeusz.struk@intel.com>
+Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/char/tpm/tpm-dev-common.c | 1 -
+ 1 file changed, 1 deletion(-)
+
+diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
+index b99e1941c52c..dc4c0a0a5129 100644
+--- a/drivers/char/tpm/tpm-dev-common.c
++++ b/drivers/char/tpm/tpm-dev-common.c
+@@ -20,7 +20,6 @@
+ #include "tpm-dev.h"
+ 
+ static struct workqueue_struct *tpm_dev_wq;
+-static DEFINE_MUTEX(tpm_dev_wq_lock);
+ 
+ static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
+ 				u8 *buf, size_t bufsiz)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0112-shmem-Use-raw_spinlock_t-for-stat_lock.patch b/debian/patches-rt/0112-shmem-Use-raw_spinlock_t-for-stat_lock.patch
new file mode 100644
index 000000000..41738b8a2
--- /dev/null
+++ b/debian/patches-rt/0112-shmem-Use-raw_spinlock_t-for-stat_lock.patch
@@ -0,0 +1,147 @@
+From 35616363024adeffc42af4d2ca91e4550d6db59c Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 14 Aug 2020 18:53:34 +0200
+Subject: [PATCH 112/323] shmem: Use raw_spinlock_t for ->stat_lock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Each CPU has SHMEM_INO_BATCH inodes available in `->ino_batch' which is
+per-CPU. Access here is serialized by disabling preemption. If the pool is
+empty, it gets reloaded from `->next_ino'. Access here is serialized by
+->stat_lock which is a spinlock_t and can not be acquired with disabled
+preemption.
+One way around it would make per-CPU ino_batch struct containing the inode
+number a local_lock_t.
+Another sollution is to promote ->stat_lock to a raw_spinlock_t. The critical
+sections are short. The mpol_put() should be moved outside of the critical
+section to avoid invoking the destrutor with disabled preemption.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/shmem_fs.h |  2 +-
+ mm/shmem.c               | 31 +++++++++++++++++--------------
+ 2 files changed, 18 insertions(+), 15 deletions(-)
+
+diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
+index a5a5d1d4d7b1..0470d1582b09 100644
+--- a/include/linux/shmem_fs.h
++++ b/include/linux/shmem_fs.h
+@@ -31,7 +31,7 @@ struct shmem_sb_info {
+ 	struct percpu_counter used_blocks;  /* How many are allocated */
+ 	unsigned long max_inodes;   /* How many inodes are allowed */
+ 	unsigned long free_inodes;  /* How many are left for allocation */
+-	spinlock_t stat_lock;	    /* Serialize shmem_sb_info changes */
++	raw_spinlock_t stat_lock;   /* Serialize shmem_sb_info changes */
+ 	umode_t mode;		    /* Mount mode for root directory */
+ 	unsigned char huge;	    /* Whether to try for hugepages */
+ 	kuid_t uid;		    /* Mount uid for root directory */
+diff --git a/mm/shmem.c b/mm/shmem.c
+index e173d83b4448..94c0964f0d1f 100644
+--- a/mm/shmem.c
++++ b/mm/shmem.c
+@@ -278,10 +278,10 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop)
+ 	ino_t ino;
+ 
+ 	if (!(sb->s_flags & SB_KERNMOUNT)) {
+-		spin_lock(&sbinfo->stat_lock);
++		raw_spin_lock(&sbinfo->stat_lock);
+ 		if (sbinfo->max_inodes) {
+ 			if (!sbinfo->free_inodes) {
+-				spin_unlock(&sbinfo->stat_lock);
++				raw_spin_unlock(&sbinfo->stat_lock);
+ 				return -ENOSPC;
+ 			}
+ 			sbinfo->free_inodes--;
+@@ -304,7 +304,7 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop)
+ 			}
+ 			*inop = ino;
+ 		}
+-		spin_unlock(&sbinfo->stat_lock);
++		raw_spin_unlock(&sbinfo->stat_lock);
+ 	} else if (inop) {
+ 		/*
+ 		 * __shmem_file_setup, one of our callers, is lock-free: it
+@@ -319,13 +319,14 @@ static int shmem_reserve_inode(struct super_block *sb, ino_t *inop)
+ 		 * to worry about things like glibc compatibility.
+ 		 */
+ 		ino_t *next_ino;
++
+ 		next_ino = per_cpu_ptr(sbinfo->ino_batch, get_cpu());
+ 		ino = *next_ino;
+ 		if (unlikely(ino % SHMEM_INO_BATCH == 0)) {
+-			spin_lock(&sbinfo->stat_lock);
++			raw_spin_lock(&sbinfo->stat_lock);
+ 			ino = sbinfo->next_ino;
+ 			sbinfo->next_ino += SHMEM_INO_BATCH;
+-			spin_unlock(&sbinfo->stat_lock);
++			raw_spin_unlock(&sbinfo->stat_lock);
+ 			if (unlikely(is_zero_ino(ino)))
+ 				ino++;
+ 		}
+@@ -341,9 +342,9 @@ static void shmem_free_inode(struct super_block *sb)
+ {
+ 	struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
+ 	if (sbinfo->max_inodes) {
+-		spin_lock(&sbinfo->stat_lock);
++		raw_spin_lock(&sbinfo->stat_lock);
+ 		sbinfo->free_inodes++;
+-		spin_unlock(&sbinfo->stat_lock);
++		raw_spin_unlock(&sbinfo->stat_lock);
+ 	}
+ }
+ 
+@@ -1484,10 +1485,10 @@ static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
+ {
+ 	struct mempolicy *mpol = NULL;
+ 	if (sbinfo->mpol) {
+-		spin_lock(&sbinfo->stat_lock);	/* prevent replace/use races */
++		raw_spin_lock(&sbinfo->stat_lock);	/* prevent replace/use races */
+ 		mpol = sbinfo->mpol;
+ 		mpol_get(mpol);
+-		spin_unlock(&sbinfo->stat_lock);
++		raw_spin_unlock(&sbinfo->stat_lock);
+ 	}
+ 	return mpol;
+ }
+@@ -3613,9 +3614,10 @@ static int shmem_reconfigure(struct fs_context *fc)
+ 	struct shmem_options *ctx = fc->fs_private;
+ 	struct shmem_sb_info *sbinfo = SHMEM_SB(fc->root->d_sb);
+ 	unsigned long inodes;
++	struct mempolicy *mpol = NULL;
+ 	const char *err;
+ 
+-	spin_lock(&sbinfo->stat_lock);
++	raw_spin_lock(&sbinfo->stat_lock);
+ 	inodes = sbinfo->max_inodes - sbinfo->free_inodes;
+ 	if ((ctx->seen & SHMEM_SEEN_BLOCKS) && ctx->blocks) {
+ 		if (!sbinfo->max_blocks) {
+@@ -3660,14 +3662,15 @@ static int shmem_reconfigure(struct fs_context *fc)
+ 	 * Preserve previous mempolicy unless mpol remount option was specified.
+ 	 */
+ 	if (ctx->mpol) {
+-		mpol_put(sbinfo->mpol);
++		mpol = sbinfo->mpol;
+ 		sbinfo->mpol = ctx->mpol;	/* transfers initial ref */
+ 		ctx->mpol = NULL;
+ 	}
+-	spin_unlock(&sbinfo->stat_lock);
++	raw_spin_unlock(&sbinfo->stat_lock);
++	mpol_put(mpol);
+ 	return 0;
+ out:
+-	spin_unlock(&sbinfo->stat_lock);
++	raw_spin_unlock(&sbinfo->stat_lock);
+ 	return invalfc(fc, "%s", err);
+ }
+ 
+@@ -3784,7 +3787,7 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc)
+ 	sbinfo->mpol = ctx->mpol;
+ 	ctx->mpol = NULL;
+ 
+-	spin_lock_init(&sbinfo->stat_lock);
++	raw_spin_lock_init(&sbinfo->stat_lock);
+ 	if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL))
+ 		goto failed;
+ 	spin_lock_init(&sbinfo->shrinklist_lock);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0113-net-Move-lockdep-where-it-belongs.patch b/debian/patches-rt/0113-net-Move-lockdep-where-it-belongs.patch
new file mode 100644
index 000000000..b7b6765b1
--- /dev/null
+++ b/debian/patches-rt/0113-net-Move-lockdep-where-it-belongs.patch
@@ -0,0 +1,46 @@
+From b3ad938c1be05a261ce70af8888271d0b85cd955 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 8 Sep 2020 07:32:20 +0200
+Subject: [PATCH 113/323] net: Move lockdep where it belongs
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ net/core/sock.c | 6 ++----
+ 1 file changed, 2 insertions(+), 4 deletions(-)
+
+diff --git a/net/core/sock.c b/net/core/sock.c
+index a069b5476df4..8839cfea108a 100644
+--- a/net/core/sock.c
++++ b/net/core/sock.c
+@@ -3082,12 +3082,11 @@ void lock_sock_nested(struct sock *sk, int subclass)
+ 	if (sk->sk_lock.owned)
+ 		__lock_sock(sk);
+ 	sk->sk_lock.owned = 1;
+-	spin_unlock(&sk->sk_lock.slock);
++	spin_unlock_bh(&sk->sk_lock.slock);
+ 	/*
+ 	 * The sk_lock has mutex_lock() semantics here:
+ 	 */
+ 	mutex_acquire(&sk->sk_lock.dep_map, subclass, 0, _RET_IP_);
+-	local_bh_enable();
+ }
+ EXPORT_SYMBOL(lock_sock_nested);
+ 
+@@ -3136,12 +3135,11 @@ bool lock_sock_fast(struct sock *sk)
+ 
+ 	__lock_sock(sk);
+ 	sk->sk_lock.owned = 1;
+-	spin_unlock(&sk->sk_lock.slock);
++	spin_unlock_bh(&sk->sk_lock.slock);
+ 	/*
+ 	 * The sk_lock has mutex_lock() semantics here:
+ 	 */
+ 	mutex_acquire(&sk->sk_lock.dep_map, 0, 0, _RET_IP_);
+-	local_bh_enable();
+ 	return true;
+ }
+ EXPORT_SYMBOL(lock_sock_fast);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0114-parisc-Remove-bogus-__IRQ_STAT-macro.patch b/debian/patches-rt/0114-parisc-Remove-bogus-__IRQ_STAT-macro.patch
new file mode 100644
index 000000000..29bae354a
--- /dev/null
+++ b/debian/patches-rt/0114-parisc-Remove-bogus-__IRQ_STAT-macro.patch
@@ -0,0 +1,31 @@
+From a73391bb3950b16f44dda9989980e77e07febe01 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 13 Nov 2020 15:02:08 +0100
+Subject: [PATCH 114/323] parisc: Remove bogus __IRQ_STAT macro
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+This is a leftover from a historical array based implementation and unused.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Link: https://lore.kernel.org/r/20201113141732.680780121@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/parisc/include/asm/hardirq.h | 1 -
+ 1 file changed, 1 deletion(-)
+
+diff --git a/arch/parisc/include/asm/hardirq.h b/arch/parisc/include/asm/hardirq.h
+index 7f7039516e53..fad29aa6f45f 100644
+--- a/arch/parisc/include/asm/hardirq.h
++++ b/arch/parisc/include/asm/hardirq.h
+@@ -32,7 +32,6 @@ typedef struct {
+ DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+ 
+ #define __ARCH_IRQ_STAT
+-#define __IRQ_STAT(cpu, member) (irq_stat[cpu].member)
+ #define inc_irq_stat(member)	this_cpu_inc(irq_stat.member)
+ #define __inc_irq_stat(member)	__this_cpu_inc(irq_stat.member)
+ #define ack_bad_irq(irq) WARN(1, "unexpected IRQ trap at vector %02x\n", irq)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0115-sh-Get-rid-of-nmi_count.patch b/debian/patches-rt/0115-sh-Get-rid-of-nmi_count.patch
new file mode 100644
index 000000000..59cbda0e0
--- /dev/null
+++ b/debian/patches-rt/0115-sh-Get-rid-of-nmi_count.patch
@@ -0,0 +1,47 @@
+From 4d4b0ae9c82f34e6cc445f9b04248ae49346a73e Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 13 Nov 2020 15:02:09 +0100
+Subject: [PATCH 115/323] sh: Get rid of nmi_count()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+nmi_count() is a historical leftover and SH is the only user. Replace it
+with regular per cpu accessors.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Link: https://lore.kernel.org/r/20201113141732.844232404@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/sh/kernel/irq.c   | 2 +-
+ arch/sh/kernel/traps.c | 2 +-
+ 2 files changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
+index 5717c7cbdd97..5addcb2c2da0 100644
+--- a/arch/sh/kernel/irq.c
++++ b/arch/sh/kernel/irq.c
+@@ -44,7 +44,7 @@ int arch_show_interrupts(struct seq_file *p, int prec)
+ 
+ 	seq_printf(p, "%*s: ", prec, "NMI");
+ 	for_each_online_cpu(j)
+-		seq_printf(p, "%10u ", nmi_count(j));
++		seq_printf(p, "%10u ", per_cpu(irq_stat.__nmi_count, j);
+ 	seq_printf(p, "  Non-maskable interrupts\n");
+ 
+ 	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
+diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c
+index 4efffc18c851..be15e41489b2 100644
+--- a/arch/sh/kernel/traps.c
++++ b/arch/sh/kernel/traps.c
+@@ -186,7 +186,7 @@ BUILD_TRAP_HANDLER(nmi)
+ 	arch_ftrace_nmi_enter();
+ 
+ 	nmi_enter();
+-	nmi_count(cpu)++;
++	this_cpu_inc(irq_stat.__nmi_count);
+ 
+ 	switch (notify_die(DIE_NMI, "NMI", regs, 0, vec & 0xff, SIGINT)) {
+ 	case NOTIFY_OK:
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0116-irqstat-Get-rid-of-nmi_count-and-__IRQ_STAT.patch b/debian/patches-rt/0116-irqstat-Get-rid-of-nmi_count-and-__IRQ_STAT.patch
new file mode 100644
index 000000000..870e1af5f
--- /dev/null
+++ b/debian/patches-rt/0116-irqstat-Get-rid-of-nmi_count-and-__IRQ_STAT.patch
@@ -0,0 +1,34 @@
+From c190c29cf4e02d1cfa67a9744ef94c2037ed071e Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 13 Nov 2020 15:02:10 +0100
+Subject: [PATCH 116/323] irqstat: Get rid of nmi_count() and __IRQ_STAT()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Nothing uses this anymore.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Link: https://lore.kernel.org/r/20201113141733.005212732@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/irq_cpustat.h | 4 ----
+ 1 file changed, 4 deletions(-)
+
+diff --git a/include/linux/irq_cpustat.h b/include/linux/irq_cpustat.h
+index 6e8895cd4d92..78fb2de3ea4d 100644
+--- a/include/linux/irq_cpustat.h
++++ b/include/linux/irq_cpustat.h
+@@ -19,10 +19,6 @@
+ 
+ #ifndef __ARCH_IRQ_STAT
+ DECLARE_PER_CPU_ALIGNED(irq_cpustat_t, irq_stat);	/* defined in asm/hardirq.h */
+-#define __IRQ_STAT(cpu, member)	(per_cpu(irq_stat.member, cpu))
+ #endif
+ 
+-/* arch dependent irq_stat fields */
+-#define nmi_count(cpu)		__IRQ_STAT((cpu), __nmi_count)	/* i386 */
+-
+ #endif	/* __irq_cpustat_h */
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0117-um-irqstat-Get-rid-of-the-duplicated-declarations.patch b/debian/patches-rt/0117-um-irqstat-Get-rid-of-the-duplicated-declarations.patch
new file mode 100644
index 000000000..ee24a1117
--- /dev/null
+++ b/debian/patches-rt/0117-um-irqstat-Get-rid-of-the-duplicated-declarations.patch
@@ -0,0 +1,48 @@
+From 44cfe18ac1cb81f3617a962640846d232bed6d65 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 13 Nov 2020 15:02:11 +0100
+Subject: [PATCH 117/323] um/irqstat: Get rid of the duplicated declarations
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+irq_cpustat_t and ack_bad_irq() are exactly the same as the asm-generic
+ones.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Link: https://lore.kernel.org/r/20201113141733.156361337@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/um/include/asm/hardirq.h | 17 +----------------
+ 1 file changed, 1 insertion(+), 16 deletions(-)
+
+diff --git a/arch/um/include/asm/hardirq.h b/arch/um/include/asm/hardirq.h
+index b426796d26fd..52e2c36267a9 100644
+--- a/arch/um/include/asm/hardirq.h
++++ b/arch/um/include/asm/hardirq.h
+@@ -2,22 +2,7 @@
+ #ifndef __ASM_UM_HARDIRQ_H
+ #define __ASM_UM_HARDIRQ_H
+ 
+-#include <linux/cache.h>
+-#include <linux/threads.h>
+-
+-typedef struct {
+-	unsigned int __softirq_pending;
+-} ____cacheline_aligned irq_cpustat_t;
+-
+-#include <linux/irq_cpustat.h>	/* Standard mappings for irq_cpustat_t above */
+-#include <linux/irq.h>
+-
+-#ifndef ack_bad_irq
+-static inline void ack_bad_irq(unsigned int irq)
+-{
+-	printk(KERN_CRIT "unexpected IRQ trap at vector %02x\n", irq);
+-}
+-#endif
++#include <asm-generic/hardirq.h>
+ 
+ #define __ARCH_IRQ_EXIT_IRQS_DISABLED 1
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0118-ARM-irqstat-Get-rid-of-duplicated-declaration.patch b/debian/patches-rt/0118-ARM-irqstat-Get-rid-of-duplicated-declaration.patch
new file mode 100644
index 000000000..a7b949523
--- /dev/null
+++ b/debian/patches-rt/0118-ARM-irqstat-Get-rid-of-duplicated-declaration.patch
@@ -0,0 +1,59 @@
+From 903c27e244a901b4c66dc1d423a6d9b3214fd868 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 13 Nov 2020 15:02:12 +0100
+Subject: [PATCH 118/323] ARM: irqstat: Get rid of duplicated declaration
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+irq_cpustat_t is exactly the same as the asm-generic one. Define
+ack_bad_irq so the generic header does not emit the generic version of it.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
+Link: https://lore.kernel.org/r/20201113141733.276505871@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/arm/include/asm/hardirq.h | 11 +++--------
+ arch/arm/include/asm/irq.h     |  2 ++
+ 2 files changed, 5 insertions(+), 8 deletions(-)
+
+diff --git a/arch/arm/include/asm/hardirq.h b/arch/arm/include/asm/hardirq.h
+index b95848ed2bc7..706efafbf972 100644
+--- a/arch/arm/include/asm/hardirq.h
++++ b/arch/arm/include/asm/hardirq.h
+@@ -2,16 +2,11 @@
+ #ifndef __ASM_HARDIRQ_H
+ #define __ASM_HARDIRQ_H
+ 
+-#include <linux/cache.h>
+-#include <linux/threads.h>
+ #include <asm/irq.h>
+ 
+-typedef struct {
+-	unsigned int __softirq_pending;
+-} ____cacheline_aligned irq_cpustat_t;
+-
+-#include <linux/irq_cpustat.h>	/* Standard mappings for irq_cpustat_t above */
+-
+ #define __ARCH_IRQ_EXIT_IRQS_DISABLED	1
++#define ack_bad_irq ack_bad_irq
++
++#include <asm-generic/hardirq.h>
+ 
+ #endif /* __ASM_HARDIRQ_H */
+diff --git a/arch/arm/include/asm/irq.h b/arch/arm/include/asm/irq.h
+index 46d41140df27..1cbcc462b07e 100644
+--- a/arch/arm/include/asm/irq.h
++++ b/arch/arm/include/asm/irq.h
+@@ -31,6 +31,8 @@ void handle_IRQ(unsigned int, struct pt_regs *);
+ void init_IRQ(void);
+ 
+ #ifdef CONFIG_SMP
++#include <linux/cpumask.h>
++
+ extern void arch_trigger_cpumask_backtrace(const cpumask_t *mask,
+ 					   bool exclude_self);
+ #define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0119-arm64-irqstat-Get-rid-of-duplicated-declaration.patch b/debian/patches-rt/0119-arm64-irqstat-Get-rid-of-duplicated-declaration.patch
new file mode 100644
index 000000000..015978430
--- /dev/null
+++ b/debian/patches-rt/0119-arm64-irqstat-Get-rid-of-duplicated-declaration.patch
@@ -0,0 +1,40 @@
+From 9d8ad1996dd7a9a4250e55ee988eac5f7e52bd8e Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 13 Nov 2020 15:02:13 +0100
+Subject: [PATCH 119/323] arm64: irqstat: Get rid of duplicated declaration
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+irq_cpustat_t is exactly the same as the asm-generic one. Define
+ack_bad_irq so the generic header does not emit the generic version of it.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Acked-by: Will Deacon <will@kernel.org>
+Acked-by: Marc Zyngier <maz@kernel.org>
+Link: https://lore.kernel.org/r/20201113141733.392015387@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/arm64/include/asm/hardirq.h | 7 ++-----
+ 1 file changed, 2 insertions(+), 5 deletions(-)
+
+diff --git a/arch/arm64/include/asm/hardirq.h b/arch/arm64/include/asm/hardirq.h
+index 5ffa4bacdad3..cbfa7b6f2e09 100644
+--- a/arch/arm64/include/asm/hardirq.h
++++ b/arch/arm64/include/asm/hardirq.h
+@@ -13,11 +13,8 @@
+ #include <asm/kvm_arm.h>
+ #include <asm/sysreg.h>
+ 
+-typedef struct {
+-	unsigned int __softirq_pending;
+-} ____cacheline_aligned irq_cpustat_t;
+-
+-#include <linux/irq_cpustat.h>	/* Standard mappings for irq_cpustat_t above */
++#define ack_bad_irq ack_bad_irq
++#include <asm-generic/hardirq.h>
+ 
+ #define __ARCH_IRQ_EXIT_IRQS_DISABLED	1
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0120-asm-generic-irqstat-Add-optional-__nmi_count-member.patch b/debian/patches-rt/0120-asm-generic-irqstat-Add-optional-__nmi_count-member.patch
new file mode 100644
index 000000000..6eddb073f
--- /dev/null
+++ b/debian/patches-rt/0120-asm-generic-irqstat-Add-optional-__nmi_count-member.patch
@@ -0,0 +1,34 @@
+From 9daa9b58eb0e0b5b143d719b4c465e8ee233def0 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 13 Nov 2020 15:02:14 +0100
+Subject: [PATCH 120/323] asm-generic/irqstat: Add optional __nmi_count member
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Add an optional __nmi_count member to irq_cpustat_t so more architectures
+can use the generic version.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Link: https://lore.kernel.org/r/20201113141733.501611990@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/asm-generic/hardirq.h | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/include/asm-generic/hardirq.h b/include/asm-generic/hardirq.h
+index d14214dfc10b..f5dd99781e3c 100644
+--- a/include/asm-generic/hardirq.h
++++ b/include/asm-generic/hardirq.h
+@@ -7,6 +7,9 @@
+ 
+ typedef struct {
+ 	unsigned int __softirq_pending;
++#ifdef ARCH_WANTS_NMI_IRQSTAT
++	unsigned int __nmi_count;
++#endif
+ } ____cacheline_aligned irq_cpustat_t;
+ 
+ #include <linux/irq_cpustat.h>	/* Standard mappings for irq_cpustat_t above */
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0121-sh-irqstat-Use-the-generic-irq_cpustat_t.patch b/debian/patches-rt/0121-sh-irqstat-Use-the-generic-irq_cpustat_t.patch
new file mode 100644
index 000000000..a141aaddf
--- /dev/null
+++ b/debian/patches-rt/0121-sh-irqstat-Use-the-generic-irq_cpustat_t.patch
@@ -0,0 +1,45 @@
+From 36f4507e26065641dd4b5e9fab744596a072b3a6 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 13 Nov 2020 15:02:15 +0100
+Subject: [PATCH 121/323] sh: irqstat: Use the generic irq_cpustat_t
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+SH can now use the generic irq_cpustat_t. Define ack_bad_irq so the generic
+header does not emit the generic version of it.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Link: https://lore.kernel.org/r/20201113141733.625146223@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/sh/include/asm/hardirq.h | 14 ++++----------
+ 1 file changed, 4 insertions(+), 10 deletions(-)
+
+diff --git a/arch/sh/include/asm/hardirq.h b/arch/sh/include/asm/hardirq.h
+index edaea3559a23..9fe4495a8e90 100644
+--- a/arch/sh/include/asm/hardirq.h
++++ b/arch/sh/include/asm/hardirq.h
+@@ -2,16 +2,10 @@
+ #ifndef __ASM_SH_HARDIRQ_H
+ #define __ASM_SH_HARDIRQ_H
+ 
+-#include <linux/threads.h>
+-#include <linux/irq.h>
+-
+-typedef struct {
+-	unsigned int __softirq_pending;
+-	unsigned int __nmi_count;		/* arch dependent */
+-} ____cacheline_aligned irq_cpustat_t;
+-
+-#include <linux/irq_cpustat.h>	/* Standard mappings for irq_cpustat_t above */
+-
+ extern void ack_bad_irq(unsigned int irq);
++#define ack_bad_irq ack_bad_irq
++#define ARCH_WANTS_NMI_IRQSTAT
++
++#include <asm-generic/hardirq.h>
+ 
+ #endif /* __ASM_SH_HARDIRQ_H */
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0122-irqstat-Move-declaration-into-asm-generic-hardirq.h.patch b/debian/patches-rt/0122-irqstat-Move-declaration-into-asm-generic-hardirq.h.patch
new file mode 100644
index 000000000..7918409ff
--- /dev/null
+++ b/debian/patches-rt/0122-irqstat-Move-declaration-into-asm-generic-hardirq.h.patch
@@ -0,0 +1,66 @@
+From 4d8e6962b3b3f9acc509359631d4396d9b729064 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 13 Nov 2020 15:02:16 +0100
+Subject: [PATCH 122/323] irqstat: Move declaration into asm-generic/hardirq.h
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Move the declaration of the irq_cpustat per cpu variable to
+asm-generic/hardirq.h and remove the now empty linux/irq_cpustat.h header.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Link: https://lore.kernel.org/r/20201113141733.737377332@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/asm-generic/hardirq.h |  3 ++-
+ include/linux/irq_cpustat.h   | 24 ------------------------
+ 2 files changed, 2 insertions(+), 25 deletions(-)
+ delete mode 100644 include/linux/irq_cpustat.h
+
+diff --git a/include/asm-generic/hardirq.h b/include/asm-generic/hardirq.h
+index f5dd99781e3c..7317e8258b48 100644
+--- a/include/asm-generic/hardirq.h
++++ b/include/asm-generic/hardirq.h
+@@ -12,7 +12,8 @@ typedef struct {
+ #endif
+ } ____cacheline_aligned irq_cpustat_t;
+ 
+-#include <linux/irq_cpustat.h>	/* Standard mappings for irq_cpustat_t above */
++DECLARE_PER_CPU_ALIGNED(irq_cpustat_t, irq_stat);
++
+ #include <linux/irq.h>
+ 
+ #ifndef ack_bad_irq
+diff --git a/include/linux/irq_cpustat.h b/include/linux/irq_cpustat.h
+deleted file mode 100644
+index 78fb2de3ea4d..000000000000
+--- a/include/linux/irq_cpustat.h
++++ /dev/null
+@@ -1,24 +0,0 @@
+-/* SPDX-License-Identifier: GPL-2.0 */
+-#ifndef __irq_cpustat_h
+-#define __irq_cpustat_h
+-
+-/*
+- * Contains default mappings for irq_cpustat_t, used by almost every
+- * architecture.  Some arch (like s390) have per cpu hardware pages and
+- * they define their own mappings for irq_stat.
+- *
+- * Keith Owens <kaos@ocs.com.au> July 2000.
+- */
+-
+-
+-/*
+- * Simple wrappers reducing source bloat.  Define all irq_stat fields
+- * here, even ones that are arch dependent.  That way we get common
+- * definitions instead of differing sets for each arch.
+- */
+-
+-#ifndef __ARCH_IRQ_STAT
+-DECLARE_PER_CPU_ALIGNED(irq_cpustat_t, irq_stat);	/* defined in asm/hardirq.h */
+-#endif
+-
+-#endif	/* __irq_cpustat_h */
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0123-preempt-Cleanup-the-macro-maze-a-bit.patch b/debian/patches-rt/0123-preempt-Cleanup-the-macro-maze-a-bit.patch
new file mode 100644
index 000000000..9e6469ec2
--- /dev/null
+++ b/debian/patches-rt/0123-preempt-Cleanup-the-macro-maze-a-bit.patch
@@ -0,0 +1,78 @@
+From b743317882baa4d44bdc55dea99865bf53623193 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 13 Nov 2020 15:02:17 +0100
+Subject: [PATCH 123/323] preempt: Cleanup the macro maze a bit
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Make the macro maze consistent and prepare it for adding the RT variant for
+BH accounting.
+
+ - Use nmi_count() for the NMI portion of preempt count
+ - Introduce in_hardirq() to make the naming consistent and non-ambiguos
+ - Use the macros to create combined checks (e.g. in_task()) so the
+   softirq representation for RT just falls into place.
+ - Update comments and move the deprecated macros aside
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Link: https://lore.kernel.org/r/20201113141733.864469886@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/preempt.h | 30 ++++++++++++++++--------------
+ 1 file changed, 16 insertions(+), 14 deletions(-)
+
+diff --git a/include/linux/preempt.h b/include/linux/preempt.h
+index 6df63cbe8bb0..69cc8b64aa3a 100644
+--- a/include/linux/preempt.h
++++ b/include/linux/preempt.h
+@@ -77,31 +77,33 @@
+ /* preempt_count() and related functions, depends on PREEMPT_NEED_RESCHED */
+ #include <asm/preempt.h>
+ 
++#define nmi_count()	(preempt_count() & NMI_MASK)
+ #define hardirq_count()	(preempt_count() & HARDIRQ_MASK)
+ #define softirq_count()	(preempt_count() & SOFTIRQ_MASK)
+-#define irq_count()	(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
+-				 | NMI_MASK))
++#define irq_count()	(nmi_count() | hardirq_count() | softirq_count())
+ 
+ /*
+- * Are we doing bottom half or hardware interrupt processing?
++ * Macros to retrieve the current execution context:
+  *
+- * in_irq()       - We're in (hard) IRQ context
++ * in_nmi()		- We're in NMI context
++ * in_hardirq()		- We're in hard IRQ context
++ * in_serving_softirq()	- We're in softirq context
++ * in_task()		- We're in task context
++ */
++#define in_nmi()		(nmi_count())
++#define in_hardirq()		(hardirq_count())
++#define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)
++#define in_task()		(!(in_nmi() | in_hardirq() | in_serving_softirq()))
++
++/*
++ * The following macros are deprecated and should not be used in new code:
++ * in_irq()       - Obsolete version of in_hardirq()
+  * in_softirq()   - We have BH disabled, or are processing softirqs
+  * in_interrupt() - We're in NMI,IRQ,SoftIRQ context or have BH disabled
+- * in_serving_softirq() - We're in softirq context
+- * in_nmi()       - We're in NMI context
+- * in_task()	  - We're in task context
+- *
+- * Note: due to the BH disabled confusion: in_softirq(),in_interrupt() really
+- *       should not be used in new code.
+  */
+ #define in_irq()		(hardirq_count())
+ #define in_softirq()		(softirq_count())
+ #define in_interrupt()		(irq_count())
+-#define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)
+-#define in_nmi()		(preempt_count() & NMI_MASK)
+-#define in_task()		(!(preempt_count() & \
+-				   (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)))
+ 
+ /*
+  * The preempt_count offset after preempt_disable();
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0124-softirq-Move-related-code-into-one-section.patch b/debian/patches-rt/0124-softirq-Move-related-code-into-one-section.patch
new file mode 100644
index 000000000..fb937d24b
--- /dev/null
+++ b/debian/patches-rt/0124-softirq-Move-related-code-into-one-section.patch
@@ -0,0 +1,169 @@
+From e40ca378bfbd05514961947d57b163831bdc3bbe Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 13 Nov 2020 15:02:18 +0100
+Subject: [PATCH 124/323] softirq: Move related code into one section
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+To prepare for adding a RT aware variant of softirq serialization and
+processing move related code into one section so the necessary #ifdeffery
+is reduced to one.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Link: https://lore.kernel.org/r/20201113141733.974214480@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/softirq.c | 107 ++++++++++++++++++++++++-----------------------
+ 1 file changed, 54 insertions(+), 53 deletions(-)
+
+diff --git a/kernel/softirq.c b/kernel/softirq.c
+index 09229ad82209..617009ccd82c 100644
+--- a/kernel/softirq.c
++++ b/kernel/softirq.c
+@@ -92,6 +92,13 @@ static bool ksoftirqd_running(unsigned long pending)
+ 		!__kthread_should_park(tsk);
+ }
+ 
++#ifdef CONFIG_TRACE_IRQFLAGS
++DEFINE_PER_CPU(int, hardirqs_enabled);
++DEFINE_PER_CPU(int, hardirq_context);
++EXPORT_PER_CPU_SYMBOL_GPL(hardirqs_enabled);
++EXPORT_PER_CPU_SYMBOL_GPL(hardirq_context);
++#endif
++
+ /*
+  * preempt_count and SOFTIRQ_OFFSET usage:
+  * - preempt_count is changed by SOFTIRQ_OFFSET on entering or leaving
+@@ -102,17 +109,11 @@ static bool ksoftirqd_running(unsigned long pending)
+  * softirq and whether we just have bh disabled.
+  */
+ 
++#ifdef CONFIG_TRACE_IRQFLAGS
+ /*
+- * This one is for softirq.c-internal use,
+- * where hardirqs are disabled legitimately:
++ * This is for softirq.c-internal use, where hardirqs are disabled
++ * legitimately:
+  */
+-#ifdef CONFIG_TRACE_IRQFLAGS
+-
+-DEFINE_PER_CPU(int, hardirqs_enabled);
+-DEFINE_PER_CPU(int, hardirq_context);
+-EXPORT_PER_CPU_SYMBOL_GPL(hardirqs_enabled);
+-EXPORT_PER_CPU_SYMBOL_GPL(hardirq_context);
+-
+ void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
+ {
+ 	unsigned long flags;
+@@ -203,6 +204,50 @@ void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
+ }
+ EXPORT_SYMBOL(__local_bh_enable_ip);
+ 
++static inline void invoke_softirq(void)
++{
++	if (ksoftirqd_running(local_softirq_pending()))
++		return;
++
++	if (!force_irqthreads) {
++#ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
++		/*
++		 * We can safely execute softirq on the current stack if
++		 * it is the irq stack, because it should be near empty
++		 * at this stage.
++		 */
++		__do_softirq();
++#else
++		/*
++		 * Otherwise, irq_exit() is called on the task stack that can
++		 * be potentially deep already. So call softirq in its own stack
++		 * to prevent from any overrun.
++		 */
++		do_softirq_own_stack();
++#endif
++	} else {
++		wakeup_softirqd();
++	}
++}
++
++asmlinkage __visible void do_softirq(void)
++{
++	__u32 pending;
++	unsigned long flags;
++
++	if (in_interrupt())
++		return;
++
++	local_irq_save(flags);
++
++	pending = local_softirq_pending();
++
++	if (pending && !ksoftirqd_running(pending))
++		do_softirq_own_stack();
++
++	local_irq_restore(flags);
++}
++
+ /*
+  * We restart softirq processing for at most MAX_SOFTIRQ_RESTART times,
+  * but break the loop if need_resched() is set or after 2 ms.
+@@ -327,24 +372,6 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
+ 	current_restore_flags(old_flags, PF_MEMALLOC);
+ }
+ 
+-asmlinkage __visible void do_softirq(void)
+-{
+-	__u32 pending;
+-	unsigned long flags;
+-
+-	if (in_interrupt())
+-		return;
+-
+-	local_irq_save(flags);
+-
+-	pending = local_softirq_pending();
+-
+-	if (pending && !ksoftirqd_running(pending))
+-		do_softirq_own_stack();
+-
+-	local_irq_restore(flags);
+-}
+-
+ /**
+  * irq_enter_rcu - Enter an interrupt context with RCU watching
+  */
+@@ -371,32 +398,6 @@ void irq_enter(void)
+ 	irq_enter_rcu();
+ }
+ 
+-static inline void invoke_softirq(void)
+-{
+-	if (ksoftirqd_running(local_softirq_pending()))
+-		return;
+-
+-	if (!force_irqthreads) {
+-#ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
+-		/*
+-		 * We can safely execute softirq on the current stack if
+-		 * it is the irq stack, because it should be near empty
+-		 * at this stage.
+-		 */
+-		__do_softirq();
+-#else
+-		/*
+-		 * Otherwise, irq_exit() is called on the task stack that can
+-		 * be potentially deep already. So call softirq in its own stack
+-		 * to prevent from any overrun.
+-		 */
+-		do_softirq_own_stack();
+-#endif
+-	} else {
+-		wakeup_softirqd();
+-	}
+-}
+-
+ static inline void tick_irq_exit(void)
+ {
+ #ifdef CONFIG_NO_HZ_COMMON
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0125-sh-irq-Add-missing-closing-parentheses-in-arch_show_.patch b/debian/patches-rt/0125-sh-irq-Add-missing-closing-parentheses-in-arch_show_.patch
new file mode 100644
index 000000000..4259c009f
--- /dev/null
+++ b/debian/patches-rt/0125-sh-irq-Add-missing-closing-parentheses-in-arch_show_.patch
@@ -0,0 +1,40 @@
+From e8f074aae182d9f11f092885cc1a1dfaedbe8807 Mon Sep 17 00:00:00 2001
+From: Geert Uytterhoeven <geert+renesas@glider.be>
+Date: Tue, 24 Nov 2020 14:06:56 +0100
+Subject: [PATCH 125/323] sh/irq: Add missing closing parentheses in
+ arch_show_interrupts()
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+    arch/sh/kernel/irq.c: In function ‘arch_show_interrupts’:
+    arch/sh/kernel/irq.c:47:58: error: expected ‘)’ before ‘;’ token
+       47 |   seq_printf(p, "%10u ", per_cpu(irq_stat.__nmi_count, j);
+	  |                                                          ^
+
+Fixes: fe3f1d5d7cd3062c ("sh: Get rid of nmi_count()")
+Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20201124130656.2741743-1-geert+renesas@glider.be
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/sh/kernel/irq.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
+index 5addcb2c2da0..ab5f790b0cd2 100644
+--- a/arch/sh/kernel/irq.c
++++ b/arch/sh/kernel/irq.c
+@@ -44,7 +44,7 @@ int arch_show_interrupts(struct seq_file *p, int prec)
+ 
+ 	seq_printf(p, "%*s: ", prec, "NMI");
+ 	for_each_online_cpu(j)
+-		seq_printf(p, "%10u ", per_cpu(irq_stat.__nmi_count, j);
++		seq_printf(p, "%10u ", per_cpu(irq_stat.__nmi_count, j));
+ 	seq_printf(p, "  Non-maskable interrupts\n");
+ 
+ 	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0126-sched-cputime-Remove-symbol-exports-from-IRQ-time-ac.patch b/debian/patches-rt/0126-sched-cputime-Remove-symbol-exports-from-IRQ-time-ac.patch
new file mode 100644
index 000000000..3926556d0
--- /dev/null
+++ b/debian/patches-rt/0126-sched-cputime-Remove-symbol-exports-from-IRQ-time-ac.patch
@@ -0,0 +1,73 @@
+From d15b621168c7c422b8e43819c45aa749f3611fa6 Mon Sep 17 00:00:00 2001
+From: Frederic Weisbecker <frederic@kernel.org>
+Date: Wed, 2 Dec 2020 12:57:28 +0100
+Subject: [PATCH 126/323] sched/cputime: Remove symbol exports from IRQ time
+ accounting
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+account_irq_enter_time() and account_irq_exit_time() are not called
+from modules. EXPORT_SYMBOL_GPL() can be safely removed from the IRQ
+cputime accounting functions called from there.
+
+Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20201202115732.27827-2-frederic@kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/s390/kernel/vtime.c | 10 +++++-----
+ kernel/sched/cputime.c   |  2 --
+ 2 files changed, 5 insertions(+), 7 deletions(-)
+
+diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
+index 579ec3a8c816..710135905deb 100644
+--- a/arch/s390/kernel/vtime.c
++++ b/arch/s390/kernel/vtime.c
+@@ -227,7 +227,7 @@ void vtime_flush(struct task_struct *tsk)
+  * Update process times based on virtual cpu times stored by entry.S
+  * to the lowcore fields user_timer, system_timer & steal_clock.
+  */
+-void vtime_account_irq_enter(struct task_struct *tsk)
++void vtime_account_kernel(struct task_struct *tsk)
+ {
+ 	u64 timer;
+ 
+@@ -246,12 +246,12 @@ void vtime_account_irq_enter(struct task_struct *tsk)
+ 
+ 	virt_timer_forward(timer);
+ }
+-EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
+-
+-void vtime_account_kernel(struct task_struct *tsk)
+-__attribute__((alias("vtime_account_irq_enter")));
+ EXPORT_SYMBOL_GPL(vtime_account_kernel);
+ 
++void vtime_account_irq_enter(struct task_struct *tsk)
++__attribute__((alias("vtime_account_kernel")));
++
++
+ /*
+  * Sorted add to a list. List is linear searched until first bigger
+  * element is found.
+diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
+index ca0eef7d3852..e03568c5f584 100644
+--- a/kernel/sched/cputime.c
++++ b/kernel/sched/cputime.c
+@@ -71,7 +71,6 @@ void irqtime_account_irq(struct task_struct *curr)
+ 	else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
+ 		irqtime_account_delta(irqtime, delta, CPUTIME_SOFTIRQ);
+ }
+-EXPORT_SYMBOL_GPL(irqtime_account_irq);
+ 
+ static u64 irqtime_tick_accounted(u64 maxtime)
+ {
+@@ -434,7 +433,6 @@ void vtime_account_irq_enter(struct task_struct *tsk)
+ 	else
+ 		vtime_account_kernel(tsk);
+ }
+-EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
+ #endif /* __ARCH_HAS_VTIME_ACCOUNT */
+ 
+ void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0127-s390-vtime-Use-the-generic-IRQ-entry-accounting.patch b/debian/patches-rt/0127-s390-vtime-Use-the-generic-IRQ-entry-accounting.patch
new file mode 100644
index 000000000..e4a67c29c
--- /dev/null
+++ b/debian/patches-rt/0127-s390-vtime-Use-the-generic-IRQ-entry-accounting.patch
@@ -0,0 +1,126 @@
+From 433f928a0fd33d67682020e134ac00885b38a2a9 Mon Sep 17 00:00:00 2001
+From: Frederic Weisbecker <frederic@kernel.org>
+Date: Wed, 2 Dec 2020 12:57:29 +0100
+Subject: [PATCH 127/323] s390/vtime: Use the generic IRQ entry accounting
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+s390 has its own version of IRQ entry accounting because it doesn't
+account the idle time the same way the other architectures do. Only
+the actual idle sleep time is accounted as idle time, the rest of the
+idle task execution is accounted as system time.
+
+Make the generic IRQ entry accounting aware of architectures that have
+their own way of accounting idle time and convert s390 to use it.
+
+This prepares s390 to get involved in further consolidations of IRQ
+time accounting.
+
+Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20201202115732.27827-3-frederic@kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/Kconfig                  |  7 ++++++-
+ arch/s390/Kconfig             |  1 +
+ arch/s390/include/asm/vtime.h |  1 -
+ arch/s390/kernel/vtime.c      |  4 ----
+ kernel/sched/cputime.c        | 13 ++-----------
+ 5 files changed, 9 insertions(+), 17 deletions(-)
+
+diff --git a/arch/Kconfig b/arch/Kconfig
+index 240277d5626c..628e1e7fe302 100644
+--- a/arch/Kconfig
++++ b/arch/Kconfig
+@@ -646,6 +646,12 @@ config HAVE_TIF_NOHZ
+ config HAVE_VIRT_CPU_ACCOUNTING
+ 	bool
+ 
++config HAVE_VIRT_CPU_ACCOUNTING_IDLE
++	bool
++	help
++	  Architecture has its own way to account idle CPU time and therefore
++	  doesn't implement vtime_account_idle().
++
+ config ARCH_HAS_SCALED_CPUTIME
+ 	bool
+ 
+@@ -660,7 +666,6 @@ config HAVE_VIRT_CPU_ACCOUNTING_GEN
+ 	  some 32-bit arches may require multiple accesses, so proper
+ 	  locking is needed to protect against concurrent accesses.
+ 
+-
+ config HAVE_IRQ_TIME_ACCOUNTING
+ 	bool
+ 	help
+diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
+index 878993982e39..2e78071551e7 100644
+--- a/arch/s390/Kconfig
++++ b/arch/s390/Kconfig
+@@ -183,6 +183,7 @@ config S390
+ 	select HAVE_RSEQ
+ 	select HAVE_SYSCALL_TRACEPOINTS
+ 	select HAVE_VIRT_CPU_ACCOUNTING
++	select HAVE_VIRT_CPU_ACCOUNTING_IDLE
+ 	select IOMMU_HELPER		if PCI
+ 	select IOMMU_SUPPORT		if PCI
+ 	select MODULES_USE_ELF_RELA
+diff --git a/arch/s390/include/asm/vtime.h b/arch/s390/include/asm/vtime.h
+index 3622d4ebc73a..fac6a67988eb 100644
+--- a/arch/s390/include/asm/vtime.h
++++ b/arch/s390/include/asm/vtime.h
+@@ -2,7 +2,6 @@
+ #ifndef _S390_VTIME_H
+ #define _S390_VTIME_H
+ 
+-#define __ARCH_HAS_VTIME_ACCOUNT
+ #define __ARCH_HAS_VTIME_TASK_SWITCH
+ 
+ #endif /* _S390_VTIME_H */
+diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
+index 710135905deb..18a97631af43 100644
+--- a/arch/s390/kernel/vtime.c
++++ b/arch/s390/kernel/vtime.c
+@@ -248,10 +248,6 @@ void vtime_account_kernel(struct task_struct *tsk)
+ }
+ EXPORT_SYMBOL_GPL(vtime_account_kernel);
+ 
+-void vtime_account_irq_enter(struct task_struct *tsk)
+-__attribute__((alias("vtime_account_kernel")));
+-
+-
+ /*
+  * Sorted add to a list. List is linear searched until first bigger
+  * element is found.
+diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
+index e03568c5f584..1d78b835ec8b 100644
+--- a/kernel/sched/cputime.c
++++ b/kernel/sched/cputime.c
+@@ -417,23 +417,14 @@ void vtime_task_switch(struct task_struct *prev)
+ }
+ # endif
+ 
+-/*
+- * Archs that account the whole time spent in the idle task
+- * (outside irq) as idle time can rely on this and just implement
+- * vtime_account_kernel() and vtime_account_idle(). Archs that
+- * have other meaning of the idle time (s390 only includes the
+- * time spent by the CPU when it's in low power mode) must override
+- * vtime_account().
+- */
+-#ifndef __ARCH_HAS_VTIME_ACCOUNT
+ void vtime_account_irq_enter(struct task_struct *tsk)
+ {
+-	if (!in_interrupt() && is_idle_task(tsk))
++	if (!IS_ENABLED(CONFIG_HAVE_VIRT_CPU_ACCOUNTING_IDLE) &&
++	    !in_interrupt() && is_idle_task(tsk))
+ 		vtime_account_idle(tsk);
+ 	else
+ 		vtime_account_kernel(tsk);
+ }
+-#endif /* __ARCH_HAS_VTIME_ACCOUNT */
+ 
+ void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
+ 		    u64 *ut, u64 *st)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0128-sched-vtime-Consolidate-IRQ-time-accounting.patch b/debian/patches-rt/0128-sched-vtime-Consolidate-IRQ-time-accounting.patch
new file mode 100644
index 000000000..bb1e03d33
--- /dev/null
+++ b/debian/patches-rt/0128-sched-vtime-Consolidate-IRQ-time-accounting.patch
@@ -0,0 +1,303 @@
+From 749e0a8d4b10240d5834e135f34c47d107aa1442 Mon Sep 17 00:00:00 2001
+From: Frederic Weisbecker <frederic@kernel.org>
+Date: Wed, 2 Dec 2020 12:57:30 +0100
+Subject: [PATCH 128/323] sched/vtime: Consolidate IRQ time accounting
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The 3 architectures implementing CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+all have their own version of irq time accounting that dispatch the
+cputime to the appropriate index: hardirq, softirq, system, idle,
+guest... from an all-in-one function.
+
+Instead of having these ad-hoc versions, move the cputime destination
+dispatch decision to the core code and leave only the actual per-index
+cputime accounting to the architecture.
+
+Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20201202115732.27827-4-frederic@kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/ia64/kernel/time.c    | 20 ++++++++++----
+ arch/powerpc/kernel/time.c | 56 +++++++++++++++++++++++++++-----------
+ arch/s390/kernel/vtime.c   | 45 +++++++++++++++++++++---------
+ include/linux/vtime.h      | 16 ++++-------
+ kernel/sched/cputime.c     | 13 ++++++---
+ 5 files changed, 102 insertions(+), 48 deletions(-)
+
+diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
+index 7abc5f37bfaf..733e0e3324b8 100644
+--- a/arch/ia64/kernel/time.c
++++ b/arch/ia64/kernel/time.c
+@@ -138,12 +138,8 @@ void vtime_account_kernel(struct task_struct *tsk)
+ 	struct thread_info *ti = task_thread_info(tsk);
+ 	__u64 stime = vtime_delta(tsk);
+ 
+-	if ((tsk->flags & PF_VCPU) && !irq_count())
++	if (tsk->flags & PF_VCPU)
+ 		ti->gtime += stime;
+-	else if (hardirq_count())
+-		ti->hardirq_time += stime;
+-	else if (in_serving_softirq())
+-		ti->softirq_time += stime;
+ 	else
+ 		ti->stime += stime;
+ }
+@@ -156,6 +152,20 @@ void vtime_account_idle(struct task_struct *tsk)
+ 	ti->idle_time += vtime_delta(tsk);
+ }
+ 
++void vtime_account_softirq(struct task_struct *tsk)
++{
++	struct thread_info *ti = task_thread_info(tsk);
++
++	ti->softirq_time += vtime_delta(tsk);
++}
++
++void vtime_account_hardirq(struct task_struct *tsk)
++{
++	struct thread_info *ti = task_thread_info(tsk);
++
++	ti->hardirq_time += vtime_delta(tsk);
++}
++
+ #endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
+ 
+ static irqreturn_t
+diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
+index ba9b54d35f57..588e081ca55b 100644
+--- a/arch/powerpc/kernel/time.c
++++ b/arch/powerpc/kernel/time.c
+@@ -312,12 +312,11 @@ static unsigned long vtime_delta_scaled(struct cpu_accounting_data *acct,
+ 	return stime_scaled;
+ }
+ 
+-static unsigned long vtime_delta(struct task_struct *tsk,
++static unsigned long vtime_delta(struct cpu_accounting_data *acct,
+ 				 unsigned long *stime_scaled,
+ 				 unsigned long *steal_time)
+ {
+ 	unsigned long now, stime;
+-	struct cpu_accounting_data *acct = get_accounting(tsk);
+ 
+ 	WARN_ON_ONCE(!irqs_disabled());
+ 
+@@ -332,29 +331,30 @@ static unsigned long vtime_delta(struct task_struct *tsk,
+ 	return stime;
+ }
+ 
++static void vtime_delta_kernel(struct cpu_accounting_data *acct,
++			       unsigned long *stime, unsigned long *stime_scaled)
++{
++	unsigned long steal_time;
++
++	*stime = vtime_delta(acct, stime_scaled, &steal_time);
++	*stime -= min(*stime, steal_time);
++	acct->steal_time += steal_time;
++}
++
+ void vtime_account_kernel(struct task_struct *tsk)
+ {
+-	unsigned long stime, stime_scaled, steal_time;
+ 	struct cpu_accounting_data *acct = get_accounting(tsk);
++	unsigned long stime, stime_scaled;
+ 
+-	stime = vtime_delta(tsk, &stime_scaled, &steal_time);
+-
+-	stime -= min(stime, steal_time);
+-	acct->steal_time += steal_time;
++	vtime_delta_kernel(acct, &stime, &stime_scaled);
+ 
+-	if ((tsk->flags & PF_VCPU) && !irq_count()) {
++	if (tsk->flags & PF_VCPU) {
+ 		acct->gtime += stime;
+ #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
+ 		acct->utime_scaled += stime_scaled;
+ #endif
+ 	} else {
+-		if (hardirq_count())
+-			acct->hardirq_time += stime;
+-		else if (in_serving_softirq())
+-			acct->softirq_time += stime;
+-		else
+-			acct->stime += stime;
+-
++		acct->stime += stime;
+ #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
+ 		acct->stime_scaled += stime_scaled;
+ #endif
+@@ -367,10 +367,34 @@ void vtime_account_idle(struct task_struct *tsk)
+ 	unsigned long stime, stime_scaled, steal_time;
+ 	struct cpu_accounting_data *acct = get_accounting(tsk);
+ 
+-	stime = vtime_delta(tsk, &stime_scaled, &steal_time);
++	stime = vtime_delta(acct, &stime_scaled, &steal_time);
+ 	acct->idle_time += stime + steal_time;
+ }
+ 
++static void vtime_account_irq_field(struct cpu_accounting_data *acct,
++				    unsigned long *field)
++{
++	unsigned long stime, stime_scaled;
++
++	vtime_delta_kernel(acct, &stime, &stime_scaled);
++	*field += stime;
++#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
++	acct->stime_scaled += stime_scaled;
++#endif
++}
++
++void vtime_account_softirq(struct task_struct *tsk)
++{
++	struct cpu_accounting_data *acct = get_accounting(tsk);
++	vtime_account_irq_field(acct, &acct->softirq_time);
++}
++
++void vtime_account_hardirq(struct task_struct *tsk)
++{
++	struct cpu_accounting_data *acct = get_accounting(tsk);
++	vtime_account_irq_field(acct, &acct->hardirq_time);
++}
++
+ static void vtime_flush_scaled(struct task_struct *tsk,
+ 			       struct cpu_accounting_data *acct)
+ {
+diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
+index 18a97631af43..9b3c5978b668 100644
+--- a/arch/s390/kernel/vtime.c
++++ b/arch/s390/kernel/vtime.c
+@@ -223,31 +223,50 @@ void vtime_flush(struct task_struct *tsk)
+ 	S390_lowcore.avg_steal_timer = avg_steal;
+ }
+ 
++static u64 vtime_delta(void)
++{
++	u64 timer = S390_lowcore.last_update_timer;
++
++	S390_lowcore.last_update_timer = get_vtimer();
++
++	return timer - S390_lowcore.last_update_timer;
++}
++
+ /*
+  * Update process times based on virtual cpu times stored by entry.S
+  * to the lowcore fields user_timer, system_timer & steal_clock.
+  */
+ void vtime_account_kernel(struct task_struct *tsk)
+ {
+-	u64 timer;
+-
+-	timer = S390_lowcore.last_update_timer;
+-	S390_lowcore.last_update_timer = get_vtimer();
+-	timer -= S390_lowcore.last_update_timer;
++	u64 delta = vtime_delta();
+ 
+-	if ((tsk->flags & PF_VCPU) && (irq_count() == 0))
+-		S390_lowcore.guest_timer += timer;
+-	else if (hardirq_count())
+-		S390_lowcore.hardirq_timer += timer;
+-	else if (in_serving_softirq())
+-		S390_lowcore.softirq_timer += timer;
++	if (tsk->flags & PF_VCPU)
++		S390_lowcore.guest_timer += delta;
+ 	else
+-		S390_lowcore.system_timer += timer;
++		S390_lowcore.system_timer += delta;
+ 
+-	virt_timer_forward(timer);
++	virt_timer_forward(delta);
+ }
+ EXPORT_SYMBOL_GPL(vtime_account_kernel);
+ 
++void vtime_account_softirq(struct task_struct *tsk)
++{
++	u64 delta = vtime_delta();
++
++	S390_lowcore.softirq_timer += delta;
++
++	virt_timer_forward(delta);
++}
++
++void vtime_account_hardirq(struct task_struct *tsk)
++{
++	u64 delta = vtime_delta();
++
++	S390_lowcore.hardirq_timer += delta;
++
++	virt_timer_forward(delta);
++}
++
+ /*
+  * Sorted add to a list. List is linear searched until first bigger
+  * element is found.
+diff --git a/include/linux/vtime.h b/include/linux/vtime.h
+index 2cdeca062db3..6c9867419615 100644
+--- a/include/linux/vtime.h
++++ b/include/linux/vtime.h
+@@ -83,16 +83,12 @@ static inline void vtime_init_idle(struct task_struct *tsk, int cpu) { }
+ #endif
+ 
+ #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+-extern void vtime_account_irq_enter(struct task_struct *tsk);
+-static inline void vtime_account_irq_exit(struct task_struct *tsk)
+-{
+-	/* On hard|softirq exit we always account to hard|softirq cputime */
+-	vtime_account_kernel(tsk);
+-}
++extern void vtime_account_irq(struct task_struct *tsk);
++extern void vtime_account_softirq(struct task_struct *tsk);
++extern void vtime_account_hardirq(struct task_struct *tsk);
+ extern void vtime_flush(struct task_struct *tsk);
+ #else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
+-static inline void vtime_account_irq_enter(struct task_struct *tsk) { }
+-static inline void vtime_account_irq_exit(struct task_struct *tsk) { }
++static inline void vtime_account_irq(struct task_struct *tsk) { }
+ static inline void vtime_flush(struct task_struct *tsk) { }
+ #endif
+ 
+@@ -105,13 +101,13 @@ static inline void irqtime_account_irq(struct task_struct *tsk) { }
+ 
+ static inline void account_irq_enter_time(struct task_struct *tsk)
+ {
+-	vtime_account_irq_enter(tsk);
++	vtime_account_irq(tsk);
+ 	irqtime_account_irq(tsk);
+ }
+ 
+ static inline void account_irq_exit_time(struct task_struct *tsk)
+ {
+-	vtime_account_irq_exit(tsk);
++	vtime_account_irq(tsk);
+ 	irqtime_account_irq(tsk);
+ }
+ 
+diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
+index 1d78b835ec8b..60129af16ed6 100644
+--- a/kernel/sched/cputime.c
++++ b/kernel/sched/cputime.c
+@@ -417,13 +417,18 @@ void vtime_task_switch(struct task_struct *prev)
+ }
+ # endif
+ 
+-void vtime_account_irq_enter(struct task_struct *tsk)
++void vtime_account_irq(struct task_struct *tsk)
+ {
+-	if (!IS_ENABLED(CONFIG_HAVE_VIRT_CPU_ACCOUNTING_IDLE) &&
+-	    !in_interrupt() && is_idle_task(tsk))
++	if (hardirq_count()) {
++		vtime_account_hardirq(tsk);
++	} else if (in_serving_softirq()) {
++		vtime_account_softirq(tsk);
++	} else if (!IS_ENABLED(CONFIG_HAVE_VIRT_CPU_ACCOUNTING_IDLE) &&
++		   is_idle_task(tsk)) {
+ 		vtime_account_idle(tsk);
+-	else
++	} else {
+ 		vtime_account_kernel(tsk);
++	}
+ }
+ 
+ void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0129-irqtime-Move-irqtime-entry-accounting-after-irq-offs.patch b/debian/patches-rt/0129-irqtime-Move-irqtime-entry-accounting-after-irq-offs.patch
new file mode 100644
index 000000000..838a13489
--- /dev/null
+++ b/debian/patches-rt/0129-irqtime-Move-irqtime-entry-accounting-after-irq-offs.patch
@@ -0,0 +1,213 @@
+From e387d228099075ac3f762ccfbbe29f9ee59678c8 Mon Sep 17 00:00:00 2001
+From: Frederic Weisbecker <frederic@kernel.org>
+Date: Wed, 2 Dec 2020 12:57:31 +0100
+Subject: [PATCH 129/323] irqtime: Move irqtime entry accounting after irq
+ offset incrementation
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+IRQ time entry is currently accounted before HARDIRQ_OFFSET or
+SOFTIRQ_OFFSET are incremented. This is convenient to decide to which
+index the cputime to account is dispatched.
+
+Unfortunately it prevents tick_irq_enter() from being called under
+HARDIRQ_OFFSET because tick_irq_enter() has to be called before the IRQ
+entry accounting due to the necessary clock catch up. As a result we
+don't benefit from appropriate lockdep coverage on tick_irq_enter().
+
+To prepare for fixing this, move the IRQ entry cputime accounting after
+the preempt offset is incremented. This requires the cputime dispatch
+code to handle the extra offset.
+
+Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Link: https://lore.kernel.org/r/20201202115732.27827-5-frederic@kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/hardirq.h |  4 ++--
+ include/linux/vtime.h   | 34 ++++++++++++++++++++++++----------
+ kernel/sched/cputime.c  | 18 +++++++++++-------
+ kernel/softirq.c        |  6 +++---
+ 4 files changed, 40 insertions(+), 22 deletions(-)
+
+diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
+index c35b71f8644a..0926e9ca4d85 100644
+--- a/include/linux/hardirq.h
++++ b/include/linux/hardirq.h
+@@ -32,9 +32,9 @@ static __always_inline void rcu_irq_enter_check_tick(void)
+  */
+ #define __irq_enter()					\
+ 	do {						\
+-		account_irq_enter_time(current);	\
+ 		preempt_count_add(HARDIRQ_OFFSET);	\
+ 		lockdep_hardirq_enter();		\
++		account_hardirq_enter(current);		\
+ 	} while (0)
+ 
+ /*
+@@ -62,8 +62,8 @@ void irq_enter_rcu(void);
+  */
+ #define __irq_exit()					\
+ 	do {						\
++		account_hardirq_exit(current);		\
+ 		lockdep_hardirq_exit();			\
+-		account_irq_exit_time(current);		\
+ 		preempt_count_sub(HARDIRQ_OFFSET);	\
+ 	} while (0)
+ 
+diff --git a/include/linux/vtime.h b/include/linux/vtime.h
+index 6c9867419615..041d6524d144 100644
+--- a/include/linux/vtime.h
++++ b/include/linux/vtime.h
+@@ -83,32 +83,46 @@ static inline void vtime_init_idle(struct task_struct *tsk, int cpu) { }
+ #endif
+ 
+ #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
+-extern void vtime_account_irq(struct task_struct *tsk);
++extern void vtime_account_irq(struct task_struct *tsk, unsigned int offset);
+ extern void vtime_account_softirq(struct task_struct *tsk);
+ extern void vtime_account_hardirq(struct task_struct *tsk);
+ extern void vtime_flush(struct task_struct *tsk);
+ #else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
+-static inline void vtime_account_irq(struct task_struct *tsk) { }
++static inline void vtime_account_irq(struct task_struct *tsk, unsigned int offset) { }
++static inline void vtime_account_softirq(struct task_struct *tsk) { }
++static inline void vtime_account_hardirq(struct task_struct *tsk) { }
+ static inline void vtime_flush(struct task_struct *tsk) { }
+ #endif
+ 
+ 
+ #ifdef CONFIG_IRQ_TIME_ACCOUNTING
+-extern void irqtime_account_irq(struct task_struct *tsk);
++extern void irqtime_account_irq(struct task_struct *tsk, unsigned int offset);
+ #else
+-static inline void irqtime_account_irq(struct task_struct *tsk) { }
++static inline void irqtime_account_irq(struct task_struct *tsk, unsigned int offset) { }
+ #endif
+ 
+-static inline void account_irq_enter_time(struct task_struct *tsk)
++static inline void account_softirq_enter(struct task_struct *tsk)
+ {
+-	vtime_account_irq(tsk);
+-	irqtime_account_irq(tsk);
++	vtime_account_irq(tsk, SOFTIRQ_OFFSET);
++	irqtime_account_irq(tsk, SOFTIRQ_OFFSET);
+ }
+ 
+-static inline void account_irq_exit_time(struct task_struct *tsk)
++static inline void account_softirq_exit(struct task_struct *tsk)
+ {
+-	vtime_account_irq(tsk);
+-	irqtime_account_irq(tsk);
++	vtime_account_softirq(tsk);
++	irqtime_account_irq(tsk, 0);
++}
++
++static inline void account_hardirq_enter(struct task_struct *tsk)
++{
++	vtime_account_irq(tsk, HARDIRQ_OFFSET);
++	irqtime_account_irq(tsk, HARDIRQ_OFFSET);
++}
++
++static inline void account_hardirq_exit(struct task_struct *tsk)
++{
++	vtime_account_hardirq(tsk);
++	irqtime_account_irq(tsk, 0);
+ }
+ 
+ #endif /* _LINUX_KERNEL_VTIME_H */
+diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
+index 60129af16ed6..02a7932c7383 100644
+--- a/kernel/sched/cputime.c
++++ b/kernel/sched/cputime.c
+@@ -44,12 +44,13 @@ static void irqtime_account_delta(struct irqtime *irqtime, u64 delta,
+ }
+ 
+ /*
+- * Called before incrementing preempt_count on {soft,}irq_enter
++ * Called after incrementing preempt_count on {soft,}irq_enter
+  * and before decrementing preempt_count on {soft,}irq_exit.
+  */
+-void irqtime_account_irq(struct task_struct *curr)
++void irqtime_account_irq(struct task_struct *curr, unsigned int offset)
+ {
+ 	struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime);
++	unsigned int pc;
+ 	s64 delta;
+ 	int cpu;
+ 
+@@ -59,6 +60,7 @@ void irqtime_account_irq(struct task_struct *curr)
+ 	cpu = smp_processor_id();
+ 	delta = sched_clock_cpu(cpu) - irqtime->irq_start_time;
+ 	irqtime->irq_start_time += delta;
++	pc = preempt_count() - offset;
+ 
+ 	/*
+ 	 * We do not account for softirq time from ksoftirqd here.
+@@ -66,9 +68,9 @@ void irqtime_account_irq(struct task_struct *curr)
+ 	 * in that case, so as not to confuse scheduler with a special task
+ 	 * that do not consume any time, but still wants to run.
+ 	 */
+-	if (hardirq_count())
++	if (pc & HARDIRQ_MASK)
+ 		irqtime_account_delta(irqtime, delta, CPUTIME_IRQ);
+-	else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
++	else if ((pc & SOFTIRQ_OFFSET) && curr != this_cpu_ksoftirqd())
+ 		irqtime_account_delta(irqtime, delta, CPUTIME_SOFTIRQ);
+ }
+ 
+@@ -417,11 +419,13 @@ void vtime_task_switch(struct task_struct *prev)
+ }
+ # endif
+ 
+-void vtime_account_irq(struct task_struct *tsk)
++void vtime_account_irq(struct task_struct *tsk, unsigned int offset)
+ {
+-	if (hardirq_count()) {
++	unsigned int pc = preempt_count() - offset;
++
++	if (pc & HARDIRQ_OFFSET) {
+ 		vtime_account_hardirq(tsk);
+-	} else if (in_serving_softirq()) {
++	} else if (pc & SOFTIRQ_OFFSET) {
+ 		vtime_account_softirq(tsk);
+ 	} else if (!IS_ENABLED(CONFIG_HAVE_VIRT_CPU_ACCOUNTING_IDLE) &&
+ 		   is_idle_task(tsk)) {
+diff --git a/kernel/softirq.c b/kernel/softirq.c
+index 617009ccd82c..b8f42b3ba8ca 100644
+--- a/kernel/softirq.c
++++ b/kernel/softirq.c
+@@ -315,10 +315,10 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
+ 	current->flags &= ~PF_MEMALLOC;
+ 
+ 	pending = local_softirq_pending();
+-	account_irq_enter_time(current);
+ 
+ 	__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
+ 	in_hardirq = lockdep_softirq_start();
++	account_softirq_enter(current);
+ 
+ restart:
+ 	/* Reset the pending bitmask before enabling irqs */
+@@ -365,8 +365,8 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
+ 		wakeup_softirqd();
+ 	}
+ 
++	account_softirq_exit(current);
+ 	lockdep_softirq_end(in_hardirq);
+-	account_irq_exit_time(current);
+ 	__local_bh_enable(SOFTIRQ_OFFSET);
+ 	WARN_ON_ONCE(in_interrupt());
+ 	current_restore_flags(old_flags, PF_MEMALLOC);
+@@ -418,7 +418,7 @@ static inline void __irq_exit_rcu(void)
+ #else
+ 	lockdep_assert_irqs_disabled();
+ #endif
+-	account_irq_exit_time(current);
++	account_hardirq_exit(current);
+ 	preempt_count_sub(HARDIRQ_OFFSET);
+ 	if (!in_interrupt() && local_softirq_pending())
+ 		invoke_softirq();
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0130-irq-Call-tick_irq_enter-inside-HARDIRQ_OFFSET.patch b/debian/patches-rt/0130-irq-Call-tick_irq_enter-inside-HARDIRQ_OFFSET.patch
new file mode 100644
index 000000000..304fef0fa
--- /dev/null
+++ b/debian/patches-rt/0130-irq-Call-tick_irq_enter-inside-HARDIRQ_OFFSET.patch
@@ -0,0 +1,51 @@
+From 5e2b7533340eb96a841068c309aac4985bd8180c Mon Sep 17 00:00:00 2001
+From: Frederic Weisbecker <frederic@kernel.org>
+Date: Wed, 2 Dec 2020 12:57:32 +0100
+Subject: [PATCH 130/323] irq: Call tick_irq_enter() inside HARDIRQ_OFFSET
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Now that account_hardirq_enter() is called after HARDIRQ_OFFSET has
+been incremented, there is nothing left that prevents us from also
+moving tick_irq_enter() after HARDIRQ_OFFSET is incremented.
+
+The desired outcome is to remove the nasty hack that prevents softirqs
+from being raised through ksoftirqd instead of the hardirq bottom half.
+Also tick_irq_enter() then becomes appropriately covered by lockdep.
+
+Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20201202115732.27827-6-frederic@kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/softirq.c | 14 +++++---------
+ 1 file changed, 5 insertions(+), 9 deletions(-)
+
+diff --git a/kernel/softirq.c b/kernel/softirq.c
+index b8f42b3ba8ca..d5bfd5e661fc 100644
+--- a/kernel/softirq.c
++++ b/kernel/softirq.c
+@@ -377,16 +377,12 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
+  */
+ void irq_enter_rcu(void)
+ {
+-	if (is_idle_task(current) && !in_interrupt()) {
+-		/*
+-		 * Prevent raise_softirq from needlessly waking up ksoftirqd
+-		 * here, as softirq will be serviced on return from interrupt.
+-		 */
+-		local_bh_disable();
++	__irq_enter_raw();
++
++	if (is_idle_task(current) && (irq_count() == HARDIRQ_OFFSET))
+ 		tick_irq_enter();
+-		_local_bh_enable();
+-	}
+-	__irq_enter();
++
++	account_hardirq_enter(current);
+ }
+ 
+ /**
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0131-smp-Wake-ksoftirqd-on-PREEMPT_RT-instead-do_softirq.patch b/debian/patches-rt/0131-smp-Wake-ksoftirqd-on-PREEMPT_RT-instead-do_softirq.patch
new file mode 100644
index 000000000..19d4f6615
--- /dev/null
+++ b/debian/patches-rt/0131-smp-Wake-ksoftirqd-on-PREEMPT_RT-instead-do_softirq.patch
@@ -0,0 +1,48 @@
+From d6a969bae816bcd5ac549038a4582d300ede6b99 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 15 Feb 2021 18:44:12 +0100
+Subject: [PATCH 131/323] smp: Wake ksoftirqd on PREEMPT_RT instead
+ do_softirq().
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The softirq implementation on PREEMPT_RT does not provide do_softirq().
+The other user of do_softirq() is replaced with a local_bh_disable()
++ enable() around the possible raise-softirq invocation. This can not be
+done here because migration_cpu_stop() is invoked with disabled
+preemption.
+
+Wake the softirq thread on PREEMPT_RT if there are any pending softirqs.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/smp.c | 14 ++++++++++++--
+ 1 file changed, 12 insertions(+), 2 deletions(-)
+
+diff --git a/kernel/smp.c b/kernel/smp.c
+index b0684b4c111e..4aaf11aa729c 100644
+--- a/kernel/smp.c
++++ b/kernel/smp.c
+@@ -450,8 +450,18 @@ void flush_smp_call_function_from_idle(void)
+ 
+ 	local_irq_save(flags);
+ 	flush_smp_call_function_queue(true);
+-	if (local_softirq_pending())
+-		do_softirq();
++
++	if (local_softirq_pending()) {
++
++		if (!IS_ENABLED(CONFIG_PREEMPT_RT)) {
++			do_softirq();
++		} else {
++			struct task_struct *ksoftirqd = this_cpu_ksoftirqd();
++
++			if (ksoftirqd && ksoftirqd->state != TASK_RUNNING)
++				wake_up_process(ksoftirqd);
++		}
++	}
+ 
+ 	local_irq_restore(flags);
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0132-tasklets-Replace-barrier-with-cpu_relax-in-tasklet_u.patch b/debian/patches-rt/0132-tasklets-Replace-barrier-with-cpu_relax-in-tasklet_u.patch
new file mode 100644
index 000000000..8908254e0
--- /dev/null
+++ b/debian/patches-rt/0132-tasklets-Replace-barrier-with-cpu_relax-in-tasklet_u.patch
@@ -0,0 +1,35 @@
+From 8127bb05947dbb12f9537095932d6a7a7a07d09e Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 9 Mar 2021 09:42:04 +0100
+Subject: [PATCH 132/323] tasklets: Replace barrier() with cpu_relax() in
+ tasklet_unlock_wait()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+A barrier() in a tight loop which waits for something to happen on a remote
+CPU is a pointless exercise. Replace it with cpu_relax() which allows HT
+siblings to make progress.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/interrupt.h | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
+index 0652b4858ba6..fad0eb9d42ab 100644
+--- a/include/linux/interrupt.h
++++ b/include/linux/interrupt.h
+@@ -672,7 +672,8 @@ static inline void tasklet_unlock(struct tasklet_struct *t)
+ 
+ static inline void tasklet_unlock_wait(struct tasklet_struct *t)
+ {
+-	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
++	while (test_bit(TASKLET_STATE_RUN, &t->state))
++		cpu_relax();
+ }
+ #else
+ #define tasklet_trylock(t) 1
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0133-tasklets-Use-static-inlines-for-stub-implementations.patch b/debian/patches-rt/0133-tasklets-Use-static-inlines-for-stub-implementations.patch
new file mode 100644
index 000000000..57ec50a2e
--- /dev/null
+++ b/debian/patches-rt/0133-tasklets-Use-static-inlines-for-stub-implementations.patch
@@ -0,0 +1,35 @@
+From fa31367f235c42f78b2375d5ade6130a3b296e22 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 9 Mar 2021 09:42:05 +0100
+Subject: [PATCH 133/323] tasklets: Use static inlines for stub implementations
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Inlines exist for a reason.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/interrupt.h | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
+index fad0eb9d42ab..75c4380afe9b 100644
+--- a/include/linux/interrupt.h
++++ b/include/linux/interrupt.h
+@@ -676,9 +676,9 @@ static inline void tasklet_unlock_wait(struct tasklet_struct *t)
+ 		cpu_relax();
+ }
+ #else
+-#define tasklet_trylock(t) 1
+-#define tasklet_unlock_wait(t) do { } while (0)
+-#define tasklet_unlock(t) do { } while (0)
++static inline int tasklet_trylock(struct tasklet_struct *t) { return 1; }
++static inline void tasklet_unlock(struct tasklet_struct *t) { }
++static inline void tasklet_unlock_wait(struct tasklet_struct *t) { }
+ #endif
+ 
+ extern void __tasklet_schedule(struct tasklet_struct *t);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0134-tasklets-Provide-tasklet_disable_in_atomic.patch b/debian/patches-rt/0134-tasklets-Provide-tasklet_disable_in_atomic.patch
new file mode 100644
index 000000000..2f6fb1ab9
--- /dev/null
+++ b/debian/patches-rt/0134-tasklets-Provide-tasklet_disable_in_atomic.patch
@@ -0,0 +1,68 @@
+From 35c080a5db30acfdfa20ca84bf9d0482e6ec1409 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 9 Mar 2021 09:42:06 +0100
+Subject: [PATCH 134/323] tasklets: Provide tasklet_disable_in_atomic()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Replacing the spin wait loops in tasklet_unlock_wait() with
+wait_var_event() is not possible as a handful of tasklet_disable()
+invocations are happening in atomic context. All other invocations are in
+teardown paths which can sleep.
+
+Provide tasklet_disable_in_atomic() and tasklet_unlock_spin_wait() to
+convert the few atomic use cases over, which allows to change
+tasklet_disable() and tasklet_unlock_wait() in a later step.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/interrupt.h | 22 ++++++++++++++++++++++
+ 1 file changed, 22 insertions(+)
+
+diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
+index 75c4380afe9b..abba3eff4f86 100644
+--- a/include/linux/interrupt.h
++++ b/include/linux/interrupt.h
+@@ -675,10 +675,21 @@ static inline void tasklet_unlock_wait(struct tasklet_struct *t)
+ 	while (test_bit(TASKLET_STATE_RUN, &t->state))
+ 		cpu_relax();
+ }
++
++/*
++ * Do not use in new code. Waiting for tasklets from atomic contexts is
++ * error prone and should be avoided.
++ */
++static inline void tasklet_unlock_spin_wait(struct tasklet_struct *t)
++{
++	while (test_bit(TASKLET_STATE_RUN, &t->state))
++		cpu_relax();
++}
+ #else
+ static inline int tasklet_trylock(struct tasklet_struct *t) { return 1; }
+ static inline void tasklet_unlock(struct tasklet_struct *t) { }
+ static inline void tasklet_unlock_wait(struct tasklet_struct *t) { }
++static inline void tasklet_unlock_spin_wait(struct tasklet_struct *t) { }
+ #endif
+ 
+ extern void __tasklet_schedule(struct tasklet_struct *t);
+@@ -703,6 +714,17 @@ static inline void tasklet_disable_nosync(struct tasklet_struct *t)
+ 	smp_mb__after_atomic();
+ }
+ 
++/*
++ * Do not use in new code. Disabling tasklets from atomic contexts is
++ * error prone and should be avoided.
++ */
++static inline void tasklet_disable_in_atomic(struct tasklet_struct *t)
++{
++	tasklet_disable_nosync(t);
++	tasklet_unlock_spin_wait(t);
++	smp_mb();
++}
++
+ static inline void tasklet_disable(struct tasklet_struct *t)
+ {
+ 	tasklet_disable_nosync(t);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0135-tasklets-Use-spin-wait-in-tasklet_disable-temporaril.patch b/debian/patches-rt/0135-tasklets-Use-spin-wait-in-tasklet_disable-temporaril.patch
new file mode 100644
index 000000000..7e32a2a7c
--- /dev/null
+++ b/debian/patches-rt/0135-tasklets-Use-spin-wait-in-tasklet_disable-temporaril.patch
@@ -0,0 +1,33 @@
+From 90d88360f539e57921ec9675603c700c351a0078 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 9 Mar 2021 09:42:07 +0100
+Subject: [PATCH 135/323] tasklets: Use spin wait in tasklet_disable()
+ temporarily
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+To ease the transition use spin waiting in tasklet_disable() until all
+usage sites from atomic context have been cleaned up.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/interrupt.h | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
+index abba3eff4f86..fe085c46f210 100644
+--- a/include/linux/interrupt.h
++++ b/include/linux/interrupt.h
+@@ -728,7 +728,8 @@ static inline void tasklet_disable_in_atomic(struct tasklet_struct *t)
+ static inline void tasklet_disable(struct tasklet_struct *t)
+ {
+ 	tasklet_disable_nosync(t);
+-	tasklet_unlock_wait(t);
++	/* Spin wait until all atomic users are converted */
++	tasklet_unlock_spin_wait(t);
+ 	smp_mb();
+ }
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0136-tasklets-Replace-spin-wait-in-tasklet_unlock_wait.patch b/debian/patches-rt/0136-tasklets-Replace-spin-wait-in-tasklet_unlock_wait.patch
new file mode 100644
index 000000000..c244c4010
--- /dev/null
+++ b/debian/patches-rt/0136-tasklets-Replace-spin-wait-in-tasklet_unlock_wait.patch
@@ -0,0 +1,90 @@
+From 1e2be8ee6d91630326a3a3bc32925205b41d73a5 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Tue, 9 Mar 2021 09:42:08 +0100
+Subject: [PATCH 136/323] tasklets: Replace spin wait in tasklet_unlock_wait()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+tasklet_unlock_wait() spin waits for TASKLET_STATE_RUN to be cleared. This
+is wasting CPU cycles in a tight loop which is especially painful in a
+guest when the CPU running the tasklet is scheduled out.
+
+tasklet_unlock_wait() is invoked from tasklet_kill() which is used in
+teardown paths and not performance critical at all. Replace the spin wait
+with wait_var_event().
+
+There are no users of tasklet_unlock_wait() which are invoked from atomic
+contexts. The usage in tasklet_disable() has been replaced temporarily with
+the spin waiting variant until the atomic users are fixed up and will be
+converted to the sleep wait variant later.
+
+Signed-off-by: Peter Zijlstra <peterz@infradead.org>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/interrupt.h | 13 ++-----------
+ kernel/softirq.c          | 18 ++++++++++++++++++
+ 2 files changed, 20 insertions(+), 11 deletions(-)
+
+diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
+index fe085c46f210..c4fafbfa28a6 100644
+--- a/include/linux/interrupt.h
++++ b/include/linux/interrupt.h
+@@ -664,17 +664,8 @@ static inline int tasklet_trylock(struct tasklet_struct *t)
+ 	return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
+ }
+ 
+-static inline void tasklet_unlock(struct tasklet_struct *t)
+-{
+-	smp_mb__before_atomic();
+-	clear_bit(TASKLET_STATE_RUN, &(t)->state);
+-}
+-
+-static inline void tasklet_unlock_wait(struct tasklet_struct *t)
+-{
+-	while (test_bit(TASKLET_STATE_RUN, &t->state))
+-		cpu_relax();
+-}
++void tasklet_unlock(struct tasklet_struct *t);
++void tasklet_unlock_wait(struct tasklet_struct *t);
+ 
+ /*
+  * Do not use in new code. Waiting for tasklets from atomic contexts is
+diff --git a/kernel/softirq.c b/kernel/softirq.c
+index d5bfd5e661fc..06bca024ce45 100644
+--- a/kernel/softirq.c
++++ b/kernel/softirq.c
+@@ -25,6 +25,7 @@
+ #include <linux/smpboot.h>
+ #include <linux/tick.h>
+ #include <linux/irq.h>
++#include <linux/wait_bit.h>
+ 
+ #define CREATE_TRACE_POINTS
+ #include <trace/events/irq.h>
+@@ -619,6 +620,23 @@ void tasklet_kill(struct tasklet_struct *t)
+ }
+ EXPORT_SYMBOL(tasklet_kill);
+ 
++#ifdef CONFIG_SMP
++void tasklet_unlock(struct tasklet_struct *t)
++{
++	smp_mb__before_atomic();
++	clear_bit(TASKLET_STATE_RUN, &t->state);
++	smp_mb__after_atomic();
++	wake_up_var(&t->state);
++}
++EXPORT_SYMBOL_GPL(tasklet_unlock);
++
++void tasklet_unlock_wait(struct tasklet_struct *t)
++{
++	wait_var_event(&t->state, !test_bit(TASKLET_STATE_RUN, &t->state));
++}
++EXPORT_SYMBOL_GPL(tasklet_unlock_wait);
++#endif
++
+ void __init softirq_init(void)
+ {
+ 	int cpu;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0137-tasklets-Replace-spin-wait-in-tasklet_kill.patch b/debian/patches-rt/0137-tasklets-Replace-spin-wait-in-tasklet_kill.patch
new file mode 100644
index 000000000..619e62b2a
--- /dev/null
+++ b/debian/patches-rt/0137-tasklets-Replace-spin-wait-in-tasklet_kill.patch
@@ -0,0 +1,74 @@
+From cc2fc16258410420e97a4873f760cffabcff49b0 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Tue, 9 Mar 2021 09:42:09 +0100
+Subject: [PATCH 137/323] tasklets: Replace spin wait in tasklet_kill()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+tasklet_kill() spin waits for TASKLET_STATE_SCHED to be cleared invoking
+yield() from inside the loop. yield() is an ill defined mechanism and the
+result might still be wasting CPU cycles in a tight loop which is
+especially painful in a guest when the CPU running the tasklet is scheduled
+out.
+
+tasklet_kill() is used in teardown paths and not performance critical at
+all. Replace the spin wait with wait_var_event().
+
+Signed-off-by: Peter Zijlstra <peterz@infradead.org>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/softirq.c | 23 +++++++++++++++--------
+ 1 file changed, 15 insertions(+), 8 deletions(-)
+
+diff --git a/kernel/softirq.c b/kernel/softirq.c
+index 06bca024ce45..ecc3ac4091c8 100644
+--- a/kernel/softirq.c
++++ b/kernel/softirq.c
+@@ -530,6 +530,16 @@ void __tasklet_hi_schedule(struct tasklet_struct *t)
+ }
+ EXPORT_SYMBOL(__tasklet_hi_schedule);
+ 
++static inline bool tasklet_clear_sched(struct tasklet_struct *t)
++{
++	if (test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) {
++		wake_up_var(&t->state);
++		return true;
++	}
++
++	return false;
++}
++
+ static void tasklet_action_common(struct softirq_action *a,
+ 				  struct tasklet_head *tl_head,
+ 				  unsigned int softirq_nr)
+@@ -549,8 +559,7 @@ static void tasklet_action_common(struct softirq_action *a,
+ 
+ 		if (tasklet_trylock(t)) {
+ 			if (!atomic_read(&t->count)) {
+-				if (!test_and_clear_bit(TASKLET_STATE_SCHED,
+-							&t->state))
++				if (!tasklet_clear_sched(t))
+ 					BUG();
+ 				if (t->use_callback)
+ 					t->callback(t);
+@@ -610,13 +619,11 @@ void tasklet_kill(struct tasklet_struct *t)
+ 	if (in_interrupt())
+ 		pr_notice("Attempt to kill tasklet from interrupt\n");
+ 
+-	while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) {
+-		do {
+-			yield();
+-		} while (test_bit(TASKLET_STATE_SCHED, &t->state));
+-	}
++	while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
++		wait_var_event(&t->state, !test_bit(TASKLET_STATE_SCHED, &t->state));
++
+ 	tasklet_unlock_wait(t);
+-	clear_bit(TASKLET_STATE_SCHED, &t->state);
++	tasklet_clear_sched(t);
+ }
+ EXPORT_SYMBOL(tasklet_kill);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0138-tasklets-Prevent-tasklet_unlock_spin_wait-deadlock-o.patch b/debian/patches-rt/0138-tasklets-Prevent-tasklet_unlock_spin_wait-deadlock-o.patch
new file mode 100644
index 000000000..9f446b54f
--- /dev/null
+++ b/debian/patches-rt/0138-tasklets-Prevent-tasklet_unlock_spin_wait-deadlock-o.patch
@@ -0,0 +1,109 @@
+From 42114155db1a5548923ac48a09b3f228b29d3b09 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 9 Mar 2021 09:42:10 +0100
+Subject: [PATCH 138/323] tasklets: Prevent tasklet_unlock_spin_wait() deadlock
+ on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+tasklet_unlock_spin_wait() spin waits for the TASKLET_STATE_SCHED bit in
+the tasklet state to be cleared. This works on !RT nicely because the
+corresponding execution can only happen on a different CPU.
+
+On RT softirq processing is preemptible, therefore a task preempting the
+softirq processing thread can spin forever.
+
+Prevent this by invoking local_bh_disable()/enable() inside the loop. In
+case that the softirq processing thread was preempted by the current task,
+current will block on the local lock which yields the CPU to the preempted
+softirq processing thread. If the tasklet is processed on a different CPU
+then the local_bh_disable()/enable() pair is just a waste of processor
+cycles.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/interrupt.h | 12 ++----------
+ kernel/softirq.c          | 28 +++++++++++++++++++++++++++-
+ 2 files changed, 29 insertions(+), 11 deletions(-)
+
+diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
+index c4fafbfa28a6..6eae70ec3a17 100644
+--- a/include/linux/interrupt.h
++++ b/include/linux/interrupt.h
+@@ -658,7 +658,7 @@ enum
+ 	TASKLET_STATE_RUN	/* Tasklet is running (SMP only) */
+ };
+ 
+-#ifdef CONFIG_SMP
++#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
+ static inline int tasklet_trylock(struct tasklet_struct *t)
+ {
+ 	return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
+@@ -666,16 +666,8 @@ static inline int tasklet_trylock(struct tasklet_struct *t)
+ 
+ void tasklet_unlock(struct tasklet_struct *t);
+ void tasklet_unlock_wait(struct tasklet_struct *t);
++void tasklet_unlock_spin_wait(struct tasklet_struct *t);
+ 
+-/*
+- * Do not use in new code. Waiting for tasklets from atomic contexts is
+- * error prone and should be avoided.
+- */
+-static inline void tasklet_unlock_spin_wait(struct tasklet_struct *t)
+-{
+-	while (test_bit(TASKLET_STATE_RUN, &t->state))
+-		cpu_relax();
+-}
+ #else
+ static inline int tasklet_trylock(struct tasklet_struct *t) { return 1; }
+ static inline void tasklet_unlock(struct tasklet_struct *t) { }
+diff --git a/kernel/softirq.c b/kernel/softirq.c
+index ecc3ac4091c8..fcb201ceed71 100644
+--- a/kernel/softirq.c
++++ b/kernel/softirq.c
+@@ -614,6 +614,32 @@ void tasklet_init(struct tasklet_struct *t,
+ }
+ EXPORT_SYMBOL(tasklet_init);
+ 
++#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
++/*
++ * Do not use in new code. Waiting for tasklets from atomic contexts is
++ * error prone and should be avoided.
++ */
++void tasklet_unlock_spin_wait(struct tasklet_struct *t)
++{
++	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) {
++		if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
++			/*
++			 * Prevent a live lock when current preempted soft
++			 * interrupt processing or prevents ksoftirqd from
++			 * running. If the tasklet runs on a different CPU
++			 * then this has no effect other than doing the BH
++			 * disable/enable dance for nothing.
++			 */
++			local_bh_disable();
++			local_bh_enable();
++		} else {
++			cpu_relax();
++		}
++	}
++}
++EXPORT_SYMBOL(tasklet_unlock_spin_wait);
++#endif
++
+ void tasklet_kill(struct tasklet_struct *t)
+ {
+ 	if (in_interrupt())
+@@ -627,7 +653,7 @@ void tasklet_kill(struct tasklet_struct *t)
+ }
+ EXPORT_SYMBOL(tasklet_kill);
+ 
+-#ifdef CONFIG_SMP
++#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
+ void tasklet_unlock(struct tasklet_struct *t)
+ {
+ 	smp_mb__before_atomic();
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0139-net-jme-Replace-link-change-tasklet-with-work.patch b/debian/patches-rt/0139-net-jme-Replace-link-change-tasklet-with-work.patch
new file mode 100644
index 000000000..927a8ce66
--- /dev/null
+++ b/debian/patches-rt/0139-net-jme-Replace-link-change-tasklet-with-work.patch
@@ -0,0 +1,88 @@
+From 8aad52579188d8ae11265d495209d51029482f38 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 9 Mar 2021 09:42:11 +0100
+Subject: [PATCH 139/323] net: jme: Replace link-change tasklet with work
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The link change tasklet disables the tasklets for tx/rx processing while
+upating hw parameters and then enables the tasklets again.
+
+This update can also be pushed into a workqueue where it can be performed
+in preemptible context. This allows tasklet_disable() to become sleeping.
+
+Replace the linkch_task tasklet with a work.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/net/ethernet/jme.c | 10 +++++-----
+ drivers/net/ethernet/jme.h |  2 +-
+ 2 files changed, 6 insertions(+), 6 deletions(-)
+
+diff --git a/drivers/net/ethernet/jme.c b/drivers/net/ethernet/jme.c
+index e9efe074edc1..f1b9284e0bea 100644
+--- a/drivers/net/ethernet/jme.c
++++ b/drivers/net/ethernet/jme.c
+@@ -1265,9 +1265,9 @@ jme_stop_shutdown_timer(struct jme_adapter *jme)
+ 	jwrite32f(jme, JME_APMC, apmc);
+ }
+ 
+-static void jme_link_change_tasklet(struct tasklet_struct *t)
++static void jme_link_change_work(struct work_struct *work)
+ {
+-	struct jme_adapter *jme = from_tasklet(jme, t, linkch_task);
++	struct jme_adapter *jme = container_of(work, struct jme_adapter, linkch_task);
+ 	struct net_device *netdev = jme->dev;
+ 	int rc;
+ 
+@@ -1510,7 +1510,7 @@ jme_intr_msi(struct jme_adapter *jme, u32 intrstat)
+ 		 * all other events are ignored
+ 		 */
+ 		jwrite32(jme, JME_IEVE, intrstat);
+-		tasklet_schedule(&jme->linkch_task);
++		schedule_work(&jme->linkch_task);
+ 		goto out_reenable;
+ 	}
+ 
+@@ -1832,7 +1832,6 @@ jme_open(struct net_device *netdev)
+ 	jme_clear_pm_disable_wol(jme);
+ 	JME_NAPI_ENABLE(jme);
+ 
+-	tasklet_setup(&jme->linkch_task, jme_link_change_tasklet);
+ 	tasklet_setup(&jme->txclean_task, jme_tx_clean_tasklet);
+ 	tasklet_setup(&jme->rxclean_task, jme_rx_clean_tasklet);
+ 	tasklet_setup(&jme->rxempty_task, jme_rx_empty_tasklet);
+@@ -1920,7 +1919,7 @@ jme_close(struct net_device *netdev)
+ 
+ 	JME_NAPI_DISABLE(jme);
+ 
+-	tasklet_kill(&jme->linkch_task);
++	cancel_work_sync(&jme->linkch_task);
+ 	tasklet_kill(&jme->txclean_task);
+ 	tasklet_kill(&jme->rxclean_task);
+ 	tasklet_kill(&jme->rxempty_task);
+@@ -3035,6 +3034,7 @@ jme_init_one(struct pci_dev *pdev,
+ 	atomic_set(&jme->rx_empty, 1);
+ 
+ 	tasklet_setup(&jme->pcc_task, jme_pcc_tasklet);
++	INIT_WORK(&jme->linkch_task, jme_link_change_work);
+ 	jme->dpi.cur = PCC_P1;
+ 
+ 	jme->reg_ghc = 0;
+diff --git a/drivers/net/ethernet/jme.h b/drivers/net/ethernet/jme.h
+index a2c3b00d939d..2af76329b4a2 100644
+--- a/drivers/net/ethernet/jme.h
++++ b/drivers/net/ethernet/jme.h
+@@ -411,7 +411,7 @@ struct jme_adapter {
+ 	struct tasklet_struct	rxempty_task;
+ 	struct tasklet_struct	rxclean_task;
+ 	struct tasklet_struct	txclean_task;
+-	struct tasklet_struct	linkch_task;
++	struct work_struct	linkch_task;
+ 	struct tasklet_struct	pcc_task;
+ 	unsigned long		flags;
+ 	u32			reg_txcs;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0140-net-sundance-Use-tasklet_disable_in_atomic.patch b/debian/patches-rt/0140-net-sundance-Use-tasklet_disable_in_atomic.patch
new file mode 100644
index 000000000..cc8eade7d
--- /dev/null
+++ b/debian/patches-rt/0140-net-sundance-Use-tasklet_disable_in_atomic.patch
@@ -0,0 +1,39 @@
+From b8d19bf463893a07bab9120bd628798515f3e6e0 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 9 Mar 2021 09:42:12 +0100
+Subject: [PATCH 140/323] net: sundance: Use tasklet_disable_in_atomic().
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+tasklet_disable() is used in the timer callback. This might be distangled,
+but without access to the hardware that's a bit risky.
+
+Replace it with tasklet_disable_in_atomic() so tasklet_disable() can be
+changed to a sleep wait once all remaining atomic users are converted.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Denis Kirjanov <kda@linux-powerpc.org>
+Cc: "David S. Miller" <davem@davemloft.net>
+Cc: Jakub Kicinski <kuba@kernel.org>
+Cc: netdev@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/net/ethernet/dlink/sundance.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/drivers/net/ethernet/dlink/sundance.c b/drivers/net/ethernet/dlink/sundance.c
+index e3a8858915b3..df0eab479d51 100644
+--- a/drivers/net/ethernet/dlink/sundance.c
++++ b/drivers/net/ethernet/dlink/sundance.c
+@@ -963,7 +963,7 @@ static void tx_timeout(struct net_device *dev, unsigned int txqueue)
+ 	unsigned long flag;
+ 
+ 	netif_stop_queue(dev);
+-	tasklet_disable(&np->tx_tasklet);
++	tasklet_disable_in_atomic(&np->tx_tasklet);
+ 	iowrite16(0, ioaddr + IntrEnable);
+ 	printk(KERN_WARNING "%s: Transmit timed out, TxStatus %2.2x "
+ 		   "TxFrameId %2.2x,"
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0141-ath9k-Use-tasklet_disable_in_atomic.patch b/debian/patches-rt/0141-ath9k-Use-tasklet_disable_in_atomic.patch
new file mode 100644
index 000000000..8e80fa205
--- /dev/null
+++ b/debian/patches-rt/0141-ath9k-Use-tasklet_disable_in_atomic.patch
@@ -0,0 +1,48 @@
+From 3e2ecd3c09d77800b53b99090c6b6372af1922e7 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 9 Mar 2021 09:42:13 +0100
+Subject: [PATCH 141/323] ath9k: Use tasklet_disable_in_atomic()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+All callers of ath9k_beacon_ensure_primary_slot() are preemptible /
+acquire a mutex except for this callchain:
+
+  spin_lock_bh(&sc->sc_pcu_lock);
+  ath_complete_reset()
+  -> ath9k_calculate_summary_state()
+     -> ath9k_beacon_ensure_primary_slot()
+
+It's unclear how that can be distangled, so use tasklet_disable_in_atomic()
+for now. This allows tasklet_disable() to become sleepable once the
+remaining atomic users are cleaned up.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: ath9k-devel@qca.qualcomm.com
+Cc: Kalle Valo <kvalo@codeaurora.org>
+Cc: "David S. Miller" <davem@davemloft.net>
+Cc: Jakub Kicinski <kuba@kernel.org>
+Cc: linux-wireless@vger.kernel.org
+Cc: netdev@vger.kernel.org
+Acked-by: Kalle Valo <kvalo@codeaurora.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/net/wireless/ath/ath9k/beacon.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/drivers/net/wireless/ath/ath9k/beacon.c b/drivers/net/wireless/ath/ath9k/beacon.c
+index 71e2ada86793..72e2e71aac0e 100644
+--- a/drivers/net/wireless/ath/ath9k/beacon.c
++++ b/drivers/net/wireless/ath/ath9k/beacon.c
+@@ -251,7 +251,7 @@ void ath9k_beacon_ensure_primary_slot(struct ath_softc *sc)
+ 	int first_slot = ATH_BCBUF;
+ 	int slot;
+ 
+-	tasklet_disable(&sc->bcon_tasklet);
++	tasklet_disable_in_atomic(&sc->bcon_tasklet);
+ 
+ 	/* Find first taken slot. */
+ 	for (slot = 0; slot < ATH_BCBUF; slot++) {
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0142-atm-eni-Use-tasklet_disable_in_atomic-in-the-send-ca.patch b/debian/patches-rt/0142-atm-eni-Use-tasklet_disable_in_atomic-in-the-send-ca.patch
new file mode 100644
index 000000000..45236c9da
--- /dev/null
+++ b/debian/patches-rt/0142-atm-eni-Use-tasklet_disable_in_atomic-in-the-send-ca.patch
@@ -0,0 +1,42 @@
+From f8cac7fb539abd4d961c942dde93a04956f9615d Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 9 Mar 2021 09:42:14 +0100
+Subject: [PATCH 142/323] atm: eni: Use tasklet_disable_in_atomic() in the
+ send() callback
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The atmdev_ops::send callback which calls tasklet_disable() is invoked with
+bottom halfs disabled from net_device_ops::ndo_start_xmit(). All other
+invocations of tasklet_disable() in this driver happen in preemptible
+context.
+
+Change the send() call to use tasklet_disable_in_atomic() which allows
+tasklet_disable() to be made sleepable once the remaining atomic context
+usage sites are cleaned up.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Chas Williams <3chas3@gmail.com>
+Cc: linux-atm-general@lists.sourceforge.net
+Cc: netdev@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/atm/eni.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/drivers/atm/eni.c b/drivers/atm/eni.c
+index 9fcc49be499f..a31ffe16e626 100644
+--- a/drivers/atm/eni.c
++++ b/drivers/atm/eni.c
+@@ -2056,7 +2056,7 @@ static int eni_send(struct atm_vcc *vcc,struct sk_buff *skb)
+ 	}
+ 	submitted++;
+ 	ATM_SKB(skb)->vcc = vcc;
+-	tasklet_disable(&ENI_DEV(vcc->dev)->task);
++	tasklet_disable_in_atomic(&ENI_DEV(vcc->dev)->task);
+ 	res = do_tx(skb);
+ 	tasklet_enable(&ENI_DEV(vcc->dev)->task);
+ 	if (res == enq_ok) return 0;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0143-PCI-hv-Use-tasklet_disable_in_atomic.patch b/debian/patches-rt/0143-PCI-hv-Use-tasklet_disable_in_atomic.patch
new file mode 100644
index 000000000..e4c764804
--- /dev/null
+++ b/debian/patches-rt/0143-PCI-hv-Use-tasklet_disable_in_atomic.patch
@@ -0,0 +1,46 @@
+From 267b1086437ac0cca8ca59197e5cc8cbe8fc6a83 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 9 Mar 2021 09:42:15 +0100
+Subject: [PATCH 143/323] PCI: hv: Use tasklet_disable_in_atomic()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The hv_compose_msi_msg() callback in irq_chip::irq_compose_msi_msg is
+invoked via irq_chip_compose_msi_msg(), which itself is always invoked from
+atomic contexts from the guts of the interrupt core code.
+
+There is no way to change this w/o rewriting the whole driver, so use
+tasklet_disable_in_atomic() which allows to make tasklet_disable()
+sleepable once the remaining atomic users are addressed.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: "K. Y. Srinivasan" <kys@microsoft.com>
+Cc: Haiyang Zhang <haiyangz@microsoft.com>
+Cc: Stephen Hemminger <sthemmin@microsoft.com>
+Cc: Wei Liu <wei.liu@kernel.org>
+Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
+Cc: Rob Herring <robh@kernel.org>
+Cc: Bjorn Helgaas <bhelgaas@google.com>
+Cc: linux-hyperv@vger.kernel.org
+Cc: linux-pci@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/pci/controller/pci-hyperv.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
+index 2d6c77dcc815..7daba964f54e 100644
+--- a/drivers/pci/controller/pci-hyperv.c
++++ b/drivers/pci/controller/pci-hyperv.c
+@@ -1518,7 +1518,7 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+ 	 * Prevents hv_pci_onchannelcallback() from running concurrently
+ 	 * in the tasklet.
+ 	 */
+-	tasklet_disable(&channel->callback_event);
++	tasklet_disable_in_atomic(&channel->callback_event);
+ 
+ 	/*
+ 	 * Since this function is called with IRQ locks held, can't
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0144-firewire-ohci-Use-tasklet_disable_in_atomic-where-re.patch b/debian/patches-rt/0144-firewire-ohci-Use-tasklet_disable_in_atomic-where-re.patch
new file mode 100644
index 000000000..184d80276
--- /dev/null
+++ b/debian/patches-rt/0144-firewire-ohci-Use-tasklet_disable_in_atomic-where-re.patch
@@ -0,0 +1,61 @@
+From 090a450216e555382abe0be8e2941ecfcc527c44 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 9 Mar 2021 09:42:16 +0100
+Subject: [PATCH 144/323] firewire: ohci: Use tasklet_disable_in_atomic() where
+ required
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+tasklet_disable() is invoked in several places. Some of them are in atomic
+context which prevents a conversion of tasklet_disable() to a sleepable
+function.
+
+The atomic callchains are:
+
+ ar_context_tasklet()
+   ohci_cancel_packet()
+     tasklet_disable()
+
+ ...
+   ohci_flush_iso_completions()
+     tasklet_disable()
+
+The invocation of tasklet_disable() from at_context_flush() is always in
+preemptible context.
+
+Use tasklet_disable_in_atomic() for the two invocations in
+ohci_cancel_packet() and ohci_flush_iso_completions().
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
+Cc: linux1394-devel@lists.sourceforge.net
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/firewire/ohci.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
+index 9811c40956e5..17c9d825188b 100644
+--- a/drivers/firewire/ohci.c
++++ b/drivers/firewire/ohci.c
+@@ -2545,7 +2545,7 @@ static int ohci_cancel_packet(struct fw_card *card, struct fw_packet *packet)
+ 	struct driver_data *driver_data = packet->driver_data;
+ 	int ret = -ENOENT;
+ 
+-	tasklet_disable(&ctx->tasklet);
++	tasklet_disable_in_atomic(&ctx->tasklet);
+ 
+ 	if (packet->ack != 0)
+ 		goto out;
+@@ -3465,7 +3465,7 @@ static int ohci_flush_iso_completions(struct fw_iso_context *base)
+ 	struct iso_context *ctx = container_of(base, struct iso_context, base);
+ 	int ret = 0;
+ 
+-	tasklet_disable(&ctx->context.tasklet);
++	tasklet_disable_in_atomic(&ctx->context.tasklet);
+ 
+ 	if (!test_and_set_bit_lock(0, &ctx->flushing_completions)) {
+ 		context_tasklet((unsigned long)&ctx->context);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0145-tasklets-Switch-tasklet_disable-to-the-sleep-wait-va.patch b/debian/patches-rt/0145-tasklets-Switch-tasklet_disable-to-the-sleep-wait-va.patch
new file mode 100644
index 000000000..5b9765685
--- /dev/null
+++ b/debian/patches-rt/0145-tasklets-Switch-tasklet_disable-to-the-sleep-wait-va.patch
@@ -0,0 +1,35 @@
+From 24fc43821f54c5f95095fb5154422b54ba2777e2 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 9 Mar 2021 09:42:17 +0100
+Subject: [PATCH 145/323] tasklets: Switch tasklet_disable() to the sleep wait
+ variant
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+ -- NOT FOR IMMEDIATE MERGING --
+
+Now that all users of tasklet_disable() are invoked from sleepable context,
+convert it to use tasklet_unlock_wait() which might sleep.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/interrupt.h | 3 +--
+ 1 file changed, 1 insertion(+), 2 deletions(-)
+
+diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
+index 6eae70ec3a17..a1c64d969532 100644
+--- a/include/linux/interrupt.h
++++ b/include/linux/interrupt.h
+@@ -711,8 +711,7 @@ static inline void tasklet_disable_in_atomic(struct tasklet_struct *t)
+ static inline void tasklet_disable(struct tasklet_struct *t)
+ {
+ 	tasklet_disable_nosync(t);
+-	/* Spin wait until all atomic users are converted */
+-	tasklet_unlock_spin_wait(t);
++	tasklet_unlock_wait(t);
+ 	smp_mb();
+ }
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0146-softirq-Add-RT-specific-softirq-accounting.patch b/debian/patches-rt/0146-softirq-Add-RT-specific-softirq-accounting.patch
new file mode 100644
index 000000000..c4bcb9bd1
--- /dev/null
+++ b/debian/patches-rt/0146-softirq-Add-RT-specific-softirq-accounting.patch
@@ -0,0 +1,75 @@
+From a69df864da6d43ae3de6a4d995eaebca51a582b4 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 9 Mar 2021 09:55:53 +0100
+Subject: [PATCH 146/323] softirq: Add RT specific softirq accounting
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+RT requires the softirq processing and local bottomhalf disabled regions to
+be preemptible. Using the normal preempt count based serialization is
+therefore not possible because this implicitely disables preemption.
+
+RT kernels use a per CPU local lock to serialize bottomhalfs. As
+local_bh_disable() can nest the lock can only be acquired on the outermost
+invocation of local_bh_disable() and released when the nest count becomes
+zero. Tasks which hold the local lock can be preempted so its required to
+keep track of the nest count per task.
+
+Add a RT only counter to task struct and adjust the relevant macros in
+preempt.h.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/hardirq.h | 1 +
+ include/linux/preempt.h | 6 +++++-
+ include/linux/sched.h   | 3 +++
+ 3 files changed, 9 insertions(+), 1 deletion(-)
+
+diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
+index 0926e9ca4d85..76878b357ffa 100644
+--- a/include/linux/hardirq.h
++++ b/include/linux/hardirq.h
+@@ -6,6 +6,7 @@
+ #include <linux/preempt.h>
+ #include <linux/lockdep.h>
+ #include <linux/ftrace_irq.h>
++#include <linux/sched.h>
+ #include <linux/vtime.h>
+ #include <asm/hardirq.h>
+ 
+diff --git a/include/linux/preempt.h b/include/linux/preempt.h
+index 69cc8b64aa3a..9881eac0698f 100644
+--- a/include/linux/preempt.h
++++ b/include/linux/preempt.h
+@@ -79,7 +79,11 @@
+ 
+ #define nmi_count()	(preempt_count() & NMI_MASK)
+ #define hardirq_count()	(preempt_count() & HARDIRQ_MASK)
+-#define softirq_count()	(preempt_count() & SOFTIRQ_MASK)
++#ifdef CONFIG_PREEMPT_RT
++# define softirq_count()	(current->softirq_disable_cnt & SOFTIRQ_MASK)
++#else
++# define softirq_count()	(preempt_count() & SOFTIRQ_MASK)
++#endif
+ #define irq_count()	(nmi_count() | hardirq_count() | softirq_count())
+ 
+ /*
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index 82de1ab42497..d31da4867bb2 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -1046,6 +1046,9 @@ struct task_struct {
+ 	int				softirq_context;
+ 	int				irq_config;
+ #endif
++#ifdef CONFIG_PREEMPT_RT
++	int				softirq_disable_cnt;
++#endif
+ 
+ #ifdef CONFIG_LOCKDEP
+ # define MAX_LOCK_DEPTH			48UL
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0147-irqtime-Make-accounting-correct-on-RT.patch b/debian/patches-rt/0147-irqtime-Make-accounting-correct-on-RT.patch
new file mode 100644
index 000000000..576b5391b
--- /dev/null
+++ b/debian/patches-rt/0147-irqtime-Make-accounting-correct-on-RT.patch
@@ -0,0 +1,54 @@
+From a4b2fa58f0b8dabae3f30be80fe317da32c5b121 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 9 Mar 2021 09:55:54 +0100
+Subject: [PATCH 147/323] irqtime: Make accounting correct on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+vtime_account_irq and irqtime_account_irq() base checks on preempt_count()
+which fails on RT because preempt_count() does not contain the softirq
+accounting which is seperate on RT.
+
+These checks do not need the full preempt count as they only operate on the
+hard and softirq sections.
+
+Use irq_count() instead which provides the correct value on both RT and non
+RT kernels. The compiler is clever enough to fold the masking for !RT:
+
+       99b:	65 8b 05 00 00 00 00 	mov    %gs:0x0(%rip),%eax
+ -     9a2:	25 ff ff ff 7f       	and    $0x7fffffff,%eax
+ +     9a2:	25 00 ff ff 00       	and    $0xffff00,%eax
+
+Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/sched/cputime.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
+index 02a7932c7383..02a5aa60fe7e 100644
+--- a/kernel/sched/cputime.c
++++ b/kernel/sched/cputime.c
+@@ -60,7 +60,7 @@ void irqtime_account_irq(struct task_struct *curr, unsigned int offset)
+ 	cpu = smp_processor_id();
+ 	delta = sched_clock_cpu(cpu) - irqtime->irq_start_time;
+ 	irqtime->irq_start_time += delta;
+-	pc = preempt_count() - offset;
++	pc = irq_count() - offset;
+ 
+ 	/*
+ 	 * We do not account for softirq time from ksoftirqd here.
+@@ -421,7 +421,7 @@ void vtime_task_switch(struct task_struct *prev)
+ 
+ void vtime_account_irq(struct task_struct *tsk, unsigned int offset)
+ {
+-	unsigned int pc = preempt_count() - offset;
++	unsigned int pc = irq_count() - offset;
+ 
+ 	if (pc & HARDIRQ_OFFSET) {
+ 		vtime_account_hardirq(tsk);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0148-softirq-Move-various-protections-into-inline-helpers.patch b/debian/patches-rt/0148-softirq-Move-various-protections-into-inline-helpers.patch
new file mode 100644
index 000000000..e08794144
--- /dev/null
+++ b/debian/patches-rt/0148-softirq-Move-various-protections-into-inline-helpers.patch
@@ -0,0 +1,108 @@
+From 7d59f358f639cc9e535a4049d663d9347aef6380 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 9 Mar 2021 09:55:55 +0100
+Subject: [PATCH 148/323] softirq: Move various protections into inline helpers
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+To allow reuse of the bulk of softirq processing code for RT and to avoid
+#ifdeffery all over the place, split protections for various code sections
+out into inline helpers so the RT variant can just replace them in one go.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/softirq.c | 39 ++++++++++++++++++++++++++++++++-------
+ 1 file changed, 32 insertions(+), 7 deletions(-)
+
+diff --git a/kernel/softirq.c b/kernel/softirq.c
+index fcb201ceed71..87fac6ac0c32 100644
+--- a/kernel/softirq.c
++++ b/kernel/softirq.c
+@@ -205,6 +205,32 @@ void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
+ }
+ EXPORT_SYMBOL(__local_bh_enable_ip);
+ 
++static inline void softirq_handle_begin(void)
++{
++	__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
++}
++
++static inline void softirq_handle_end(void)
++{
++	__local_bh_enable(SOFTIRQ_OFFSET);
++	WARN_ON_ONCE(in_interrupt());
++}
++
++static inline void ksoftirqd_run_begin(void)
++{
++	local_irq_disable();
++}
++
++static inline void ksoftirqd_run_end(void)
++{
++	local_irq_enable();
++}
++
++static inline bool should_wake_ksoftirqd(void)
++{
++	return true;
++}
++
+ static inline void invoke_softirq(void)
+ {
+ 	if (ksoftirqd_running(local_softirq_pending()))
+@@ -317,7 +343,7 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
+ 
+ 	pending = local_softirq_pending();
+ 
+-	__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
++	softirq_handle_begin();
+ 	in_hardirq = lockdep_softirq_start();
+ 	account_softirq_enter(current);
+ 
+@@ -368,8 +394,7 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
+ 
+ 	account_softirq_exit(current);
+ 	lockdep_softirq_end(in_hardirq);
+-	__local_bh_enable(SOFTIRQ_OFFSET);
+-	WARN_ON_ONCE(in_interrupt());
++	softirq_handle_end();
+ 	current_restore_flags(old_flags, PF_MEMALLOC);
+ }
+ 
+@@ -464,7 +489,7 @@ inline void raise_softirq_irqoff(unsigned int nr)
+ 	 * Otherwise we wake up ksoftirqd to make sure we
+ 	 * schedule the softirq soon.
+ 	 */
+-	if (!in_interrupt())
++	if (!in_interrupt() && should_wake_ksoftirqd())
+ 		wakeup_softirqd();
+ }
+ 
+@@ -692,18 +717,18 @@ static int ksoftirqd_should_run(unsigned int cpu)
+ 
+ static void run_ksoftirqd(unsigned int cpu)
+ {
+-	local_irq_disable();
++	ksoftirqd_run_begin();
+ 	if (local_softirq_pending()) {
+ 		/*
+ 		 * We can safely run softirq on inline stack, as we are not deep
+ 		 * in the task stack here.
+ 		 */
+ 		__do_softirq();
+-		local_irq_enable();
++		ksoftirqd_run_end();
+ 		cond_resched();
+ 		return;
+ 	}
+-	local_irq_enable();
++	ksoftirqd_run_end();
+ }
+ 
+ #ifdef CONFIG_HOTPLUG_CPU
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0149-softirq-Make-softirq-control-and-processing-RT-aware.patch b/debian/patches-rt/0149-softirq-Make-softirq-control-and-processing-RT-aware.patch
new file mode 100644
index 000000000..22a88a79c
--- /dev/null
+++ b/debian/patches-rt/0149-softirq-Make-softirq-control-and-processing-RT-aware.patch
@@ -0,0 +1,267 @@
+From d2c5f9de8094418b5ebade0ff54219371ec0a5ef Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 9 Mar 2021 09:55:56 +0100
+Subject: [PATCH 149/323] softirq: Make softirq control and processing RT aware
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Provide a local lock based serialization for soft interrupts on RT which
+allows the local_bh_disabled() sections and servicing soft interrupts to be
+preemptible.
+
+Provide the necessary inline helpers which allow to reuse the bulk of the
+softirq processing code.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/bottom_half.h |   2 +-
+ kernel/softirq.c            | 188 ++++++++++++++++++++++++++++++++++--
+ 2 files changed, 182 insertions(+), 8 deletions(-)
+
+diff --git a/include/linux/bottom_half.h b/include/linux/bottom_half.h
+index a19519f4241d..e4dd613a070e 100644
+--- a/include/linux/bottom_half.h
++++ b/include/linux/bottom_half.h
+@@ -4,7 +4,7 @@
+ 
+ #include <linux/preempt.h>
+ 
+-#ifdef CONFIG_TRACE_IRQFLAGS
++#if defined(CONFIG_PREEMPT_RT) || defined(CONFIG_TRACE_IRQFLAGS)
+ extern void __local_bh_disable_ip(unsigned long ip, unsigned int cnt);
+ #else
+ static __always_inline void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
+diff --git a/kernel/softirq.c b/kernel/softirq.c
+index 87fac6ac0c32..ed13f6097de8 100644
+--- a/kernel/softirq.c
++++ b/kernel/softirq.c
+@@ -13,6 +13,7 @@
+ #include <linux/kernel_stat.h>
+ #include <linux/interrupt.h>
+ #include <linux/init.h>
++#include <linux/local_lock.h>
+ #include <linux/mm.h>
+ #include <linux/notifier.h>
+ #include <linux/percpu.h>
+@@ -101,20 +102,189 @@ EXPORT_PER_CPU_SYMBOL_GPL(hardirq_context);
+ #endif
+ 
+ /*
+- * preempt_count and SOFTIRQ_OFFSET usage:
+- * - preempt_count is changed by SOFTIRQ_OFFSET on entering or leaving
+- *   softirq processing.
+- * - preempt_count is changed by SOFTIRQ_DISABLE_OFFSET (= 2 * SOFTIRQ_OFFSET)
++ * SOFTIRQ_OFFSET usage:
++ *
++ * On !RT kernels 'count' is the preempt counter, on RT kernels this applies
++ * to a per CPU counter and to task::softirqs_disabled_cnt.
++ *
++ * - count is changed by SOFTIRQ_OFFSET on entering or leaving softirq
++ *   processing.
++ *
++ * - count is changed by SOFTIRQ_DISABLE_OFFSET (= 2 * SOFTIRQ_OFFSET)
+  *   on local_bh_disable or local_bh_enable.
++ *
+  * This lets us distinguish between whether we are currently processing
+  * softirq and whether we just have bh disabled.
+  */
++#ifdef CONFIG_PREEMPT_RT
+ 
+-#ifdef CONFIG_TRACE_IRQFLAGS
+ /*
+- * This is for softirq.c-internal use, where hardirqs are disabled
++ * RT accounts for BH disabled sections in task::softirqs_disabled_cnt and
++ * also in per CPU softirq_ctrl::cnt. This is necessary to allow tasks in a
++ * softirq disabled section to be preempted.
++ *
++ * The per task counter is used for softirq_count(), in_softirq() and
++ * in_serving_softirqs() because these counts are only valid when the task
++ * holding softirq_ctrl::lock is running.
++ *
++ * The per CPU counter prevents pointless wakeups of ksoftirqd in case that
++ * the task which is in a softirq disabled section is preempted or blocks.
++ */
++struct softirq_ctrl {
++	local_lock_t	lock;
++	int		cnt;
++};
++
++static DEFINE_PER_CPU(struct softirq_ctrl, softirq_ctrl) = {
++	.lock	= INIT_LOCAL_LOCK(softirq_ctrl.lock),
++};
++
++void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
++{
++	unsigned long flags;
++	int newcnt;
++
++	WARN_ON_ONCE(in_hardirq());
++
++	/* First entry of a task into a BH disabled section? */
++	if (!current->softirq_disable_cnt) {
++		if (preemptible()) {
++			local_lock(&softirq_ctrl.lock);
++			/* Required to meet the RCU bottomhalf requirements. */
++			rcu_read_lock();
++		} else {
++			DEBUG_LOCKS_WARN_ON(this_cpu_read(softirq_ctrl.cnt));
++		}
++	}
++
++	/*
++	 * Track the per CPU softirq disabled state. On RT this is per CPU
++	 * state to allow preemption of bottom half disabled sections.
++	 */
++	newcnt = __this_cpu_add_return(softirq_ctrl.cnt, cnt);
++	/*
++	 * Reflect the result in the task state to prevent recursion on the
++	 * local lock and to make softirq_count() & al work.
++	 */
++	current->softirq_disable_cnt = newcnt;
++
++	if (IS_ENABLED(CONFIG_TRACE_IRQFLAGS) && newcnt == cnt) {
++		raw_local_irq_save(flags);
++		lockdep_softirqs_off(ip);
++		raw_local_irq_restore(flags);
++	}
++}
++EXPORT_SYMBOL(__local_bh_disable_ip);
++
++static void __local_bh_enable(unsigned int cnt, bool unlock)
++{
++	unsigned long flags;
++	int newcnt;
++
++	DEBUG_LOCKS_WARN_ON(current->softirq_disable_cnt !=
++			    this_cpu_read(softirq_ctrl.cnt));
++
++	if (IS_ENABLED(CONFIG_TRACE_IRQFLAGS) && softirq_count() == cnt) {
++		raw_local_irq_save(flags);
++		lockdep_softirqs_on(_RET_IP_);
++		raw_local_irq_restore(flags);
++	}
++
++	newcnt = __this_cpu_sub_return(softirq_ctrl.cnt, cnt);
++	current->softirq_disable_cnt = newcnt;
++
++	if (!newcnt && unlock) {
++		rcu_read_unlock();
++		local_unlock(&softirq_ctrl.lock);
++	}
++}
++
++void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
++{
++	bool preempt_on = preemptible();
++	unsigned long flags;
++	u32 pending;
++	int curcnt;
++
++	WARN_ON_ONCE(in_irq());
++	lockdep_assert_irqs_enabled();
++
++	local_irq_save(flags);
++	curcnt = __this_cpu_read(softirq_ctrl.cnt);
++
++	/*
++	 * If this is not reenabling soft interrupts, no point in trying to
++	 * run pending ones.
++	 */
++	if (curcnt != cnt)
++		goto out;
++
++	pending = local_softirq_pending();
++	if (!pending || ksoftirqd_running(pending))
++		goto out;
++
++	/*
++	 * If this was called from non preemptible context, wake up the
++	 * softirq daemon.
++	 */
++	if (!preempt_on) {
++		wakeup_softirqd();
++		goto out;
++	}
++
++	/*
++	 * Adjust softirq count to SOFTIRQ_OFFSET which makes
++	 * in_serving_softirq() become true.
++	 */
++	cnt = SOFTIRQ_OFFSET;
++	__local_bh_enable(cnt, false);
++	__do_softirq();
++
++out:
++	__local_bh_enable(cnt, preempt_on);
++	local_irq_restore(flags);
++}
++EXPORT_SYMBOL(__local_bh_enable_ip);
++
++/*
++ * Invoked from ksoftirqd_run() outside of the interrupt disabled section
++ * to acquire the per CPU local lock for reentrancy protection.
++ */
++static inline void ksoftirqd_run_begin(void)
++{
++	__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
++	local_irq_disable();
++}
++
++/* Counterpart to ksoftirqd_run_begin() */
++static inline void ksoftirqd_run_end(void)
++{
++	__local_bh_enable(SOFTIRQ_OFFSET, true);
++	WARN_ON_ONCE(in_interrupt());
++	local_irq_enable();
++}
++
++static inline void softirq_handle_begin(void) { }
++static inline void softirq_handle_end(void) { }
++
++static inline bool should_wake_ksoftirqd(void)
++{
++	return !this_cpu_read(softirq_ctrl.cnt);
++}
++
++static inline void invoke_softirq(void)
++{
++	if (should_wake_ksoftirqd())
++		wakeup_softirqd();
++}
++
++#else /* CONFIG_PREEMPT_RT */
++
++/*
++ * This one is for softirq.c-internal use, where hardirqs are disabled
+  * legitimately:
+  */
++#ifdef CONFIG_TRACE_IRQFLAGS
+ void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
+ {
+ 	unsigned long flags;
+@@ -275,6 +445,8 @@ asmlinkage __visible void do_softirq(void)
+ 	local_irq_restore(flags);
+ }
+ 
++#endif /* !CONFIG_PREEMPT_RT */
++
+ /*
+  * We restart softirq processing for at most MAX_SOFTIRQ_RESTART times,
+  * but break the loop if need_resched() is set or after 2 ms.
+@@ -379,8 +551,10 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
+ 		pending >>= softirq_bit;
+ 	}
+ 
+-	if (__this_cpu_read(ksoftirqd) == current)
++	if (!IS_ENABLED(CONFIG_PREEMPT_RT) &&
++	    __this_cpu_read(ksoftirqd) == current)
+ 		rcu_softirq_qs();
++
+ 	local_irq_disable();
+ 
+ 	pending = local_softirq_pending();
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0150-tick-sched-Prevent-false-positive-softirq-pending-wa.patch b/debian/patches-rt/0150-tick-sched-Prevent-false-positive-softirq-pending-wa.patch
new file mode 100644
index 000000000..179b20d7b
--- /dev/null
+++ b/debian/patches-rt/0150-tick-sched-Prevent-false-positive-softirq-pending-wa.patch
@@ -0,0 +1,84 @@
+From 8f4c53c804fbc30a305bf13376f5748a55ec4944 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 9 Mar 2021 09:55:57 +0100
+Subject: [PATCH 150/323] tick/sched: Prevent false positive softirq pending
+ warnings on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+On RT a task which has soft interrupts disabled can block on a lock and
+schedule out to idle while soft interrupts are pending. This triggers the
+warning in the NOHZ idle code which complains about going idle with pending
+soft interrupts. But as the task is blocked soft interrupt processing is
+temporarily blocked as well which means that such a warning is a false
+positive.
+
+To prevent that check the per CPU state which indicates that a scheduled
+out task has soft interrupts disabled.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/bottom_half.h |  6 ++++++
+ kernel/softirq.c            | 15 +++++++++++++++
+ kernel/time/tick-sched.c    |  2 +-
+ 3 files changed, 22 insertions(+), 1 deletion(-)
+
+diff --git a/include/linux/bottom_half.h b/include/linux/bottom_half.h
+index e4dd613a070e..eed86eb0a1de 100644
+--- a/include/linux/bottom_half.h
++++ b/include/linux/bottom_half.h
+@@ -32,4 +32,10 @@ static inline void local_bh_enable(void)
+ 	__local_bh_enable_ip(_THIS_IP_, SOFTIRQ_DISABLE_OFFSET);
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT
++extern bool local_bh_blocked(void);
++#else
++static inline bool local_bh_blocked(void) { return false; }
++#endif
++
+ #endif /* _LINUX_BH_H */
+diff --git a/kernel/softirq.c b/kernel/softirq.c
+index ed13f6097de8..c9adc5c46248 100644
+--- a/kernel/softirq.c
++++ b/kernel/softirq.c
+@@ -139,6 +139,21 @@ static DEFINE_PER_CPU(struct softirq_ctrl, softirq_ctrl) = {
+ 	.lock	= INIT_LOCAL_LOCK(softirq_ctrl.lock),
+ };
+ 
++/**
++ * local_bh_blocked() - Check for idle whether BH processing is blocked
++ *
++ * Returns false if the per CPU softirq::cnt is 0 otherwise true.
++ *
++ * This is invoked from the idle task to guard against false positive
++ * softirq pending warnings, which would happen when the task which holds
++ * softirq_ctrl::lock was the only running task on the CPU and blocks on
++ * some other lock.
++ */
++bool local_bh_blocked(void)
++{
++	return __this_cpu_read(softirq_ctrl.cnt) != 0;
++}
++
+ void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
+ {
+ 	unsigned long flags;
+diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
+index fc79b04b5947..fb10be8e5e92 100644
+--- a/kernel/time/tick-sched.c
++++ b/kernel/time/tick-sched.c
+@@ -982,7 +982,7 @@ static bool can_stop_idle_tick(int cpu, struct tick_sched *ts)
+ 	if (unlikely(local_softirq_pending())) {
+ 		static int ratelimit;
+ 
+-		if (ratelimit < 10 &&
++		if (ratelimit < 10 && !local_bh_blocked() &&
+ 		    (local_softirq_pending() & SOFTIRQ_STOP_IDLE_MASK)) {
+ 			pr_warn("NOHZ tick-stop error: Non-RCU local softirq work is pending, handler #%02x!!!\n",
+ 				(unsigned int) local_softirq_pending());
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0151-rcu-Prevent-false-positive-softirq-warning-on-RT.patch b/debian/patches-rt/0151-rcu-Prevent-false-positive-softirq-warning-on-RT.patch
new file mode 100644
index 000000000..14d81c8a1
--- /dev/null
+++ b/debian/patches-rt/0151-rcu-Prevent-false-positive-softirq-warning-on-RT.patch
@@ -0,0 +1,35 @@
+From cce7be95962e51a5270439e8c31500ed38123c49 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 9 Mar 2021 09:55:58 +0100
+Subject: [PATCH 151/323] rcu: Prevent false positive softirq warning on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Soft interrupt disabled sections can legitimately be preempted or schedule
+out when blocking on a lock on RT enabled kernels so the RCU preempt check
+warning has to be disabled for RT kernels.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/rcupdate.h | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
+index ef8d56b18da6..bb9681309e0d 100644
+--- a/include/linux/rcupdate.h
++++ b/include/linux/rcupdate.h
+@@ -338,7 +338,8 @@ static inline void rcu_preempt_sleep_check(void) { }
+ #define rcu_sleep_check()						\
+ 	do {								\
+ 		rcu_preempt_sleep_check();				\
+-		RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map),	\
++		if (!IS_ENABLED(CONFIG_PREEMPT_RT))			\
++		    RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map),	\
+ 				 "Illegal context switch in RCU-bh read-side critical section"); \
+ 		RCU_LOCKDEP_WARN(lock_is_held(&rcu_sched_lock_map),	\
+ 				 "Illegal context switch in RCU-sched read-side critical section"); \
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0152-chelsio-cxgb-Replace-the-workqueue-with-threaded-int.patch b/debian/patches-rt/0152-chelsio-cxgb-Replace-the-workqueue-with-threaded-int.patch
new file mode 100644
index 000000000..45fec4e55
--- /dev/null
+++ b/debian/patches-rt/0152-chelsio-cxgb-Replace-the-workqueue-with-threaded-int.patch
@@ -0,0 +1,271 @@
+From a3a5c955eb9767e09f62d7d4c1af2f8f5b0fe565 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 2 Feb 2021 18:01:03 +0100
+Subject: [PATCH 152/323] chelsio: cxgb: Replace the workqueue with threaded
+ interrupt
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The external interrupt (F_PL_INTR_EXT) needs to be handled in a process
+context and this is accomplished by utilizing a workqueue.
+
+The process context can also be provided by a threaded interrupt instead
+of a workqueue. The threaded interrupt can be used later for other
+interrupt related processing which require non-atomic context without
+using yet another workqueue. free_irq() also ensures that the thread is
+done which is currently missing (the worker could continue after the
+module has been removed).
+
+Save pending flags in pending_thread_intr. Use the same mechanism
+to disable F_PL_INTR_EXT as interrupt source like it is used before the
+worker is scheduled. Enable the interrupt again once
+t1_elmer0_ext_intr_handler() is done.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/net/ethernet/chelsio/cxgb/common.h |  5 +--
+ drivers/net/ethernet/chelsio/cxgb/cxgb2.c  | 44 ++--------------------
+ drivers/net/ethernet/chelsio/cxgb/sge.c    | 33 ++++++++++++++--
+ drivers/net/ethernet/chelsio/cxgb/sge.h    |  1 +
+ drivers/net/ethernet/chelsio/cxgb/subr.c   | 26 +++++++++----
+ 5 files changed, 55 insertions(+), 54 deletions(-)
+
+diff --git a/drivers/net/ethernet/chelsio/cxgb/common.h b/drivers/net/ethernet/chelsio/cxgb/common.h
+index 6475060649e9..e999a9b9fe6c 100644
+--- a/drivers/net/ethernet/chelsio/cxgb/common.h
++++ b/drivers/net/ethernet/chelsio/cxgb/common.h
+@@ -238,7 +238,6 @@ struct adapter {
+ 	int msg_enable;
+ 	u32 mmio_len;
+ 
+-	struct work_struct ext_intr_handler_task;
+ 	struct adapter_params params;
+ 
+ 	/* Terminator modules. */
+@@ -257,6 +256,7 @@ struct adapter {
+ 
+ 	/* guards async operations */
+ 	spinlock_t async_lock ____cacheline_aligned;
++	u32 pending_thread_intr;
+ 	u32 slow_intr_mask;
+ 	int t1powersave;
+ };
+@@ -334,8 +334,7 @@ void t1_interrupts_enable(adapter_t *adapter);
+ void t1_interrupts_disable(adapter_t *adapter);
+ void t1_interrupts_clear(adapter_t *adapter);
+ int t1_elmer0_ext_intr_handler(adapter_t *adapter);
+-void t1_elmer0_ext_intr(adapter_t *adapter);
+-int t1_slow_intr_handler(adapter_t *adapter);
++irqreturn_t t1_slow_intr_handler(adapter_t *adapter);
+ 
+ int t1_link_start(struct cphy *phy, struct cmac *mac, struct link_config *lc);
+ const struct board_info *t1_get_board_info(unsigned int board_id);
+diff --git a/drivers/net/ethernet/chelsio/cxgb/cxgb2.c b/drivers/net/ethernet/chelsio/cxgb/cxgb2.c
+index c6db85fe1629..737c24136e2f 100644
+--- a/drivers/net/ethernet/chelsio/cxgb/cxgb2.c
++++ b/drivers/net/ethernet/chelsio/cxgb/cxgb2.c
+@@ -211,9 +211,10 @@ static int cxgb_up(struct adapter *adapter)
+ 	t1_interrupts_clear(adapter);
+ 
+ 	adapter->params.has_msi = !disable_msi && !pci_enable_msi(adapter->pdev);
+-	err = request_irq(adapter->pdev->irq, t1_interrupt,
+-			  adapter->params.has_msi ? 0 : IRQF_SHARED,
+-			  adapter->name, adapter);
++	err = request_threaded_irq(adapter->pdev->irq, t1_interrupt,
++				   t1_interrupt_thread,
++				   adapter->params.has_msi ? 0 : IRQF_SHARED,
++				   adapter->name, adapter);
+ 	if (err) {
+ 		if (adapter->params.has_msi)
+ 			pci_disable_msi(adapter->pdev);
+@@ -916,41 +917,6 @@ static void mac_stats_task(struct work_struct *work)
+ 	spin_unlock(&adapter->work_lock);
+ }
+ 
+-/*
+- * Processes elmer0 external interrupts in process context.
+- */
+-static void ext_intr_task(struct work_struct *work)
+-{
+-	struct adapter *adapter =
+-		container_of(work, struct adapter, ext_intr_handler_task);
+-
+-	t1_elmer0_ext_intr_handler(adapter);
+-
+-	/* Now reenable external interrupts */
+-	spin_lock_irq(&adapter->async_lock);
+-	adapter->slow_intr_mask |= F_PL_INTR_EXT;
+-	writel(F_PL_INTR_EXT, adapter->regs + A_PL_CAUSE);
+-	writel(adapter->slow_intr_mask | F_PL_INTR_SGE_DATA,
+-		   adapter->regs + A_PL_ENABLE);
+-	spin_unlock_irq(&adapter->async_lock);
+-}
+-
+-/*
+- * Interrupt-context handler for elmer0 external interrupts.
+- */
+-void t1_elmer0_ext_intr(struct adapter *adapter)
+-{
+-	/*
+-	 * Schedule a task to handle external interrupts as we require
+-	 * a process context.  We disable EXT interrupts in the interim
+-	 * and let the task reenable them when it's done.
+-	 */
+-	adapter->slow_intr_mask &= ~F_PL_INTR_EXT;
+-	writel(adapter->slow_intr_mask | F_PL_INTR_SGE_DATA,
+-		   adapter->regs + A_PL_ENABLE);
+-	schedule_work(&adapter->ext_intr_handler_task);
+-}
+-
+ void t1_fatal_err(struct adapter *adapter)
+ {
+ 	if (adapter->flags & FULL_INIT_DONE) {
+@@ -1062,8 +1028,6 @@ static int init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
+ 			spin_lock_init(&adapter->async_lock);
+ 			spin_lock_init(&adapter->mac_lock);
+ 
+-			INIT_WORK(&adapter->ext_intr_handler_task,
+-				  ext_intr_task);
+ 			INIT_DELAYED_WORK(&adapter->stats_update_task,
+ 					  mac_stats_task);
+ 
+diff --git a/drivers/net/ethernet/chelsio/cxgb/sge.c b/drivers/net/ethernet/chelsio/cxgb/sge.c
+index 2d9c2b5a690a..5aef9ae1ecfe 100644
+--- a/drivers/net/ethernet/chelsio/cxgb/sge.c
++++ b/drivers/net/ethernet/chelsio/cxgb/sge.c
+@@ -1619,11 +1619,38 @@ int t1_poll(struct napi_struct *napi, int budget)
+ 	return work_done;
+ }
+ 
++irqreturn_t t1_interrupt_thread(int irq, void *data)
++{
++	struct adapter *adapter = data;
++	u32 pending_thread_intr;
++
++	spin_lock_irq(&adapter->async_lock);
++	pending_thread_intr = adapter->pending_thread_intr;
++	adapter->pending_thread_intr = 0;
++	spin_unlock_irq(&adapter->async_lock);
++
++	if (!pending_thread_intr)
++		return IRQ_NONE;
++
++	if (pending_thread_intr & F_PL_INTR_EXT)
++		t1_elmer0_ext_intr_handler(adapter);
++
++	spin_lock_irq(&adapter->async_lock);
++	adapter->slow_intr_mask |= F_PL_INTR_EXT;
++
++	writel(F_PL_INTR_EXT, adapter->regs + A_PL_CAUSE);
++	writel(adapter->slow_intr_mask | F_PL_INTR_SGE_DATA,
++	       adapter->regs + A_PL_ENABLE);
++	spin_unlock_irq(&adapter->async_lock);
++
++	return IRQ_HANDLED;
++}
++
+ irqreturn_t t1_interrupt(int irq, void *data)
+ {
+ 	struct adapter *adapter = data;
+ 	struct sge *sge = adapter->sge;
+-	int handled;
++	irqreturn_t handled;
+ 
+ 	if (likely(responses_pending(adapter))) {
+ 		writel(F_PL_INTR_SGE_DATA, adapter->regs + A_PL_CAUSE);
+@@ -1645,10 +1672,10 @@ irqreturn_t t1_interrupt(int irq, void *data)
+ 	handled = t1_slow_intr_handler(adapter);
+ 	spin_unlock(&adapter->async_lock);
+ 
+-	if (!handled)
++	if (handled == IRQ_NONE)
+ 		sge->stats.unhandled_irqs++;
+ 
+-	return IRQ_RETVAL(handled != 0);
++	return handled;
+ }
+ 
+ /*
+diff --git a/drivers/net/ethernet/chelsio/cxgb/sge.h b/drivers/net/ethernet/chelsio/cxgb/sge.h
+index a1ba591b3431..76516d2a8aa9 100644
+--- a/drivers/net/ethernet/chelsio/cxgb/sge.h
++++ b/drivers/net/ethernet/chelsio/cxgb/sge.h
+@@ -74,6 +74,7 @@ struct sge *t1_sge_create(struct adapter *, struct sge_params *);
+ int t1_sge_configure(struct sge *, struct sge_params *);
+ int t1_sge_set_coalesce_params(struct sge *, struct sge_params *);
+ void t1_sge_destroy(struct sge *);
++irqreturn_t t1_interrupt_thread(int irq, void *data);
+ irqreturn_t t1_interrupt(int irq, void *cookie);
+ int t1_poll(struct napi_struct *, int);
+ 
+diff --git a/drivers/net/ethernet/chelsio/cxgb/subr.c b/drivers/net/ethernet/chelsio/cxgb/subr.c
+index ea0f8741d7cf..d90ad07ff1a4 100644
+--- a/drivers/net/ethernet/chelsio/cxgb/subr.c
++++ b/drivers/net/ethernet/chelsio/cxgb/subr.c
+@@ -210,7 +210,7 @@ static int fpga_phy_intr_handler(adapter_t *adapter)
+ /*
+  * Slow path interrupt handler for FPGAs.
+  */
+-static int fpga_slow_intr(adapter_t *adapter)
++static irqreturn_t fpga_slow_intr(adapter_t *adapter)
+ {
+ 	u32 cause = readl(adapter->regs + A_PL_CAUSE);
+ 
+@@ -238,7 +238,7 @@ static int fpga_slow_intr(adapter_t *adapter)
+ 	if (cause)
+ 		writel(cause, adapter->regs + A_PL_CAUSE);
+ 
+-	return cause != 0;
++	return cause == 0 ? IRQ_NONE : IRQ_HANDLED;
+ }
+ #endif
+ 
+@@ -842,13 +842,14 @@ void t1_interrupts_clear(adapter_t* adapter)
+ /*
+  * Slow path interrupt handler for ASICs.
+  */
+-static int asic_slow_intr(adapter_t *adapter)
++static irqreturn_t asic_slow_intr(adapter_t *adapter)
+ {
+ 	u32 cause = readl(adapter->regs + A_PL_CAUSE);
++	irqreturn_t ret = IRQ_HANDLED;
+ 
+ 	cause &= adapter->slow_intr_mask;
+ 	if (!cause)
+-		return 0;
++		return IRQ_NONE;
+ 	if (cause & F_PL_INTR_SGE_ERR)
+ 		t1_sge_intr_error_handler(adapter->sge);
+ 	if (cause & F_PL_INTR_TP)
+@@ -857,16 +858,25 @@ static int asic_slow_intr(adapter_t *adapter)
+ 		t1_espi_intr_handler(adapter->espi);
+ 	if (cause & F_PL_INTR_PCIX)
+ 		t1_pci_intr_handler(adapter);
+-	if (cause & F_PL_INTR_EXT)
+-		t1_elmer0_ext_intr(adapter);
++	if (cause & F_PL_INTR_EXT) {
++		/* Wake the threaded interrupt to handle external interrupts as
++		 * we require a process context. We disable EXT interrupts in
++		 * the interim and let the thread reenable them when it's done.
++		 */
++		adapter->pending_thread_intr |= F_PL_INTR_EXT;
++		adapter->slow_intr_mask &= ~F_PL_INTR_EXT;
++		writel(adapter->slow_intr_mask | F_PL_INTR_SGE_DATA,
++		       adapter->regs + A_PL_ENABLE);
++		ret = IRQ_WAKE_THREAD;
++	}
+ 
+ 	/* Clear the interrupts just processed. */
+ 	writel(cause, adapter->regs + A_PL_CAUSE);
+ 	readl(adapter->regs + A_PL_CAUSE); /* flush writes */
+-	return 1;
++	return ret;
+ }
+ 
+-int t1_slow_intr_handler(adapter_t *adapter)
++irqreturn_t t1_slow_intr_handler(adapter_t *adapter)
+ {
+ #ifdef CONFIG_CHELSIO_T1_1G
+ 	if (!t1_is_asic(adapter))
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0153-chelsio-cxgb-Disable-the-card-on-error-in-threaded-i.patch b/debian/patches-rt/0153-chelsio-cxgb-Disable-the-card-on-error-in-threaded-i.patch
new file mode 100644
index 000000000..910927009
--- /dev/null
+++ b/debian/patches-rt/0153-chelsio-cxgb-Disable-the-card-on-error-in-threaded-i.patch
@@ -0,0 +1,215 @@
+From 676e60d5a1de49b6188285212b7655ccd463f984 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 2 Feb 2021 18:01:04 +0100
+Subject: [PATCH 153/323] chelsio: cxgb: Disable the card on error in threaded
+ interrupt
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+t1_fatal_err() is invoked from the interrupt handler. The bad part is
+that it invokes (via t1_sge_stop()) del_timer_sync() and tasklet_kill().
+Both functions must not be called from an interrupt because it is
+possible that it will wait for the completion of the timer/tasklet it
+just interrupted.
+
+In case of a fatal error, use t1_interrupts_disable() to disable all
+interrupt sources and then wake the interrupt thread with
+F_PL_INTR_SGE_ERR as pending flag. The threaded-interrupt will stop the
+card via t1_sge_stop() and not re-enable the interrupts again.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/net/ethernet/chelsio/cxgb/common.h |  1 -
+ drivers/net/ethernet/chelsio/cxgb/cxgb2.c  | 10 ------
+ drivers/net/ethernet/chelsio/cxgb/sge.c    | 20 +++++++++---
+ drivers/net/ethernet/chelsio/cxgb/sge.h    |  2 +-
+ drivers/net/ethernet/chelsio/cxgb/subr.c   | 38 +++++++++++++++-------
+ 5 files changed, 44 insertions(+), 27 deletions(-)
+
+diff --git a/drivers/net/ethernet/chelsio/cxgb/common.h b/drivers/net/ethernet/chelsio/cxgb/common.h
+index e999a9b9fe6c..0321be77366c 100644
+--- a/drivers/net/ethernet/chelsio/cxgb/common.h
++++ b/drivers/net/ethernet/chelsio/cxgb/common.h
+@@ -346,7 +346,6 @@ int t1_get_board_rev(adapter_t *adapter, const struct board_info *bi,
+ int t1_init_hw_modules(adapter_t *adapter);
+ int t1_init_sw_modules(adapter_t *adapter, const struct board_info *bi);
+ void t1_free_sw_modules(adapter_t *adapter);
+-void t1_fatal_err(adapter_t *adapter);
+ void t1_link_changed(adapter_t *adapter, int port_id);
+ void t1_link_negotiated(adapter_t *adapter, int port_id, int link_stat,
+ 			    int speed, int duplex, int pause);
+diff --git a/drivers/net/ethernet/chelsio/cxgb/cxgb2.c b/drivers/net/ethernet/chelsio/cxgb/cxgb2.c
+index 737c24136e2f..2a28a38da036 100644
+--- a/drivers/net/ethernet/chelsio/cxgb/cxgb2.c
++++ b/drivers/net/ethernet/chelsio/cxgb/cxgb2.c
+@@ -917,16 +917,6 @@ static void mac_stats_task(struct work_struct *work)
+ 	spin_unlock(&adapter->work_lock);
+ }
+ 
+-void t1_fatal_err(struct adapter *adapter)
+-{
+-	if (adapter->flags & FULL_INIT_DONE) {
+-		t1_sge_stop(adapter->sge);
+-		t1_interrupts_disable(adapter);
+-	}
+-	pr_alert("%s: encountered fatal error, operation suspended\n",
+-		 adapter->name);
+-}
+-
+ static const struct net_device_ops cxgb_netdev_ops = {
+ 	.ndo_open		= cxgb_open,
+ 	.ndo_stop		= cxgb_close,
+diff --git a/drivers/net/ethernet/chelsio/cxgb/sge.c b/drivers/net/ethernet/chelsio/cxgb/sge.c
+index 5aef9ae1ecfe..cda01f22c71c 100644
+--- a/drivers/net/ethernet/chelsio/cxgb/sge.c
++++ b/drivers/net/ethernet/chelsio/cxgb/sge.c
+@@ -940,10 +940,11 @@ void t1_sge_intr_clear(struct sge *sge)
+ /*
+  * SGE 'Error' interrupt handler
+  */
+-int t1_sge_intr_error_handler(struct sge *sge)
++bool t1_sge_intr_error_handler(struct sge *sge)
+ {
+ 	struct adapter *adapter = sge->adapter;
+ 	u32 cause = readl(adapter->regs + A_SG_INT_CAUSE);
++	bool wake = false;
+ 
+ 	if (adapter->port[0].dev->hw_features & NETIF_F_TSO)
+ 		cause &= ~F_PACKET_TOO_BIG;
+@@ -967,11 +968,14 @@ int t1_sge_intr_error_handler(struct sge *sge)
+ 		sge->stats.pkt_mismatch++;
+ 		pr_alert("%s: SGE packet mismatch\n", adapter->name);
+ 	}
+-	if (cause & SGE_INT_FATAL)
+-		t1_fatal_err(adapter);
++	if (cause & SGE_INT_FATAL) {
++		t1_interrupts_disable(adapter);
++		adapter->pending_thread_intr |= F_PL_INTR_SGE_ERR;
++		wake = true;
++	}
+ 
+ 	writel(cause, adapter->regs + A_SG_INT_CAUSE);
+-	return 0;
++	return wake;
+ }
+ 
+ const struct sge_intr_counts *t1_sge_get_intr_counts(const struct sge *sge)
+@@ -1635,6 +1639,14 @@ irqreturn_t t1_interrupt_thread(int irq, void *data)
+ 	if (pending_thread_intr & F_PL_INTR_EXT)
+ 		t1_elmer0_ext_intr_handler(adapter);
+ 
++	/* This error is fatal, interrupts remain off */
++	if (pending_thread_intr & F_PL_INTR_SGE_ERR) {
++		pr_alert("%s: encountered fatal error, operation suspended\n",
++			 adapter->name);
++		t1_sge_stop(adapter->sge);
++		return IRQ_HANDLED;
++	}
++
+ 	spin_lock_irq(&adapter->async_lock);
+ 	adapter->slow_intr_mask |= F_PL_INTR_EXT;
+ 
+diff --git a/drivers/net/ethernet/chelsio/cxgb/sge.h b/drivers/net/ethernet/chelsio/cxgb/sge.h
+index 76516d2a8aa9..716705b96f26 100644
+--- a/drivers/net/ethernet/chelsio/cxgb/sge.h
++++ b/drivers/net/ethernet/chelsio/cxgb/sge.h
+@@ -82,7 +82,7 @@ netdev_tx_t t1_start_xmit(struct sk_buff *skb, struct net_device *dev);
+ void t1_vlan_mode(struct adapter *adapter, netdev_features_t features);
+ void t1_sge_start(struct sge *);
+ void t1_sge_stop(struct sge *);
+-int t1_sge_intr_error_handler(struct sge *);
++bool t1_sge_intr_error_handler(struct sge *sge);
+ void t1_sge_intr_enable(struct sge *);
+ void t1_sge_intr_disable(struct sge *);
+ void t1_sge_intr_clear(struct sge *);
+diff --git a/drivers/net/ethernet/chelsio/cxgb/subr.c b/drivers/net/ethernet/chelsio/cxgb/subr.c
+index d90ad07ff1a4..310add28fcf5 100644
+--- a/drivers/net/ethernet/chelsio/cxgb/subr.c
++++ b/drivers/net/ethernet/chelsio/cxgb/subr.c
+@@ -170,7 +170,7 @@ void t1_link_changed(adapter_t *adapter, int port_id)
+ 	t1_link_negotiated(adapter, port_id, link_ok, speed, duplex, fc);
+ }
+ 
+-static int t1_pci_intr_handler(adapter_t *adapter)
++static bool t1_pci_intr_handler(adapter_t *adapter)
+ {
+ 	u32 pcix_cause;
+ 
+@@ -179,9 +179,13 @@ static int t1_pci_intr_handler(adapter_t *adapter)
+ 	if (pcix_cause) {
+ 		pci_write_config_dword(adapter->pdev, A_PCICFG_INTR_CAUSE,
+ 				       pcix_cause);
+-		t1_fatal_err(adapter);    /* PCI errors are fatal */
++		/* PCI errors are fatal */
++		t1_interrupts_disable(adapter);
++		adapter->pending_thread_intr |= F_PL_INTR_SGE_ERR;
++		pr_alert("%s: PCI error encountered.\n", adapter->name);
++		return true;
+ 	}
+-	return 0;
++	return false;
+ }
+ 
+ #ifdef CONFIG_CHELSIO_T1_1G
+@@ -213,10 +217,13 @@ static int fpga_phy_intr_handler(adapter_t *adapter)
+ static irqreturn_t fpga_slow_intr(adapter_t *adapter)
+ {
+ 	u32 cause = readl(adapter->regs + A_PL_CAUSE);
++	irqreturn_t ret = IRQ_NONE;
+ 
+ 	cause &= ~F_PL_INTR_SGE_DATA;
+-	if (cause & F_PL_INTR_SGE_ERR)
+-		t1_sge_intr_error_handler(adapter->sge);
++	if (cause & F_PL_INTR_SGE_ERR) {
++		if (t1_sge_intr_error_handler(adapter->sge))
++			ret = IRQ_WAKE_THREAD;
++	}
+ 
+ 	if (cause & FPGA_PCIX_INTERRUPT_GMAC)
+ 		fpga_phy_intr_handler(adapter);
+@@ -231,13 +238,18 @@ static irqreturn_t fpga_slow_intr(adapter_t *adapter)
+ 		/* Clear TP interrupt */
+ 		writel(tp_cause, adapter->regs + FPGA_TP_ADDR_INTERRUPT_CAUSE);
+ 	}
+-	if (cause & FPGA_PCIX_INTERRUPT_PCIX)
+-		t1_pci_intr_handler(adapter);
++	if (cause & FPGA_PCIX_INTERRUPT_PCIX) {
++		if (t1_pci_intr_handler(adapter))
++			ret = IRQ_WAKE_THREAD;
++	}
+ 
+ 	/* Clear the interrupts just processed. */
+ 	if (cause)
+ 		writel(cause, adapter->regs + A_PL_CAUSE);
+ 
++	if (ret != IRQ_NONE)
++		return ret;
++
+ 	return cause == 0 ? IRQ_NONE : IRQ_HANDLED;
+ }
+ #endif
+@@ -850,14 +862,18 @@ static irqreturn_t asic_slow_intr(adapter_t *adapter)
+ 	cause &= adapter->slow_intr_mask;
+ 	if (!cause)
+ 		return IRQ_NONE;
+-	if (cause & F_PL_INTR_SGE_ERR)
+-		t1_sge_intr_error_handler(adapter->sge);
++	if (cause & F_PL_INTR_SGE_ERR) {
++		if (t1_sge_intr_error_handler(adapter->sge))
++			ret = IRQ_WAKE_THREAD;
++	}
+ 	if (cause & F_PL_INTR_TP)
+ 		t1_tp_intr_handler(adapter->tp);
+ 	if (cause & F_PL_INTR_ESPI)
+ 		t1_espi_intr_handler(adapter->espi);
+-	if (cause & F_PL_INTR_PCIX)
+-		t1_pci_intr_handler(adapter);
++	if (cause & F_PL_INTR_PCIX) {
++		if (t1_pci_intr_handler(adapter))
++			ret = IRQ_WAKE_THREAD;
++	}
+ 	if (cause & F_PL_INTR_EXT) {
+ 		/* Wake the threaded interrupt to handle external interrupts as
+ 		 * we require a process context. We disable EXT interrupts in
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0154-x86-fpu-Simplify-fpregs_-un-lock.patch b/debian/patches-rt/0154-x86-fpu-Simplify-fpregs_-un-lock.patch
new file mode 100644
index 000000000..1cde7fb8e
--- /dev/null
+++ b/debian/patches-rt/0154-x86-fpu-Simplify-fpregs_-un-lock.patch
@@ -0,0 +1,47 @@
+From 8ca0011428a338becf8c390a74dba375610d693f Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 27 Oct 2020 11:09:50 +0100
+Subject: [PATCH 154/323] x86/fpu: Simplify fpregs_[un]lock()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+There is no point in disabling preemption and then disabling bottom
+halfs.
+
+Just disabling bottom halfs is sufficient as it implicitly disables
+preemption on !RT kernels.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20201027101349.455380473@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/x86/include/asm/fpu/api.h | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
+index 8b9bfaad6e66..5174c0a640ef 100644
+--- a/arch/x86/include/asm/fpu/api.h
++++ b/arch/x86/include/asm/fpu/api.h
+@@ -40,17 +40,18 @@ static inline void kernel_fpu_begin(void)
+  * A context switch will (and softirq might) save CPU's FPU registers to
+  * fpu->state and set TIF_NEED_FPU_LOAD leaving CPU's FPU registers in
+  * a random state.
++ *
++ * local_bh_disable() protects against both preemption and soft interrupts
++ * on !RT kernels.
+  */
+ static inline void fpregs_lock(void)
+ {
+-	preempt_disable();
+ 	local_bh_disable();
+ }
+ 
+ static inline void fpregs_unlock(void)
+ {
+ 	local_bh_enable();
+-	preempt_enable();
+ }
+ 
+ #ifdef CONFIG_X86_DEBUG_FPU
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0155-x86-fpu-Make-kernel-FPU-protection-RT-friendly.patch b/debian/patches-rt/0155-x86-fpu-Make-kernel-FPU-protection-RT-friendly.patch
new file mode 100644
index 000000000..f28c1aace
--- /dev/null
+++ b/debian/patches-rt/0155-x86-fpu-Make-kernel-FPU-protection-RT-friendly.patch
@@ -0,0 +1,64 @@
+From f6a993a6144299a8693fa151d042c3997238cd54 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 27 Oct 2020 11:09:51 +0100
+Subject: [PATCH 155/323] x86/fpu: Make kernel FPU protection RT friendly
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Non RT kernels need to protect FPU against preemption and bottom half
+processing. This is achieved by disabling bottom halfs via
+local_bh_disable() which implictly disables preemption.
+
+On RT kernels this protection mechanism is not sufficient because
+local_bh_disable() does not disable preemption. It serializes bottom half
+related processing via a CPU local lock.
+
+As bottom halfs are running always in thread context on RT kernels
+disabling preemption is the proper choice as it implicitly prevents bottom
+half processing.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/r/20201027101349.588965083@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/x86/include/asm/fpu/api.h | 18 ++++++++++++++++--
+ 1 file changed, 16 insertions(+), 2 deletions(-)
+
+diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
+index 5174c0a640ef..ad2fee785310 100644
+--- a/arch/x86/include/asm/fpu/api.h
++++ b/arch/x86/include/asm/fpu/api.h
+@@ -43,15 +43,29 @@ static inline void kernel_fpu_begin(void)
+  *
+  * local_bh_disable() protects against both preemption and soft interrupts
+  * on !RT kernels.
++ *
++ * On RT kernels local_bh_disable() is not sufficient because it only
++ * serializes soft interrupt related sections via a local lock, but stays
++ * preemptible. Disabling preemption is the right choice here as bottom
++ * half processing is always in thread context on RT kernels so it
++ * implicitly prevents bottom half processing as well.
++ *
++ * Disabling preemption also serializes against kernel_fpu_begin().
+  */
+ static inline void fpregs_lock(void)
+ {
+-	local_bh_disable();
++	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
++		local_bh_disable();
++	else
++		preempt_disable();
+ }
+ 
+ static inline void fpregs_unlock(void)
+ {
+-	local_bh_enable();
++	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
++		local_bh_enable();
++	else
++		preempt_enable();
+ }
+ 
+ #ifdef CONFIG_X86_DEBUG_FPU
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0156-locking-rtmutex-Remove-cruft.patch b/debian/patches-rt/0156-locking-rtmutex-Remove-cruft.patch
new file mode 100644
index 000000000..a39953384
--- /dev/null
+++ b/debian/patches-rt/0156-locking-rtmutex-Remove-cruft.patch
@@ -0,0 +1,99 @@
+From 46072fa492b76df5aaf47fea23d280f72d7100a8 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 29 Sep 2020 15:21:17 +0200
+Subject: [PATCH 156/323] locking/rtmutex: Remove cruft
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Most of this is around since the very beginning. I'm not sure if this
+was used while the rtmutex-deadlock-tester was around but today it seems
+to only waste memory:
+- save_state: No users
+- name: Assigned and printed if a dead lock was detected. I'm keeping it
+  but want to point out that lockdep has the same information.
+- file + line: Printed if ::name was NULL. This is only used for
+  in-kernel locks so it ::name shouldn't be NULL and then ::file and
+  ::line isn't used.
+- magic: Assigned to NULL by rt_mutex_destroy().
+
+Remove members of rt_mutex which are not used.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/rtmutex.h         | 7 ++-----
+ kernel/locking/rtmutex-debug.c  | 7 +------
+ kernel/locking/rtmutex.c        | 3 ---
+ kernel/locking/rtmutex_common.h | 1 -
+ 4 files changed, 3 insertions(+), 15 deletions(-)
+
+diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
+index 6fd615a0eea9..16f974a22f51 100644
+--- a/include/linux/rtmutex.h
++++ b/include/linux/rtmutex.h
+@@ -32,10 +32,7 @@ struct rt_mutex {
+ 	struct rb_root_cached   waiters;
+ 	struct task_struct	*owner;
+ #ifdef CONFIG_DEBUG_RT_MUTEXES
+-	int			save_state;
+-	const char		*name, *file;
+-	int			line;
+-	void			*magic;
++	const char		*name;
+ #endif
+ #ifdef CONFIG_DEBUG_LOCK_ALLOC
+ 	struct lockdep_map	dep_map;
+@@ -60,7 +57,7 @@ struct hrtimer_sleeper;
+ 
+ #ifdef CONFIG_DEBUG_RT_MUTEXES
+ # define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
+-	, .name = #mutexname, .file = __FILE__, .line = __LINE__
++	, .name = #mutexname
+ 
+ # define rt_mutex_init(mutex) \
+ do { \
+diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c
+index 36e69100e8e0..7e411b946d4c 100644
+--- a/kernel/locking/rtmutex-debug.c
++++ b/kernel/locking/rtmutex-debug.c
+@@ -42,12 +42,7 @@ static void printk_task(struct task_struct *p)
+ 
+ static void printk_lock(struct rt_mutex *lock, int print_owner)
+ {
+-	if (lock->name)
+-		printk(" [%p] {%s}\n",
+-			lock, lock->name);
+-	else
+-		printk(" [%p] {%s:%d}\n",
+-			lock, lock->file, lock->line);
++	printk(" [%p] {%s}\n", lock, lock->name);
+ 
+ 	if (print_owner && rt_mutex_owner(lock)) {
+ 		printk(".. ->owner: %p\n", lock->owner);
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index f00dd928fc71..4792fc7abe7d 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -1655,9 +1655,6 @@ void __sched rt_mutex_futex_unlock(struct rt_mutex *lock)
+ void rt_mutex_destroy(struct rt_mutex *lock)
+ {
+ 	WARN_ON(rt_mutex_is_locked(lock));
+-#ifdef CONFIG_DEBUG_RT_MUTEXES
+-	lock->magic = NULL;
+-#endif
+ }
+ EXPORT_SYMBOL_GPL(rt_mutex_destroy);
+ 
+diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
+index ca6fb489007b..e6913103d7ff 100644
+--- a/kernel/locking/rtmutex_common.h
++++ b/kernel/locking/rtmutex_common.h
+@@ -30,7 +30,6 @@ struct rt_mutex_waiter {
+ 	struct task_struct	*task;
+ 	struct rt_mutex		*lock;
+ #ifdef CONFIG_DEBUG_RT_MUTEXES
+-	unsigned long		ip;
+ 	struct pid		*deadlock_task_pid;
+ 	struct rt_mutex		*deadlock_lock;
+ #endif
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0157-locking-rtmutex-Remove-output-from-deadlock-detector.patch b/debian/patches-rt/0157-locking-rtmutex-Remove-output-from-deadlock-detector.patch
new file mode 100644
index 000000000..6f0878b80
--- /dev/null
+++ b/debian/patches-rt/0157-locking-rtmutex-Remove-output-from-deadlock-detector.patch
@@ -0,0 +1,312 @@
+From e9b488ea6cb82e796f8d331b037cb7de76d15657 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 29 Sep 2020 16:05:11 +0200
+Subject: [PATCH 157/323] locking/rtmutex: Remove output from deadlock
+ detector.
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+In commit
+  f5694788ad8da ("rt_mutex: Add lockdep annotations")
+
+rtmutex gained lockdep annotation for rt_mutex_lock() and and related
+functions.
+lockdep will see the locking order and may complain about a deadlock
+before rtmutex' own mechanism gets a chance to detect it.
+The rtmutex deadlock detector will only complain locks with the
+RT_MUTEX_MIN_CHAINWALK and a waiter must be pending. That means it
+works only for in-kernel locks because the futex interface always uses
+RT_MUTEX_FULL_CHAINWALK.
+The requirement for an active waiter limits the detector to actual
+deadlocks and makes it possible to report potential deadlocks like
+lockdep does.
+It looks like lockdep is better suited for reporting deadlocks.
+
+Remove rtmutex' debug print on deadlock detection.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/rtmutex.h         |  7 ---
+ kernel/locking/rtmutex-debug.c  | 97 ---------------------------------
+ kernel/locking/rtmutex-debug.h  | 11 ----
+ kernel/locking/rtmutex.c        |  9 ---
+ kernel/locking/rtmutex.h        |  7 ---
+ kernel/locking/rtmutex_common.h |  4 --
+ 6 files changed, 135 deletions(-)
+
+diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
+index 16f974a22f51..88a0ba806066 100644
+--- a/include/linux/rtmutex.h
++++ b/include/linux/rtmutex.h
+@@ -31,9 +31,6 @@ struct rt_mutex {
+ 	raw_spinlock_t		wait_lock;
+ 	struct rb_root_cached   waiters;
+ 	struct task_struct	*owner;
+-#ifdef CONFIG_DEBUG_RT_MUTEXES
+-	const char		*name;
+-#endif
+ #ifdef CONFIG_DEBUG_LOCK_ALLOC
+ 	struct lockdep_map	dep_map;
+ #endif
+@@ -56,8 +53,6 @@ struct hrtimer_sleeper;
+ #endif
+ 
+ #ifdef CONFIG_DEBUG_RT_MUTEXES
+-# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
+-	, .name = #mutexname
+ 
+ # define rt_mutex_init(mutex) \
+ do { \
+@@ -67,7 +62,6 @@ do { \
+ 
+  extern void rt_mutex_debug_task_free(struct task_struct *tsk);
+ #else
+-# define __DEBUG_RT_MUTEX_INITIALIZER(mutexname)
+ # define rt_mutex_init(mutex)			__rt_mutex_init(mutex, NULL, NULL)
+ # define rt_mutex_debug_task_free(t)			do { } while (0)
+ #endif
+@@ -83,7 +77,6 @@ do { \
+ 	{ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
+ 	, .waiters = RB_ROOT_CACHED \
+ 	, .owner = NULL \
+-	__DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
+ 	__DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)}
+ 
+ #define DEFINE_RT_MUTEX(mutexname) \
+diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c
+index 7e411b946d4c..fb150100335f 100644
+--- a/kernel/locking/rtmutex-debug.c
++++ b/kernel/locking/rtmutex-debug.c
+@@ -32,105 +32,12 @@
+ 
+ #include "rtmutex_common.h"
+ 
+-static void printk_task(struct task_struct *p)
+-{
+-	if (p)
+-		printk("%16s:%5d [%p, %3d]", p->comm, task_pid_nr(p), p, p->prio);
+-	else
+-		printk("<none>");
+-}
+-
+-static void printk_lock(struct rt_mutex *lock, int print_owner)
+-{
+-	printk(" [%p] {%s}\n", lock, lock->name);
+-
+-	if (print_owner && rt_mutex_owner(lock)) {
+-		printk(".. ->owner: %p\n", lock->owner);
+-		printk(".. held by:  ");
+-		printk_task(rt_mutex_owner(lock));
+-		printk("\n");
+-	}
+-}
+-
+ void rt_mutex_debug_task_free(struct task_struct *task)
+ {
+ 	DEBUG_LOCKS_WARN_ON(!RB_EMPTY_ROOT(&task->pi_waiters.rb_root));
+ 	DEBUG_LOCKS_WARN_ON(task->pi_blocked_on);
+ }
+ 
+-/*
+- * We fill out the fields in the waiter to store the information about
+- * the deadlock. We print when we return. act_waiter can be NULL in
+- * case of a remove waiter operation.
+- */
+-void debug_rt_mutex_deadlock(enum rtmutex_chainwalk chwalk,
+-			     struct rt_mutex_waiter *act_waiter,
+-			     struct rt_mutex *lock)
+-{
+-	struct task_struct *task;
+-
+-	if (!debug_locks || chwalk == RT_MUTEX_FULL_CHAINWALK || !act_waiter)
+-		return;
+-
+-	task = rt_mutex_owner(act_waiter->lock);
+-	if (task && task != current) {
+-		act_waiter->deadlock_task_pid = get_pid(task_pid(task));
+-		act_waiter->deadlock_lock = lock;
+-	}
+-}
+-
+-void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
+-{
+-	struct task_struct *task;
+-
+-	if (!waiter->deadlock_lock || !debug_locks)
+-		return;
+-
+-	rcu_read_lock();
+-	task = pid_task(waiter->deadlock_task_pid, PIDTYPE_PID);
+-	if (!task) {
+-		rcu_read_unlock();
+-		return;
+-	}
+-
+-	if (!debug_locks_off()) {
+-		rcu_read_unlock();
+-		return;
+-	}
+-
+-	pr_warn("\n");
+-	pr_warn("============================================\n");
+-	pr_warn("WARNING: circular locking deadlock detected!\n");
+-	pr_warn("%s\n", print_tainted());
+-	pr_warn("--------------------------------------------\n");
+-	printk("%s/%d is deadlocking current task %s/%d\n\n",
+-	       task->comm, task_pid_nr(task),
+-	       current->comm, task_pid_nr(current));
+-
+-	printk("\n1) %s/%d is trying to acquire this lock:\n",
+-	       current->comm, task_pid_nr(current));
+-	printk_lock(waiter->lock, 1);
+-
+-	printk("\n2) %s/%d is blocked on this lock:\n",
+-		task->comm, task_pid_nr(task));
+-	printk_lock(waiter->deadlock_lock, 1);
+-
+-	debug_show_held_locks(current);
+-	debug_show_held_locks(task);
+-
+-	printk("\n%s/%d's [blocked] stackdump:\n\n",
+-		task->comm, task_pid_nr(task));
+-	show_stack(task, NULL, KERN_DEFAULT);
+-	printk("\n%s/%d's [current] stackdump:\n\n",
+-		current->comm, task_pid_nr(current));
+-	dump_stack();
+-	debug_show_all_locks();
+-	rcu_read_unlock();
+-
+-	printk("[ turning off deadlock detection."
+-	       "Please report this trace. ]\n\n");
+-}
+-
+ void debug_rt_mutex_lock(struct rt_mutex *lock)
+ {
+ }
+@@ -153,12 +60,10 @@ void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock)
+ void debug_rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+ {
+ 	memset(waiter, 0x11, sizeof(*waiter));
+-	waiter->deadlock_task_pid = NULL;
+ }
+ 
+ void debug_rt_mutex_free_waiter(struct rt_mutex_waiter *waiter)
+ {
+-	put_pid(waiter->deadlock_task_pid);
+ 	memset(waiter, 0x22, sizeof(*waiter));
+ }
+ 
+@@ -168,10 +73,8 @@ void debug_rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock_cl
+ 	 * Make sure we are not reinitializing a held lock:
+ 	 */
+ 	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+-	lock->name = name;
+ 
+ #ifdef CONFIG_DEBUG_LOCK_ALLOC
+ 	lockdep_init_map(&lock->dep_map, name, key, 0);
+ #endif
+ }
+-
+diff --git a/kernel/locking/rtmutex-debug.h b/kernel/locking/rtmutex-debug.h
+index fc549713bba3..659e93e256c6 100644
+--- a/kernel/locking/rtmutex-debug.h
++++ b/kernel/locking/rtmutex-debug.h
+@@ -18,20 +18,9 @@ extern void debug_rt_mutex_unlock(struct rt_mutex *lock);
+ extern void debug_rt_mutex_proxy_lock(struct rt_mutex *lock,
+ 				      struct task_struct *powner);
+ extern void debug_rt_mutex_proxy_unlock(struct rt_mutex *lock);
+-extern void debug_rt_mutex_deadlock(enum rtmutex_chainwalk chwalk,
+-				    struct rt_mutex_waiter *waiter,
+-				    struct rt_mutex *lock);
+-extern void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter);
+-# define debug_rt_mutex_reset_waiter(w)			\
+-	do { (w)->deadlock_lock = NULL; } while (0)
+ 
+ static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
+ 						  enum rtmutex_chainwalk walk)
+ {
+ 	return (waiter != NULL);
+ }
+-
+-static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w)
+-{
+-	debug_rt_mutex_print_deadlock(w);
+-}
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index 4792fc7abe7d..9aa4d545020a 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -597,7 +597,6 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
+ 	 * walk, we detected a deadlock.
+ 	 */
+ 	if (lock == orig_lock || rt_mutex_owner(lock) == top_task) {
+-		debug_rt_mutex_deadlock(chwalk, orig_waiter, lock);
+ 		raw_spin_unlock(&lock->wait_lock);
+ 		ret = -EDEADLK;
+ 		goto out_unlock_pi;
+@@ -1189,8 +1188,6 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ 
+ 		raw_spin_unlock_irq(&lock->wait_lock);
+ 
+-		debug_rt_mutex_print_deadlock(waiter);
+-
+ 		schedule();
+ 
+ 		raw_spin_lock_irq(&lock->wait_lock);
+@@ -1211,10 +1208,6 @@ static void rt_mutex_handle_deadlock(int res, int detect_deadlock,
+ 	if (res != -EDEADLOCK || detect_deadlock)
+ 		return;
+ 
+-	/*
+-	 * Yell lowdly and stop the task right here.
+-	 */
+-	rt_mutex_print_deadlock(w);
+ 	while (1) {
+ 		set_current_state(TASK_INTERRUPTIBLE);
+ 		schedule();
+@@ -1763,8 +1756,6 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
+ 		ret = 0;
+ 	}
+ 
+-	debug_rt_mutex_print_deadlock(waiter);
+-
+ 	return ret;
+ }
+ 
+diff --git a/kernel/locking/rtmutex.h b/kernel/locking/rtmutex.h
+index 732f96abf462..338ccd29119a 100644
+--- a/kernel/locking/rtmutex.h
++++ b/kernel/locking/rtmutex.h
+@@ -19,15 +19,8 @@
+ #define debug_rt_mutex_proxy_unlock(l)			do { } while (0)
+ #define debug_rt_mutex_unlock(l)			do { } while (0)
+ #define debug_rt_mutex_init(m, n, k)			do { } while (0)
+-#define debug_rt_mutex_deadlock(d, a ,l)		do { } while (0)
+-#define debug_rt_mutex_print_deadlock(w)		do { } while (0)
+ #define debug_rt_mutex_reset_waiter(w)			do { } while (0)
+ 
+-static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w)
+-{
+-	WARN(1, "rtmutex deadlock detected\n");
+-}
+-
+ static inline bool debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *w,
+ 						  enum rtmutex_chainwalk walk)
+ {
+diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
+index e6913103d7ff..b1455dc2366f 100644
+--- a/kernel/locking/rtmutex_common.h
++++ b/kernel/locking/rtmutex_common.h
+@@ -29,10 +29,6 @@ struct rt_mutex_waiter {
+ 	struct rb_node          pi_tree_entry;
+ 	struct task_struct	*task;
+ 	struct rt_mutex		*lock;
+-#ifdef CONFIG_DEBUG_RT_MUTEXES
+-	struct pid		*deadlock_task_pid;
+-	struct rt_mutex		*deadlock_lock;
+-#endif
+ 	int prio;
+ 	u64 deadline;
+ };
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0158-locking-rtmutex-Move-rt_mutex_init-outside-of-CONFIG.patch b/debian/patches-rt/0158-locking-rtmutex-Move-rt_mutex_init-outside-of-CONFIG.patch
new file mode 100644
index 000000000..91e3d2b55
--- /dev/null
+++ b/debian/patches-rt/0158-locking-rtmutex-Move-rt_mutex_init-outside-of-CONFIG.patch
@@ -0,0 +1,60 @@
+From e25aa4319847e6a6769075a1f38c98d8cf3246f9 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 29 Sep 2020 16:32:49 +0200
+Subject: [PATCH 158/323] locking/rtmutex: Move rt_mutex_init() outside of
+ CONFIG_DEBUG_RT_MUTEXES
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+rt_mutex_init() only initializes lockdep if CONFIG_DEBUG_RT_MUTEXES is
+enabled. The static initializer (DEFINE_RT_MUTEX) does not have such a
+restriction.
+
+Move rt_mutex_init() outside of CONFIG_DEBUG_RT_MUTEXES.
+Move the remaining functions in this CONFIG_DEBUG_RT_MUTEXES block to
+the upper block.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/rtmutex.h | 12 +++---------
+ 1 file changed, 3 insertions(+), 9 deletions(-)
+
+diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
+index 88a0ba806066..2dc10b582d4a 100644
+--- a/include/linux/rtmutex.h
++++ b/include/linux/rtmutex.h
+@@ -43,6 +43,7 @@ struct hrtimer_sleeper;
+  extern int rt_mutex_debug_check_no_locks_freed(const void *from,
+ 						unsigned long len);
+  extern void rt_mutex_debug_check_no_locks_held(struct task_struct *task);
++ extern void rt_mutex_debug_task_free(struct task_struct *tsk);
+ #else
+  static inline int rt_mutex_debug_check_no_locks_freed(const void *from,
+ 						       unsigned long len)
+@@ -50,22 +51,15 @@ struct hrtimer_sleeper;
+ 	return 0;
+  }
+ # define rt_mutex_debug_check_no_locks_held(task)	do { } while (0)
++# define rt_mutex_debug_task_free(t)			do { } while (0)
+ #endif
+ 
+-#ifdef CONFIG_DEBUG_RT_MUTEXES
+-
+-# define rt_mutex_init(mutex) \
++#define rt_mutex_init(mutex) \
+ do { \
+ 	static struct lock_class_key __key; \
+ 	__rt_mutex_init(mutex, __func__, &__key); \
+ } while (0)
+ 
+- extern void rt_mutex_debug_task_free(struct task_struct *tsk);
+-#else
+-# define rt_mutex_init(mutex)			__rt_mutex_init(mutex, NULL, NULL)
+-# define rt_mutex_debug_task_free(t)			do { } while (0)
+-#endif
+-
+ #ifdef CONFIG_DEBUG_LOCK_ALLOC
+ #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname) \
+ 	, .dep_map = { .name = #mutexname }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0159-locking-rtmutex-Remove-rt_mutex_timed_lock.patch b/debian/patches-rt/0159-locking-rtmutex-Remove-rt_mutex_timed_lock.patch
new file mode 100644
index 000000000..5573d0e56
--- /dev/null
+++ b/debian/patches-rt/0159-locking-rtmutex-Remove-rt_mutex_timed_lock.patch
@@ -0,0 +1,98 @@
+From 6ec5055da1da31b64ab24ba9ff1739d05e46bb7f Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 7 Oct 2020 12:11:33 +0200
+Subject: [PATCH 159/323] locking/rtmutex: Remove rt_mutex_timed_lock()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+rt_mutex_timed_lock() has no callers since commit
+   c051b21f71d1f ("rtmutex: Confine deadlock logic to futex")
+
+Remove rt_mutex_timed_lock().
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/rtmutex.h  |  3 ---
+ kernel/locking/rtmutex.c | 46 ----------------------------------------
+ 2 files changed, 49 deletions(-)
+
+diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
+index 2dc10b582d4a..243fabc2c85f 100644
+--- a/include/linux/rtmutex.h
++++ b/include/linux/rtmutex.h
+@@ -99,9 +99,6 @@ extern void rt_mutex_lock(struct rt_mutex *lock);
+ #endif
+ 
+ extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
+-extern int rt_mutex_timed_lock(struct rt_mutex *lock,
+-			       struct hrtimer_sleeper *timeout);
+-
+ extern int rt_mutex_trylock(struct rt_mutex *lock);
+ 
+ extern void rt_mutex_unlock(struct rt_mutex *lock);
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index 9aa4d545020a..b5d5c570a8ac 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -1405,21 +1405,6 @@ rt_mutex_fastlock(struct rt_mutex *lock, int state,
+ 	return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
+ }
+ 
+-static inline int
+-rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
+-			struct hrtimer_sleeper *timeout,
+-			enum rtmutex_chainwalk chwalk,
+-			int (*slowfn)(struct rt_mutex *lock, int state,
+-				      struct hrtimer_sleeper *timeout,
+-				      enum rtmutex_chainwalk chwalk))
+-{
+-	if (chwalk == RT_MUTEX_MIN_CHAINWALK &&
+-	    likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
+-		return 0;
+-
+-	return slowfn(lock, state, timeout, chwalk);
+-}
+-
+ static inline int
+ rt_mutex_fasttrylock(struct rt_mutex *lock,
+ 		     int (*slowfn)(struct rt_mutex *lock))
+@@ -1527,37 +1512,6 @@ int __sched __rt_mutex_futex_trylock(struct rt_mutex *lock)
+ 	return __rt_mutex_slowtrylock(lock);
+ }
+ 
+-/**
+- * rt_mutex_timed_lock - lock a rt_mutex interruptible
+- *			the timeout structure is provided
+- *			by the caller
+- *
+- * @lock:		the rt_mutex to be locked
+- * @timeout:		timeout structure or NULL (no timeout)
+- *
+- * Returns:
+- *  0		on success
+- * -EINTR	when interrupted by a signal
+- * -ETIMEDOUT	when the timeout expired
+- */
+-int
+-rt_mutex_timed_lock(struct rt_mutex *lock, struct hrtimer_sleeper *timeout)
+-{
+-	int ret;
+-
+-	might_sleep();
+-
+-	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+-	ret = rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout,
+-				       RT_MUTEX_MIN_CHAINWALK,
+-				       rt_mutex_slowlock);
+-	if (ret)
+-		mutex_release(&lock->dep_map, _RET_IP_);
+-
+-	return ret;
+-}
+-EXPORT_SYMBOL_GPL(rt_mutex_timed_lock);
+-
+ /**
+  * rt_mutex_trylock - try to lock a rt_mutex
+  *
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0160-locking-rtmutex-Handle-the-various-new-futex-race-co.patch b/debian/patches-rt/0160-locking-rtmutex-Handle-the-various-new-futex-race-co.patch
new file mode 100644
index 000000000..3e02c70df
--- /dev/null
+++ b/debian/patches-rt/0160-locking-rtmutex-Handle-the-various-new-futex-race-co.patch
@@ -0,0 +1,255 @@
+From faad74e290468f037de33422cb1799c05477242d Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 10 Jun 2011 11:04:15 +0200
+Subject: [PATCH 160/323] locking/rtmutex: Handle the various new futex race
+ conditions
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+RT opens a few new interesting race conditions in the rtmutex/futex
+combo due to futex hash bucket lock being a 'sleeping' spinlock and
+therefor not disabling preemption.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ kernel/futex/core.c             | 77 ++++++++++++++++++++++++++-------
+ kernel/locking/rtmutex.c        | 36 ++++++++++++---
+ kernel/locking/rtmutex_common.h |  2 +
+ 3 files changed, 94 insertions(+), 21 deletions(-)
+
+diff --git a/kernel/futex/core.c b/kernel/futex/core.c
+index cde0ca876b93..706cd446ec71 100644
+--- a/kernel/futex/core.c
++++ b/kernel/futex/core.c
+@@ -2165,6 +2165,16 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
+ 				 */
+ 				requeue_pi_wake_futex(this, &key2, hb2);
+ 				continue;
++			} else if (ret == -EAGAIN) {
++				/*
++				 * Waiter was woken by timeout or
++				 * signal and has set pi_blocked_on to
++				 * PI_WAKEUP_INPROGRESS before we
++				 * tried to enqueue it on the rtmutex.
++				 */
++				this->pi_state = NULL;
++				put_pi_state(pi_state);
++				continue;
+ 			} else if (ret) {
+ 				/*
+ 				 * rt_mutex_start_proxy_lock() detected a
+@@ -3182,7 +3192,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
+ {
+ 	struct hrtimer_sleeper timeout, *to;
+ 	struct rt_mutex_waiter rt_waiter;
+-	struct futex_hash_bucket *hb;
++	struct futex_hash_bucket *hb, *hb2;
+ 	union futex_key key2 = FUTEX_KEY_INIT;
+ 	struct futex_q q = futex_q_init;
+ 	int res, ret;
+@@ -3234,20 +3244,55 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
+ 	/* Queue the futex_q, drop the hb lock, wait for wakeup. */
+ 	futex_wait_queue_me(hb, &q, to);
+ 
+-	spin_lock(&hb->lock);
+-	ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);
+-	spin_unlock(&hb->lock);
+-	if (ret)
+-		goto out;
++	/*
++	 * On RT we must avoid races with requeue and trying to block
++	 * on two mutexes (hb->lock and uaddr2's rtmutex) by
++	 * serializing access to pi_blocked_on with pi_lock.
++	 */
++	raw_spin_lock_irq(&current->pi_lock);
++	if (current->pi_blocked_on) {
++		/*
++		 * We have been requeued or are in the process of
++		 * being requeued.
++		 */
++		raw_spin_unlock_irq(&current->pi_lock);
++	} else {
++		/*
++		 * Setting pi_blocked_on to PI_WAKEUP_INPROGRESS
++		 * prevents a concurrent requeue from moving us to the
++		 * uaddr2 rtmutex. After that we can safely acquire
++		 * (and possibly block on) hb->lock.
++		 */
++		current->pi_blocked_on = PI_WAKEUP_INPROGRESS;
++		raw_spin_unlock_irq(&current->pi_lock);
++
++		spin_lock(&hb->lock);
++
++		/*
++		 * Clean up pi_blocked_on. We might leak it otherwise
++		 * when we succeeded with the hb->lock in the fast
++		 * path.
++		 */
++		raw_spin_lock_irq(&current->pi_lock);
++		current->pi_blocked_on = NULL;
++		raw_spin_unlock_irq(&current->pi_lock);
++
++		ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);
++		spin_unlock(&hb->lock);
++		if (ret)
++			goto out;
++	}
+ 
+ 	/*
+-	 * In order for us to be here, we know our q.key == key2, and since
+-	 * we took the hb->lock above, we also know that futex_requeue() has
+-	 * completed and we no longer have to concern ourselves with a wakeup
+-	 * race with the atomic proxy lock acquisition by the requeue code. The
+-	 * futex_requeue dropped our key1 reference and incremented our key2
+-	 * reference count.
++	 * In order to be here, we have either been requeued, are in
++	 * the process of being requeued, or requeue successfully
++	 * acquired uaddr2 on our behalf.  If pi_blocked_on was
++	 * non-null above, we may be racing with a requeue.  Do not
++	 * rely on q->lock_ptr to be hb2->lock until after blocking on
++	 * hb->lock or hb2->lock. The futex_requeue dropped our key1
++	 * reference and incremented our key2 reference count.
+ 	 */
++	hb2 = hash_futex(&key2);
+ 
+ 	/* Check if the requeue code acquired the second futex for us. */
+ 	if (!q.rt_waiter) {
+@@ -3256,14 +3301,15 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
+ 		 * did a lock-steal - fix up the PI-state in that case.
+ 		 */
+ 		if (q.pi_state && (q.pi_state->owner != current)) {
+-			spin_lock(q.lock_ptr);
++			spin_lock(&hb2->lock);
++			BUG_ON(&hb2->lock != q.lock_ptr);
+ 			ret = fixup_pi_state_owner(uaddr2, &q, current);
+ 			/*
+ 			 * Drop the reference to the pi state which
+ 			 * the requeue_pi() code acquired for us.
+ 			 */
+ 			put_pi_state(q.pi_state);
+-			spin_unlock(q.lock_ptr);
++			spin_unlock(&hb2->lock);
+ 			/*
+ 			 * Adjust the return value. It's either -EFAULT or
+ 			 * success (1) but the caller expects 0 for success.
+@@ -3282,7 +3328,8 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
+ 		pi_mutex = &q.pi_state->pi_mutex;
+ 		ret = rt_mutex_wait_proxy_lock(pi_mutex, to, &rt_waiter);
+ 
+-		spin_lock(q.lock_ptr);
++		spin_lock(&hb2->lock);
++		BUG_ON(&hb2->lock != q.lock_ptr);
+ 		if (ret && !rt_mutex_cleanup_proxy_lock(pi_mutex, &rt_waiter))
+ 			ret = 0;
+ 
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index b5d5c570a8ac..2ef5a6eb95da 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -136,6 +136,11 @@ static void fixup_rt_mutex_waiters(struct rt_mutex *lock)
+ 		WRITE_ONCE(*p, owner & ~RT_MUTEX_HAS_WAITERS);
+ }
+ 
++static int rt_mutex_real_waiter(struct rt_mutex_waiter *waiter)
++{
++	return waiter && waiter != PI_WAKEUP_INPROGRESS;
++}
++
+ /*
+  * We can speed up the acquire/release, if there's no debugging state to be
+  * set up.
+@@ -378,7 +383,8 @@ int max_lock_depth = 1024;
+ 
+ static inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
+ {
+-	return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL;
++	return rt_mutex_real_waiter(p->pi_blocked_on) ?
++		p->pi_blocked_on->lock : NULL;
+ }
+ 
+ /*
+@@ -514,7 +520,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
+ 	 * reached or the state of the chain has changed while we
+ 	 * dropped the locks.
+ 	 */
+-	if (!waiter)
++	if (!rt_mutex_real_waiter(waiter))
+ 		goto out_unlock_pi;
+ 
+ 	/*
+@@ -947,6 +953,22 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
+ 		return -EDEADLK;
+ 
+ 	raw_spin_lock(&task->pi_lock);
++	/*
++	 * In the case of futex requeue PI, this will be a proxy
++	 * lock. The task will wake unaware that it is enqueueed on
++	 * this lock. Avoid blocking on two locks and corrupting
++	 * pi_blocked_on via the PI_WAKEUP_INPROGRESS
++	 * flag. futex_wait_requeue_pi() sets this when it wakes up
++	 * before requeue (due to a signal or timeout). Do not enqueue
++	 * the task if PI_WAKEUP_INPROGRESS is set.
++	 */
++	if (task != current && task->pi_blocked_on == PI_WAKEUP_INPROGRESS) {
++		raw_spin_unlock(&task->pi_lock);
++		return -EAGAIN;
++	}
++
++       BUG_ON(rt_mutex_real_waiter(task->pi_blocked_on));
++
+ 	waiter->task = task;
+ 	waiter->lock = lock;
+ 	waiter->prio = task->prio;
+@@ -970,7 +992,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
+ 		rt_mutex_enqueue_pi(owner, waiter);
+ 
+ 		rt_mutex_adjust_prio(owner);
+-		if (owner->pi_blocked_on)
++		if (rt_mutex_real_waiter(owner->pi_blocked_on))
+ 			chain_walk = 1;
+ 	} else if (rt_mutex_cond_detect_deadlock(waiter, chwalk)) {
+ 		chain_walk = 1;
+@@ -1066,7 +1088,7 @@ static void remove_waiter(struct rt_mutex *lock,
+ {
+ 	bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock));
+ 	struct task_struct *owner = rt_mutex_owner(lock);
+-	struct rt_mutex *next_lock;
++	struct rt_mutex *next_lock = NULL;
+ 
+ 	lockdep_assert_held(&lock->wait_lock);
+ 
+@@ -1092,7 +1114,8 @@ static void remove_waiter(struct rt_mutex *lock,
+ 	rt_mutex_adjust_prio(owner);
+ 
+ 	/* Store the lock on which owner is blocked or NULL */
+-	next_lock = task_blocked_on_lock(owner);
++	if (rt_mutex_real_waiter(owner->pi_blocked_on))
++		next_lock = task_blocked_on_lock(owner);
+ 
+ 	raw_spin_unlock(&owner->pi_lock);
+ 
+@@ -1128,7 +1151,8 @@ void rt_mutex_adjust_pi(struct task_struct *task)
+ 	raw_spin_lock_irqsave(&task->pi_lock, flags);
+ 
+ 	waiter = task->pi_blocked_on;
+-	if (!waiter || rt_mutex_waiter_equal(waiter, task_to_waiter(task))) {
++	if (!rt_mutex_real_waiter(waiter) ||
++	    rt_mutex_waiter_equal(waiter, task_to_waiter(task))) {
+ 		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ 		return;
+ 	}
+diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
+index b1455dc2366f..096b16cfb096 100644
+--- a/kernel/locking/rtmutex_common.h
++++ b/kernel/locking/rtmutex_common.h
+@@ -125,6 +125,8 @@ enum rtmutex_chainwalk {
+ /*
+  * PI-futex support (proxy locking functions, etc.):
+  */
++#define PI_WAKEUP_INPROGRESS	((struct rt_mutex_waiter *) 1)
++
+ extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
+ extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
+ 				       struct task_struct *proxy_owner);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0161-futex-Fix-bug-on-when-a-requeued-RT-task-times-out.patch b/debian/patches-rt/0161-futex-Fix-bug-on-when-a-requeued-RT-task-times-out.patch
new file mode 100644
index 000000000..bab95baf2
--- /dev/null
+++ b/debian/patches-rt/0161-futex-Fix-bug-on-when-a-requeued-RT-task-times-out.patch
@@ -0,0 +1,118 @@
+From 787b0032cdfc388293dcde2c4bc3a2c40b6d9cf2 Mon Sep 17 00:00:00 2001
+From: Steven Rostedt <rostedt@goodmis.org>
+Date: Tue, 14 Jul 2015 14:26:34 +0200
+Subject: [PATCH 161/323] futex: Fix bug on when a requeued RT task times out
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Requeue with timeout causes a bug with PREEMPT_RT.
+
+The bug comes from a timed out condition.
+
+	TASK 1				TASK 2
+	------				------
+    futex_wait_requeue_pi()
+	futex_wait_queue_me()
+	<timed out>
+
+					double_lock_hb();
+
+	raw_spin_lock(pi_lock);
+	if (current->pi_blocked_on) {
+	} else {
+	    current->pi_blocked_on = PI_WAKE_INPROGRESS;
+	    run_spin_unlock(pi_lock);
+	    spin_lock(hb->lock); <-- blocked!
+
+					plist_for_each_entry_safe(this) {
+					    rt_mutex_start_proxy_lock();
+						task_blocks_on_rt_mutex();
+						BUG_ON(task->pi_blocked_on)!!!!
+
+The BUG_ON() actually has a check for PI_WAKE_INPROGRESS, but the
+problem is that, after TASK 1 sets PI_WAKE_INPROGRESS, it then tries to
+grab the hb->lock, which it fails to do so. As the hb->lock is a mutex,
+it will block and set the "pi_blocked_on" to the hb->lock.
+
+When TASK 2 goes to requeue it, the check for PI_WAKE_INPROGESS fails
+because the task1's pi_blocked_on is no longer set to that, but instead,
+set to the hb->lock.
+
+The fix:
+
+When calling rt_mutex_start_proxy_lock() a check is made to see
+if the proxy tasks pi_blocked_on is set. If so, exit out early.
+Otherwise set it to a new flag PI_REQUEUE_INPROGRESS, which notifies
+the proxy task that it is being requeued, and will handle things
+appropriately.
+
+Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ kernel/locking/rtmutex.c        | 31 ++++++++++++++++++++++++++++++-
+ kernel/locking/rtmutex_common.h |  1 +
+ 2 files changed, 31 insertions(+), 1 deletion(-)
+
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index 2ef5a6eb95da..d8755d5ef227 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -138,7 +138,8 @@ static void fixup_rt_mutex_waiters(struct rt_mutex *lock)
+ 
+ static int rt_mutex_real_waiter(struct rt_mutex_waiter *waiter)
+ {
+-	return waiter && waiter != PI_WAKEUP_INPROGRESS;
++	return waiter && waiter != PI_WAKEUP_INPROGRESS &&
++		waiter != PI_REQUEUE_INPROGRESS;
+ }
+ 
+ /*
+@@ -1720,6 +1721,34 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
+ 	if (try_to_take_rt_mutex(lock, task, NULL))
+ 		return 1;
+ 
++#ifdef CONFIG_PREEMPT_RT
++	/*
++	 * In PREEMPT_RT there's an added race.
++	 * If the task, that we are about to requeue, times out,
++	 * it can set the PI_WAKEUP_INPROGRESS. This tells the requeue
++	 * to skip this task. But right after the task sets
++	 * its pi_blocked_on to PI_WAKEUP_INPROGRESS it can then
++	 * block on the spin_lock(&hb->lock), which in RT is an rtmutex.
++	 * This will replace the PI_WAKEUP_INPROGRESS with the actual
++	 * lock that it blocks on. We *must not* place this task
++	 * on this proxy lock in that case.
++	 *
++	 * To prevent this race, we first take the task's pi_lock
++	 * and check if it has updated its pi_blocked_on. If it has,
++	 * we assume that it woke up and we return -EAGAIN.
++	 * Otherwise, we set the task's pi_blocked_on to
++	 * PI_REQUEUE_INPROGRESS, so that if the task is waking up
++	 * it will know that we are in the process of requeuing it.
++	 */
++	raw_spin_lock(&task->pi_lock);
++	if (task->pi_blocked_on) {
++		raw_spin_unlock(&task->pi_lock);
++		return -EAGAIN;
++	}
++	task->pi_blocked_on = PI_REQUEUE_INPROGRESS;
++	raw_spin_unlock(&task->pi_lock);
++#endif
++
+ 	/* We enforce deadlock detection for futexes */
+ 	ret = task_blocks_on_rt_mutex(lock, waiter, task,
+ 				      RT_MUTEX_FULL_CHAINWALK);
+diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
+index 096b16cfb096..37cd6b3bf6f4 100644
+--- a/kernel/locking/rtmutex_common.h
++++ b/kernel/locking/rtmutex_common.h
+@@ -126,6 +126,7 @@ enum rtmutex_chainwalk {
+  * PI-futex support (proxy locking functions, etc.):
+  */
+ #define PI_WAKEUP_INPROGRESS	((struct rt_mutex_waiter *) 1)
++#define PI_REQUEUE_INPROGRESS	((struct rt_mutex_waiter *) 2)
+ 
+ extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
+ extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0162-locking-rtmutex-Make-lock_killable-work.patch b/debian/patches-rt/0162-locking-rtmutex-Make-lock_killable-work.patch
new file mode 100644
index 000000000..aebd5f60e
--- /dev/null
+++ b/debian/patches-rt/0162-locking-rtmutex-Make-lock_killable-work.patch
@@ -0,0 +1,50 @@
+From 09e10e723c3bc6ceb0d1b64e0a6b3b9e2ec52225 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Sat, 1 Apr 2017 12:50:59 +0200
+Subject: [PATCH 162/323] locking/rtmutex: Make lock_killable work
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Locking an rt mutex killable does not work because signal handling is
+restricted to TASK_INTERRUPTIBLE.
+
+Use signal_pending_state() unconditionally.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/locking/rtmutex.c | 19 +++++++------------
+ 1 file changed, 7 insertions(+), 12 deletions(-)
+
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index d8755d5ef227..c3f3c23fefef 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -1197,18 +1197,13 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ 		if (try_to_take_rt_mutex(lock, current, waiter))
+ 			break;
+ 
+-		/*
+-		 * TASK_INTERRUPTIBLE checks for signals and
+-		 * timeout. Ignored otherwise.
+-		 */
+-		if (likely(state == TASK_INTERRUPTIBLE)) {
+-			/* Signal pending? */
+-			if (signal_pending(current))
+-				ret = -EINTR;
+-			if (timeout && !timeout->task)
+-				ret = -ETIMEDOUT;
+-			if (ret)
+-				break;
++		if (timeout && !timeout->task) {
++			ret = -ETIMEDOUT;
++			break;
++		}
++		if (signal_pending_state(state, current)) {
++			ret = -EINTR;
++			break;
+ 		}
+ 
+ 		raw_spin_unlock_irq(&lock->wait_lock);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0163-locking-spinlock-Split-the-lock-types-header.patch b/debian/patches-rt/0163-locking-spinlock-Split-the-lock-types-header.patch
new file mode 100644
index 000000000..a28543235
--- /dev/null
+++ b/debian/patches-rt/0163-locking-spinlock-Split-the-lock-types-header.patch
@@ -0,0 +1,253 @@
+From 79fca819370ecec3ce47fe9cb5f70efbacb613ad Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 29 Jun 2011 19:34:01 +0200
+Subject: [PATCH 163/323] locking/spinlock: Split the lock types header
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Split raw_spinlock into its own file and the remaining spinlock_t into
+its own non-RT header. The non-RT header will be replaced later by sleeping
+spinlocks.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/rwlock_types.h        |  4 ++
+ include/linux/spinlock_types.h      | 87 +----------------------------
+ include/linux/spinlock_types_nort.h | 39 +++++++++++++
+ include/linux/spinlock_types_raw.h  | 65 +++++++++++++++++++++
+ 4 files changed, 110 insertions(+), 85 deletions(-)
+ create mode 100644 include/linux/spinlock_types_nort.h
+ create mode 100644 include/linux/spinlock_types_raw.h
+
+diff --git a/include/linux/rwlock_types.h b/include/linux/rwlock_types.h
+index 3bd03e18061c..0ad226b5d8fd 100644
+--- a/include/linux/rwlock_types.h
++++ b/include/linux/rwlock_types.h
+@@ -1,6 +1,10 @@
+ #ifndef __LINUX_RWLOCK_TYPES_H
+ #define __LINUX_RWLOCK_TYPES_H
+ 
++#if !defined(__LINUX_SPINLOCK_TYPES_H)
++# error "Do not include directly, include spinlock_types.h"
++#endif
++
+ /*
+  * include/linux/rwlock_types.h - generic rwlock type definitions
+  *				  and initializers
+diff --git a/include/linux/spinlock_types.h b/include/linux/spinlock_types.h
+index b981caafe8bf..5c8664d57fb8 100644
+--- a/include/linux/spinlock_types.h
++++ b/include/linux/spinlock_types.h
+@@ -9,92 +9,9 @@
+  * Released under the General Public License (GPL).
+  */
+ 
+-#if defined(CONFIG_SMP)
+-# include <asm/spinlock_types.h>
+-#else
+-# include <linux/spinlock_types_up.h>
+-#endif
++#include <linux/spinlock_types_raw.h>
+ 
+-#include <linux/lockdep_types.h>
+-
+-typedef struct raw_spinlock {
+-	arch_spinlock_t raw_lock;
+-#ifdef CONFIG_DEBUG_SPINLOCK
+-	unsigned int magic, owner_cpu;
+-	void *owner;
+-#endif
+-#ifdef CONFIG_DEBUG_LOCK_ALLOC
+-	struct lockdep_map dep_map;
+-#endif
+-} raw_spinlock_t;
+-
+-#define SPINLOCK_MAGIC		0xdead4ead
+-
+-#define SPINLOCK_OWNER_INIT	((void *)-1L)
+-
+-#ifdef CONFIG_DEBUG_LOCK_ALLOC
+-# define RAW_SPIN_DEP_MAP_INIT(lockname)		\
+-	.dep_map = {					\
+-		.name = #lockname,			\
+-		.wait_type_inner = LD_WAIT_SPIN,	\
+-	}
+-# define SPIN_DEP_MAP_INIT(lockname)			\
+-	.dep_map = {					\
+-		.name = #lockname,			\
+-		.wait_type_inner = LD_WAIT_CONFIG,	\
+-	}
+-#else
+-# define RAW_SPIN_DEP_MAP_INIT(lockname)
+-# define SPIN_DEP_MAP_INIT(lockname)
+-#endif
+-
+-#ifdef CONFIG_DEBUG_SPINLOCK
+-# define SPIN_DEBUG_INIT(lockname)		\
+-	.magic = SPINLOCK_MAGIC,		\
+-	.owner_cpu = -1,			\
+-	.owner = SPINLOCK_OWNER_INIT,
+-#else
+-# define SPIN_DEBUG_INIT(lockname)
+-#endif
+-
+-#define __RAW_SPIN_LOCK_INITIALIZER(lockname)	\
+-	{					\
+-	.raw_lock = __ARCH_SPIN_LOCK_UNLOCKED,	\
+-	SPIN_DEBUG_INIT(lockname)		\
+-	RAW_SPIN_DEP_MAP_INIT(lockname) }
+-
+-#define __RAW_SPIN_LOCK_UNLOCKED(lockname)	\
+-	(raw_spinlock_t) __RAW_SPIN_LOCK_INITIALIZER(lockname)
+-
+-#define DEFINE_RAW_SPINLOCK(x)	raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x)
+-
+-typedef struct spinlock {
+-	union {
+-		struct raw_spinlock rlock;
+-
+-#ifdef CONFIG_DEBUG_LOCK_ALLOC
+-# define LOCK_PADSIZE (offsetof(struct raw_spinlock, dep_map))
+-		struct {
+-			u8 __padding[LOCK_PADSIZE];
+-			struct lockdep_map dep_map;
+-		};
+-#endif
+-	};
+-} spinlock_t;
+-
+-#define ___SPIN_LOCK_INITIALIZER(lockname)	\
+-	{					\
+-	.raw_lock = __ARCH_SPIN_LOCK_UNLOCKED,	\
+-	SPIN_DEBUG_INIT(lockname)		\
+-	SPIN_DEP_MAP_INIT(lockname) }
+-
+-#define __SPIN_LOCK_INITIALIZER(lockname) \
+-	{ { .rlock = ___SPIN_LOCK_INITIALIZER(lockname) } }
+-
+-#define __SPIN_LOCK_UNLOCKED(lockname) \
+-	(spinlock_t) __SPIN_LOCK_INITIALIZER(lockname)
+-
+-#define DEFINE_SPINLOCK(x)	spinlock_t x = __SPIN_LOCK_UNLOCKED(x)
++#include <linux/spinlock_types_nort.h>
+ 
+ #include <linux/rwlock_types.h>
+ 
+diff --git a/include/linux/spinlock_types_nort.h b/include/linux/spinlock_types_nort.h
+new file mode 100644
+index 000000000000..e4549f0dd197
+--- /dev/null
++++ b/include/linux/spinlock_types_nort.h
+@@ -0,0 +1,39 @@
++#ifndef __LINUX_SPINLOCK_TYPES_NORT_H
++#define __LINUX_SPINLOCK_TYPES_NORT_H
++
++#ifndef __LINUX_SPINLOCK_TYPES_H
++#error "Do not include directly. Include spinlock_types.h instead"
++#endif
++
++/*
++ * The non RT version maps spinlocks to raw_spinlocks
++ */
++typedef struct spinlock {
++	union {
++		struct raw_spinlock rlock;
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++# define LOCK_PADSIZE (offsetof(struct raw_spinlock, dep_map))
++		struct {
++			u8 __padding[LOCK_PADSIZE];
++			struct lockdep_map dep_map;
++		};
++#endif
++	};
++} spinlock_t;
++
++#define ___SPIN_LOCK_INITIALIZER(lockname)	\
++{						\
++	.raw_lock = __ARCH_SPIN_LOCK_UNLOCKED,	\
++	SPIN_DEBUG_INIT(lockname)		\
++	SPIN_DEP_MAP_INIT(lockname) }
++
++#define __SPIN_LOCK_INITIALIZER(lockname) \
++	{ { .rlock = ___SPIN_LOCK_INITIALIZER(lockname) } }
++
++#define __SPIN_LOCK_UNLOCKED(lockname) \
++	(spinlock_t) __SPIN_LOCK_INITIALIZER(lockname)
++
++#define DEFINE_SPINLOCK(x)	spinlock_t x = __SPIN_LOCK_UNLOCKED(x)
++
++#endif
+diff --git a/include/linux/spinlock_types_raw.h b/include/linux/spinlock_types_raw.h
+new file mode 100644
+index 000000000000..1d4a180e983d
+--- /dev/null
++++ b/include/linux/spinlock_types_raw.h
+@@ -0,0 +1,65 @@
++#ifndef __LINUX_SPINLOCK_TYPES_RAW_H
++#define __LINUX_SPINLOCK_TYPES_RAW_H
++
++#include <linux/types.h>
++
++#if defined(CONFIG_SMP)
++# include <asm/spinlock_types.h>
++#else
++# include <linux/spinlock_types_up.h>
++#endif
++
++#include <linux/lockdep_types.h>
++
++typedef struct raw_spinlock {
++	arch_spinlock_t raw_lock;
++#ifdef CONFIG_DEBUG_SPINLOCK
++	unsigned int magic, owner_cpu;
++	void *owner;
++#endif
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	struct lockdep_map dep_map;
++#endif
++} raw_spinlock_t;
++
++#define SPINLOCK_MAGIC		0xdead4ead
++
++#define SPINLOCK_OWNER_INIT	((void *)-1L)
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++# define RAW_SPIN_DEP_MAP_INIT(lockname)		\
++	.dep_map = {					\
++		.name = #lockname,			\
++		.wait_type_inner = LD_WAIT_SPIN,	\
++	}
++# define SPIN_DEP_MAP_INIT(lockname)			\
++	.dep_map = {					\
++		.name = #lockname,			\
++		.wait_type_inner = LD_WAIT_CONFIG,	\
++	}
++#else
++# define RAW_SPIN_DEP_MAP_INIT(lockname)
++# define SPIN_DEP_MAP_INIT(lockname)
++#endif
++
++#ifdef CONFIG_DEBUG_SPINLOCK
++# define SPIN_DEBUG_INIT(lockname)		\
++	.magic = SPINLOCK_MAGIC,		\
++	.owner_cpu = -1,			\
++	.owner = SPINLOCK_OWNER_INIT,
++#else
++# define SPIN_DEBUG_INIT(lockname)
++#endif
++
++#define __RAW_SPIN_LOCK_INITIALIZER(lockname)	\
++{						\
++	.raw_lock = __ARCH_SPIN_LOCK_UNLOCKED,	\
++	SPIN_DEBUG_INIT(lockname)		\
++	RAW_SPIN_DEP_MAP_INIT(lockname) }
++
++#define __RAW_SPIN_LOCK_UNLOCKED(lockname)	\
++	(raw_spinlock_t) __RAW_SPIN_LOCK_INITIALIZER(lockname)
++
++#define DEFINE_RAW_SPINLOCK(x)  raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x)
++
++#endif
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0164-locking-rtmutex-Avoid-include-hell.patch b/debian/patches-rt/0164-locking-rtmutex-Avoid-include-hell.patch
new file mode 100644
index 000000000..09d1bf4dd
--- /dev/null
+++ b/debian/patches-rt/0164-locking-rtmutex-Avoid-include-hell.patch
@@ -0,0 +1,30 @@
+From 1b45f1cea53e6a886ba8bfab1c7617c32c66555d Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 29 Jun 2011 20:06:39 +0200
+Subject: [PATCH 164/323] locking/rtmutex: Avoid include hell
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Include only the required raw types. This avoids pulling in the
+complete spinlock header which in turn requires rtmutex.h at some point.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/rtmutex.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
+index 243fabc2c85f..add1dab27df5 100644
+--- a/include/linux/rtmutex.h
++++ b/include/linux/rtmutex.h
+@@ -15,7 +15,7 @@
+ 
+ #include <linux/linkage.h>
+ #include <linux/rbtree.h>
+-#include <linux/spinlock_types.h>
++#include <linux/spinlock_types_raw.h>
+ 
+ extern int max_lock_depth; /* for sysctl */
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0165-lockdep-Reduce-header-files-in-debug_locks.h.patch b/debian/patches-rt/0165-lockdep-Reduce-header-files-in-debug_locks.h.patch
new file mode 100644
index 000000000..bfe1d5ecd
--- /dev/null
+++ b/debian/patches-rt/0165-lockdep-Reduce-header-files-in-debug_locks.h.patch
@@ -0,0 +1,33 @@
+From 740bc44f8756ed7c76a697de3eb3eae130c2de77 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 14 Aug 2020 16:55:25 +0200
+Subject: [PATCH 165/323] lockdep: Reduce header files in debug_locks.h
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The inclusion of printk.h leads to circular dependency if spinlock_t is
+based on rt_mutex.
+
+Include only atomic.h (xchg()) and cache.h (__read_mostly).
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/debug_locks.h | 3 +--
+ 1 file changed, 1 insertion(+), 2 deletions(-)
+
+diff --git a/include/linux/debug_locks.h b/include/linux/debug_locks.h
+index edb5c186b0b7..3f49e65169c6 100644
+--- a/include/linux/debug_locks.h
++++ b/include/linux/debug_locks.h
+@@ -3,8 +3,7 @@
+ #define __LINUX_DEBUG_LOCKING_H
+ 
+ #include <linux/atomic.h>
+-#include <linux/bug.h>
+-#include <linux/printk.h>
++#include <linux/cache.h>
+ 
+ struct task_struct;
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0166-locking-split-out-the-rbtree-definition.patch b/debian/patches-rt/0166-locking-split-out-the-rbtree-definition.patch
new file mode 100644
index 000000000..d8189ef50
--- /dev/null
+++ b/debian/patches-rt/0166-locking-split-out-the-rbtree-definition.patch
@@ -0,0 +1,120 @@
+From b9604fd91b7d02c92ddb504c330e1793f0694318 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 14 Aug 2020 17:08:41 +0200
+Subject: [PATCH 166/323] locking: split out the rbtree definition
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+rtmutex.h needs the definition for rb_root_cached. By including kernel.h
+we will get to spinlock.h which requires rtmutex.h again.
+
+Split out the required struct definition and move it into its own header
+file which can be included by rtmutex.h
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/rbtree.h      | 27 +--------------------------
+ include/linux/rbtree_type.h | 31 +++++++++++++++++++++++++++++++
+ include/linux/rtmutex.h     |  2 +-
+ 3 files changed, 33 insertions(+), 27 deletions(-)
+ create mode 100644 include/linux/rbtree_type.h
+
+diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
+index d7db17996322..c33b0e16d04b 100644
+--- a/include/linux/rbtree.h
++++ b/include/linux/rbtree.h
+@@ -19,19 +19,9 @@
+ 
+ #include <linux/kernel.h>
+ #include <linux/stddef.h>
++#include <linux/rbtree_type.h>
+ #include <linux/rcupdate.h>
+ 
+-struct rb_node {
+-	unsigned long  __rb_parent_color;
+-	struct rb_node *rb_right;
+-	struct rb_node *rb_left;
+-} __attribute__((aligned(sizeof(long))));
+-    /* The alignment might seem pointless, but allegedly CRIS needs it */
+-
+-struct rb_root {
+-	struct rb_node *rb_node;
+-};
+-
+ #define rb_parent(r)   ((struct rb_node *)((r)->__rb_parent_color & ~3))
+ 
+ #define RB_ROOT	(struct rb_root) { NULL, }
+@@ -112,21 +102,6 @@ static inline void rb_link_node_rcu(struct rb_node *node, struct rb_node *parent
+ 			typeof(*pos), field); 1; }); \
+ 	     pos = n)
+ 
+-/*
+- * Leftmost-cached rbtrees.
+- *
+- * We do not cache the rightmost node based on footprint
+- * size vs number of potential users that could benefit
+- * from O(1) rb_last(). Just not worth it, users that want
+- * this feature can always implement the logic explicitly.
+- * Furthermore, users that want to cache both pointers may
+- * find it a bit asymmetric, but that's ok.
+- */
+-struct rb_root_cached {
+-	struct rb_root rb_root;
+-	struct rb_node *rb_leftmost;
+-};
+-
+ #define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL }
+ 
+ /* Same as rb_first(), but O(1) */
+diff --git a/include/linux/rbtree_type.h b/include/linux/rbtree_type.h
+new file mode 100644
+index 000000000000..77a89dd2c7c6
+--- /dev/null
++++ b/include/linux/rbtree_type.h
+@@ -0,0 +1,31 @@
++/* SPDX-License-Identifier: GPL-2.0-or-later */
++#ifndef _LINUX_RBTREE_TYPE_H
++#define _LINUX_RBTREE_TYPE_H
++
++struct rb_node {
++	unsigned long  __rb_parent_color;
++	struct rb_node *rb_right;
++	struct rb_node *rb_left;
++} __attribute__((aligned(sizeof(long))));
++/* The alignment might seem pointless, but allegedly CRIS needs it */
++
++struct rb_root {
++	struct rb_node *rb_node;
++};
++
++/*
++ * Leftmost-cached rbtrees.
++ *
++ * We do not cache the rightmost node based on footprint
++ * size vs number of potential users that could benefit
++ * from O(1) rb_last(). Just not worth it, users that want
++ * this feature can always implement the logic explicitly.
++ * Furthermore, users that want to cache both pointers may
++ * find it a bit asymmetric, but that's ok.
++ */
++struct rb_root_cached {
++	struct rb_root rb_root;
++	struct rb_node *rb_leftmost;
++};
++
++#endif
+diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
+index add1dab27df5..b828b938c876 100644
+--- a/include/linux/rtmutex.h
++++ b/include/linux/rtmutex.h
+@@ -14,7 +14,7 @@
+ #define __LINUX_RT_MUTEX_H
+ 
+ #include <linux/linkage.h>
+-#include <linux/rbtree.h>
++#include <linux/rbtree_type.h>
+ #include <linux/spinlock_types_raw.h>
+ 
+ extern int max_lock_depth; /* for sysctl */
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0167-locking-rtmutex-Provide-rt_mutex_slowlock_locked.patch b/debian/patches-rt/0167-locking-rtmutex-Provide-rt_mutex_slowlock_locked.patch
new file mode 100644
index 000000000..125846fe5
--- /dev/null
+++ b/debian/patches-rt/0167-locking-rtmutex-Provide-rt_mutex_slowlock_locked.patch
@@ -0,0 +1,145 @@
+From dbd55916b6a3efb4b812322d7502b174b4cceb69 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 12 Oct 2017 16:14:22 +0200
+Subject: [PATCH 167/323] locking/rtmutex: Provide rt_mutex_slowlock_locked()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+This is the inner-part of rt_mutex_slowlock(), required for rwsem-rt.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/locking/rtmutex.c        | 67 +++++++++++++++++++--------------
+ kernel/locking/rtmutex_common.h |  7 ++++
+ 2 files changed, 45 insertions(+), 29 deletions(-)
+
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index c3f3c23fefef..395a3e8b2463 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -1234,35 +1234,16 @@ static void rt_mutex_handle_deadlock(int res, int detect_deadlock,
+ 	}
+ }
+ 
+-/*
+- * Slow path lock function:
+- */
+-static int __sched
+-rt_mutex_slowlock(struct rt_mutex *lock, int state,
+-		  struct hrtimer_sleeper *timeout,
+-		  enum rtmutex_chainwalk chwalk)
++int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
++				     struct hrtimer_sleeper *timeout,
++				     enum rtmutex_chainwalk chwalk,
++				     struct rt_mutex_waiter *waiter)
+ {
+-	struct rt_mutex_waiter waiter;
+-	unsigned long flags;
+-	int ret = 0;
+-
+-	rt_mutex_init_waiter(&waiter);
+-
+-	/*
+-	 * Technically we could use raw_spin_[un]lock_irq() here, but this can
+-	 * be called in early boot if the cmpxchg() fast path is disabled
+-	 * (debug, no architecture support). In this case we will acquire the
+-	 * rtmutex with lock->wait_lock held. But we cannot unconditionally
+-	 * enable interrupts in that early boot case. So we need to use the
+-	 * irqsave/restore variants.
+-	 */
+-	raw_spin_lock_irqsave(&lock->wait_lock, flags);
++	int ret;
+ 
+ 	/* Try to acquire the lock again: */
+-	if (try_to_take_rt_mutex(lock, current, NULL)) {
+-		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
++	if (try_to_take_rt_mutex(lock, current, NULL))
+ 		return 0;
+-	}
+ 
+ 	set_current_state(state);
+ 
+@@ -1270,16 +1251,16 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ 	if (unlikely(timeout))
+ 		hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS);
+ 
+-	ret = task_blocks_on_rt_mutex(lock, &waiter, current, chwalk);
++	ret = task_blocks_on_rt_mutex(lock, waiter, current, chwalk);
+ 
+ 	if (likely(!ret))
+ 		/* sleep on the mutex */
+-		ret = __rt_mutex_slowlock(lock, state, timeout, &waiter);
++		ret = __rt_mutex_slowlock(lock, state, timeout, waiter);
+ 
+ 	if (unlikely(ret)) {
+ 		__set_current_state(TASK_RUNNING);
+-		remove_waiter(lock, &waiter);
+-		rt_mutex_handle_deadlock(ret, chwalk, &waiter);
++		remove_waiter(lock, waiter);
++		rt_mutex_handle_deadlock(ret, chwalk, waiter);
+ 	}
+ 
+ 	/*
+@@ -1287,6 +1268,34 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ 	 * unconditionally. We might have to fix that up.
+ 	 */
+ 	fixup_rt_mutex_waiters(lock);
++	return ret;
++}
++
++/*
++ * Slow path lock function:
++ */
++static int __sched
++rt_mutex_slowlock(struct rt_mutex *lock, int state,
++		  struct hrtimer_sleeper *timeout,
++		  enum rtmutex_chainwalk chwalk)
++{
++	struct rt_mutex_waiter waiter;
++	unsigned long flags;
++	int ret = 0;
++
++	rt_mutex_init_waiter(&waiter);
++
++	/*
++	 * Technically we could use raw_spin_[un]lock_irq() here, but this can
++	 * be called in early boot if the cmpxchg() fast path is disabled
++	 * (debug, no architecture support). In this case we will acquire the
++	 * rtmutex with lock->wait_lock held. But we cannot unconditionally
++	 * enable interrupts in that early boot case. So we need to use the
++	 * irqsave/restore variants.
++	 */
++	raw_spin_lock_irqsave(&lock->wait_lock, flags);
++
++	ret = rt_mutex_slowlock_locked(lock, state, timeout, chwalk, &waiter);
+ 
+ 	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+ 
+diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
+index 37cd6b3bf6f4..b5a2affa59d5 100644
+--- a/kernel/locking/rtmutex_common.h
++++ b/kernel/locking/rtmutex_common.h
+@@ -15,6 +15,7 @@
+ 
+ #include <linux/rtmutex.h>
+ #include <linux/sched/wake_q.h>
++#include <linux/sched/debug.h>
+ 
+ /*
+  * This is the control structure for tasks blocked on a rt_mutex,
+@@ -153,6 +154,12 @@ extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
+ 				 struct wake_q_head *wqh);
+ 
+ extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
++/* RW semaphore special interface */
++
++int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
++				     struct hrtimer_sleeper *timeout,
++				     enum rtmutex_chainwalk chwalk,
++				     struct rt_mutex_waiter *waiter);
+ 
+ #ifdef CONFIG_DEBUG_RT_MUTEXES
+ # include "rtmutex-debug.h"
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0168-locking-rtmutex-export-lockdep-less-version-of-rt_mu.patch b/debian/patches-rt/0168-locking-rtmutex-export-lockdep-less-version-of-rt_mu.patch
new file mode 100644
index 000000000..6978baba3
--- /dev/null
+++ b/debian/patches-rt/0168-locking-rtmutex-export-lockdep-less-version-of-rt_mu.patch
@@ -0,0 +1,130 @@
+From 0472803e0c929a5b0c4cb02a1e667d745e12fc51 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 12 Oct 2017 16:36:39 +0200
+Subject: [PATCH 168/323] locking/rtmutex: export lockdep-less version of
+ rt_mutex's lock, trylock and unlock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Required for lock implementation ontop of rtmutex.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/locking/rtmutex.c        | 54 +++++++++++++++++++++++----------
+ kernel/locking/rtmutex_common.h |  3 ++
+ 2 files changed, 41 insertions(+), 16 deletions(-)
+
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index 395a3e8b2463..40ae934c6caa 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -1469,12 +1469,33 @@ rt_mutex_fastunlock(struct rt_mutex *lock,
+ 		rt_mutex_postunlock(&wake_q);
+ }
+ 
+-static inline void __rt_mutex_lock(struct rt_mutex *lock, unsigned int subclass)
++int __sched __rt_mutex_lock_state(struct rt_mutex *lock, int state)
+ {
+ 	might_sleep();
++	return rt_mutex_fastlock(lock, state, rt_mutex_slowlock);
++}
++
++/**
++ * rt_mutex_lock_state - lock a rt_mutex with a given state
++ *
++ * @lock:      The rt_mutex to be locked
++ * @state:     The state to set when blocking on the rt_mutex
++ */
++static inline int __sched rt_mutex_lock_state(struct rt_mutex *lock,
++					      unsigned int subclass, int state)
++{
++	int ret;
+ 
+ 	mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+-	rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, rt_mutex_slowlock);
++	ret = __rt_mutex_lock_state(lock, state);
++	if (ret)
++		mutex_release(&lock->dep_map, _RET_IP_);
++	return ret;
++}
++
++static inline void __rt_mutex_lock(struct rt_mutex *lock, unsigned int subclass)
++{
++	rt_mutex_lock_state(lock, subclass, TASK_UNINTERRUPTIBLE);
+ }
+ 
+ #ifdef CONFIG_DEBUG_LOCK_ALLOC
+@@ -1515,16 +1536,7 @@ EXPORT_SYMBOL_GPL(rt_mutex_lock);
+  */
+ int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock)
+ {
+-	int ret;
+-
+-	might_sleep();
+-
+-	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+-	ret = rt_mutex_fastlock(lock, TASK_INTERRUPTIBLE, rt_mutex_slowlock);
+-	if (ret)
+-		mutex_release(&lock->dep_map, _RET_IP_);
+-
+-	return ret;
++	return rt_mutex_lock_state(lock, 0, TASK_INTERRUPTIBLE);
+ }
+ EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
+ 
+@@ -1541,6 +1553,14 @@ int __sched __rt_mutex_futex_trylock(struct rt_mutex *lock)
+ 	return __rt_mutex_slowtrylock(lock);
+ }
+ 
++int __sched __rt_mutex_trylock(struct rt_mutex *lock)
++{
++	if (WARN_ON_ONCE(in_irq() || in_nmi() || in_serving_softirq()))
++		return 0;
++
++	return rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);
++}
++
+ /**
+  * rt_mutex_trylock - try to lock a rt_mutex
+  *
+@@ -1556,10 +1576,7 @@ int __sched rt_mutex_trylock(struct rt_mutex *lock)
+ {
+ 	int ret;
+ 
+-	if (WARN_ON_ONCE(in_irq() || in_nmi() || in_serving_softirq()))
+-		return 0;
+-
+-	ret = rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);
++	ret = __rt_mutex_trylock(lock);
+ 	if (ret)
+ 		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+ 
+@@ -1567,6 +1584,11 @@ int __sched rt_mutex_trylock(struct rt_mutex *lock)
+ }
+ EXPORT_SYMBOL_GPL(rt_mutex_trylock);
+ 
++void __sched __rt_mutex_unlock(struct rt_mutex *lock)
++{
++	rt_mutex_fastunlock(lock, rt_mutex_slowunlock);
++}
++
+ /**
+  * rt_mutex_unlock - unlock a rt_mutex
+  *
+diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
+index b5a2affa59d5..9d1e974ca9c3 100644
+--- a/kernel/locking/rtmutex_common.h
++++ b/kernel/locking/rtmutex_common.h
+@@ -156,6 +156,9 @@ extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
+ extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
+ /* RW semaphore special interface */
+ 
++extern int __rt_mutex_lock_state(struct rt_mutex *lock, int state);
++extern int __rt_mutex_trylock(struct rt_mutex *lock);
++extern void __rt_mutex_unlock(struct rt_mutex *lock);
+ int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+ 				     struct hrtimer_sleeper *timeout,
+ 				     enum rtmutex_chainwalk chwalk,
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0169-sched-Add-saved_state-for-tasks-blocked-on-sleeping-.patch b/debian/patches-rt/0169-sched-Add-saved_state-for-tasks-blocked-on-sleeping-.patch
new file mode 100644
index 000000000..83106676c
--- /dev/null
+++ b/debian/patches-rt/0169-sched-Add-saved_state-for-tasks-blocked-on-sleeping-.patch
@@ -0,0 +1,116 @@
+From 622996bf8475bf1d06cbb523dacc7469e7b9c864 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Sat, 25 Jun 2011 09:21:04 +0200
+Subject: [PATCH 169/323] sched: Add saved_state for tasks blocked on sleeping
+ locks
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Spinlocks are state preserving in !RT. RT changes the state when a
+task gets blocked on a lock. So we need to remember the state before
+the lock contention. If a regular wakeup (not a RTmutex related
+wakeup) happens, the saved_state is updated to running. When the lock
+sleep is done, the saved state is restored.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/sched.h |  3 +++
+ kernel/sched/core.c   | 34 ++++++++++++++++++++++++++++++++--
+ kernel/sched/sched.h  |  1 +
+ 3 files changed, 36 insertions(+), 2 deletions(-)
+
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index d31da4867bb2..73defe42fd23 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -659,6 +659,8 @@ struct task_struct {
+ #endif
+ 	/* -1 unrunnable, 0 runnable, >0 stopped: */
+ 	volatile long			state;
++	/* saved state for "spinlock sleepers" */
++	volatile long			saved_state;
+ 
+ 	/*
+ 	 * This begins the randomizable portion of task_struct. Only
+@@ -1782,6 +1784,7 @@ extern struct task_struct *find_get_task_by_vpid(pid_t nr);
+ 
+ extern int wake_up_state(struct task_struct *tsk, unsigned int state);
+ extern int wake_up_process(struct task_struct *tsk);
++extern int wake_up_lock_sleeper(struct task_struct *tsk);
+ extern void wake_up_new_task(struct task_struct *tsk);
+ 
+ #ifdef CONFIG_SMP
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 390b51366f5e..f6d40256c0d4 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -3305,7 +3305,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
+ 	int cpu, success = 0;
+ 
+ 	preempt_disable();
+-	if (p == current) {
++	if (!IS_ENABLED(CONFIG_PREEMPT_RT) && p == current) {
+ 		/*
+ 		 * We're waking current, this means 'p->on_rq' and 'task_cpu(p)
+ 		 * == smp_processor_id()'. Together this means we can special
+@@ -3335,8 +3335,26 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
+ 	 */
+ 	raw_spin_lock_irqsave(&p->pi_lock, flags);
+ 	smp_mb__after_spinlock();
+-	if (!(p->state & state))
++	if (!(p->state & state)) {
++		/*
++		 * The task might be running due to a spinlock sleeper
++		 * wakeup. Check the saved state and set it to running
++		 * if the wakeup condition is true.
++		 */
++		if (!(wake_flags & WF_LOCK_SLEEPER)) {
++			if (p->saved_state & state) {
++				p->saved_state = TASK_RUNNING;
++				success = 1;
++			}
++		}
+ 		goto unlock;
++	}
++	/*
++	 * If this is a regular wakeup, then we can unconditionally
++	 * clear the saved state of a "lock sleeper".
++	 */
++	if (!(wake_flags & WF_LOCK_SLEEPER))
++		p->saved_state = TASK_RUNNING;
+ 
+ 	trace_sched_waking(p);
+ 
+@@ -3525,6 +3543,18 @@ int wake_up_process(struct task_struct *p)
+ }
+ EXPORT_SYMBOL(wake_up_process);
+ 
++/**
++ * wake_up_lock_sleeper - Wake up a specific process blocked on a "sleeping lock"
++ * @p: The process to be woken up.
++ *
++ * Same as wake_up_process() above, but wake_flags=WF_LOCK_SLEEPER to indicate
++ * the nature of the wakeup.
++ */
++int wake_up_lock_sleeper(struct task_struct *p)
++{
++	return try_to_wake_up(p, TASK_UNINTERRUPTIBLE, WF_LOCK_SLEEPER);
++}
++
+ int wake_up_state(struct task_struct *p, unsigned int state)
+ {
+ 	return try_to_wake_up(p, state, 0);
+diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
+index c26b1c7009f4..d4bfc51358d3 100644
+--- a/kernel/sched/sched.h
++++ b/kernel/sched/sched.h
+@@ -1753,6 +1753,7 @@ static inline int task_on_rq_migrating(struct task_struct *p)
+ #define WF_FORK			0x02		/* Child wakeup after fork */
+ #define WF_MIGRATED		0x04		/* Internal use, task got migrated */
+ #define WF_ON_CPU		0x08		/* Wakee is on_cpu */
++#define WF_LOCK_SLEEPER		0x10		/* Wakeup spinlock "sleeper" */
+ 
+ /*
+  * To aid in avoiding the subversion of "niceness" due to uneven distribution
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0170-locking-rtmutex-add-sleeping-lock-implementation.patch b/debian/patches-rt/0170-locking-rtmutex-add-sleeping-lock-implementation.patch
new file mode 100644
index 000000000..e8755a734
--- /dev/null
+++ b/debian/patches-rt/0170-locking-rtmutex-add-sleeping-lock-implementation.patch
@@ -0,0 +1,1214 @@
+From 4c85c347eeb7dae59269d3a4a07388a00de563bf Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 12 Oct 2017 17:11:19 +0200
+Subject: [PATCH 170/323] locking/rtmutex: add sleeping lock implementation
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ include/linux/kernel.h            |   5 +
+ include/linux/preempt.h           |   4 +
+ include/linux/rtmutex.h           |  19 +-
+ include/linux/sched.h             |   7 +
+ include/linux/sched/wake_q.h      |  13 +-
+ include/linux/spinlock_rt.h       | 155 +++++++++++
+ include/linux/spinlock_types_rt.h |  38 +++
+ kernel/futex/core.c               |  10 +-
+ kernel/locking/rtmutex.c          | 444 +++++++++++++++++++++++++++---
+ kernel/locking/rtmutex_common.h   |  14 +-
+ kernel/sched/core.c               |  39 ++-
+ 11 files changed, 693 insertions(+), 55 deletions(-)
+ create mode 100644 include/linux/spinlock_rt.h
+ create mode 100644 include/linux/spinlock_types_rt.h
+
+diff --git a/include/linux/kernel.h b/include/linux/kernel.h
+index 55d48d5627c7..7b4fdd5b2f7b 100644
+--- a/include/linux/kernel.h
++++ b/include/linux/kernel.h
+@@ -223,6 +223,10 @@ extern void __cant_migrate(const char *file, int line);
+  */
+ # define might_sleep() \
+ 	do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
++
++# define might_sleep_no_state_check() \
++	do { ___might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
++
+ /**
+  * cant_sleep - annotation for functions that cannot sleep
+  *
+@@ -266,6 +270,7 @@ extern void __cant_migrate(const char *file, int line);
+   static inline void __might_sleep(const char *file, int line,
+ 				   int preempt_offset) { }
+ # define might_sleep() do { might_resched(); } while (0)
++# define might_sleep_no_state_check() do { might_resched(); } while (0)
+ # define cant_sleep() do { } while (0)
+ # define cant_migrate()		do { } while (0)
+ # define sched_annotate_sleep() do { } while (0)
+diff --git a/include/linux/preempt.h b/include/linux/preempt.h
+index 9881eac0698f..4d244e295e85 100644
+--- a/include/linux/preempt.h
++++ b/include/linux/preempt.h
+@@ -121,7 +121,11 @@
+ /*
+  * The preempt_count offset after spin_lock()
+  */
++#if !defined(CONFIG_PREEMPT_RT)
+ #define PREEMPT_LOCK_OFFSET	PREEMPT_DISABLE_OFFSET
++#else
++#define PREEMPT_LOCK_OFFSET	0
++#endif
+ 
+ /*
+  * The preempt_count offset needed for things like:
+diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
+index b828b938c876..b02009f53026 100644
+--- a/include/linux/rtmutex.h
++++ b/include/linux/rtmutex.h
+@@ -19,6 +19,10 @@
+ 
+ extern int max_lock_depth; /* for sysctl */
+ 
++#ifdef CONFIG_DEBUG_MUTEXES
++#include <linux/debug_locks.h>
++#endif
++
+ /**
+  * The rt_mutex structure
+  *
+@@ -31,6 +35,7 @@ struct rt_mutex {
+ 	raw_spinlock_t		wait_lock;
+ 	struct rb_root_cached   waiters;
+ 	struct task_struct	*owner;
++	int			save_state;
+ #ifdef CONFIG_DEBUG_LOCK_ALLOC
+ 	struct lockdep_map	dep_map;
+ #endif
+@@ -67,11 +72,19 @@ do { \
+ #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)
+ #endif
+ 
+-#define __RT_MUTEX_INITIALIZER(mutexname) \
+-	{ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
++#define __RT_MUTEX_INITIALIZER_PLAIN(mutexname) \
++	  .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
+ 	, .waiters = RB_ROOT_CACHED \
+ 	, .owner = NULL \
+-	__DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)}
++	__DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)
++
++#define __RT_MUTEX_INITIALIZER(mutexname) \
++	{ __RT_MUTEX_INITIALIZER_PLAIN(mutexname) \
++	, .save_state = 0 }
++
++#define __RT_MUTEX_INITIALIZER_SAVE_STATE(mutexname) \
++	{ __RT_MUTEX_INITIALIZER_PLAIN(mutexname)    \
++	, .save_state = 1 }
+ 
+ #define DEFINE_RT_MUTEX(mutexname) \
+ 	struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index 73defe42fd23..3650fdaac4ca 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -141,6 +141,9 @@ struct io_uring_task;
+ 		smp_store_mb(current->state, (state_value));	\
+ 	} while (0)
+ 
++#define __set_current_state_no_track(state_value)		\
++	current->state = (state_value);
++
+ #define set_special_state(state_value)					\
+ 	do {								\
+ 		unsigned long flags; /* may shadow */			\
+@@ -194,6 +197,9 @@ struct io_uring_task;
+ #define set_current_state(state_value)					\
+ 	smp_store_mb(current->state, (state_value))
+ 
++#define __set_current_state_no_track(state_value)	\
++	__set_current_state(state_value)
++
+ /*
+  * set_special_state() should be used for those states when the blocking task
+  * can not use the regular condition based wait-loop. In that case we must
+@@ -1021,6 +1027,7 @@ struct task_struct {
+ 	raw_spinlock_t			pi_lock;
+ 
+ 	struct wake_q_node		wake_q;
++	struct wake_q_node		wake_q_sleeper;
+ 
+ #ifdef CONFIG_RT_MUTEXES
+ 	/* PI waiters blocked on a rt_mutex held by this task: */
+diff --git a/include/linux/sched/wake_q.h b/include/linux/sched/wake_q.h
+index 26a2013ac39c..6e2dff721547 100644
+--- a/include/linux/sched/wake_q.h
++++ b/include/linux/sched/wake_q.h
+@@ -58,6 +58,17 @@ static inline bool wake_q_empty(struct wake_q_head *head)
+ 
+ extern void wake_q_add(struct wake_q_head *head, struct task_struct *task);
+ extern void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task);
+-extern void wake_up_q(struct wake_q_head *head);
++extern void wake_q_add_sleeper(struct wake_q_head *head, struct task_struct *task);
++extern void __wake_up_q(struct wake_q_head *head, bool sleeper);
++
++static inline void wake_up_q(struct wake_q_head *head)
++{
++	__wake_up_q(head, false);
++}
++
++static inline void wake_up_q_sleeper(struct wake_q_head *head)
++{
++	__wake_up_q(head, true);
++}
+ 
+ #endif /* _LINUX_SCHED_WAKE_Q_H */
+diff --git a/include/linux/spinlock_rt.h b/include/linux/spinlock_rt.h
+new file mode 100644
+index 000000000000..3085132eae38
+--- /dev/null
++++ b/include/linux/spinlock_rt.h
+@@ -0,0 +1,155 @@
++// SPDX-License-Identifier: GPL-2.0-only
++#ifndef __LINUX_SPINLOCK_RT_H
++#define __LINUX_SPINLOCK_RT_H
++
++#ifndef __LINUX_SPINLOCK_H
++#error Do not include directly. Use spinlock.h
++#endif
++
++#include <linux/bug.h>
++
++extern void
++__rt_spin_lock_init(spinlock_t *lock, const char *name, struct lock_class_key *key);
++
++#define spin_lock_init(slock)				\
++do {							\
++	static struct lock_class_key __key;		\
++							\
++	rt_mutex_init(&(slock)->lock);			\
++	__rt_spin_lock_init(slock, #slock, &__key);	\
++} while (0)
++
++extern void __lockfunc rt_spin_lock(spinlock_t *lock);
++extern void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass);
++extern void __lockfunc rt_spin_lock_nest_lock(spinlock_t *lock, struct lockdep_map *nest_lock);
++extern void __lockfunc rt_spin_unlock(spinlock_t *lock);
++extern void __lockfunc rt_spin_lock_unlock(spinlock_t *lock);
++extern int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags);
++extern int __lockfunc rt_spin_trylock_bh(spinlock_t *lock);
++extern int __lockfunc rt_spin_trylock(spinlock_t *lock);
++extern int atomic_dec_and_spin_lock(atomic_t *atomic, spinlock_t *lock);
++
++/*
++ * lockdep-less calls, for derived types like rwlock:
++ * (for trylock they can use rt_mutex_trylock() directly.
++ * Migrate disable handling must be done at the call site.
++ */
++extern void __lockfunc __rt_spin_lock(struct rt_mutex *lock);
++extern void __lockfunc __rt_spin_trylock(struct rt_mutex *lock);
++extern void __lockfunc __rt_spin_unlock(struct rt_mutex *lock);
++
++#define spin_lock(lock)			rt_spin_lock(lock)
++
++#define spin_lock_bh(lock)			\
++	do {					\
++		local_bh_disable();		\
++		rt_spin_lock(lock);		\
++	} while (0)
++
++#define spin_lock_irq(lock)		spin_lock(lock)
++
++#define spin_do_trylock(lock)		__cond_lock(lock, rt_spin_trylock(lock))
++
++#define spin_trylock(lock)			\
++({						\
++	int __locked;				\
++	__locked = spin_do_trylock(lock);	\
++	__locked;				\
++})
++
++#ifdef CONFIG_LOCKDEP
++# define spin_lock_nested(lock, subclass)		\
++	do {						\
++		rt_spin_lock_nested(lock, subclass);	\
++	} while (0)
++
++#define spin_lock_bh_nested(lock, subclass)		\
++	do {						\
++		local_bh_disable();			\
++		rt_spin_lock_nested(lock, subclass);	\
++	} while (0)
++
++# define spin_lock_nest_lock(lock, subclass)		\
++	do {                                                           \
++		typecheck(struct lockdep_map *, &(subclass)->dep_map);	\
++		rt_spin_lock_nest_lock(lock, &(subclass)->dep_map);	\
++	} while (0)
++
++# define spin_lock_irqsave_nested(lock, flags, subclass) \
++	do {						 \
++		typecheck(unsigned long, flags);	 \
++		flags = 0;				 \
++		rt_spin_lock_nested(lock, subclass);	 \
++	} while (0)
++#else
++# define spin_lock_nested(lock, subclass)	spin_lock(((void)(subclass), (lock)))
++# define spin_lock_nest_lock(lock, subclass)	spin_lock(((void)(subclass), (lock)))
++# define spin_lock_bh_nested(lock, subclass)	spin_lock_bh(((void)(subclass), (lock)))
++
++# define spin_lock_irqsave_nested(lock, flags, subclass) \
++	do {						 \
++		typecheck(unsigned long, flags);	 \
++		flags = 0;				 \
++		spin_lock(((void)(subclass), (lock)));	 \
++	} while (0)
++#endif
++
++#define spin_lock_irqsave(lock, flags)			 \
++	do {						 \
++		typecheck(unsigned long, flags);	 \
++		flags = 0;				 \
++		spin_lock(lock);			 \
++	} while (0)
++
++#define spin_unlock(lock)			rt_spin_unlock(lock)
++
++#define spin_unlock_bh(lock)				\
++	do {						\
++		rt_spin_unlock(lock);			\
++		local_bh_enable();			\
++	} while (0)
++
++#define spin_unlock_irq(lock)		spin_unlock(lock)
++
++#define spin_unlock_irqrestore(lock, flags)		\
++	do {						\
++		typecheck(unsigned long, flags);	\
++		(void) flags;				\
++		spin_unlock(lock);			\
++	} while (0)
++
++#define spin_trylock_bh(lock)	__cond_lock(lock, rt_spin_trylock_bh(lock))
++#define spin_trylock_irq(lock)	spin_trylock(lock)
++
++#define spin_trylock_irqsave(lock, flags)		\
++({							\
++	int __locked;					\
++							\
++	typecheck(unsigned long, flags);		\
++	flags = 0;					\
++	__locked = spin_trylock(lock);			\
++	__locked;					\
++})
++
++#ifdef CONFIG_GENERIC_LOCKBREAK
++# define spin_is_contended(lock)	((lock)->break_lock)
++#else
++# define spin_is_contended(lock)	(((void)(lock), 0))
++#endif
++
++static inline int spin_can_lock(spinlock_t *lock)
++{
++	return !rt_mutex_is_locked(&lock->lock);
++}
++
++static inline int spin_is_locked(spinlock_t *lock)
++{
++	return rt_mutex_is_locked(&lock->lock);
++}
++
++static inline void assert_spin_locked(spinlock_t *lock)
++{
++	BUG_ON(!spin_is_locked(lock));
++}
++
++#endif
+diff --git a/include/linux/spinlock_types_rt.h b/include/linux/spinlock_types_rt.h
+new file mode 100644
+index 000000000000..446da786e5d5
+--- /dev/null
++++ b/include/linux/spinlock_types_rt.h
+@@ -0,0 +1,38 @@
++// SPDX-License-Identifier: GPL-2.0-only
++#ifndef __LINUX_SPINLOCK_TYPES_RT_H
++#define __LINUX_SPINLOCK_TYPES_RT_H
++
++#ifndef __LINUX_SPINLOCK_TYPES_H
++#error "Do not include directly. Include spinlock_types.h instead"
++#endif
++
++#include <linux/cache.h>
++
++/*
++ * PREEMPT_RT: spinlocks - an RT mutex plus lock-break field:
++ */
++typedef struct spinlock {
++	struct rt_mutex		lock;
++	unsigned int		break_lock;
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	struct lockdep_map	dep_map;
++#endif
++} spinlock_t;
++
++#define __RT_SPIN_INITIALIZER(name) \
++	{ \
++	.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock), \
++	.save_state = 1, \
++	}
++/*
++.wait_list = PLIST_HEAD_INIT_RAW((name).lock.wait_list, (name).lock.wait_lock)
++*/
++
++#define __SPIN_LOCK_UNLOCKED(name)			\
++	{ .lock = __RT_SPIN_INITIALIZER(name.lock),		\
++	  SPIN_DEP_MAP_INIT(name) }
++
++#define DEFINE_SPINLOCK(name) \
++	spinlock_t name = __SPIN_LOCK_UNLOCKED(name)
++
++#endif
+diff --git a/kernel/futex/core.c b/kernel/futex/core.c
+index 706cd446ec71..909dcd708a52 100644
+--- a/kernel/futex/core.c
++++ b/kernel/futex/core.c
+@@ -1508,6 +1508,7 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_
+ 	struct task_struct *new_owner;
+ 	bool postunlock = false;
+ 	DEFINE_WAKE_Q(wake_q);
++	DEFINE_WAKE_Q(wake_sleeper_q);
+ 	int ret = 0;
+ 
+ 	new_owner = rt_mutex_next_owner(&pi_state->pi_mutex);
+@@ -1557,14 +1558,15 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_
+ 		 * not fail.
+ 		 */
+ 		pi_state_update_owner(pi_state, new_owner);
+-		postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
++		postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q,
++						     &wake_sleeper_q);
+ 	}
+ 
+ out_unlock:
+ 	raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
+ 
+ 	if (postunlock)
+-		rt_mutex_postunlock(&wake_q);
++		rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
+ 
+ 	return ret;
+ }
+@@ -2867,7 +2869,7 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
+ 		goto no_block;
+ 	}
+ 
+-	rt_mutex_init_waiter(&rt_waiter);
++	rt_mutex_init_waiter(&rt_waiter, false);
+ 
+ 	/*
+ 	 * On PREEMPT_RT_FULL, when hb->lock becomes an rt_mutex, we must not
+@@ -3213,7 +3215,7 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
+ 	 * The waiter is allocated on our stack, manipulated by the requeue
+ 	 * code while we sleep on uaddr.
+ 	 */
+-	rt_mutex_init_waiter(&rt_waiter);
++	rt_mutex_init_waiter(&rt_waiter, false);
+ 
+ 	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, FUTEX_WRITE);
+ 	if (unlikely(ret != 0))
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index 40ae934c6caa..35cdbbb5daa9 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -8,6 +8,11 @@
+  *  Copyright (C) 2005-2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+  *  Copyright (C) 2005 Kihon Technologies Inc., Steven Rostedt
+  *  Copyright (C) 2006 Esben Nielsen
++ * Adaptive Spinlocks:
++ *  Copyright (C) 2008 Novell, Inc., Gregory Haskins, Sven Dietrich,
++ *				     and Peter Morreale,
++ * Adaptive Spinlocks simplification:
++ *  Copyright (C) 2008 Red Hat, Inc., Steven Rostedt <srostedt@redhat.com>
+  *
+  *  See Documentation/locking/rt-mutex-design.rst for details.
+  */
+@@ -233,7 +238,7 @@ static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
+  * Only use with rt_mutex_waiter_{less,equal}()
+  */
+ #define task_to_waiter(p)	\
+-	&(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = (p)->dl.deadline }
++	&(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = (p)->dl.deadline, .task = (p) }
+ 
+ static inline int
+ rt_mutex_waiter_less(struct rt_mutex_waiter *left,
+@@ -273,6 +278,27 @@ rt_mutex_waiter_equal(struct rt_mutex_waiter *left,
+ 	return 1;
+ }
+ 
++#define STEAL_NORMAL  0
++#define STEAL_LATERAL 1
++
++static inline int
++rt_mutex_steal(struct rt_mutex *lock, struct rt_mutex_waiter *waiter, int mode)
++{
++	struct rt_mutex_waiter *top_waiter = rt_mutex_top_waiter(lock);
++
++	if (waiter == top_waiter || rt_mutex_waiter_less(waiter, top_waiter))
++		return 1;
++
++	/*
++	 * Note that RT tasks are excluded from lateral-steals
++	 * to prevent the introduction of an unbounded latency.
++	 */
++	if (mode == STEAL_NORMAL || rt_task(waiter->task))
++		return 0;
++
++	return rt_mutex_waiter_equal(waiter, top_waiter);
++}
++
+ static void
+ rt_mutex_enqueue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter)
+ {
+@@ -377,6 +403,14 @@ static bool rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
+ 	return debug_rt_mutex_detect_deadlock(waiter, chwalk);
+ }
+ 
++static void rt_mutex_wake_waiter(struct rt_mutex_waiter *waiter)
++{
++	if (waiter->savestate)
++		wake_up_lock_sleeper(waiter->task);
++	else
++		wake_up_process(waiter->task);
++}
++
+ /*
+  * Max number of times we'll walk the boosting chain:
+  */
+@@ -700,13 +734,16 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
+ 	 * follow here. This is the end of the chain we are walking.
+ 	 */
+ 	if (!rt_mutex_owner(lock)) {
++		struct rt_mutex_waiter *lock_top_waiter;
++
+ 		/*
+ 		 * If the requeue [7] above changed the top waiter,
+ 		 * then we need to wake the new top waiter up to try
+ 		 * to get the lock.
+ 		 */
+-		if (prerequeue_top_waiter != rt_mutex_top_waiter(lock))
+-			wake_up_process(rt_mutex_top_waiter(lock)->task);
++		lock_top_waiter = rt_mutex_top_waiter(lock);
++		if (prerequeue_top_waiter != lock_top_waiter)
++			rt_mutex_wake_waiter(lock_top_waiter);
+ 		raw_spin_unlock_irq(&lock->wait_lock);
+ 		return 0;
+ 	}
+@@ -807,9 +844,11 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
+  * @task:   The task which wants to acquire the lock
+  * @waiter: The waiter that is queued to the lock's wait tree if the
+  *	    callsite called task_blocked_on_lock(), otherwise NULL
++ * @mode:   Lock steal mode (STEAL_NORMAL, STEAL_LATERAL)
+  */
+-static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+-				struct rt_mutex_waiter *waiter)
++static int __try_to_take_rt_mutex(struct rt_mutex *lock,
++				  struct task_struct *task,
++				  struct rt_mutex_waiter *waiter, int mode)
+ {
+ 	lockdep_assert_held(&lock->wait_lock);
+ 
+@@ -845,12 +884,11 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+ 	 */
+ 	if (waiter) {
+ 		/*
+-		 * If waiter is not the highest priority waiter of
+-		 * @lock, give up.
++		 * If waiter is not the highest priority waiter of @lock,
++		 * or its peer when lateral steal is allowed, give up.
+ 		 */
+-		if (waiter != rt_mutex_top_waiter(lock))
++		if (!rt_mutex_steal(lock, waiter, mode))
+ 			return 0;
+-
+ 		/*
+ 		 * We can acquire the lock. Remove the waiter from the
+ 		 * lock waiters tree.
+@@ -868,14 +906,12 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+ 		 */
+ 		if (rt_mutex_has_waiters(lock)) {
+ 			/*
+-			 * If @task->prio is greater than or equal to
+-			 * the top waiter priority (kernel view),
+-			 * @task lost.
++			 * If @task->prio is greater than the top waiter
++			 * priority (kernel view), or equal to it when a
++			 * lateral steal is forbidden, @task lost.
+ 			 */
+-			if (!rt_mutex_waiter_less(task_to_waiter(task),
+-						  rt_mutex_top_waiter(lock)))
++			if (!rt_mutex_steal(lock, task_to_waiter(task), mode))
+ 				return 0;
+-
+ 			/*
+ 			 * The current top waiter stays enqueued. We
+ 			 * don't have to change anything in the lock
+@@ -922,6 +958,289 @@ static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+ 	return 1;
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT
++/*
++ * preemptible spin_lock functions:
++ */
++static inline void rt_spin_lock_fastlock(struct rt_mutex *lock,
++					 void  (*slowfn)(struct rt_mutex *lock))
++{
++	might_sleep_no_state_check();
++
++	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
++		return;
++	else
++		slowfn(lock);
++}
++
++static inline void rt_spin_lock_fastunlock(struct rt_mutex *lock,
++					   void  (*slowfn)(struct rt_mutex *lock))
++{
++	if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
++		return;
++	else
++		slowfn(lock);
++}
++#ifdef CONFIG_SMP
++/*
++ * Note that owner is a speculative pointer and dereferencing relies
++ * on rcu_read_lock() and the check against the lock owner.
++ */
++static int adaptive_wait(struct rt_mutex *lock,
++			 struct task_struct *owner)
++{
++	int res = 0;
++
++	rcu_read_lock();
++	for (;;) {
++		if (owner != rt_mutex_owner(lock))
++			break;
++		/*
++		 * Ensure that owner->on_cpu is dereferenced _after_
++		 * checking the above to be valid.
++		 */
++		barrier();
++		if (!owner->on_cpu) {
++			res = 1;
++			break;
++		}
++		cpu_relax();
++	}
++	rcu_read_unlock();
++	return res;
++}
++#else
++static int adaptive_wait(struct rt_mutex *lock,
++			 struct task_struct *orig_owner)
++{
++	return 1;
++}
++#endif
++
++static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
++				   struct rt_mutex_waiter *waiter,
++				   struct task_struct *task,
++				   enum rtmutex_chainwalk chwalk);
++/*
++ * Slow path lock function spin_lock style: this variant is very
++ * careful not to miss any non-lock wakeups.
++ *
++ * We store the current state under p->pi_lock in p->saved_state and
++ * the try_to_wake_up() code handles this accordingly.
++ */
++void __sched rt_spin_lock_slowlock_locked(struct rt_mutex *lock,
++					  struct rt_mutex_waiter *waiter,
++					  unsigned long flags)
++{
++	struct task_struct *lock_owner, *self = current;
++	struct rt_mutex_waiter *top_waiter;
++	int ret;
++
++	if (__try_to_take_rt_mutex(lock, self, NULL, STEAL_LATERAL))
++		return;
++
++	BUG_ON(rt_mutex_owner(lock) == self);
++
++	/*
++	 * We save whatever state the task is in and we'll restore it
++	 * after acquiring the lock taking real wakeups into account
++	 * as well. We are serialized via pi_lock against wakeups. See
++	 * try_to_wake_up().
++	 */
++	raw_spin_lock(&self->pi_lock);
++	self->saved_state = self->state;
++	__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
++	raw_spin_unlock(&self->pi_lock);
++
++	ret = task_blocks_on_rt_mutex(lock, waiter, self, RT_MUTEX_MIN_CHAINWALK);
++	BUG_ON(ret);
++
++	for (;;) {
++		/* Try to acquire the lock again. */
++		if (__try_to_take_rt_mutex(lock, self, waiter, STEAL_LATERAL))
++			break;
++
++		top_waiter = rt_mutex_top_waiter(lock);
++		lock_owner = rt_mutex_owner(lock);
++
++		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
++
++		if (top_waiter != waiter || adaptive_wait(lock, lock_owner))
++			schedule();
++
++		raw_spin_lock_irqsave(&lock->wait_lock, flags);
++
++		raw_spin_lock(&self->pi_lock);
++		__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
++		raw_spin_unlock(&self->pi_lock);
++	}
++
++	/*
++	 * Restore the task state to current->saved_state. We set it
++	 * to the original state above and the try_to_wake_up() code
++	 * has possibly updated it when a real (non-rtmutex) wakeup
++	 * happened while we were blocked. Clear saved_state so
++	 * try_to_wakeup() does not get confused.
++	 */
++	raw_spin_lock(&self->pi_lock);
++	__set_current_state_no_track(self->saved_state);
++	self->saved_state = TASK_RUNNING;
++	raw_spin_unlock(&self->pi_lock);
++
++	/*
++	 * try_to_take_rt_mutex() sets the waiter bit
++	 * unconditionally. We might have to fix that up:
++	 */
++	fixup_rt_mutex_waiters(lock);
++
++	BUG_ON(rt_mutex_has_waiters(lock) && waiter == rt_mutex_top_waiter(lock));
++	BUG_ON(!RB_EMPTY_NODE(&waiter->tree_entry));
++}
++
++static void noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
++{
++	struct rt_mutex_waiter waiter;
++	unsigned long flags;
++
++	rt_mutex_init_waiter(&waiter, true);
++
++	raw_spin_lock_irqsave(&lock->wait_lock, flags);
++	rt_spin_lock_slowlock_locked(lock, &waiter, flags);
++	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
++	debug_rt_mutex_free_waiter(&waiter);
++}
++
++static bool __sched __rt_mutex_unlock_common(struct rt_mutex *lock,
++					     struct wake_q_head *wake_q,
++					     struct wake_q_head *wq_sleeper);
++/*
++ * Slow path to release a rt_mutex spin_lock style
++ */
++void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
++{
++	unsigned long flags;
++	DEFINE_WAKE_Q(wake_q);
++	DEFINE_WAKE_Q(wake_sleeper_q);
++	bool postunlock;
++
++	raw_spin_lock_irqsave(&lock->wait_lock, flags);
++	postunlock = __rt_mutex_unlock_common(lock, &wake_q, &wake_sleeper_q);
++	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
++
++	if (postunlock)
++		rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
++}
++
++void __lockfunc rt_spin_lock(spinlock_t *lock)
++{
++	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
++	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
++	migrate_disable();
++}
++EXPORT_SYMBOL(rt_spin_lock);
++
++void __lockfunc __rt_spin_lock(struct rt_mutex *lock)
++{
++	rt_spin_lock_fastlock(lock, rt_spin_lock_slowlock);
++}
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass)
++{
++	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
++	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
++	migrate_disable();
++}
++EXPORT_SYMBOL(rt_spin_lock_nested);
++
++void __lockfunc rt_spin_lock_nest_lock(spinlock_t *lock,
++				       struct lockdep_map *nest_lock)
++{
++	spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
++	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
++	migrate_disable();
++}
++EXPORT_SYMBOL(rt_spin_lock_nest_lock);
++#endif
++
++void __lockfunc rt_spin_unlock(spinlock_t *lock)
++{
++	/* NOTE: we always pass in '1' for nested, for simplicity */
++	spin_release(&lock->dep_map, _RET_IP_);
++	migrate_enable();
++	rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock);
++}
++EXPORT_SYMBOL(rt_spin_unlock);
++
++void __lockfunc __rt_spin_unlock(struct rt_mutex *lock)
++{
++	rt_spin_lock_fastunlock(lock, rt_spin_lock_slowunlock);
++}
++EXPORT_SYMBOL(__rt_spin_unlock);
++
++/*
++ * Wait for the lock to get unlocked: instead of polling for an unlock
++ * (like raw spinlocks do), we lock and unlock, to force the kernel to
++ * schedule if there's contention:
++ */
++void __lockfunc rt_spin_lock_unlock(spinlock_t *lock)
++{
++	spin_lock(lock);
++	spin_unlock(lock);
++}
++EXPORT_SYMBOL(rt_spin_lock_unlock);
++
++int __lockfunc rt_spin_trylock(spinlock_t *lock)
++{
++	int ret;
++
++	ret = __rt_mutex_trylock(&lock->lock);
++	if (ret) {
++		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
++		migrate_disable();
++	}
++	return ret;
++}
++EXPORT_SYMBOL(rt_spin_trylock);
++
++int __lockfunc rt_spin_trylock_bh(spinlock_t *lock)
++{
++	int ret;
++
++	local_bh_disable();
++	ret = __rt_mutex_trylock(&lock->lock);
++	if (ret) {
++		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
++		migrate_disable();
++	} else {
++		local_bh_enable();
++	}
++	return ret;
++}
++EXPORT_SYMBOL(rt_spin_trylock_bh);
++
++void
++__rt_spin_lock_init(spinlock_t *lock, const char *name, struct lock_class_key *key)
++{
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	/*
++	 * Make sure we are not reinitializing a held lock:
++	 */
++	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
++	lockdep_init_map(&lock->dep_map, name, key, 0);
++#endif
++}
++EXPORT_SYMBOL(__rt_spin_lock_init);
++
++#endif /* PREEMPT_RT */
++
++static inline int
++try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
++		     struct rt_mutex_waiter *waiter)
++{
++	return __try_to_take_rt_mutex(lock, task, waiter, STEAL_NORMAL);
++}
++
+ /*
+  * Task blocks on lock.
+  *
+@@ -1035,6 +1354,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
+  * Called with lock->wait_lock held and interrupts disabled.
+  */
+ static void mark_wakeup_next_waiter(struct wake_q_head *wake_q,
++				    struct wake_q_head *wake_sleeper_q,
+ 				    struct rt_mutex *lock)
+ {
+ 	struct rt_mutex_waiter *waiter;
+@@ -1074,7 +1394,10 @@ static void mark_wakeup_next_waiter(struct wake_q_head *wake_q,
+ 	 * Pairs with preempt_enable() in rt_mutex_postunlock();
+ 	 */
+ 	preempt_disable();
+-	wake_q_add(wake_q, waiter->task);
++	if (waiter->savestate)
++		wake_q_add_sleeper(wake_sleeper_q, waiter->task);
++	else
++		wake_q_add(wake_q, waiter->task);
+ 	raw_spin_unlock(&current->pi_lock);
+ }
+ 
+@@ -1158,21 +1481,22 @@ void rt_mutex_adjust_pi(struct task_struct *task)
+ 		return;
+ 	}
+ 	next_lock = waiter->lock;
+-	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ 
+ 	/* gets dropped in rt_mutex_adjust_prio_chain()! */
+ 	get_task_struct(task);
+ 
++	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ 	rt_mutex_adjust_prio_chain(task, RT_MUTEX_MIN_CHAINWALK, NULL,
+ 				   next_lock, NULL, task);
+ }
+ 
+-void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
++void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter, bool savestate)
+ {
+ 	debug_rt_mutex_init_waiter(waiter);
+ 	RB_CLEAR_NODE(&waiter->pi_tree_entry);
+ 	RB_CLEAR_NODE(&waiter->tree_entry);
+ 	waiter->task = NULL;
++	waiter->savestate = savestate;
+ }
+ 
+ /**
+@@ -1283,7 +1607,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ 	unsigned long flags;
+ 	int ret = 0;
+ 
+-	rt_mutex_init_waiter(&waiter);
++	rt_mutex_init_waiter(&waiter, false);
+ 
+ 	/*
+ 	 * Technically we could use raw_spin_[un]lock_irq() here, but this can
+@@ -1356,7 +1680,8 @@ static inline int rt_mutex_slowtrylock(struct rt_mutex *lock)
+  * Return whether the current task needs to call rt_mutex_postunlock().
+  */
+ static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
+-					struct wake_q_head *wake_q)
++					struct wake_q_head *wake_q,
++					struct wake_q_head *wake_sleeper_q)
+ {
+ 	unsigned long flags;
+ 
+@@ -1410,7 +1735,7 @@ static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
+ 	 *
+ 	 * Queue the next waiter for wakeup once we release the wait_lock.
+ 	 */
+-	mark_wakeup_next_waiter(wake_q, lock);
++	mark_wakeup_next_waiter(wake_q, wake_sleeper_q, lock);
+ 	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+ 
+ 	return true; /* call rt_mutex_postunlock() */
+@@ -1447,9 +1772,11 @@ rt_mutex_fasttrylock(struct rt_mutex *lock,
+ /*
+  * Performs the wakeup of the top-waiter and re-enables preemption.
+  */
+-void rt_mutex_postunlock(struct wake_q_head *wake_q)
++void rt_mutex_postunlock(struct wake_q_head *wake_q,
++			 struct wake_q_head *wake_sleeper_q)
+ {
+ 	wake_up_q(wake_q);
++	wake_up_q_sleeper(wake_sleeper_q);
+ 
+ 	/* Pairs with preempt_disable() in rt_mutex_slowunlock() */
+ 	preempt_enable();
+@@ -1458,15 +1785,17 @@ void rt_mutex_postunlock(struct wake_q_head *wake_q)
+ static inline void
+ rt_mutex_fastunlock(struct rt_mutex *lock,
+ 		    bool (*slowfn)(struct rt_mutex *lock,
+-				   struct wake_q_head *wqh))
++				   struct wake_q_head *wqh,
++				   struct wake_q_head *wq_sleeper))
+ {
+ 	DEFINE_WAKE_Q(wake_q);
++	DEFINE_WAKE_Q(wake_sleeper_q);
+ 
+ 	if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
+ 		return;
+ 
+-	if (slowfn(lock, &wake_q))
+-		rt_mutex_postunlock(&wake_q);
++	if (slowfn(lock, &wake_q, &wake_sleeper_q))
++		rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
+ }
+ 
+ int __sched __rt_mutex_lock_state(struct rt_mutex *lock, int state)
+@@ -1597,16 +1926,13 @@ void __sched __rt_mutex_unlock(struct rt_mutex *lock)
+ void __sched rt_mutex_unlock(struct rt_mutex *lock)
+ {
+ 	mutex_release(&lock->dep_map, _RET_IP_);
+-	rt_mutex_fastunlock(lock, rt_mutex_slowunlock);
++	__rt_mutex_unlock(lock);
+ }
+ EXPORT_SYMBOL_GPL(rt_mutex_unlock);
+ 
+-/**
+- * Futex variant, that since futex variants do not use the fast-path, can be
+- * simple and will not need to retry.
+- */
+-bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
+-				    struct wake_q_head *wake_q)
++static bool __sched __rt_mutex_unlock_common(struct rt_mutex *lock,
++					     struct wake_q_head *wake_q,
++					     struct wake_q_head *wq_sleeper)
+ {
+ 	lockdep_assert_held(&lock->wait_lock);
+ 
+@@ -1623,23 +1949,35 @@ bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
+ 	 * avoid inversion prior to the wakeup.  preempt_disable()
+ 	 * therein pairs with rt_mutex_postunlock().
+ 	 */
+-	mark_wakeup_next_waiter(wake_q, lock);
++	mark_wakeup_next_waiter(wake_q, wq_sleeper, lock);
+ 
+ 	return true; /* call postunlock() */
+ }
+ 
++/**
++ * Futex variant, that since futex variants do not use the fast-path, can be
++ * simple and will not need to retry.
++ */
++bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
++				     struct wake_q_head *wake_q,
++				     struct wake_q_head *wq_sleeper)
++{
++	return __rt_mutex_unlock_common(lock, wake_q, wq_sleeper);
++}
++
+ void __sched rt_mutex_futex_unlock(struct rt_mutex *lock)
+ {
+ 	DEFINE_WAKE_Q(wake_q);
++	DEFINE_WAKE_Q(wake_sleeper_q);
+ 	unsigned long flags;
+ 	bool postunlock;
+ 
+ 	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+-	postunlock = __rt_mutex_futex_unlock(lock, &wake_q);
++	postunlock = __rt_mutex_futex_unlock(lock, &wake_q, &wake_sleeper_q);
+ 	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+ 
+ 	if (postunlock)
+-		rt_mutex_postunlock(&wake_q);
++		rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
+ }
+ 
+ /**
+@@ -1675,7 +2013,7 @@ void __rt_mutex_init(struct rt_mutex *lock, const char *name,
+ 	if (name && key)
+ 		debug_rt_mutex_init(lock, name, key);
+ }
+-EXPORT_SYMBOL_GPL(__rt_mutex_init);
++EXPORT_SYMBOL(__rt_mutex_init);
+ 
+ /**
+  * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
+@@ -1695,6 +2033,14 @@ void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
+ 				struct task_struct *proxy_owner)
+ {
+ 	__rt_mutex_init(lock, NULL, NULL);
++#ifdef CONFIG_DEBUG_SPINLOCK
++	/*
++	 * get another key class for the wait_lock. LOCK_PI and UNLOCK_PI is
++	 * holding the ->wait_lock of the proxy_lock while unlocking a sleeping
++	 * lock.
++	 */
++	raw_spin_lock_init(&lock->wait_lock);
++#endif
+ 	debug_rt_mutex_proxy_lock(lock, proxy_owner);
+ 	rt_mutex_set_owner(lock, proxy_owner);
+ }
+@@ -1717,6 +2063,26 @@ void rt_mutex_proxy_unlock(struct rt_mutex *lock)
+ 	rt_mutex_set_owner(lock, NULL);
+ }
+ 
++static void fixup_rt_mutex_blocked(struct rt_mutex *lock)
++{
++	struct task_struct *tsk = current;
++	/*
++	 * RT has a problem here when the wait got interrupted by a timeout
++	 * or a signal. task->pi_blocked_on is still set. The task must
++	 * acquire the hash bucket lock when returning from this function.
++	 *
++	 * If the hash bucket lock is contended then the
++	 * BUG_ON(rt_mutex_real_waiter(task->pi_blocked_on)) in
++	 * task_blocks_on_rt_mutex() will trigger. This can be avoided by
++	 * clearing task->pi_blocked_on which removes the task from the
++	 * boosting chain of the rtmutex. That's correct because the task
++	 * is not longer blocked on it.
++	 */
++	raw_spin_lock(&tsk->pi_lock);
++	tsk->pi_blocked_on = NULL;
++	raw_spin_unlock(&tsk->pi_lock);
++}
++
+ /**
+  * __rt_mutex_start_proxy_lock() - Start lock acquisition for another task
+  * @lock:		the rt_mutex to take
+@@ -1789,6 +2155,9 @@ int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
+ 		ret = 0;
+ 	}
+ 
++	if (ret)
++		fixup_rt_mutex_blocked(lock);
++
+ 	return ret;
+ }
+ 
+@@ -1878,6 +2247,9 @@ int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
+ 	 * have to fix that up.
+ 	 */
+ 	fixup_rt_mutex_waiters(lock);
++	if (ret)
++		fixup_rt_mutex_blocked(lock);
++
+ 	raw_spin_unlock_irq(&lock->wait_lock);
+ 
+ 	return ret;
+diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
+index 9d1e974ca9c3..c1a280167e3c 100644
+--- a/kernel/locking/rtmutex_common.h
++++ b/kernel/locking/rtmutex_common.h
+@@ -31,6 +31,7 @@ struct rt_mutex_waiter {
+ 	struct task_struct	*task;
+ 	struct rt_mutex		*lock;
+ 	int prio;
++	bool			savestate;
+ 	u64 deadline;
+ };
+ 
+@@ -133,7 +134,7 @@ extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
+ extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
+ 				       struct task_struct *proxy_owner);
+ extern void rt_mutex_proxy_unlock(struct rt_mutex *lock);
+-extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
++extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter, bool savetate);
+ extern int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
+ 				     struct rt_mutex_waiter *waiter,
+ 				     struct task_struct *task);
+@@ -151,9 +152,12 @@ extern int __rt_mutex_futex_trylock(struct rt_mutex *l);
+ 
+ extern void rt_mutex_futex_unlock(struct rt_mutex *lock);
+ extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
+-				 struct wake_q_head *wqh);
++				 struct wake_q_head *wqh,
++				 struct wake_q_head *wq_sleeper);
++
++extern void rt_mutex_postunlock(struct wake_q_head *wake_q,
++				struct wake_q_head *wake_sleeper_q);
+ 
+-extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
+ /* RW semaphore special interface */
+ 
+ extern int __rt_mutex_lock_state(struct rt_mutex *lock, int state);
+@@ -163,6 +167,10 @@ int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+ 				     struct hrtimer_sleeper *timeout,
+ 				     enum rtmutex_chainwalk chwalk,
+ 				     struct rt_mutex_waiter *waiter);
++void __sched rt_spin_lock_slowlock_locked(struct rt_mutex *lock,
++					  struct rt_mutex_waiter *waiter,
++					  unsigned long flags);
++void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock);
+ 
+ #ifdef CONFIG_DEBUG_RT_MUTEXES
+ # include "rtmutex-debug.h"
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index f6d40256c0d4..be5d41ed6ff2 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -511,9 +511,15 @@ static bool set_nr_if_polling(struct task_struct *p)
+ #endif
+ #endif
+ 
+-static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task)
++static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task,
++			 bool sleeper)
+ {
+-	struct wake_q_node *node = &task->wake_q;
++	struct wake_q_node *node;
++
++	if (sleeper)
++		node = &task->wake_q_sleeper;
++	else
++		node = &task->wake_q;
+ 
+ 	/*
+ 	 * Atomically grab the task, if ->wake_q is !nil already it means
+@@ -549,7 +555,13 @@ static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task)
+  */
+ void wake_q_add(struct wake_q_head *head, struct task_struct *task)
+ {
+-	if (__wake_q_add(head, task))
++	if (__wake_q_add(head, task, false))
++		get_task_struct(task);
++}
++
++void wake_q_add_sleeper(struct wake_q_head *head, struct task_struct *task)
++{
++	if (__wake_q_add(head, task, true))
+ 		get_task_struct(task);
+ }
+ 
+@@ -572,28 +584,39 @@ void wake_q_add(struct wake_q_head *head, struct task_struct *task)
+  */
+ void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task)
+ {
+-	if (!__wake_q_add(head, task))
++	if (!__wake_q_add(head, task, false))
+ 		put_task_struct(task);
+ }
+ 
+-void wake_up_q(struct wake_q_head *head)
++void __wake_up_q(struct wake_q_head *head, bool sleeper)
+ {
+ 	struct wake_q_node *node = head->first;
+ 
+ 	while (node != WAKE_Q_TAIL) {
+ 		struct task_struct *task;
+ 
+-		task = container_of(node, struct task_struct, wake_q);
++		if (sleeper)
++			task = container_of(node, struct task_struct, wake_q_sleeper);
++		else
++			task = container_of(node, struct task_struct, wake_q);
++
+ 		BUG_ON(!task);
+ 		/* Task can safely be re-inserted now: */
+ 		node = node->next;
+-		task->wake_q.next = NULL;
+ 
++		if (sleeper)
++			task->wake_q_sleeper.next = NULL;
++		else
++			task->wake_q.next = NULL;
+ 		/*
+ 		 * wake_up_process() executes a full barrier, which pairs with
+ 		 * the queueing in wake_q_add() so as not to miss wakeups.
+ 		 */
+-		wake_up_process(task);
++		if (sleeper)
++			wake_up_lock_sleeper(task);
++		else
++			wake_up_process(task);
++
+ 		put_task_struct(task);
+ 	}
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0171-locking-rtmutex-Allow-rt_mutex_trylock-on-PREEMPT_RT.patch b/debian/patches-rt/0171-locking-rtmutex-Allow-rt_mutex_trylock-on-PREEMPT_RT.patch
new file mode 100644
index 000000000..4c2c1b803
--- /dev/null
+++ b/debian/patches-rt/0171-locking-rtmutex-Allow-rt_mutex_trylock-on-PREEMPT_RT.patch
@@ -0,0 +1,37 @@
+From bcc9f5e2b7eb56660512649787ab651fc138d9e4 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 2 Dec 2015 11:34:07 +0100
+Subject: [PATCH 171/323] locking/rtmutex: Allow rt_mutex_trylock() on
+ PREEMPT_RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Non PREEMPT_RT kernel can deadlock on rt_mutex_trylock() in softirq
+context.
+On PREEMPT_RT the softirq context is handled in thread context. This
+avoids the deadlock in the slow path and PI-boosting will be done on the
+correct thread.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/locking/rtmutex.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index 35cdbbb5daa9..1bf7a04688c5 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -1884,7 +1884,11 @@ int __sched __rt_mutex_futex_trylock(struct rt_mutex *lock)
+ 
+ int __sched __rt_mutex_trylock(struct rt_mutex *lock)
+ {
++#ifdef CONFIG_PREEMPT_RT
++	if (WARN_ON_ONCE(in_irq() || in_nmi()))
++#else
+ 	if (WARN_ON_ONCE(in_irq() || in_nmi() || in_serving_softirq()))
++#endif
+ 		return 0;
+ 
+ 	return rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0172-locking-rtmutex-add-mutex-implementation-based-on-rt.patch b/debian/patches-rt/0172-locking-rtmutex-add-mutex-implementation-based-on-rt.patch
new file mode 100644
index 000000000..655fd8534
--- /dev/null
+++ b/debian/patches-rt/0172-locking-rtmutex-add-mutex-implementation-based-on-rt.patch
@@ -0,0 +1,385 @@
+From c363a86a2fab38d43a50a8841e2b6d64b87ae69b Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 12 Oct 2017 17:17:03 +0200
+Subject: [PATCH 172/323] locking/rtmutex: add mutex implementation based on
+ rtmutex
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/mutex_rt.h  | 130 ++++++++++++++++++++++
+ kernel/locking/mutex-rt.c | 224 ++++++++++++++++++++++++++++++++++++++
+ 2 files changed, 354 insertions(+)
+ create mode 100644 include/linux/mutex_rt.h
+ create mode 100644 kernel/locking/mutex-rt.c
+
+diff --git a/include/linux/mutex_rt.h b/include/linux/mutex_rt.h
+new file mode 100644
+index 000000000000..f0b2e07cd5c5
+--- /dev/null
++++ b/include/linux/mutex_rt.h
+@@ -0,0 +1,130 @@
++// SPDX-License-Identifier: GPL-2.0-only
++#ifndef __LINUX_MUTEX_RT_H
++#define __LINUX_MUTEX_RT_H
++
++#ifndef __LINUX_MUTEX_H
++#error "Please include mutex.h"
++#endif
++
++#include <linux/rtmutex.h>
++
++/* FIXME: Just for __lockfunc */
++#include <linux/spinlock.h>
++
++struct mutex {
++	struct rt_mutex		lock;
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	struct lockdep_map	dep_map;
++#endif
++};
++
++#define __MUTEX_INITIALIZER(mutexname)					\
++	{								\
++		.lock = __RT_MUTEX_INITIALIZER(mutexname.lock)		\
++		__DEP_MAP_MUTEX_INITIALIZER(mutexname)			\
++	}
++
++#define DEFINE_MUTEX(mutexname)						\
++	struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
++
++extern void __mutex_do_init(struct mutex *lock, const char *name, struct lock_class_key *key);
++extern void __lockfunc _mutex_lock(struct mutex *lock);
++extern void __lockfunc _mutex_lock_io_nested(struct mutex *lock, int subclass);
++extern int __lockfunc _mutex_lock_interruptible(struct mutex *lock);
++extern int __lockfunc _mutex_lock_killable(struct mutex *lock);
++extern void __lockfunc _mutex_lock_nested(struct mutex *lock, int subclass);
++extern void __lockfunc _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock);
++extern int __lockfunc _mutex_lock_interruptible_nested(struct mutex *lock, int subclass);
++extern int __lockfunc _mutex_lock_killable_nested(struct mutex *lock, int subclass);
++extern int __lockfunc _mutex_trylock(struct mutex *lock);
++extern void __lockfunc _mutex_unlock(struct mutex *lock);
++
++#define mutex_is_locked(l)		rt_mutex_is_locked(&(l)->lock)
++#define mutex_lock(l)			_mutex_lock(l)
++#define mutex_lock_interruptible(l)	_mutex_lock_interruptible(l)
++#define mutex_lock_killable(l)		_mutex_lock_killable(l)
++#define mutex_trylock(l)		_mutex_trylock(l)
++#define mutex_unlock(l)			_mutex_unlock(l)
++#define mutex_lock_io(l)		_mutex_lock_io_nested(l, 0);
++
++#define __mutex_owner(l)		((l)->lock.owner)
++
++#ifdef CONFIG_DEBUG_MUTEXES
++#define mutex_destroy(l)		rt_mutex_destroy(&(l)->lock)
++#else
++static inline void mutex_destroy(struct mutex *lock) {}
++#endif
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++# define mutex_lock_nested(l, s)	_mutex_lock_nested(l, s)
++# define mutex_lock_interruptible_nested(l, s) \
++					_mutex_lock_interruptible_nested(l, s)
++# define mutex_lock_killable_nested(l, s) \
++					_mutex_lock_killable_nested(l, s)
++# define mutex_lock_io_nested(l, s)	_mutex_lock_io_nested(l, s)
++
++# define mutex_lock_nest_lock(lock, nest_lock)				\
++do {									\
++	typecheck(struct lockdep_map *, &(nest_lock)->dep_map);		\
++	_mutex_lock_nest_lock(lock, &(nest_lock)->dep_map);		\
++} while (0)
++
++#else
++# define mutex_lock_nested(l, s)	_mutex_lock(l)
++# define mutex_lock_interruptible_nested(l, s) \
++					_mutex_lock_interruptible(l)
++# define mutex_lock_killable_nested(l, s) \
++					_mutex_lock_killable(l)
++# define mutex_lock_nest_lock(lock, nest_lock) mutex_lock(lock)
++# define mutex_lock_io_nested(l, s)	_mutex_lock_io_nested(l, s)
++#endif
++
++# define mutex_init(mutex)				\
++do {							\
++	static struct lock_class_key __key;		\
++							\
++	rt_mutex_init(&(mutex)->lock);			\
++	__mutex_do_init((mutex), #mutex, &__key);	\
++} while (0)
++
++# define __mutex_init(mutex, name, key)			\
++do {							\
++	rt_mutex_init(&(mutex)->lock);			\
++	__mutex_do_init((mutex), name, key);		\
++} while (0)
++
++/**
++ * These values are chosen such that FAIL and SUCCESS match the
++ * values of the regular mutex_trylock().
++ */
++enum mutex_trylock_recursive_enum {
++	MUTEX_TRYLOCK_FAILED    = 0,
++	MUTEX_TRYLOCK_SUCCESS   = 1,
++	MUTEX_TRYLOCK_RECURSIVE,
++};
++/**
++ * mutex_trylock_recursive - trylock variant that allows recursive locking
++ * @lock: mutex to be locked
++ *
++ * This function should not be used, _ever_. It is purely for hysterical GEM
++ * raisins, and once those are gone this will be removed.
++ *
++ * Returns:
++ *  MUTEX_TRYLOCK_FAILED    - trylock failed,
++ *  MUTEX_TRYLOCK_SUCCESS   - lock acquired,
++ *  MUTEX_TRYLOCK_RECURSIVE - we already owned the lock.
++ */
++int __rt_mutex_owner_current(struct rt_mutex *lock);
++
++static inline /* __deprecated */ __must_check enum mutex_trylock_recursive_enum
++mutex_trylock_recursive(struct mutex *lock)
++{
++	if (unlikely(__rt_mutex_owner_current(&lock->lock)))
++		return MUTEX_TRYLOCK_RECURSIVE;
++
++	return mutex_trylock(lock);
++}
++
++extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
++
++#endif
+diff --git a/kernel/locking/mutex-rt.c b/kernel/locking/mutex-rt.c
+new file mode 100644
+index 000000000000..2b849e6b9b4a
+--- /dev/null
++++ b/kernel/locking/mutex-rt.c
+@@ -0,0 +1,224 @@
++// SPDX-License-Identifier: GPL-2.0-only
++/*
++ * Real-Time Preemption Support
++ *
++ * started by Ingo Molnar:
++ *
++ *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
++ *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
++ *
++ * historic credit for proving that Linux spinlocks can be implemented via
++ * RT-aware mutexes goes to many people: The Pmutex project (Dirk Grambow
++ * and others) who prototyped it on 2.4 and did lots of comparative
++ * research and analysis; TimeSys, for proving that you can implement a
++ * fully preemptible kernel via the use of IRQ threading and mutexes;
++ * Bill Huey for persuasively arguing on lkml that the mutex model is the
++ * right one; and to MontaVista, who ported pmutexes to 2.6.
++ *
++ * This code is a from-scratch implementation and is not based on pmutexes,
++ * but the idea of converting spinlocks to mutexes is used here too.
++ *
++ * lock debugging, locking tree, deadlock detection:
++ *
++ *  Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
++ *  Released under the General Public License (GPL).
++ *
++ * Includes portions of the generic R/W semaphore implementation from:
++ *
++ *  Copyright (c) 2001   David Howells (dhowells@redhat.com).
++ *  - Derived partially from idea by Andrea Arcangeli <andrea@suse.de>
++ *  - Derived also from comments by Linus
++ *
++ * Pending ownership of locks and ownership stealing:
++ *
++ *  Copyright (C) 2005, Kihon Technologies Inc., Steven Rostedt
++ *
++ *   (also by Steven Rostedt)
++ *    - Converted single pi_lock to individual task locks.
++ *
++ * By Esben Nielsen:
++ *    Doing priority inheritance with help of the scheduler.
++ *
++ *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
++ *  - major rework based on Esben Nielsens initial patch
++ *  - replaced thread_info references by task_struct refs
++ *  - removed task->pending_owner dependency
++ *  - BKL drop/reacquire for semaphore style locks to avoid deadlocks
++ *    in the scheduler return path as discussed with Steven Rostedt
++ *
++ *  Copyright (C) 2006, Kihon Technologies Inc.
++ *    Steven Rostedt <rostedt@goodmis.org>
++ *  - debugged and patched Thomas Gleixner's rework.
++ *  - added back the cmpxchg to the rework.
++ *  - turned atomic require back on for SMP.
++ */
++
++#include <linux/spinlock.h>
++#include <linux/rtmutex.h>
++#include <linux/sched.h>
++#include <linux/delay.h>
++#include <linux/module.h>
++#include <linux/kallsyms.h>
++#include <linux/syscalls.h>
++#include <linux/interrupt.h>
++#include <linux/plist.h>
++#include <linux/fs.h>
++#include <linux/futex.h>
++#include <linux/hrtimer.h>
++#include <linux/blkdev.h>
++
++#include "rtmutex_common.h"
++
++/*
++ * struct mutex functions
++ */
++void __mutex_do_init(struct mutex *mutex, const char *name,
++		     struct lock_class_key *key)
++{
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	/*
++	 * Make sure we are not reinitializing a held lock:
++	 */
++	debug_check_no_locks_freed((void *)mutex, sizeof(*mutex));
++	lockdep_init_map(&mutex->dep_map, name, key, 0);
++#endif
++	mutex->lock.save_state = 0;
++}
++EXPORT_SYMBOL(__mutex_do_init);
++
++static int _mutex_lock_blk_flush(struct mutex *lock, int state)
++{
++	/*
++	 * Flush blk before ->pi_blocked_on is set. At schedule() time it is too
++	 * late if one of the callbacks needs to acquire a sleeping lock.
++	 */
++	if (blk_needs_flush_plug(current))
++		blk_schedule_flush_plug(current);
++	return __rt_mutex_lock_state(&lock->lock, state);
++}
++
++void __lockfunc _mutex_lock(struct mutex *lock)
++{
++	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
++	_mutex_lock_blk_flush(lock, TASK_UNINTERRUPTIBLE);
++}
++EXPORT_SYMBOL(_mutex_lock);
++
++void __lockfunc _mutex_lock_io_nested(struct mutex *lock, int subclass)
++{
++	int token;
++
++	token = io_schedule_prepare();
++
++	mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
++	__rt_mutex_lock_state(&lock->lock, TASK_UNINTERRUPTIBLE);
++
++	io_schedule_finish(token);
++}
++EXPORT_SYMBOL_GPL(_mutex_lock_io_nested);
++
++int __lockfunc _mutex_lock_interruptible(struct mutex *lock)
++{
++	int ret;
++
++	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
++	ret = _mutex_lock_blk_flush(lock, TASK_INTERRUPTIBLE);
++	if (ret)
++		mutex_release(&lock->dep_map, _RET_IP_);
++	return ret;
++}
++EXPORT_SYMBOL(_mutex_lock_interruptible);
++
++int __lockfunc _mutex_lock_killable(struct mutex *lock)
++{
++	int ret;
++
++	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
++	ret = _mutex_lock_blk_flush(lock, TASK_KILLABLE);
++	if (ret)
++		mutex_release(&lock->dep_map, _RET_IP_);
++	return ret;
++}
++EXPORT_SYMBOL(_mutex_lock_killable);
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++void __lockfunc _mutex_lock_nested(struct mutex *lock, int subclass)
++{
++	mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
++	_mutex_lock_blk_flush(lock, TASK_UNINTERRUPTIBLE);
++}
++EXPORT_SYMBOL(_mutex_lock_nested);
++
++void __lockfunc _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
++{
++	mutex_acquire_nest(&lock->dep_map, 0, 0, nest, _RET_IP_);
++	_mutex_lock_blk_flush(lock, TASK_UNINTERRUPTIBLE);
++}
++EXPORT_SYMBOL(_mutex_lock_nest_lock);
++
++int __lockfunc _mutex_lock_interruptible_nested(struct mutex *lock, int subclass)
++{
++	int ret;
++
++	mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
++	ret = _mutex_lock_blk_flush(lock, TASK_INTERRUPTIBLE);
++	if (ret)
++		mutex_release(&lock->dep_map, _RET_IP_);
++	return ret;
++}
++EXPORT_SYMBOL(_mutex_lock_interruptible_nested);
++
++int __lockfunc _mutex_lock_killable_nested(struct mutex *lock, int subclass)
++{
++	int ret;
++
++	mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
++	ret = _mutex_lock_blk_flush(lock, TASK_KILLABLE);
++	if (ret)
++		mutex_release(&lock->dep_map, _RET_IP_);
++	return ret;
++}
++EXPORT_SYMBOL(_mutex_lock_killable_nested);
++#endif
++
++int __lockfunc _mutex_trylock(struct mutex *lock)
++{
++	int ret = __rt_mutex_trylock(&lock->lock);
++
++	if (ret)
++		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
++
++	return ret;
++}
++EXPORT_SYMBOL(_mutex_trylock);
++
++void __lockfunc _mutex_unlock(struct mutex *lock)
++{
++	mutex_release(&lock->dep_map, _RET_IP_);
++	__rt_mutex_unlock(&lock->lock);
++}
++EXPORT_SYMBOL(_mutex_unlock);
++
++/**
++ * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
++ * @cnt: the atomic which we are to dec
++ * @lock: the mutex to return holding if we dec to 0
++ *
++ * return true and hold lock if we dec to 0, return false otherwise
++ */
++int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
++{
++	/* dec if we can't possibly hit 0 */
++	if (atomic_add_unless(cnt, -1, 1))
++		return 0;
++	/* we might hit 0, so take the lock */
++	mutex_lock(lock);
++	if (!atomic_dec_and_test(cnt)) {
++		/* when we actually did the dec, we didn't hit 0 */
++		mutex_unlock(lock);
++		return 0;
++	}
++	/* we hit 0, and we hold the lock */
++	return 1;
++}
++EXPORT_SYMBOL(atomic_dec_and_mutex_lock);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0173-locking-rtmutex-add-rwsem-implementation-based-on-rt.patch b/debian/patches-rt/0173-locking-rtmutex-add-rwsem-implementation-based-on-rt.patch
new file mode 100644
index 000000000..d1595ab45
--- /dev/null
+++ b/debian/patches-rt/0173-locking-rtmutex-add-rwsem-implementation-based-on-rt.patch
@@ -0,0 +1,455 @@
+From 9095a37abced402fb5197fef8d126069f63ebfb4 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 12 Oct 2017 17:28:34 +0200
+Subject: [PATCH 173/323] locking/rtmutex: add rwsem implementation based on
+ rtmutex
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The RT specific R/W semaphore implementation restricts the number of readers
+to one because a writer cannot block on multiple readers and inherit its
+priority or budget.
+
+The single reader restricting is painful in various ways:
+
+ - Performance bottleneck for multi-threaded applications in the page fault
+   path (mmap sem)
+
+ - Progress blocker for drivers which are carefully crafted to avoid the
+   potential reader/writer deadlock in mainline.
+
+The analysis of the writer code paths shows, that properly written RT tasks
+should not take them. Syscalls like mmap(), file access which take mmap sem
+write locked have unbound latencies which are completely unrelated to mmap
+sem. Other R/W sem users like graphics drivers are not suitable for RT tasks
+either.
+
+So there is little risk to hurt RT tasks when the RT rwsem implementation is
+changed in the following way:
+
+ - Allow concurrent readers
+
+ - Make writers block until the last reader left the critical section. This
+   blocking is not subject to priority/budget inheritance.
+
+ - Readers blocked on a writer inherit their priority/budget in the normal
+   way.
+
+There is a drawback with this scheme. R/W semaphores become writer unfair
+though the applications which have triggered writer starvation (mostly on
+mmap_sem) in the past are not really the typical workloads running on a RT
+system. So while it's unlikely to hit writer starvation, it's possible. If
+there are unexpected workloads on RT systems triggering it, we need to rethink
+the approach.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/rwsem-rt.h  |  70 +++++++++
+ kernel/locking/rwsem-rt.c | 318 ++++++++++++++++++++++++++++++++++++++
+ 2 files changed, 388 insertions(+)
+ create mode 100644 include/linux/rwsem-rt.h
+ create mode 100644 kernel/locking/rwsem-rt.c
+
+diff --git a/include/linux/rwsem-rt.h b/include/linux/rwsem-rt.h
+new file mode 100644
+index 000000000000..0ba8aae9a198
+--- /dev/null
++++ b/include/linux/rwsem-rt.h
+@@ -0,0 +1,70 @@
++// SPDX-License-Identifier: GPL-2.0-only
++#ifndef _LINUX_RWSEM_RT_H
++#define _LINUX_RWSEM_RT_H
++
++#ifndef _LINUX_RWSEM_H
++#error "Include rwsem.h"
++#endif
++
++#include <linux/rtmutex.h>
++#include <linux/swait.h>
++
++#define READER_BIAS		(1U << 31)
++#define WRITER_BIAS		(1U << 30)
++
++struct rw_semaphore {
++	atomic_t		readers;
++	struct rt_mutex		rtmutex;
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	struct lockdep_map	dep_map;
++#endif
++};
++
++#define __RWSEM_INITIALIZER(name)				\
++{								\
++	.readers = ATOMIC_INIT(READER_BIAS),			\
++	.rtmutex = __RT_MUTEX_INITIALIZER(name.rtmutex),	\
++	RW_DEP_MAP_INIT(name)					\
++}
++
++#define DECLARE_RWSEM(lockname) \
++	struct rw_semaphore lockname = __RWSEM_INITIALIZER(lockname)
++
++extern void  __rwsem_init(struct rw_semaphore *rwsem, const char *name,
++			  struct lock_class_key *key);
++
++#define __init_rwsem(sem, name, key)			\
++do {							\
++		rt_mutex_init(&(sem)->rtmutex);		\
++		__rwsem_init((sem), (name), (key));	\
++} while (0)
++
++#define init_rwsem(sem)					\
++do {							\
++	static struct lock_class_key __key;		\
++							\
++	__init_rwsem((sem), #sem, &__key);		\
++} while (0)
++
++static inline int rwsem_is_locked(struct rw_semaphore *sem)
++{
++	return atomic_read(&sem->readers) != READER_BIAS;
++}
++
++static inline int rwsem_is_contended(struct rw_semaphore *sem)
++{
++	return atomic_read(&sem->readers) > 0;
++}
++
++extern void __down_read(struct rw_semaphore *sem);
++extern int __down_read_interruptible(struct rw_semaphore *sem);
++extern int __down_read_killable(struct rw_semaphore *sem);
++extern int __down_read_trylock(struct rw_semaphore *sem);
++extern void __down_write(struct rw_semaphore *sem);
++extern int __must_check __down_write_killable(struct rw_semaphore *sem);
++extern int __down_write_trylock(struct rw_semaphore *sem);
++extern void __up_read(struct rw_semaphore *sem);
++extern void __up_write(struct rw_semaphore *sem);
++extern void __downgrade_write(struct rw_semaphore *sem);
++
++#endif
+diff --git a/kernel/locking/rwsem-rt.c b/kernel/locking/rwsem-rt.c
+new file mode 100644
+index 000000000000..a0771c150041
+--- /dev/null
++++ b/kernel/locking/rwsem-rt.c
+@@ -0,0 +1,318 @@
++// SPDX-License-Identifier: GPL-2.0-only
++#include <linux/rwsem.h>
++#include <linux/sched/debug.h>
++#include <linux/sched/signal.h>
++#include <linux/export.h>
++#include <linux/blkdev.h>
++
++#include "rtmutex_common.h"
++
++/*
++ * RT-specific reader/writer semaphores
++ *
++ * down_write()
++ *  1) Lock sem->rtmutex
++ *  2) Remove the reader BIAS to force readers into the slow path
++ *  3) Wait until all readers have left the critical region
++ *  4) Mark it write locked
++ *
++ * up_write()
++ *  1) Remove the write locked marker
++ *  2) Set the reader BIAS so readers can use the fast path again
++ *  3) Unlock sem->rtmutex to release blocked readers
++ *
++ * down_read()
++ *  1) Try fast path acquisition (reader BIAS is set)
++ *  2) Take sem->rtmutex.wait_lock which protects the writelocked flag
++ *  3) If !writelocked, acquire it for read
++ *  4) If writelocked, block on sem->rtmutex
++ *  5) unlock sem->rtmutex, goto 1)
++ *
++ * up_read()
++ *  1) Try fast path release (reader count != 1)
++ *  2) Wake the writer waiting in down_write()#3
++ *
++ * down_read()#3 has the consequence, that rw semaphores on RT are not writer
++ * fair, but writers, which should be avoided in RT tasks (think mmap_sem),
++ * are subject to the rtmutex priority/DL inheritance mechanism.
++ *
++ * It's possible to make the rw semaphores writer fair by keeping a list of
++ * active readers. A blocked writer would force all newly incoming readers to
++ * block on the rtmutex, but the rtmutex would have to be proxy locked for one
++ * reader after the other. We can't use multi-reader inheritance because there
++ * is no way to support that with SCHED_DEADLINE. Implementing the one by one
++ * reader boosting/handover mechanism is a major surgery for a very dubious
++ * value.
++ *
++ * The risk of writer starvation is there, but the pathological use cases
++ * which trigger it are not necessarily the typical RT workloads.
++ */
++
++void __rwsem_init(struct rw_semaphore *sem, const char *name,
++		  struct lock_class_key *key)
++{
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	/*
++	 * Make sure we are not reinitializing a held semaphore:
++	 */
++	debug_check_no_locks_freed((void *)sem, sizeof(*sem));
++	lockdep_init_map(&sem->dep_map, name, key, 0);
++#endif
++	atomic_set(&sem->readers, READER_BIAS);
++}
++EXPORT_SYMBOL(__rwsem_init);
++
++int __down_read_trylock(struct rw_semaphore *sem)
++{
++	int r, old;
++
++	/*
++	 * Increment reader count, if sem->readers < 0, i.e. READER_BIAS is
++	 * set.
++	 */
++	for (r = atomic_read(&sem->readers); r < 0;) {
++		old = atomic_cmpxchg(&sem->readers, r, r + 1);
++		if (likely(old == r))
++			return 1;
++		r = old;
++	}
++	return 0;
++}
++
++static int __sched __down_read_common(struct rw_semaphore *sem, int state)
++{
++	struct rt_mutex *m = &sem->rtmutex;
++	struct rt_mutex_waiter waiter;
++	int ret;
++
++	if (__down_read_trylock(sem))
++		return 0;
++
++	/*
++	 * Flush blk before ->pi_blocked_on is set. At schedule() time it is too
++	 * late if one of the callbacks needs to acquire a sleeping lock.
++	 */
++	if (blk_needs_flush_plug(current))
++		blk_schedule_flush_plug(current);
++
++	might_sleep();
++	raw_spin_lock_irq(&m->wait_lock);
++	/*
++	 * Allow readers as long as the writer has not completely
++	 * acquired the semaphore for write.
++	 */
++	if (atomic_read(&sem->readers) != WRITER_BIAS) {
++		atomic_inc(&sem->readers);
++		raw_spin_unlock_irq(&m->wait_lock);
++		return 0;
++	}
++
++	/*
++	 * Call into the slow lock path with the rtmutex->wait_lock
++	 * held, so this can't result in the following race:
++	 *
++	 * Reader1		Reader2		Writer
++	 *			down_read()
++	 *					down_write()
++	 *					rtmutex_lock(m)
++	 *					swait()
++	 * down_read()
++	 * unlock(m->wait_lock)
++	 *			up_read()
++	 *			swake()
++	 *					lock(m->wait_lock)
++	 *					sem->writelocked=true
++	 *					unlock(m->wait_lock)
++	 *
++	 *					up_write()
++	 *					sem->writelocked=false
++	 *					rtmutex_unlock(m)
++	 *			down_read()
++	 *					down_write()
++	 *					rtmutex_lock(m)
++	 *					swait()
++	 * rtmutex_lock(m)
++	 *
++	 * That would put Reader1 behind the writer waiting on
++	 * Reader2 to call up_read() which might be unbound.
++	 */
++	rt_mutex_init_waiter(&waiter, false);
++	ret = rt_mutex_slowlock_locked(m, state, NULL, RT_MUTEX_MIN_CHAINWALK,
++				       &waiter);
++	/*
++	 * The slowlock() above is guaranteed to return with the rtmutex (for
++	 * ret = 0) is now held, so there can't be a writer active. Increment
++	 * the reader count and immediately drop the rtmutex again.
++	 * For ret != 0 we don't hold the rtmutex and need unlock the wait_lock.
++	 * We don't own the lock then.
++	 */
++	if (!ret)
++		atomic_inc(&sem->readers);
++	raw_spin_unlock_irq(&m->wait_lock);
++	if (!ret)
++		__rt_mutex_unlock(m);
++
++	debug_rt_mutex_free_waiter(&waiter);
++	return ret;
++}
++
++void __down_read(struct rw_semaphore *sem)
++{
++	int ret;
++
++	ret = __down_read_common(sem, TASK_UNINTERRUPTIBLE);
++	WARN_ON_ONCE(ret);
++}
++
++int __down_read_interruptible(struct rw_semaphore *sem)
++{
++	int ret;
++
++	ret = __down_read_common(sem, TASK_INTERRUPTIBLE);
++	if (likely(!ret))
++		return ret;
++	WARN_ONCE(ret != -EINTR, "Unexpected state: %d\n", ret);
++	return -EINTR;
++}
++
++int __down_read_killable(struct rw_semaphore *sem)
++{
++	int ret;
++
++	ret = __down_read_common(sem, TASK_KILLABLE);
++	if (likely(!ret))
++		return ret;
++	WARN_ONCE(ret != -EINTR, "Unexpected state: %d\n", ret);
++	return -EINTR;
++}
++
++void __up_read(struct rw_semaphore *sem)
++{
++	struct rt_mutex *m = &sem->rtmutex;
++	struct task_struct *tsk;
++
++	/*
++	 * sem->readers can only hit 0 when a writer is waiting for the
++	 * active readers to leave the critical region.
++	 */
++	if (!atomic_dec_and_test(&sem->readers))
++		return;
++
++	might_sleep();
++	raw_spin_lock_irq(&m->wait_lock);
++	/*
++	 * Wake the writer, i.e. the rtmutex owner. It might release the
++	 * rtmutex concurrently in the fast path (due to a signal), but to
++	 * clean up the rwsem it needs to acquire m->wait_lock. The worst
++	 * case which can happen is a spurious wakeup.
++	 */
++	tsk = rt_mutex_owner(m);
++	if (tsk)
++		wake_up_process(tsk);
++
++	raw_spin_unlock_irq(&m->wait_lock);
++}
++
++static void __up_write_unlock(struct rw_semaphore *sem, int bias,
++			      unsigned long flags)
++{
++	struct rt_mutex *m = &sem->rtmutex;
++
++	atomic_add(READER_BIAS - bias, &sem->readers);
++	raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++	__rt_mutex_unlock(m);
++}
++
++static int __sched __down_write_common(struct rw_semaphore *sem, int state)
++{
++	struct rt_mutex *m = &sem->rtmutex;
++	unsigned long flags;
++
++	/*
++	 * Flush blk before ->pi_blocked_on is set. At schedule() time it is too
++	 * late if one of the callbacks needs to acquire a sleeping lock.
++	 */
++	if (blk_needs_flush_plug(current))
++		blk_schedule_flush_plug(current);
++
++	/* Take the rtmutex as a first step */
++	if (__rt_mutex_lock_state(m, state))
++		return -EINTR;
++
++	/* Force readers into slow path */
++	atomic_sub(READER_BIAS, &sem->readers);
++	might_sleep();
++
++	set_current_state(state);
++	for (;;) {
++		raw_spin_lock_irqsave(&m->wait_lock, flags);
++		/* Have all readers left the critical region? */
++		if (!atomic_read(&sem->readers)) {
++			atomic_set(&sem->readers, WRITER_BIAS);
++			__set_current_state(TASK_RUNNING);
++			raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++			return 0;
++		}
++
++		if (signal_pending_state(state, current)) {
++			__set_current_state(TASK_RUNNING);
++			__up_write_unlock(sem, 0, flags);
++			return -EINTR;
++		}
++		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++
++		if (atomic_read(&sem->readers) != 0) {
++			schedule();
++			set_current_state(state);
++		}
++	}
++}
++
++void __sched __down_write(struct rw_semaphore *sem)
++{
++	__down_write_common(sem, TASK_UNINTERRUPTIBLE);
++}
++
++int __sched __down_write_killable(struct rw_semaphore *sem)
++{
++	return __down_write_common(sem, TASK_KILLABLE);
++}
++
++int __down_write_trylock(struct rw_semaphore *sem)
++{
++	struct rt_mutex *m = &sem->rtmutex;
++	unsigned long flags;
++
++	if (!__rt_mutex_trylock(m))
++		return 0;
++
++	atomic_sub(READER_BIAS, &sem->readers);
++
++	raw_spin_lock_irqsave(&m->wait_lock, flags);
++	if (!atomic_read(&sem->readers)) {
++		atomic_set(&sem->readers, WRITER_BIAS);
++		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++		return 1;
++	}
++	__up_write_unlock(sem, 0, flags);
++	return 0;
++}
++
++void __up_write(struct rw_semaphore *sem)
++{
++	struct rt_mutex *m = &sem->rtmutex;
++	unsigned long flags;
++
++	raw_spin_lock_irqsave(&m->wait_lock, flags);
++	__up_write_unlock(sem, WRITER_BIAS, flags);
++}
++
++void __downgrade_write(struct rw_semaphore *sem)
++{
++	struct rt_mutex *m = &sem->rtmutex;
++	unsigned long flags;
++
++	raw_spin_lock_irqsave(&m->wait_lock, flags);
++	/* Release it and account current as reader */
++	__up_write_unlock(sem, WRITER_BIAS - 1, flags);
++}
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0174-locking-rtmutex-add-rwlock-implementation-based-on-r.patch b/debian/patches-rt/0174-locking-rtmutex-add-rwlock-implementation-based-on-r.patch
new file mode 100644
index 000000000..481610364
--- /dev/null
+++ b/debian/patches-rt/0174-locking-rtmutex-add-rwlock-implementation-based-on-r.patch
@@ -0,0 +1,548 @@
+From 85ee193953134a79ee60def58e6d8c98b8cd8e55 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 12 Oct 2017 17:18:06 +0200
+Subject: [PATCH 174/323] locking/rtmutex: add rwlock implementation based on
+ rtmutex
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The implementation is bias-based, similar to the rwsem implementation.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/rwlock_rt.h       | 109 +++++++++++
+ include/linux/rwlock_types_rt.h |  56 ++++++
+ kernel/Kconfig.locks            |   2 +-
+ kernel/locking/rwlock-rt.c      | 328 ++++++++++++++++++++++++++++++++
+ 4 files changed, 494 insertions(+), 1 deletion(-)
+ create mode 100644 include/linux/rwlock_rt.h
+ create mode 100644 include/linux/rwlock_types_rt.h
+ create mode 100644 kernel/locking/rwlock-rt.c
+
+diff --git a/include/linux/rwlock_rt.h b/include/linux/rwlock_rt.h
+new file mode 100644
+index 000000000000..aafdb0a685d5
+--- /dev/null
++++ b/include/linux/rwlock_rt.h
+@@ -0,0 +1,109 @@
++// SPDX-License-Identifier: GPL-2.0-only
++#ifndef __LINUX_RWLOCK_RT_H
++#define __LINUX_RWLOCK_RT_H
++
++#ifndef __LINUX_SPINLOCK_H
++#error Do not include directly. Use spinlock.h
++#endif
++
++extern void __lockfunc rt_write_lock(rwlock_t *rwlock);
++extern void __lockfunc rt_read_lock(rwlock_t *rwlock);
++extern int __lockfunc rt_write_trylock(rwlock_t *rwlock);
++extern int __lockfunc rt_read_trylock(rwlock_t *rwlock);
++extern void __lockfunc rt_write_unlock(rwlock_t *rwlock);
++extern void __lockfunc rt_read_unlock(rwlock_t *rwlock);
++extern int __lockfunc rt_read_can_lock(rwlock_t *rwlock);
++extern int __lockfunc rt_write_can_lock(rwlock_t *rwlock);
++extern void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key);
++
++#define read_can_lock(rwlock)		rt_read_can_lock(rwlock)
++#define write_can_lock(rwlock)		rt_write_can_lock(rwlock)
++
++#define read_trylock(lock)	__cond_lock(lock, rt_read_trylock(lock))
++#define write_trylock(lock)	__cond_lock(lock, rt_write_trylock(lock))
++
++static inline int __write_trylock_rt_irqsave(rwlock_t *lock, unsigned long *flags)
++{
++	*flags = 0;
++	return rt_write_trylock(lock);
++}
++
++#define write_trylock_irqsave(lock, flags)		\
++	__cond_lock(lock, __write_trylock_rt_irqsave(lock, &(flags)))
++
++#define read_lock_irqsave(lock, flags)			\
++	do {						\
++		typecheck(unsigned long, flags);	\
++		rt_read_lock(lock);			\
++		flags = 0;				\
++	} while (0)
++
++#define write_lock_irqsave(lock, flags)			\
++	do {						\
++		typecheck(unsigned long, flags);	\
++		rt_write_lock(lock);			\
++		flags = 0;				\
++	} while (0)
++
++#define read_lock(lock)		rt_read_lock(lock)
++
++#define read_lock_bh(lock)				\
++	do {						\
++		local_bh_disable();			\
++		rt_read_lock(lock);			\
++	} while (0)
++
++#define read_lock_irq(lock)	read_lock(lock)
++
++#define write_lock(lock)	rt_write_lock(lock)
++
++#define write_lock_bh(lock)				\
++	do {						\
++		local_bh_disable();			\
++		rt_write_lock(lock);			\
++	} while (0)
++
++#define write_lock_irq(lock)	write_lock(lock)
++
++#define read_unlock(lock)	rt_read_unlock(lock)
++
++#define read_unlock_bh(lock)				\
++	do {						\
++		rt_read_unlock(lock);			\
++		local_bh_enable();			\
++	} while (0)
++
++#define read_unlock_irq(lock)	read_unlock(lock)
++
++#define write_unlock(lock)	rt_write_unlock(lock)
++
++#define write_unlock_bh(lock)				\
++	do {						\
++		rt_write_unlock(lock);			\
++		local_bh_enable();			\
++	} while (0)
++
++#define write_unlock_irq(lock)	write_unlock(lock)
++
++#define read_unlock_irqrestore(lock, flags)		\
++	do {						\
++		typecheck(unsigned long, flags);	\
++		(void) flags;				\
++		rt_read_unlock(lock);			\
++	} while (0)
++
++#define write_unlock_irqrestore(lock, flags) \
++	do {						\
++		typecheck(unsigned long, flags);	\
++		(void) flags;				\
++		rt_write_unlock(lock);			\
++	} while (0)
++
++#define rwlock_init(rwl)				\
++do {							\
++	static struct lock_class_key __key;		\
++							\
++	__rt_rwlock_init(rwl, #rwl, &__key);		\
++} while (0)
++
++#endif
+diff --git a/include/linux/rwlock_types_rt.h b/include/linux/rwlock_types_rt.h
+new file mode 100644
+index 000000000000..4762391d659b
+--- /dev/null
++++ b/include/linux/rwlock_types_rt.h
+@@ -0,0 +1,56 @@
++// SPDX-License-Identifier: GPL-2.0-only
++#ifndef __LINUX_RWLOCK_TYPES_RT_H
++#define __LINUX_RWLOCK_TYPES_RT_H
++
++#ifndef __LINUX_SPINLOCK_TYPES_H
++#error "Do not include directly. Include spinlock_types.h instead"
++#endif
++
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++# define RW_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
++#else
++# define RW_DEP_MAP_INIT(lockname)
++#endif
++
++typedef struct rt_rw_lock rwlock_t;
++
++#define __RW_LOCK_UNLOCKED(name) __RWLOCK_RT_INITIALIZER(name)
++
++#define DEFINE_RWLOCK(name) \
++	rwlock_t name = __RW_LOCK_UNLOCKED(name)
++
++/*
++ * A reader biased implementation primarily for CPU pinning.
++ *
++ * Can be selected as general replacement for the single reader RT rwlock
++ * variant
++ */
++struct rt_rw_lock {
++	struct rt_mutex		rtmutex;
++	atomic_t		readers;
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	struct lockdep_map	dep_map;
++#endif
++};
++
++#define READER_BIAS	(1U << 31)
++#define WRITER_BIAS	(1U << 30)
++
++#define __RWLOCK_RT_INITIALIZER(name)					\
++{									\
++	.readers = ATOMIC_INIT(READER_BIAS),				\
++	.rtmutex = __RT_MUTEX_INITIALIZER_SAVE_STATE(name.rtmutex),	\
++	RW_DEP_MAP_INIT(name)						\
++}
++
++void __rwlock_biased_rt_init(struct rt_rw_lock *lock, const char *name,
++			     struct lock_class_key *key);
++
++#define rwlock_biased_rt_init(rwlock)					\
++	do {								\
++		static struct lock_class_key __key;			\
++									\
++		__rwlock_biased_rt_init((rwlock), #rwlock, &__key);	\
++	} while (0)
++
++#endif
+diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
+index 3de8fd11873b..4198f0273ecd 100644
+--- a/kernel/Kconfig.locks
++++ b/kernel/Kconfig.locks
+@@ -251,7 +251,7 @@ config ARCH_USE_QUEUED_RWLOCKS
+ 
+ config QUEUED_RWLOCKS
+ 	def_bool y if ARCH_USE_QUEUED_RWLOCKS
+-	depends on SMP
++	depends on SMP && !PREEMPT_RT
+ 
+ config ARCH_HAS_MMIOWB
+ 	bool
+diff --git a/kernel/locking/rwlock-rt.c b/kernel/locking/rwlock-rt.c
+new file mode 100644
+index 000000000000..1ee16b8fedd7
+--- /dev/null
++++ b/kernel/locking/rwlock-rt.c
+@@ -0,0 +1,328 @@
++// SPDX-License-Identifier: GPL-2.0-only
++#include <linux/sched/debug.h>
++#include <linux/export.h>
++
++#include "rtmutex_common.h"
++#include <linux/rwlock_types_rt.h>
++
++/*
++ * RT-specific reader/writer locks
++ *
++ * write_lock()
++ *  1) Lock lock->rtmutex
++ *  2) Remove the reader BIAS to force readers into the slow path
++ *  3) Wait until all readers have left the critical region
++ *  4) Mark it write locked
++ *
++ * write_unlock()
++ *  1) Remove the write locked marker
++ *  2) Set the reader BIAS so readers can use the fast path again
++ *  3) Unlock lock->rtmutex to release blocked readers
++ *
++ * read_lock()
++ *  1) Try fast path acquisition (reader BIAS is set)
++ *  2) Take lock->rtmutex.wait_lock which protects the writelocked flag
++ *  3) If !writelocked, acquire it for read
++ *  4) If writelocked, block on lock->rtmutex
++ *  5) unlock lock->rtmutex, goto 1)
++ *
++ * read_unlock()
++ *  1) Try fast path release (reader count != 1)
++ *  2) Wake the writer waiting in write_lock()#3
++ *
++ * read_lock()#3 has the consequence, that rw locks on RT are not writer
++ * fair, but writers, which should be avoided in RT tasks (think tasklist
++ * lock), are subject to the rtmutex priority/DL inheritance mechanism.
++ *
++ * It's possible to make the rw locks writer fair by keeping a list of
++ * active readers. A blocked writer would force all newly incoming readers
++ * to block on the rtmutex, but the rtmutex would have to be proxy locked
++ * for one reader after the other. We can't use multi-reader inheritance
++ * because there is no way to support that with
++ * SCHED_DEADLINE. Implementing the one by one reader boosting/handover
++ * mechanism is a major surgery for a very dubious value.
++ *
++ * The risk of writer starvation is there, but the pathological use cases
++ * which trigger it are not necessarily the typical RT workloads.
++ */
++
++void __rwlock_biased_rt_init(struct rt_rw_lock *lock, const char *name,
++			     struct lock_class_key *key)
++{
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++	/*
++	 * Make sure we are not reinitializing a held semaphore:
++	 */
++	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
++	lockdep_init_map(&lock->dep_map, name, key, 0);
++#endif
++	atomic_set(&lock->readers, READER_BIAS);
++	rt_mutex_init(&lock->rtmutex);
++	lock->rtmutex.save_state = 1;
++}
++
++static int __read_rt_trylock(struct rt_rw_lock *lock)
++{
++	int r, old;
++
++	/*
++	 * Increment reader count, if lock->readers < 0, i.e. READER_BIAS is
++	 * set.
++	 */
++	for (r = atomic_read(&lock->readers); r < 0;) {
++		old = atomic_cmpxchg(&lock->readers, r, r + 1);
++		if (likely(old == r))
++			return 1;
++		r = old;
++	}
++	return 0;
++}
++
++static void __read_rt_lock(struct rt_rw_lock *lock)
++{
++	struct rt_mutex *m = &lock->rtmutex;
++	struct rt_mutex_waiter waiter;
++	unsigned long flags;
++
++	if (__read_rt_trylock(lock))
++		return;
++
++	raw_spin_lock_irqsave(&m->wait_lock, flags);
++	/*
++	 * Allow readers as long as the writer has not completely
++	 * acquired the semaphore for write.
++	 */
++	if (atomic_read(&lock->readers) != WRITER_BIAS) {
++		atomic_inc(&lock->readers);
++		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++		return;
++	}
++
++	/*
++	 * Call into the slow lock path with the rtmutex->wait_lock
++	 * held, so this can't result in the following race:
++	 *
++	 * Reader1		Reader2		Writer
++	 *			read_lock()
++	 *					write_lock()
++	 *					rtmutex_lock(m)
++	 *					swait()
++	 * read_lock()
++	 * unlock(m->wait_lock)
++	 *			read_unlock()
++	 *			swake()
++	 *					lock(m->wait_lock)
++	 *					lock->writelocked=true
++	 *					unlock(m->wait_lock)
++	 *
++	 *					write_unlock()
++	 *					lock->writelocked=false
++	 *					rtmutex_unlock(m)
++	 *			read_lock()
++	 *					write_lock()
++	 *					rtmutex_lock(m)
++	 *					swait()
++	 * rtmutex_lock(m)
++	 *
++	 * That would put Reader1 behind the writer waiting on
++	 * Reader2 to call read_unlock() which might be unbound.
++	 */
++	rt_mutex_init_waiter(&waiter, true);
++	rt_spin_lock_slowlock_locked(m, &waiter, flags);
++	/*
++	 * The slowlock() above is guaranteed to return with the rtmutex is
++	 * now held, so there can't be a writer active. Increment the reader
++	 * count and immediately drop the rtmutex again.
++	 */
++	atomic_inc(&lock->readers);
++	raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++	rt_spin_lock_slowunlock(m);
++
++	debug_rt_mutex_free_waiter(&waiter);
++}
++
++static void __read_rt_unlock(struct rt_rw_lock *lock)
++{
++	struct rt_mutex *m = &lock->rtmutex;
++	struct task_struct *tsk;
++
++	/*
++	 * sem->readers can only hit 0 when a writer is waiting for the
++	 * active readers to leave the critical region.
++	 */
++	if (!atomic_dec_and_test(&lock->readers))
++		return;
++
++	raw_spin_lock_irq(&m->wait_lock);
++	/*
++	 * Wake the writer, i.e. the rtmutex owner. It might release the
++	 * rtmutex concurrently in the fast path, but to clean up the rw
++	 * lock it needs to acquire m->wait_lock. The worst case which can
++	 * happen is a spurious wakeup.
++	 */
++	tsk = rt_mutex_owner(m);
++	if (tsk)
++		wake_up_process(tsk);
++
++	raw_spin_unlock_irq(&m->wait_lock);
++}
++
++static void __write_unlock_common(struct rt_rw_lock *lock, int bias,
++				  unsigned long flags)
++{
++	struct rt_mutex *m = &lock->rtmutex;
++
++	atomic_add(READER_BIAS - bias, &lock->readers);
++	raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++	rt_spin_lock_slowunlock(m);
++}
++
++static void __write_rt_lock(struct rt_rw_lock *lock)
++{
++	struct rt_mutex *m = &lock->rtmutex;
++	struct task_struct *self = current;
++	unsigned long flags;
++
++	/* Take the rtmutex as a first step */
++	__rt_spin_lock(m);
++
++	/* Force readers into slow path */
++	atomic_sub(READER_BIAS, &lock->readers);
++
++	raw_spin_lock_irqsave(&m->wait_lock, flags);
++
++	raw_spin_lock(&self->pi_lock);
++	self->saved_state = self->state;
++	__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
++	raw_spin_unlock(&self->pi_lock);
++
++	for (;;) {
++		/* Have all readers left the critical region? */
++		if (!atomic_read(&lock->readers)) {
++			atomic_set(&lock->readers, WRITER_BIAS);
++			raw_spin_lock(&self->pi_lock);
++			__set_current_state_no_track(self->saved_state);
++			self->saved_state = TASK_RUNNING;
++			raw_spin_unlock(&self->pi_lock);
++			raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++			return;
++		}
++
++		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++
++		if (atomic_read(&lock->readers) != 0)
++			schedule();
++
++		raw_spin_lock_irqsave(&m->wait_lock, flags);
++
++		raw_spin_lock(&self->pi_lock);
++		__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
++		raw_spin_unlock(&self->pi_lock);
++	}
++}
++
++static int __write_rt_trylock(struct rt_rw_lock *lock)
++{
++	struct rt_mutex *m = &lock->rtmutex;
++	unsigned long flags;
++
++	if (!__rt_mutex_trylock(m))
++		return 0;
++
++	atomic_sub(READER_BIAS, &lock->readers);
++
++	raw_spin_lock_irqsave(&m->wait_lock, flags);
++	if (!atomic_read(&lock->readers)) {
++		atomic_set(&lock->readers, WRITER_BIAS);
++		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
++		return 1;
++	}
++	__write_unlock_common(lock, 0, flags);
++	return 0;
++}
++
++static void __write_rt_unlock(struct rt_rw_lock *lock)
++{
++	struct rt_mutex *m = &lock->rtmutex;
++	unsigned long flags;
++
++	raw_spin_lock_irqsave(&m->wait_lock, flags);
++	__write_unlock_common(lock, WRITER_BIAS, flags);
++}
++
++int __lockfunc rt_read_can_lock(rwlock_t *rwlock)
++{
++	return  atomic_read(&rwlock->readers) < 0;
++}
++
++int __lockfunc rt_write_can_lock(rwlock_t *rwlock)
++{
++	return atomic_read(&rwlock->readers) == READER_BIAS;
++}
++
++/*
++ * The common functions which get wrapped into the rwlock API.
++ */
++int __lockfunc rt_read_trylock(rwlock_t *rwlock)
++{
++	int ret;
++
++	ret = __read_rt_trylock(rwlock);
++	if (ret) {
++		rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_);
++		migrate_disable();
++	}
++	return ret;
++}
++EXPORT_SYMBOL(rt_read_trylock);
++
++int __lockfunc rt_write_trylock(rwlock_t *rwlock)
++{
++	int ret;
++
++	ret = __write_rt_trylock(rwlock);
++	if (ret) {
++		rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
++		migrate_disable();
++	}
++	return ret;
++}
++EXPORT_SYMBOL(rt_write_trylock);
++
++void __lockfunc rt_read_lock(rwlock_t *rwlock)
++{
++	rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_);
++	__read_rt_lock(rwlock);
++	migrate_disable();
++}
++EXPORT_SYMBOL(rt_read_lock);
++
++void __lockfunc rt_write_lock(rwlock_t *rwlock)
++{
++	rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
++	__write_rt_lock(rwlock);
++	migrate_disable();
++}
++EXPORT_SYMBOL(rt_write_lock);
++
++void __lockfunc rt_read_unlock(rwlock_t *rwlock)
++{
++	rwlock_release(&rwlock->dep_map, _RET_IP_);
++	migrate_enable();
++	__read_rt_unlock(rwlock);
++}
++EXPORT_SYMBOL(rt_read_unlock);
++
++void __lockfunc rt_write_unlock(rwlock_t *rwlock)
++{
++	rwlock_release(&rwlock->dep_map, _RET_IP_);
++	migrate_enable();
++	__write_rt_unlock(rwlock);
++}
++EXPORT_SYMBOL(rt_write_unlock);
++
++void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key)
++{
++	__rwlock_biased_rt_init(rwlock, name, key);
++}
++EXPORT_SYMBOL(__rt_rwlock_init);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0175-locking-rtmutex-wire-up-RT-s-locking.patch b/debian/patches-rt/0175-locking-rtmutex-wire-up-RT-s-locking.patch
new file mode 100644
index 000000000..4a55d2f15
--- /dev/null
+++ b/debian/patches-rt/0175-locking-rtmutex-wire-up-RT-s-locking.patch
@@ -0,0 +1,348 @@
+From 48720bc07f81cfe49fe8e2a7afa1f18acd9227dd Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 12 Oct 2017 17:31:14 +0200
+Subject: [PATCH 175/323] locking/rtmutex: wire up RT's locking
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/mutex.h             | 26 ++++++++++++++++----------
+ include/linux/rwsem.h             | 12 ++++++++++++
+ include/linux/spinlock.h          | 12 +++++++++++-
+ include/linux/spinlock_api_smp.h  |  4 +++-
+ include/linux/spinlock_types.h    | 11 ++++++++---
+ include/linux/spinlock_types_up.h |  2 +-
+ kernel/Kconfig.preempt            |  1 +
+ kernel/locking/Makefile           | 10 +++++++---
+ kernel/locking/rwsem.c            |  6 ++++++
+ kernel/locking/spinlock.c         |  7 +++++++
+ kernel/locking/spinlock_debug.c   |  5 +++++
+ 11 files changed, 77 insertions(+), 19 deletions(-)
+
+diff --git a/include/linux/mutex.h b/include/linux/mutex.h
+index 4d671fba3cab..e45774a337d2 100644
+--- a/include/linux/mutex.h
++++ b/include/linux/mutex.h
+@@ -22,6 +22,20 @@
+ 
+ struct ww_acquire_ctx;
+ 
++#ifdef CONFIG_DEBUG_LOCK_ALLOC
++# define __DEP_MAP_MUTEX_INITIALIZER(lockname)			\
++		, .dep_map = {					\
++			.name = #lockname,			\
++			.wait_type_inner = LD_WAIT_SLEEP,	\
++		}
++#else
++# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
++#endif
++
++#ifdef CONFIG_PREEMPT_RT
++# include <linux/mutex_rt.h>
++#else
++
+ /*
+  * Simple, straightforward mutexes with strict semantics:
+  *
+@@ -119,16 +133,6 @@ do {									\
+ 	__mutex_init((mutex), #mutex, &__key);				\
+ } while (0)
+ 
+-#ifdef CONFIG_DEBUG_LOCK_ALLOC
+-# define __DEP_MAP_MUTEX_INITIALIZER(lockname)			\
+-		, .dep_map = {					\
+-			.name = #lockname,			\
+-			.wait_type_inner = LD_WAIT_SLEEP,	\
+-		}
+-#else
+-# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
+-#endif
+-
+ #define __MUTEX_INITIALIZER(lockname) \
+ 		{ .owner = ATOMIC_LONG_INIT(0) \
+ 		, .wait_lock = __SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
+@@ -224,4 +228,6 @@ enum mutex_trylock_recursive_enum {
+ extern /* __deprecated */ __must_check enum mutex_trylock_recursive_enum
+ mutex_trylock_recursive(struct mutex *lock);
+ 
++#endif /* !PREEMPT_RT */
++
+ #endif /* __LINUX_MUTEX_H */
+diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
+index 4c715be48717..9323af8a9244 100644
+--- a/include/linux/rwsem.h
++++ b/include/linux/rwsem.h
+@@ -16,6 +16,11 @@
+ #include <linux/spinlock.h>
+ #include <linux/atomic.h>
+ #include <linux/err.h>
++
++#ifdef CONFIG_PREEMPT_RT
++#include <linux/rwsem-rt.h>
++#else /* PREEMPT_RT */
++
+ #ifdef CONFIG_RWSEM_SPIN_ON_OWNER
+ #include <linux/osq_lock.h>
+ #endif
+@@ -119,6 +124,13 @@ static inline int rwsem_is_contended(struct rw_semaphore *sem)
+ 	return !list_empty(&sem->wait_list);
+ }
+ 
++#endif /* !PREEMPT_RT */
++
++/*
++ * The functions below are the same for all rwsem implementations including
++ * the RT specific variant.
++ */
++
+ /*
+  * lock for reading
+  */
+diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
+index 79897841a2cc..c3c70291b46c 100644
+--- a/include/linux/spinlock.h
++++ b/include/linux/spinlock.h
+@@ -309,7 +309,11 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
+ })
+ 
+ /* Include rwlock functions */
+-#include <linux/rwlock.h>
++#ifdef CONFIG_PREEMPT_RT
++# include <linux/rwlock_rt.h>
++#else
++# include <linux/rwlock.h>
++#endif
+ 
+ /*
+  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
+@@ -320,6 +324,10 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
+ # include <linux/spinlock_api_up.h>
+ #endif
+ 
++#ifdef CONFIG_PREEMPT_RT
++# include <linux/spinlock_rt.h>
++#else /* PREEMPT_RT */
++
+ /*
+  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
+  */
+@@ -454,6 +462,8 @@ static __always_inline int spin_is_contended(spinlock_t *lock)
+ 
+ #define assert_spin_locked(lock)	assert_raw_spin_locked(&(lock)->rlock)
+ 
++#endif /* !PREEMPT_RT */
++
+ /*
+  * Pull the atomic_t declaration:
+  * (asm-mips/atomic.h needs above definitions)
+diff --git a/include/linux/spinlock_api_smp.h b/include/linux/spinlock_api_smp.h
+index 19a9be9d97ee..da38149f2843 100644
+--- a/include/linux/spinlock_api_smp.h
++++ b/include/linux/spinlock_api_smp.h
+@@ -187,6 +187,8 @@ static inline int __raw_spin_trylock_bh(raw_spinlock_t *lock)
+ 	return 0;
+ }
+ 
+-#include <linux/rwlock_api_smp.h>
++#ifndef CONFIG_PREEMPT_RT
++# include <linux/rwlock_api_smp.h>
++#endif
+ 
+ #endif /* __LINUX_SPINLOCK_API_SMP_H */
+diff --git a/include/linux/spinlock_types.h b/include/linux/spinlock_types.h
+index 5c8664d57fb8..8d896d3e1a01 100644
+--- a/include/linux/spinlock_types.h
++++ b/include/linux/spinlock_types.h
+@@ -11,8 +11,13 @@
+ 
+ #include <linux/spinlock_types_raw.h>
+ 
+-#include <linux/spinlock_types_nort.h>
+-
+-#include <linux/rwlock_types.h>
++#ifndef CONFIG_PREEMPT_RT
++# include <linux/spinlock_types_nort.h>
++# include <linux/rwlock_types.h>
++#else
++# include <linux/rtmutex.h>
++# include <linux/spinlock_types_rt.h>
++# include <linux/rwlock_types_rt.h>
++#endif
+ 
+ #endif /* __LINUX_SPINLOCK_TYPES_H */
+diff --git a/include/linux/spinlock_types_up.h b/include/linux/spinlock_types_up.h
+index c09b6407ae1b..d9b371fa13e0 100644
+--- a/include/linux/spinlock_types_up.h
++++ b/include/linux/spinlock_types_up.h
+@@ -1,7 +1,7 @@
+ #ifndef __LINUX_SPINLOCK_TYPES_UP_H
+ #define __LINUX_SPINLOCK_TYPES_UP_H
+ 
+-#ifndef __LINUX_SPINLOCK_TYPES_H
++#if !defined(__LINUX_SPINLOCK_TYPES_H) && !defined(__LINUX_RT_MUTEX_H)
+ # error "please don't include this file directly"
+ #endif
+ 
+diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
+index bf82259cff96..cbe3aa495519 100644
+--- a/kernel/Kconfig.preempt
++++ b/kernel/Kconfig.preempt
+@@ -59,6 +59,7 @@ config PREEMPT_RT
+ 	bool "Fully Preemptible Kernel (Real-Time)"
+ 	depends on EXPERT && ARCH_SUPPORTS_RT
+ 	select PREEMPTION
++	select RT_MUTEXES
+ 	help
+ 	  This option turns the kernel into a real-time kernel by replacing
+ 	  various locking primitives (spinlocks, rwlocks, etc.) with
+diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
+index 6d11cfb9b41f..c7fbf737e16e 100644
+--- a/kernel/locking/Makefile
++++ b/kernel/locking/Makefile
+@@ -3,7 +3,7 @@
+ # and is generally not a function of system call inputs.
+ KCOV_INSTRUMENT		:= n
+ 
+-obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o
++obj-y += semaphore.o rwsem.o percpu-rwsem.o
+ 
+ # Avoid recursion lockdep -> KCSAN -> ... -> lockdep.
+ KCSAN_SANITIZE_lockdep.o := n
+@@ -15,19 +15,23 @@ CFLAGS_REMOVE_mutex-debug.o = $(CC_FLAGS_FTRACE)
+ CFLAGS_REMOVE_rtmutex-debug.o = $(CC_FLAGS_FTRACE)
+ endif
+ 
+-obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
+ obj-$(CONFIG_LOCKDEP) += lockdep.o
+ ifeq ($(CONFIG_PROC_FS),y)
+ obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
+ endif
+ obj-$(CONFIG_SMP) += spinlock.o
+-obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o
+ obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
+ obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o
+ obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
+ obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
+ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
+ obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
++ifneq ($(CONFIG_PREEMPT_RT),y)
++obj-y += mutex.o
++obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o
++obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
++endif
++obj-$(CONFIG_PREEMPT_RT) += mutex-rt.o rwsem-rt.o rwlock-rt.o
+ obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o
+ obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
+ obj-$(CONFIG_WW_MUTEX_SELFTEST) += test-ww_mutex.o
+diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
+index cc5cc889b5b7..f7c909ef1261 100644
+--- a/kernel/locking/rwsem.c
++++ b/kernel/locking/rwsem.c
+@@ -28,6 +28,7 @@
+ #include <linux/rwsem.h>
+ #include <linux/atomic.h>
+ 
++#ifndef CONFIG_PREEMPT_RT
+ #include "lock_events.h"
+ 
+ /*
+@@ -1494,6 +1495,7 @@ static inline void __downgrade_write(struct rw_semaphore *sem)
+ 	if (tmp & RWSEM_FLAG_WAITERS)
+ 		rwsem_downgrade_wake(sem);
+ }
++#endif
+ 
+ /*
+  * lock for reading
+@@ -1657,7 +1659,9 @@ void down_read_non_owner(struct rw_semaphore *sem)
+ {
+ 	might_sleep();
+ 	__down_read(sem);
++#ifndef CONFIG_PREEMPT_RT
+ 	__rwsem_set_reader_owned(sem, NULL);
++#endif
+ }
+ EXPORT_SYMBOL(down_read_non_owner);
+ 
+@@ -1686,7 +1690,9 @@ EXPORT_SYMBOL(down_write_killable_nested);
+ 
+ void up_read_non_owner(struct rw_semaphore *sem)
+ {
++#ifndef CONFIG_PREEMPT_RT
+ 	DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
++#endif
+ 	__up_read(sem);
+ }
+ EXPORT_SYMBOL(up_read_non_owner);
+diff --git a/kernel/locking/spinlock.c b/kernel/locking/spinlock.c
+index 0ff08380f531..45445a2f1799 100644
+--- a/kernel/locking/spinlock.c
++++ b/kernel/locking/spinlock.c
+@@ -124,8 +124,11 @@ void __lockfunc __raw_##op##_lock_bh(locktype##_t *lock)		\
+  *         __[spin|read|write]_lock_bh()
+  */
+ BUILD_LOCK_OPS(spin, raw_spinlock);
++
++#ifndef CONFIG_PREEMPT_RT
+ BUILD_LOCK_OPS(read, rwlock);
+ BUILD_LOCK_OPS(write, rwlock);
++#endif
+ 
+ #endif
+ 
+@@ -209,6 +212,8 @@ void __lockfunc _raw_spin_unlock_bh(raw_spinlock_t *lock)
+ EXPORT_SYMBOL(_raw_spin_unlock_bh);
+ #endif
+ 
++#ifndef CONFIG_PREEMPT_RT
++
+ #ifndef CONFIG_INLINE_READ_TRYLOCK
+ int __lockfunc _raw_read_trylock(rwlock_t *lock)
+ {
+@@ -353,6 +358,8 @@ void __lockfunc _raw_write_unlock_bh(rwlock_t *lock)
+ EXPORT_SYMBOL(_raw_write_unlock_bh);
+ #endif
+ 
++#endif /* !PREEMPT_RT */
++
+ #ifdef CONFIG_DEBUG_LOCK_ALLOC
+ 
+ void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
+diff --git a/kernel/locking/spinlock_debug.c b/kernel/locking/spinlock_debug.c
+index b9d93087ee66..72e306e0e8a3 100644
+--- a/kernel/locking/spinlock_debug.c
++++ b/kernel/locking/spinlock_debug.c
+@@ -31,6 +31,7 @@ void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
+ 
+ EXPORT_SYMBOL(__raw_spin_lock_init);
+ 
++#ifndef CONFIG_PREEMPT_RT
+ void __rwlock_init(rwlock_t *lock, const char *name,
+ 		   struct lock_class_key *key)
+ {
+@@ -48,6 +49,7 @@ void __rwlock_init(rwlock_t *lock, const char *name,
+ }
+ 
+ EXPORT_SYMBOL(__rwlock_init);
++#endif
+ 
+ static void spin_dump(raw_spinlock_t *lock, const char *msg)
+ {
+@@ -139,6 +141,7 @@ void do_raw_spin_unlock(raw_spinlock_t *lock)
+ 	arch_spin_unlock(&lock->raw_lock);
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT
+ static void rwlock_bug(rwlock_t *lock, const char *msg)
+ {
+ 	if (!debug_locks_off())
+@@ -228,3 +231,5 @@ void do_raw_write_unlock(rwlock_t *lock)
+ 	debug_write_unlock(lock);
+ 	arch_write_unlock(&lock->raw_lock);
+ }
++
++#endif
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0176-locking-rtmutex-add-ww_mutex-addon-for-mutex-rt.patch b/debian/patches-rt/0176-locking-rtmutex-add-ww_mutex-addon-for-mutex-rt.patch
new file mode 100644
index 000000000..4199d82f9
--- /dev/null
+++ b/debian/patches-rt/0176-locking-rtmutex-add-ww_mutex-addon-for-mutex-rt.patch
@@ -0,0 +1,456 @@
+From 47ba586f2ade0d9f8cc9281cb08529146bfc3c5d Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Thu, 12 Oct 2017 17:34:38 +0200
+Subject: [PATCH 176/323] locking/rtmutex: add ww_mutex addon for mutex-rt
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/mutex.h           |   8 -
+ include/linux/ww_mutex.h        |   8 +
+ kernel/locking/rtmutex.c        | 262 ++++++++++++++++++++++++++++++--
+ kernel/locking/rtmutex_common.h |   2 +
+ kernel/locking/rwsem-rt.c       |   2 +-
+ 5 files changed, 262 insertions(+), 20 deletions(-)
+
+diff --git a/include/linux/mutex.h b/include/linux/mutex.h
+index e45774a337d2..90923d3008fc 100644
+--- a/include/linux/mutex.h
++++ b/include/linux/mutex.h
+@@ -82,14 +82,6 @@ struct mutex {
+ struct ww_class;
+ struct ww_acquire_ctx;
+ 
+-struct ww_mutex {
+-	struct mutex base;
+-	struct ww_acquire_ctx *ctx;
+-#ifdef CONFIG_DEBUG_MUTEXES
+-	struct ww_class *ww_class;
+-#endif
+-};
+-
+ /*
+  * This is the control structure for tasks blocked on mutex,
+  * which resides on the blocked task's kernel stack:
+diff --git a/include/linux/ww_mutex.h b/include/linux/ww_mutex.h
+index 6ecf2a0220db..3145de598645 100644
+--- a/include/linux/ww_mutex.h
++++ b/include/linux/ww_mutex.h
+@@ -28,6 +28,14 @@ struct ww_class {
+ 	unsigned int is_wait_die;
+ };
+ 
++struct ww_mutex {
++	struct mutex base;
++	struct ww_acquire_ctx *ctx;
++#ifdef CONFIG_DEBUG_MUTEXES
++	struct ww_class *ww_class;
++#endif
++};
++
+ struct ww_acquire_ctx {
+ 	struct task_struct *task;
+ 	unsigned long stamp;
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index 1bf7a04688c5..c095d1b92f70 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -24,6 +24,7 @@
+ #include <linux/sched/wake_q.h>
+ #include <linux/sched/debug.h>
+ #include <linux/timer.h>
++#include <linux/ww_mutex.h>
+ 
+ #include "rtmutex_common.h"
+ 
+@@ -1234,6 +1235,40 @@ EXPORT_SYMBOL(__rt_spin_lock_init);
+ 
+ #endif /* PREEMPT_RT */
+ 
++#ifdef CONFIG_PREEMPT_RT
++	static inline int __sched
++__mutex_lock_check_stamp(struct rt_mutex *lock, struct ww_acquire_ctx *ctx)
++{
++	struct ww_mutex *ww = container_of(lock, struct ww_mutex, base.lock);
++	struct ww_acquire_ctx *hold_ctx = READ_ONCE(ww->ctx);
++
++	if (!hold_ctx)
++		return 0;
++
++	if (unlikely(ctx == hold_ctx))
++		return -EALREADY;
++
++	if (ctx->stamp - hold_ctx->stamp <= LONG_MAX &&
++	    (ctx->stamp != hold_ctx->stamp || ctx > hold_ctx)) {
++#ifdef CONFIG_DEBUG_MUTEXES
++		DEBUG_LOCKS_WARN_ON(ctx->contending_lock);
++		ctx->contending_lock = ww;
++#endif
++		return -EDEADLK;
++	}
++
++	return 0;
++}
++#else
++	static inline int __sched
++__mutex_lock_check_stamp(struct rt_mutex *lock, struct ww_acquire_ctx *ctx)
++{
++	BUG();
++	return 0;
++}
++
++#endif
++
+ static inline int
+ try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+ 		     struct rt_mutex_waiter *waiter)
+@@ -1512,7 +1547,8 @@ void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter, bool savestate)
+ static int __sched
+ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ 		    struct hrtimer_sleeper *timeout,
+-		    struct rt_mutex_waiter *waiter)
++		    struct rt_mutex_waiter *waiter,
++		    struct ww_acquire_ctx *ww_ctx)
+ {
+ 	int ret = 0;
+ 
+@@ -1530,6 +1566,12 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ 			break;
+ 		}
+ 
++		if (ww_ctx && ww_ctx->acquired > 0) {
++			ret = __mutex_lock_check_stamp(lock, ww_ctx);
++			if (ret)
++				break;
++		}
++
+ 		raw_spin_unlock_irq(&lock->wait_lock);
+ 
+ 		schedule();
+@@ -1558,16 +1600,106 @@ static void rt_mutex_handle_deadlock(int res, int detect_deadlock,
+ 	}
+ }
+ 
++static __always_inline void ww_mutex_lock_acquired(struct ww_mutex *ww,
++						   struct ww_acquire_ctx *ww_ctx)
++{
++#ifdef CONFIG_DEBUG_MUTEXES
++	/*
++	 * If this WARN_ON triggers, you used ww_mutex_lock to acquire,
++	 * but released with a normal mutex_unlock in this call.
++	 *
++	 * This should never happen, always use ww_mutex_unlock.
++	 */
++	DEBUG_LOCKS_WARN_ON(ww->ctx);
++
++	/*
++	 * Not quite done after calling ww_acquire_done() ?
++	 */
++	DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire);
++
++	if (ww_ctx->contending_lock) {
++		/*
++		 * After -EDEADLK you tried to
++		 * acquire a different ww_mutex? Bad!
++		 */
++		DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww);
++
++		/*
++		 * You called ww_mutex_lock after receiving -EDEADLK,
++		 * but 'forgot' to unlock everything else first?
++		 */
++		DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0);
++		ww_ctx->contending_lock = NULL;
++	}
++
++	/*
++	 * Naughty, using a different class will lead to undefined behavior!
++	 */
++	DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class);
++#endif
++	ww_ctx->acquired++;
++}
++
++#ifdef CONFIG_PREEMPT_RT
++static void ww_mutex_account_lock(struct rt_mutex *lock,
++				  struct ww_acquire_ctx *ww_ctx)
++{
++	struct ww_mutex *ww = container_of(lock, struct ww_mutex, base.lock);
++	struct rt_mutex_waiter *waiter, *n;
++
++	/*
++	 * This branch gets optimized out for the common case,
++	 * and is only important for ww_mutex_lock.
++	 */
++	ww_mutex_lock_acquired(ww, ww_ctx);
++	ww->ctx = ww_ctx;
++
++	/*
++	 * Give any possible sleeping processes the chance to wake up,
++	 * so they can recheck if they have to back off.
++	 */
++	rbtree_postorder_for_each_entry_safe(waiter, n, &lock->waiters.rb_root,
++					     tree_entry) {
++		/* XXX debug rt mutex waiter wakeup */
++
++		BUG_ON(waiter->lock != lock);
++		rt_mutex_wake_waiter(waiter);
++	}
++}
++
++#else
++
++static void ww_mutex_account_lock(struct rt_mutex *lock,
++				  struct ww_acquire_ctx *ww_ctx)
++{
++	BUG();
++}
++#endif
++
+ int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+ 				     struct hrtimer_sleeper *timeout,
+ 				     enum rtmutex_chainwalk chwalk,
++				     struct ww_acquire_ctx *ww_ctx,
+ 				     struct rt_mutex_waiter *waiter)
+ {
+ 	int ret;
+ 
++#ifdef CONFIG_PREEMPT_RT
++	if (ww_ctx) {
++		struct ww_mutex *ww;
++
++		ww = container_of(lock, struct ww_mutex, base.lock);
++		if (unlikely(ww_ctx == READ_ONCE(ww->ctx)))
++			return -EALREADY;
++	}
++#endif
++
+ 	/* Try to acquire the lock again: */
+-	if (try_to_take_rt_mutex(lock, current, NULL))
++	if (try_to_take_rt_mutex(lock, current, NULL)) {
++		if (ww_ctx)
++			ww_mutex_account_lock(lock, ww_ctx);
+ 		return 0;
++	}
+ 
+ 	set_current_state(state);
+ 
+@@ -1577,14 +1709,24 @@ int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+ 
+ 	ret = task_blocks_on_rt_mutex(lock, waiter, current, chwalk);
+ 
+-	if (likely(!ret))
++	if (likely(!ret)) {
+ 		/* sleep on the mutex */
+-		ret = __rt_mutex_slowlock(lock, state, timeout, waiter);
++		ret = __rt_mutex_slowlock(lock, state, timeout, waiter,
++					  ww_ctx);
++	} else if (ww_ctx) {
++		/* ww_mutex received EDEADLK, let it become EALREADY */
++		ret = __mutex_lock_check_stamp(lock, ww_ctx);
++		BUG_ON(!ret);
++	}
+ 
+ 	if (unlikely(ret)) {
+ 		__set_current_state(TASK_RUNNING);
+ 		remove_waiter(lock, waiter);
+-		rt_mutex_handle_deadlock(ret, chwalk, waiter);
++		/* ww_mutex wants to report EDEADLK/EALREADY, let it */
++		if (!ww_ctx)
++			rt_mutex_handle_deadlock(ret, chwalk, waiter);
++	} else if (ww_ctx) {
++		ww_mutex_account_lock(lock, ww_ctx);
+ 	}
+ 
+ 	/*
+@@ -1601,7 +1743,8 @@ int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+ static int __sched
+ rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ 		  struct hrtimer_sleeper *timeout,
+-		  enum rtmutex_chainwalk chwalk)
++		  enum rtmutex_chainwalk chwalk,
++		  struct ww_acquire_ctx *ww_ctx)
+ {
+ 	struct rt_mutex_waiter waiter;
+ 	unsigned long flags;
+@@ -1619,7 +1762,8 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ 	 */
+ 	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+ 
+-	ret = rt_mutex_slowlock_locked(lock, state, timeout, chwalk, &waiter);
++	ret = rt_mutex_slowlock_locked(lock, state, timeout, chwalk, ww_ctx,
++				       &waiter);
+ 
+ 	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+ 
+@@ -1749,14 +1893,16 @@ static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
+  */
+ static inline int
+ rt_mutex_fastlock(struct rt_mutex *lock, int state,
++		  struct ww_acquire_ctx *ww_ctx,
+ 		  int (*slowfn)(struct rt_mutex *lock, int state,
+ 				struct hrtimer_sleeper *timeout,
+-				enum rtmutex_chainwalk chwalk))
++				enum rtmutex_chainwalk chwalk,
++				struct ww_acquire_ctx *ww_ctx))
+ {
+ 	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
+ 		return 0;
+ 
+-	return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
++	return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK, ww_ctx);
+ }
+ 
+ static inline int
+@@ -1801,7 +1947,7 @@ rt_mutex_fastunlock(struct rt_mutex *lock,
+ int __sched __rt_mutex_lock_state(struct rt_mutex *lock, int state)
+ {
+ 	might_sleep();
+-	return rt_mutex_fastlock(lock, state, rt_mutex_slowlock);
++	return rt_mutex_fastlock(lock, state, NULL, rt_mutex_slowlock);
+ }
+ 
+ /**
+@@ -2245,7 +2391,7 @@ int rt_mutex_wait_proxy_lock(struct rt_mutex *lock,
+ 	raw_spin_lock_irq(&lock->wait_lock);
+ 	/* sleep on the mutex */
+ 	set_current_state(TASK_INTERRUPTIBLE);
+-	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter);
++	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter, NULL);
+ 	/*
+ 	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
+ 	 * have to fix that up.
+@@ -2315,3 +2461,97 @@ bool rt_mutex_cleanup_proxy_lock(struct rt_mutex *lock,
+ 
+ 	return cleanup;
+ }
++
++static inline int
++ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
++{
++#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
++	unsigned int tmp;
++
++	if (ctx->deadlock_inject_countdown-- == 0) {
++		tmp = ctx->deadlock_inject_interval;
++		if (tmp > UINT_MAX/4)
++			tmp = UINT_MAX;
++		else
++			tmp = tmp*2 + tmp + tmp/2;
++
++		ctx->deadlock_inject_interval = tmp;
++		ctx->deadlock_inject_countdown = tmp;
++		ctx->contending_lock = lock;
++
++		ww_mutex_unlock(lock);
++
++		return -EDEADLK;
++	}
++#endif
++
++	return 0;
++}
++
++#ifdef CONFIG_PREEMPT_RT
++int __sched
++ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
++{
++	int ret;
++
++	might_sleep();
++
++	mutex_acquire_nest(&lock->base.dep_map, 0, 0,
++			   ctx ? &ctx->dep_map : NULL, _RET_IP_);
++	ret = rt_mutex_slowlock(&lock->base.lock, TASK_INTERRUPTIBLE, NULL, 0,
++				ctx);
++	if (ret)
++		mutex_release(&lock->base.dep_map, _RET_IP_);
++	else if (!ret && ctx && ctx->acquired > 1)
++		return ww_mutex_deadlock_injection(lock, ctx);
++
++	return ret;
++}
++EXPORT_SYMBOL_GPL(ww_mutex_lock_interruptible);
++
++int __sched
++ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
++{
++	int ret;
++
++	might_sleep();
++
++	mutex_acquire_nest(&lock->base.dep_map, 0, 0,
++			   ctx ? &ctx->dep_map : NULL, _RET_IP_);
++	ret = rt_mutex_slowlock(&lock->base.lock, TASK_UNINTERRUPTIBLE, NULL, 0,
++				ctx);
++	if (ret)
++		mutex_release(&lock->base.dep_map, _RET_IP_);
++	else if (!ret && ctx && ctx->acquired > 1)
++		return ww_mutex_deadlock_injection(lock, ctx);
++
++	return ret;
++}
++EXPORT_SYMBOL_GPL(ww_mutex_lock);
++
++void __sched ww_mutex_unlock(struct ww_mutex *lock)
++{
++	/*
++	 * The unlocking fastpath is the 0->1 transition from 'locked'
++	 * into 'unlocked' state:
++	 */
++	if (lock->ctx) {
++#ifdef CONFIG_DEBUG_MUTEXES
++		DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired);
++#endif
++		if (lock->ctx->acquired > 0)
++			lock->ctx->acquired--;
++		lock->ctx = NULL;
++	}
++
++	mutex_release(&lock->base.dep_map, _RET_IP_);
++	__rt_mutex_unlock(&lock->base.lock);
++}
++EXPORT_SYMBOL(ww_mutex_unlock);
++
++int __rt_mutex_owner_current(struct rt_mutex *lock)
++{
++	return rt_mutex_owner(lock) == current;
++}
++EXPORT_SYMBOL(__rt_mutex_owner_current);
++#endif
+diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
+index c1a280167e3c..248a7d91583b 100644
+--- a/kernel/locking/rtmutex_common.h
++++ b/kernel/locking/rtmutex_common.h
+@@ -159,6 +159,7 @@ extern void rt_mutex_postunlock(struct wake_q_head *wake_q,
+ 				struct wake_q_head *wake_sleeper_q);
+ 
+ /* RW semaphore special interface */
++struct ww_acquire_ctx;
+ 
+ extern int __rt_mutex_lock_state(struct rt_mutex *lock, int state);
+ extern int __rt_mutex_trylock(struct rt_mutex *lock);
+@@ -166,6 +167,7 @@ extern void __rt_mutex_unlock(struct rt_mutex *lock);
+ int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+ 				     struct hrtimer_sleeper *timeout,
+ 				     enum rtmutex_chainwalk chwalk,
++				     struct ww_acquire_ctx *ww_ctx,
+ 				     struct rt_mutex_waiter *waiter);
+ void __sched rt_spin_lock_slowlock_locked(struct rt_mutex *lock,
+ 					  struct rt_mutex_waiter *waiter,
+diff --git a/kernel/locking/rwsem-rt.c b/kernel/locking/rwsem-rt.c
+index a0771c150041..274172d5bb3a 100644
+--- a/kernel/locking/rwsem-rt.c
++++ b/kernel/locking/rwsem-rt.c
+@@ -138,7 +138,7 @@ static int __sched __down_read_common(struct rw_semaphore *sem, int state)
+ 	 */
+ 	rt_mutex_init_waiter(&waiter, false);
+ 	ret = rt_mutex_slowlock_locked(m, state, NULL, RT_MUTEX_MIN_CHAINWALK,
+-				       &waiter);
++				       NULL, &waiter);
+ 	/*
+ 	 * The slowlock() above is guaranteed to return with the rtmutex (for
+ 	 * ret = 0) is now held, so there can't be a writer active. Increment
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0177-locking-rtmutex-Use-custom-scheduling-function-for-s.patch b/debian/patches-rt/0177-locking-rtmutex-Use-custom-scheduling-function-for-s.patch
new file mode 100644
index 000000000..9cabce468
--- /dev/null
+++ b/debian/patches-rt/0177-locking-rtmutex-Use-custom-scheduling-function-for-s.patch
@@ -0,0 +1,243 @@
+From 0a34a9993d2798ba232792f998e5ae5fe7519730 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 6 Oct 2020 13:07:17 +0200
+Subject: [PATCH 177/323] locking/rtmutex: Use custom scheduling function for
+ spin-schedule()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+PREEMPT_RT builds the rwsem, mutex, spinlock and rwlock typed locks on
+top of a rtmutex lock. While blocked task->pi_blocked_on is set
+(tsk_is_pi_blocked()) and task needs to schedule away while waiting.
+
+The schedule process must distinguish between blocking on a regular
+sleeping lock (rwsem and mutex) and a RT-only sleeping lock (spinlock
+and rwlock):
+- rwsem and mutex must flush block requests (blk_schedule_flush_plug())
+  even if blocked on a lock. This can not deadlock because this also
+  happens for non-RT.
+  There should be a warning if the scheduling point is within a RCU read
+  section.
+
+- spinlock and rwlock must not flush block requests. This will deadlock
+  if the callback attempts to acquire a lock which is already acquired.
+  Similarly to being preempted, there should be no warning if the
+  scheduling point is within a RCU read section.
+
+Add preempt_schedule_lock() which is invoked if scheduling is required
+while blocking on a PREEMPT_RT-only sleeping lock.
+Remove tsk_is_pi_blocked() from the scheduler path which is no longer
+needed with the additional scheduler entry point.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/arm64/include/asm/preempt.h |  3 +++
+ arch/x86/include/asm/preempt.h   |  3 +++
+ include/asm-generic/preempt.h    |  3 +++
+ include/linux/sched/rt.h         |  8 --------
+ kernel/locking/rtmutex.c         |  2 +-
+ kernel/locking/rwlock-rt.c       |  2 +-
+ kernel/sched/core.c              | 32 +++++++++++++++++++++-----------
+ 7 files changed, 32 insertions(+), 21 deletions(-)
+
+diff --git a/arch/arm64/include/asm/preempt.h b/arch/arm64/include/asm/preempt.h
+index e83f0982b99c..f1486b32502c 100644
+--- a/arch/arm64/include/asm/preempt.h
++++ b/arch/arm64/include/asm/preempt.h
+@@ -81,6 +81,9 @@ static inline bool should_resched(int preempt_offset)
+ 
+ #ifdef CONFIG_PREEMPTION
+ void preempt_schedule(void);
++#ifdef CONFIG_PREEMPT_RT
++void preempt_schedule_lock(void);
++#endif
+ #define __preempt_schedule() preempt_schedule()
+ void preempt_schedule_notrace(void);
+ #define __preempt_schedule_notrace() preempt_schedule_notrace()
+diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
+index a334dd0d7c42..50e0c0ab7b97 100644
+--- a/arch/x86/include/asm/preempt.h
++++ b/arch/x86/include/asm/preempt.h
+@@ -103,6 +103,9 @@ static __always_inline bool should_resched(int preempt_offset)
+ }
+ 
+ #ifdef CONFIG_PREEMPTION
++#ifdef CONFIG_PREEMPT_RT
++  extern void preempt_schedule_lock(void);
++#endif
+   extern asmlinkage void preempt_schedule_thunk(void);
+ # define __preempt_schedule() \
+ 	asm volatile ("call preempt_schedule_thunk" : ASM_CALL_CONSTRAINT)
+diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h
+index b4d43a4af5f7..ac255e889462 100644
+--- a/include/asm-generic/preempt.h
++++ b/include/asm-generic/preempt.h
+@@ -79,6 +79,9 @@ static __always_inline bool should_resched(int preempt_offset)
+ }
+ 
+ #ifdef CONFIG_PREEMPTION
++#ifdef CONFIG_PREEMPT_RT
++extern void preempt_schedule_lock(void);
++#endif
+ extern asmlinkage void preempt_schedule(void);
+ #define __preempt_schedule() preempt_schedule()
+ extern asmlinkage void preempt_schedule_notrace(void);
+diff --git a/include/linux/sched/rt.h b/include/linux/sched/rt.h
+index e5af028c08b4..994c25640e15 100644
+--- a/include/linux/sched/rt.h
++++ b/include/linux/sched/rt.h
+@@ -39,20 +39,12 @@ static inline struct task_struct *rt_mutex_get_top_task(struct task_struct *p)
+ }
+ extern void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task);
+ extern void rt_mutex_adjust_pi(struct task_struct *p);
+-static inline bool tsk_is_pi_blocked(struct task_struct *tsk)
+-{
+-	return tsk->pi_blocked_on != NULL;
+-}
+ #else
+ static inline struct task_struct *rt_mutex_get_top_task(struct task_struct *task)
+ {
+ 	return NULL;
+ }
+ # define rt_mutex_adjust_pi(p)		do { } while (0)
+-static inline bool tsk_is_pi_blocked(struct task_struct *tsk)
+-{
+-	return false;
+-}
+ #endif
+ 
+ extern void normalize_rt_tasks(void);
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index c095d1b92f70..2fe178651254 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -1067,7 +1067,7 @@ void __sched rt_spin_lock_slowlock_locked(struct rt_mutex *lock,
+ 		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+ 
+ 		if (top_waiter != waiter || adaptive_wait(lock, lock_owner))
+-			schedule();
++			preempt_schedule_lock();
+ 
+ 		raw_spin_lock_irqsave(&lock->wait_lock, flags);
+ 
+diff --git a/kernel/locking/rwlock-rt.c b/kernel/locking/rwlock-rt.c
+index 1ee16b8fedd7..16be7111aae7 100644
+--- a/kernel/locking/rwlock-rt.c
++++ b/kernel/locking/rwlock-rt.c
+@@ -211,7 +211,7 @@ static void __write_rt_lock(struct rt_rw_lock *lock)
+ 		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+ 
+ 		if (atomic_read(&lock->readers) != 0)
+-			schedule();
++			preempt_schedule_lock();
+ 
+ 		raw_spin_lock_irqsave(&m->wait_lock, flags);
+ 
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index be5d41ed6ff2..aaeed4b14278 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -5001,7 +5001,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
+  *
+  * WARNING: must be called with preemption disabled!
+  */
+-static void __sched notrace __schedule(bool preempt)
++static void __sched notrace __schedule(bool preempt, bool spinning_lock)
+ {
+ 	struct task_struct *prev, *next;
+ 	unsigned long *switch_count;
+@@ -5054,7 +5054,7 @@ static void __sched notrace __schedule(bool preempt)
+ 	 *  - ptrace_{,un}freeze_traced() can change ->state underneath us.
+ 	 */
+ 	prev_state = prev->state;
+-	if (!preempt && prev_state) {
++	if ((!preempt || spinning_lock) && prev_state) {
+ 		if (signal_pending_state(prev_state, prev)) {
+ 			prev->state = TASK_RUNNING;
+ 		} else {
+@@ -5138,7 +5138,7 @@ void __noreturn do_task_dead(void)
+ 	/* Tell freezer to ignore us: */
+ 	current->flags |= PF_NOFREEZE;
+ 
+-	__schedule(false);
++	__schedule(false, false);
+ 	BUG();
+ 
+ 	/* Avoid "noreturn function does return" - but don't continue if BUG() is a NOP: */
+@@ -5171,9 +5171,6 @@ static inline void sched_submit_work(struct task_struct *tsk)
+ 		preempt_enable_no_resched();
+ 	}
+ 
+-	if (tsk_is_pi_blocked(tsk))
+-		return;
+-
+ 	/*
+ 	 * If we are going to sleep and we have plugged IO queued,
+ 	 * make sure to submit it to avoid deadlocks.
+@@ -5199,7 +5196,7 @@ asmlinkage __visible void __sched schedule(void)
+ 	sched_submit_work(tsk);
+ 	do {
+ 		preempt_disable();
+-		__schedule(false);
++		__schedule(false, false);
+ 		sched_preempt_enable_no_resched();
+ 	} while (need_resched());
+ 	sched_update_worker(tsk);
+@@ -5227,7 +5224,7 @@ void __sched schedule_idle(void)
+ 	 */
+ 	WARN_ON_ONCE(current->state);
+ 	do {
+-		__schedule(false);
++		__schedule(false, false);
+ 	} while (need_resched());
+ }
+ 
+@@ -5280,7 +5277,7 @@ static void __sched notrace preempt_schedule_common(void)
+ 		 */
+ 		preempt_disable_notrace();
+ 		preempt_latency_start(1);
+-		__schedule(true);
++		__schedule(true, false);
+ 		preempt_latency_stop(1);
+ 		preempt_enable_no_resched_notrace();
+ 
+@@ -5310,6 +5307,19 @@ asmlinkage __visible void __sched notrace preempt_schedule(void)
+ NOKPROBE_SYMBOL(preempt_schedule);
+ EXPORT_SYMBOL(preempt_schedule);
+ 
++#ifdef CONFIG_PREEMPT_RT
++void __sched notrace preempt_schedule_lock(void)
++{
++	do {
++		preempt_disable();
++		__schedule(true, true);
++		sched_preempt_enable_no_resched();
++	} while (need_resched());
++}
++NOKPROBE_SYMBOL(preempt_schedule_lock);
++EXPORT_SYMBOL(preempt_schedule_lock);
++#endif
++
+ /**
+  * preempt_schedule_notrace - preempt_schedule called by tracing
+  *
+@@ -5353,7 +5363,7 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
+ 		 * an infinite recursion.
+ 		 */
+ 		prev_ctx = exception_enter();
+-		__schedule(true);
++		__schedule(true, false);
+ 		exception_exit(prev_ctx);
+ 
+ 		preempt_latency_stop(1);
+@@ -5382,7 +5392,7 @@ asmlinkage __visible void __sched preempt_schedule_irq(void)
+ 	do {
+ 		preempt_disable();
+ 		local_irq_enable();
+-		__schedule(true);
++		__schedule(true, false);
+ 		local_irq_disable();
+ 		sched_preempt_enable_no_resched();
+ 	} while (need_resched());
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0178-signal-Revert-ptrace-preempt-magic.patch b/debian/patches-rt/0178-signal-Revert-ptrace-preempt-magic.patch
new file mode 100644
index 000000000..c90e0baa5
--- /dev/null
+++ b/debian/patches-rt/0178-signal-Revert-ptrace-preempt-magic.patch
@@ -0,0 +1,39 @@
+From 3d8d7beacea4da55fdd1b45bc8d5c19da1438dcb Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 21 Sep 2011 19:57:12 +0200
+Subject: [PATCH 178/323] signal: Revert ptrace preempt magic
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Upstream commit '53da1d9456fe7f8 fix ptrace slowness' is nothing more
+than a bandaid around the ptrace design trainwreck. It's not a
+correctness issue, it's merily a cosmetic bandaid.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ kernel/signal.c | 8 --------
+ 1 file changed, 8 deletions(-)
+
+diff --git a/kernel/signal.c b/kernel/signal.c
+index e487c4660921..5ab628e2afc5 100644
+--- a/kernel/signal.c
++++ b/kernel/signal.c
+@@ -2193,16 +2193,8 @@ static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t
+ 		if (gstop_done && ptrace_reparented(current))
+ 			do_notify_parent_cldstop(current, false, why);
+ 
+-		/*
+-		 * Don't want to allow preemption here, because
+-		 * sys_ptrace() needs this task to be inactive.
+-		 *
+-		 * XXX: implement read_unlock_no_resched().
+-		 */
+-		preempt_disable();
+ 		read_unlock(&tasklist_lock);
+ 		cgroup_enter_frozen();
+-		preempt_enable_no_resched();
+ 		freezable_schedule();
+ 		cgroup_leave_frozen(true);
+ 	} else {
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0179-preempt-Provide-preempt_-_-no-rt-variants.patch b/debian/patches-rt/0179-preempt-Provide-preempt_-_-no-rt-variants.patch
new file mode 100644
index 000000000..044b63df6
--- /dev/null
+++ b/debian/patches-rt/0179-preempt-Provide-preempt_-_-no-rt-variants.patch
@@ -0,0 +1,53 @@
+From 500d1733493dabbf5baf698854070d3cb1b0990f Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 24 Jul 2009 12:38:56 +0200
+Subject: [PATCH 179/323] preempt: Provide preempt_*_(no)rt variants
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+RT needs a few preempt_disable/enable points which are not necessary
+otherwise. Implement variants to avoid #ifdeffery.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/preempt.h | 18 +++++++++++++++++-
+ 1 file changed, 17 insertions(+), 1 deletion(-)
+
+diff --git a/include/linux/preempt.h b/include/linux/preempt.h
+index 4d244e295e85..5ceac863e729 100644
+--- a/include/linux/preempt.h
++++ b/include/linux/preempt.h
+@@ -188,7 +188,11 @@ do { \
+ 	preempt_count_dec(); \
+ } while (0)
+ 
+-#define preempt_enable_no_resched() sched_preempt_enable_no_resched()
++#ifdef CONFIG_PREEMPT_RT
++# define preempt_enable_no_resched() sched_preempt_enable_no_resched()
++#else
++# define preempt_enable_no_resched() preempt_enable()
++#endif
+ 
+ #define preemptible()	(preempt_count() == 0 && !irqs_disabled())
+ 
+@@ -282,6 +286,18 @@ do { \
+ 		set_preempt_need_resched(); \
+ } while (0)
+ 
++#ifdef CONFIG_PREEMPT_RT
++# define preempt_disable_rt()		preempt_disable()
++# define preempt_enable_rt()		preempt_enable()
++# define preempt_disable_nort()		barrier()
++# define preempt_enable_nort()		barrier()
++#else
++# define preempt_disable_rt()		barrier()
++# define preempt_enable_rt()		barrier()
++# define preempt_disable_nort()		preempt_disable()
++# define preempt_enable_nort()		preempt_enable()
++#endif
++
+ #ifdef CONFIG_PREEMPT_NOTIFIERS
+ 
+ struct preempt_notifier;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0180-mm-vmstat-Protect-per-cpu-variables-with-preempt-dis.patch b/debian/patches-rt/0180-mm-vmstat-Protect-per-cpu-variables-with-preempt-dis.patch
new file mode 100644
index 000000000..6512c18a9
--- /dev/null
+++ b/debian/patches-rt/0180-mm-vmstat-Protect-per-cpu-variables-with-preempt-dis.patch
@@ -0,0 +1,145 @@
+From a066e44619e1a6f661cd861015a5b658adead8bc Mon Sep 17 00:00:00 2001
+From: Ingo Molnar <mingo@elte.hu>
+Date: Fri, 3 Jul 2009 08:30:13 -0500
+Subject: [PATCH 180/323] mm/vmstat: Protect per cpu variables with preempt
+ disable on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Disable preemption on -RT for the vmstat code. On vanila the code runs in
+IRQ-off regions while on -RT it is not. "preempt_disable" ensures that the
+same ressources is not updated in parallel due to preemption.
+
+Signed-off-by: Ingo Molnar <mingo@elte.hu>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/vmstat.h |  4 ++++
+ mm/vmstat.c            | 12 ++++++++++++
+ 2 files changed, 16 insertions(+)
+
+diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
+index 322dcbfcc933..9a3a10ea3e3c 100644
+--- a/include/linux/vmstat.h
++++ b/include/linux/vmstat.h
+@@ -63,7 +63,9 @@ DECLARE_PER_CPU(struct vm_event_state, vm_event_states);
+  */
+ static inline void __count_vm_event(enum vm_event_item item)
+ {
++	preempt_disable_rt();
+ 	raw_cpu_inc(vm_event_states.event[item]);
++	preempt_enable_rt();
+ }
+ 
+ static inline void count_vm_event(enum vm_event_item item)
+@@ -73,7 +75,9 @@ static inline void count_vm_event(enum vm_event_item item)
+ 
+ static inline void __count_vm_events(enum vm_event_item item, long delta)
+ {
++	preempt_disable_rt();
+ 	raw_cpu_add(vm_event_states.event[item], delta);
++	preempt_enable_rt();
+ }
+ 
+ static inline void count_vm_events(enum vm_event_item item, long delta)
+diff --git a/mm/vmstat.c b/mm/vmstat.c
+index e292e63afebf..598e9317c7e0 100644
+--- a/mm/vmstat.c
++++ b/mm/vmstat.c
+@@ -321,6 +321,7 @@ void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
+ 	long x;
+ 	long t;
+ 
++	preempt_disable_rt();
+ 	x = delta + __this_cpu_read(*p);
+ 
+ 	t = __this_cpu_read(pcp->stat_threshold);
+@@ -330,6 +331,7 @@ void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
+ 		x = 0;
+ 	}
+ 	__this_cpu_write(*p, x);
++	preempt_enable_rt();
+ }
+ EXPORT_SYMBOL(__mod_zone_page_state);
+ 
+@@ -346,6 +348,7 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
+ 		delta >>= PAGE_SHIFT;
+ 	}
+ 
++	preempt_disable_rt();
+ 	x = delta + __this_cpu_read(*p);
+ 
+ 	t = __this_cpu_read(pcp->stat_threshold);
+@@ -355,6 +358,7 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
+ 		x = 0;
+ 	}
+ 	__this_cpu_write(*p, x);
++	preempt_enable_rt();
+ }
+ EXPORT_SYMBOL(__mod_node_page_state);
+ 
+@@ -387,6 +391,7 @@ void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
+ 	s8 __percpu *p = pcp->vm_stat_diff + item;
+ 	s8 v, t;
+ 
++	preempt_disable_rt();
+ 	v = __this_cpu_inc_return(*p);
+ 	t = __this_cpu_read(pcp->stat_threshold);
+ 	if (unlikely(v > t)) {
+@@ -395,6 +400,7 @@ void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
+ 		zone_page_state_add(v + overstep, zone, item);
+ 		__this_cpu_write(*p, -overstep);
+ 	}
++	preempt_enable_rt();
+ }
+ 
+ void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+@@ -405,6 +411,7 @@ void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+ 
+ 	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
+ 
++	preempt_disable_rt();
+ 	v = __this_cpu_inc_return(*p);
+ 	t = __this_cpu_read(pcp->stat_threshold);
+ 	if (unlikely(v > t)) {
+@@ -413,6 +420,7 @@ void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+ 		node_page_state_add(v + overstep, pgdat, item);
+ 		__this_cpu_write(*p, -overstep);
+ 	}
++	preempt_enable_rt();
+ }
+ 
+ void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
+@@ -433,6 +441,7 @@ void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
+ 	s8 __percpu *p = pcp->vm_stat_diff + item;
+ 	s8 v, t;
+ 
++	preempt_disable_rt();
+ 	v = __this_cpu_dec_return(*p);
+ 	t = __this_cpu_read(pcp->stat_threshold);
+ 	if (unlikely(v < - t)) {
+@@ -441,6 +450,7 @@ void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
+ 		zone_page_state_add(v - overstep, zone, item);
+ 		__this_cpu_write(*p, overstep);
+ 	}
++	preempt_enable_rt();
+ }
+ 
+ void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+@@ -451,6 +461,7 @@ void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+ 
+ 	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
+ 
++	preempt_disable_rt();
+ 	v = __this_cpu_dec_return(*p);
+ 	t = __this_cpu_read(pcp->stat_threshold);
+ 	if (unlikely(v < - t)) {
+@@ -459,6 +470,7 @@ void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
+ 		node_page_state_add(v - overstep, pgdat, item);
+ 		__this_cpu_write(*p, overstep);
+ 	}
++	preempt_enable_rt();
+ }
+ 
+ void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0181-mm-memcontrol-Disable-preemption-in-__mod_memcg_lruv.patch b/debian/patches-rt/0181-mm-memcontrol-Disable-preemption-in-__mod_memcg_lruv.patch
new file mode 100644
index 000000000..2df18df08
--- /dev/null
+++ b/debian/patches-rt/0181-mm-memcontrol-Disable-preemption-in-__mod_memcg_lruv.patch
@@ -0,0 +1,44 @@
+From 6f35e0e3a90abef410034d9900a21e68131aa5d5 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 28 Oct 2020 18:15:32 +0100
+Subject: [PATCH 181/323] mm/memcontrol: Disable preemption in
+ __mod_memcg_lruvec_state()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The callers expect disabled preemption/interrupts while invoking
+__mod_memcg_lruvec_state(). This works mainline because a lock of
+somekind is acquired.
+
+Use preempt_disable_rt() where per-CPU variables are accessed and a
+stable pointer is expected. This is also done in __mod_zone_page_state()
+for the same reason.
+
+Cc: stable-rt@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/memcontrol.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/mm/memcontrol.c b/mm/memcontrol.c
+index ddc8ed096dec..49566afaef1c 100644
+--- a/mm/memcontrol.c
++++ b/mm/memcontrol.c
+@@ -816,6 +816,7 @@ void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
+ 	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
+ 	memcg = pn->memcg;
+ 
++	preempt_disable_rt();
+ 	/* Update memcg */
+ 	__mod_memcg_state(memcg, idx, val);
+ 
+@@ -835,6 +836,7 @@ void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
+ 		x = 0;
+ 	}
+ 	__this_cpu_write(pn->lruvec_stat_cpu->count[idx], x);
++	preempt_enable_rt();
+ }
+ 
+ /**
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0182-xfrm-Use-sequence-counter-with-associated-spinlock.patch b/debian/patches-rt/0182-xfrm-Use-sequence-counter-with-associated-spinlock.patch
new file mode 100644
index 000000000..abce9d9d0
--- /dev/null
+++ b/debian/patches-rt/0182-xfrm-Use-sequence-counter-with-associated-spinlock.patch
@@ -0,0 +1,46 @@
+From 17aae888f2940f55065824bd7c267df06be47fbb Mon Sep 17 00:00:00 2001
+From: "Ahmed S. Darwish" <a.darwish@linutronix.de>
+Date: Wed, 10 Jun 2020 12:53:22 +0200
+Subject: [PATCH 182/323] xfrm: Use sequence counter with associated spinlock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+A sequence counter write side critical section must be protected by some
+form of locking to serialize writers. A plain seqcount_t does not
+contain the information of which lock must be held when entering a write
+side critical section.
+
+Use the new seqcount_spinlock_t data type, which allows to associate a
+spinlock with the sequence counter. This enables lockdep to verify that
+the spinlock used for writer serialization is held when the write side
+critical section is entered.
+
+If lockdep is disabled this lock association is compiled out and has
+neither storage size nor runtime overhead.
+
+Upstream-status: The xfrm locking used for seqcoun writer serialization
+appears to be broken. If that's the case, a proper fix will need to be
+submitted upstream. (e.g. make the seqcount per network namespace?)
+
+Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ net/xfrm/xfrm_state.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
+index ba73014805a4..14e1f36bdda5 100644
+--- a/net/xfrm/xfrm_state.c
++++ b/net/xfrm/xfrm_state.c
+@@ -2691,7 +2691,8 @@ int __net_init xfrm_state_init(struct net *net)
+ 	net->xfrm.state_num = 0;
+ 	INIT_WORK(&net->xfrm.state_hash_work, xfrm_hash_resize);
+ 	spin_lock_init(&net->xfrm.xfrm_state_lock);
+-	seqcount_init(&net->xfrm.xfrm_state_hash_generation);
++	seqcount_spinlock_init(&net->xfrm.xfrm_state_hash_generation,
++			       &net->xfrm.xfrm_state_lock);
+ 	return 0;
+ 
+ out_byspi:
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0183-u64_stats-Disable-preemption-on-32bit-UP-SMP-with-RT.patch b/debian/patches-rt/0183-u64_stats-Disable-preemption-on-32bit-UP-SMP-with-RT.patch
new file mode 100644
index 000000000..f100e0717
--- /dev/null
+++ b/debian/patches-rt/0183-u64_stats-Disable-preemption-on-32bit-UP-SMP-with-RT.patch
@@ -0,0 +1,152 @@
+From e6ec60749d80fcdde8451a7a544a218f7c5ef393 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 17 Aug 2020 12:28:10 +0200
+Subject: [PATCH 183/323] u64_stats: Disable preemption on 32bit-UP/SMP with RT
+ during updates
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+On RT the seqcount_t is required even on UP because the softirq can be
+preempted. The IRQ handler is threaded so it is also preemptible.
+
+Disable preemption on 32bit-RT during value updates. There is no need to
+disable interrupts on RT because the handler is run threaded. Therefore
+disabling preemption is enough to guarantee that the update is not
+interruped.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/u64_stats_sync.h | 42 ++++++++++++++++++++++------------
+ 1 file changed, 28 insertions(+), 14 deletions(-)
+
+diff --git a/include/linux/u64_stats_sync.h b/include/linux/u64_stats_sync.h
+index e81856c0ba13..66eb968a09d4 100644
+--- a/include/linux/u64_stats_sync.h
++++ b/include/linux/u64_stats_sync.h
+@@ -66,7 +66,7 @@
+ #include <linux/seqlock.h>
+ 
+ struct u64_stats_sync {
+-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
++#if BITS_PER_LONG==32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
+ 	seqcount_t	seq;
+ #endif
+ };
+@@ -115,7 +115,7 @@ static inline void u64_stats_inc(u64_stats_t *p)
+ }
+ #endif
+ 
+-#if BITS_PER_LONG == 32 && defined(CONFIG_SMP)
++#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
+ #define u64_stats_init(syncp)	seqcount_init(&(syncp)->seq)
+ #else
+ static inline void u64_stats_init(struct u64_stats_sync *syncp)
+@@ -125,15 +125,19 @@ static inline void u64_stats_init(struct u64_stats_sync *syncp)
+ 
+ static inline void u64_stats_update_begin(struct u64_stats_sync *syncp)
+ {
+-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
++#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
++	if (IS_ENABLED(CONFIG_PREEMPT_RT))
++		preempt_disable();
+ 	write_seqcount_begin(&syncp->seq);
+ #endif
+ }
+ 
+ static inline void u64_stats_update_end(struct u64_stats_sync *syncp)
+ {
+-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
++#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
+ 	write_seqcount_end(&syncp->seq);
++	if (IS_ENABLED(CONFIG_PREEMPT_RT))
++		preempt_enable();
+ #endif
+ }
+ 
+@@ -142,8 +146,11 @@ u64_stats_update_begin_irqsave(struct u64_stats_sync *syncp)
+ {
+ 	unsigned long flags = 0;
+ 
+-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
+-	local_irq_save(flags);
++#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
++	if (IS_ENABLED(CONFIG_PREEMPT_RT))
++		preempt_disable();
++	else
++		local_irq_save(flags);
+ 	write_seqcount_begin(&syncp->seq);
+ #endif
+ 	return flags;
+@@ -153,15 +160,18 @@ static inline void
+ u64_stats_update_end_irqrestore(struct u64_stats_sync *syncp,
+ 				unsigned long flags)
+ {
+-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
++#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
+ 	write_seqcount_end(&syncp->seq);
+-	local_irq_restore(flags);
++	if (IS_ENABLED(CONFIG_PREEMPT_RT))
++		preempt_enable();
++	else
++		local_irq_restore(flags);
+ #endif
+ }
+ 
+ static inline unsigned int __u64_stats_fetch_begin(const struct u64_stats_sync *syncp)
+ {
+-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
++#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
+ 	return read_seqcount_begin(&syncp->seq);
+ #else
+ 	return 0;
+@@ -170,7 +180,7 @@ static inline unsigned int __u64_stats_fetch_begin(const struct u64_stats_sync *
+ 
+ static inline unsigned int u64_stats_fetch_begin(const struct u64_stats_sync *syncp)
+ {
+-#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)
++#if BITS_PER_LONG == 32 && (!defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_RT))
+ 	preempt_disable();
+ #endif
+ 	return __u64_stats_fetch_begin(syncp);
+@@ -179,7 +189,7 @@ static inline unsigned int u64_stats_fetch_begin(const struct u64_stats_sync *sy
+ static inline bool __u64_stats_fetch_retry(const struct u64_stats_sync *syncp,
+ 					 unsigned int start)
+ {
+-#if BITS_PER_LONG==32 && defined(CONFIG_SMP)
++#if BITS_PER_LONG == 32 && (defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT))
+ 	return read_seqcount_retry(&syncp->seq, start);
+ #else
+ 	return false;
+@@ -189,7 +199,7 @@ static inline bool __u64_stats_fetch_retry(const struct u64_stats_sync *syncp,
+ static inline bool u64_stats_fetch_retry(const struct u64_stats_sync *syncp,
+ 					 unsigned int start)
+ {
+-#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)
++#if BITS_PER_LONG == 32 && (!defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_RT))
+ 	preempt_enable();
+ #endif
+ 	return __u64_stats_fetch_retry(syncp, start);
+@@ -203,7 +213,9 @@ static inline bool u64_stats_fetch_retry(const struct u64_stats_sync *syncp,
+  */
+ static inline unsigned int u64_stats_fetch_begin_irq(const struct u64_stats_sync *syncp)
+ {
+-#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)
++#if BITS_PER_LONG == 32 && defined(CONFIG_PREEMPT_RT)
++	preempt_disable();
++#elif BITS_PER_LONG == 32 && !defined(CONFIG_SMP)
+ 	local_irq_disable();
+ #endif
+ 	return __u64_stats_fetch_begin(syncp);
+@@ -212,7 +224,9 @@ static inline unsigned int u64_stats_fetch_begin_irq(const struct u64_stats_sync
+ static inline bool u64_stats_fetch_retry_irq(const struct u64_stats_sync *syncp,
+ 					     unsigned int start)
+ {
+-#if BITS_PER_LONG==32 && !defined(CONFIG_SMP)
++#if BITS_PER_LONG == 32 && defined(CONFIG_PREEMPT_RT)
++	preempt_enable();
++#elif BITS_PER_LONG == 32 && !defined(CONFIG_SMP)
+ 	local_irq_enable();
+ #endif
+ 	return __u64_stats_fetch_retry(syncp, start);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0184-fs-dcache-use-swait_queue-instead-of-waitqueue.patch b/debian/patches-rt/0184-fs-dcache-use-swait_queue-instead-of-waitqueue.patch
new file mode 100644
index 000000000..8a43098f4
--- /dev/null
+++ b/debian/patches-rt/0184-fs-dcache-use-swait_queue-instead-of-waitqueue.patch
@@ -0,0 +1,263 @@
+From aeadd35a13f446ec84a832549b2815fc3de30917 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 14 Sep 2016 14:35:49 +0200
+Subject: [PATCH 184/323] fs/dcache: use swait_queue instead of waitqueue
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+__d_lookup_done() invokes wake_up_all() while holding a hlist_bl_lock()
+which disables preemption. As a workaround convert it to swait.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ fs/afs/dir_silly.c      |  2 +-
+ fs/cifs/readdir.c       |  2 +-
+ fs/dcache.c             | 27 +++++++++++++++------------
+ fs/fuse/readdir.c       |  2 +-
+ fs/namei.c              |  4 ++--
+ fs/nfs/dir.c            |  4 ++--
+ fs/nfs/unlink.c         |  4 ++--
+ fs/proc/base.c          |  3 ++-
+ fs/proc/proc_sysctl.c   |  2 +-
+ include/linux/dcache.h  |  4 ++--
+ include/linux/nfs_xdr.h |  2 +-
+ kernel/sched/swait.c    |  1 +
+ 12 files changed, 31 insertions(+), 26 deletions(-)
+
+diff --git a/fs/afs/dir_silly.c b/fs/afs/dir_silly.c
+index dae9a57d7ec0..9a6a0ec4d1fb 100644
+--- a/fs/afs/dir_silly.c
++++ b/fs/afs/dir_silly.c
+@@ -239,7 +239,7 @@ int afs_silly_iput(struct dentry *dentry, struct inode *inode)
+ 	struct dentry *alias;
+ 	int ret;
+ 
+-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
++	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
+ 
+ 	_enter("%p{%pd},%llx", dentry, dentry, vnode->fid.vnode);
+ 
+diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
+index 799be3a5d25e..d5165a7da071 100644
+--- a/fs/cifs/readdir.c
++++ b/fs/cifs/readdir.c
+@@ -81,7 +81,7 @@ cifs_prime_dcache(struct dentry *parent, struct qstr *name,
+ 	struct inode *inode;
+ 	struct super_block *sb = parent->d_sb;
+ 	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
+-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
++	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
+ 
+ 	cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
+ 
+diff --git a/fs/dcache.c b/fs/dcache.c
+index ea0485861d93..1f4255ef8722 100644
+--- a/fs/dcache.c
++++ b/fs/dcache.c
+@@ -2518,21 +2518,24 @@ static inline void end_dir_add(struct inode *dir, unsigned n)
+ 
+ static void d_wait_lookup(struct dentry *dentry)
+ {
+-	if (d_in_lookup(dentry)) {
+-		DECLARE_WAITQUEUE(wait, current);
+-		add_wait_queue(dentry->d_wait, &wait);
+-		do {
+-			set_current_state(TASK_UNINTERRUPTIBLE);
+-			spin_unlock(&dentry->d_lock);
+-			schedule();
+-			spin_lock(&dentry->d_lock);
+-		} while (d_in_lookup(dentry));
+-	}
++	struct swait_queue __wait;
++
++	if (!d_in_lookup(dentry))
++		return;
++
++	INIT_LIST_HEAD(&__wait.task_list);
++	do {
++		prepare_to_swait_exclusive(dentry->d_wait, &__wait, TASK_UNINTERRUPTIBLE);
++		spin_unlock(&dentry->d_lock);
++		schedule();
++		spin_lock(&dentry->d_lock);
++	} while (d_in_lookup(dentry));
++	finish_swait(dentry->d_wait, &__wait);
+ }
+ 
+ struct dentry *d_alloc_parallel(struct dentry *parent,
+ 				const struct qstr *name,
+-				wait_queue_head_t *wq)
++				struct swait_queue_head *wq)
+ {
+ 	unsigned int hash = name->hash;
+ 	struct hlist_bl_head *b = in_lookup_hash(parent, hash);
+@@ -2647,7 +2650,7 @@ void __d_lookup_done(struct dentry *dentry)
+ 	hlist_bl_lock(b);
+ 	dentry->d_flags &= ~DCACHE_PAR_LOOKUP;
+ 	__hlist_bl_del(&dentry->d_u.d_in_lookup_hash);
+-	wake_up_all(dentry->d_wait);
++	swake_up_all(dentry->d_wait);
+ 	dentry->d_wait = NULL;
+ 	hlist_bl_unlock(b);
+ 	INIT_HLIST_NODE(&dentry->d_u.d_alias);
+diff --git a/fs/fuse/readdir.c b/fs/fuse/readdir.c
+index 14e99ffa57af..eb899feaf82d 100644
+--- a/fs/fuse/readdir.c
++++ b/fs/fuse/readdir.c
+@@ -160,7 +160,7 @@ static int fuse_direntplus_link(struct file *file,
+ 	struct inode *dir = d_inode(parent);
+ 	struct fuse_conn *fc;
+ 	struct inode *inode;
+-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
++	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
+ 
+ 	if (!o->nodeid) {
+ 		/*
+diff --git a/fs/namei.c b/fs/namei.c
+index 3ff954a2bbd1..01e3f8195ee1 100644
+--- a/fs/namei.c
++++ b/fs/namei.c
+@@ -1532,7 +1532,7 @@ static struct dentry *__lookup_slow(const struct qstr *name,
+ {
+ 	struct dentry *dentry, *old;
+ 	struct inode *inode = dir->d_inode;
+-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
++	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
+ 
+ 	/* Don't go there if it's already dead */
+ 	if (unlikely(IS_DEADDIR(inode)))
+@@ -3085,7 +3085,7 @@ static struct dentry *lookup_open(struct nameidata *nd, struct file *file,
+ 	struct dentry *dentry;
+ 	int error, create_error = 0;
+ 	umode_t mode = op->mode;
+-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
++	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
+ 
+ 	if (unlikely(IS_DEADDIR(dir_inode)))
+ 		return ERR_PTR(-ENOENT);
+diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
+index 9f88ca7b2001..bc8a78ecfe1c 100644
+--- a/fs/nfs/dir.c
++++ b/fs/nfs/dir.c
+@@ -484,7 +484,7 @@ void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry,
+ 		unsigned long dir_verifier)
+ {
+ 	struct qstr filename = QSTR_INIT(entry->name, entry->len);
+-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
++	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
+ 	struct dentry *dentry;
+ 	struct dentry *alias;
+ 	struct inode *inode;
+@@ -1660,7 +1660,7 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
+ 		    struct file *file, unsigned open_flags,
+ 		    umode_t mode)
+ {
+-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
++	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
+ 	struct nfs_open_context *ctx;
+ 	struct dentry *res;
+ 	struct iattr attr = { .ia_valid = ATTR_OPEN };
+diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
+index b27ebdccef70..f86c98a7ed04 100644
+--- a/fs/nfs/unlink.c
++++ b/fs/nfs/unlink.c
+@@ -13,7 +13,7 @@
+ #include <linux/sunrpc/clnt.h>
+ #include <linux/nfs_fs.h>
+ #include <linux/sched.h>
+-#include <linux/wait.h>
++#include <linux/swait.h>
+ #include <linux/namei.h>
+ #include <linux/fsnotify.h>
+ 
+@@ -180,7 +180,7 @@ nfs_async_unlink(struct dentry *dentry, const struct qstr *name)
+ 
+ 	data->cred = get_current_cred();
+ 	data->res.dir_attr = &data->dir_attr;
+-	init_waitqueue_head(&data->wq);
++	init_swait_queue_head(&data->wq);
+ 
+ 	status = -EBUSY;
+ 	spin_lock(&dentry->d_lock);
+diff --git a/fs/proc/base.c b/fs/proc/base.c
+index 712948e97991..585d0afd1af6 100644
+--- a/fs/proc/base.c
++++ b/fs/proc/base.c
+@@ -96,6 +96,7 @@
+ #include <linux/posix-timers.h>
+ #include <linux/time_namespace.h>
+ #include <linux/resctrl.h>
++#include <linux/swait.h>
+ #include <trace/events/oom.h>
+ #include "internal.h"
+ #include "fd.h"
+@@ -2066,7 +2067,7 @@ bool proc_fill_cache(struct file *file, struct dir_context *ctx,
+ 
+ 	child = d_hash_and_lookup(dir, &qname);
+ 	if (!child) {
+-		DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
++		DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
+ 		child = d_alloc_parallel(dir, &qname, &wq);
+ 		if (IS_ERR(child))
+ 			goto end_instantiate;
+diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
+index aff9593feb73..d1a29668bff8 100644
+--- a/fs/proc/proc_sysctl.c
++++ b/fs/proc/proc_sysctl.c
+@@ -684,7 +684,7 @@ static bool proc_sys_fill_cache(struct file *file,
+ 
+ 	child = d_lookup(dir, &qname);
+ 	if (!child) {
+-		DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
++		DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
+ 		child = d_alloc_parallel(dir, &qname, &wq);
+ 		if (IS_ERR(child))
+ 			return false;
+diff --git a/include/linux/dcache.h b/include/linux/dcache.h
+index 6f95c3300cbb..c1290db778bd 100644
+--- a/include/linux/dcache.h
++++ b/include/linux/dcache.h
+@@ -106,7 +106,7 @@ struct dentry {
+ 
+ 	union {
+ 		struct list_head d_lru;		/* LRU list */
+-		wait_queue_head_t *d_wait;	/* in-lookup ones only */
++		struct swait_queue_head *d_wait;	/* in-lookup ones only */
+ 	};
+ 	struct list_head d_child;	/* child of parent list */
+ 	struct list_head d_subdirs;	/* our children */
+@@ -238,7 +238,7 @@ extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op
+ extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
+ extern struct dentry * d_alloc_anon(struct super_block *);
+ extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *,
+-					wait_queue_head_t *);
++					struct swait_queue_head *);
+ extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
+ extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
+ extern struct dentry * d_exact_alias(struct dentry *, struct inode *);
+diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
+index 33442fd018a0..4612bb5be6ca 100644
+--- a/include/linux/nfs_xdr.h
++++ b/include/linux/nfs_xdr.h
+@@ -1675,7 +1675,7 @@ struct nfs_unlinkdata {
+ 	struct nfs_removeargs args;
+ 	struct nfs_removeres res;
+ 	struct dentry *dentry;
+-	wait_queue_head_t wq;
++	struct swait_queue_head wq;
+ 	const struct cred *cred;
+ 	struct nfs_fattr dir_attr;
+ 	long timeout;
+diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c
+index e1c655f928c7..f230b1ac7f91 100644
+--- a/kernel/sched/swait.c
++++ b/kernel/sched/swait.c
+@@ -64,6 +64,7 @@ void swake_up_all(struct swait_queue_head *q)
+ 	struct swait_queue *curr;
+ 	LIST_HEAD(tmp);
+ 
++	WARN_ON(irqs_disabled());
+ 	raw_spin_lock_irq(&q->lock);
+ 	list_splice_init(&q->task_list, &tmp);
+ 	while (!list_empty(&tmp)) {
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0185-fs-dcache-disable-preemption-on-i_dir_seq-s-write-si.patch b/debian/patches-rt/0185-fs-dcache-disable-preemption-on-i_dir_seq-s-write-si.patch
new file mode 100644
index 000000000..e687b4d2d
--- /dev/null
+++ b/debian/patches-rt/0185-fs-dcache-disable-preemption-on-i_dir_seq-s-write-si.patch
@@ -0,0 +1,99 @@
+From 06c5210bfc8eff16e0d1df2430c7fcb07eae6c67 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 20 Oct 2017 11:29:53 +0200
+Subject: [PATCH 185/323] fs/dcache: disable preemption on i_dir_seq's write
+ side
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+i_dir_seq is an opencoded seqcounter. Based on the code it looks like we
+could have two writers in parallel despite the fact that the d_lock is
+held. The problem is that during the write process on RT the preemption
+is still enabled and if this process is interrupted by a reader with RT
+priority then we lock up.
+To avoid that lock up I am disabling the preemption during the update.
+The rename of i_dir_seq is here to ensure to catch new write sides in
+future.
+
+Cc: stable-rt@vger.kernel.org
+Reported-by: Oleg.Karfich@wago.com
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ fs/dcache.c        | 12 +++++++-----
+ fs/inode.c         |  2 +-
+ include/linux/fs.h |  2 +-
+ 3 files changed, 9 insertions(+), 7 deletions(-)
+
+diff --git a/fs/dcache.c b/fs/dcache.c
+index 1f4255ef8722..26a187abf13a 100644
+--- a/fs/dcache.c
++++ b/fs/dcache.c
+@@ -2503,9 +2503,10 @@ EXPORT_SYMBOL(d_rehash);
+ static inline unsigned start_dir_add(struct inode *dir)
+ {
+ 
++	preempt_disable_rt();
+ 	for (;;) {
+-		unsigned n = dir->i_dir_seq;
+-		if (!(n & 1) && cmpxchg(&dir->i_dir_seq, n, n + 1) == n)
++		unsigned n = dir->__i_dir_seq;
++		if (!(n & 1) && cmpxchg(&dir->__i_dir_seq, n, n + 1) == n)
+ 			return n;
+ 		cpu_relax();
+ 	}
+@@ -2513,7 +2514,8 @@ static inline unsigned start_dir_add(struct inode *dir)
+ 
+ static inline void end_dir_add(struct inode *dir, unsigned n)
+ {
+-	smp_store_release(&dir->i_dir_seq, n + 2);
++	smp_store_release(&dir->__i_dir_seq, n + 2);
++	preempt_enable_rt();
+ }
+ 
+ static void d_wait_lookup(struct dentry *dentry)
+@@ -2549,7 +2551,7 @@ struct dentry *d_alloc_parallel(struct dentry *parent,
+ 
+ retry:
+ 	rcu_read_lock();
+-	seq = smp_load_acquire(&parent->d_inode->i_dir_seq);
++	seq = smp_load_acquire(&parent->d_inode->__i_dir_seq);
+ 	r_seq = read_seqbegin(&rename_lock);
+ 	dentry = __d_lookup_rcu(parent, name, &d_seq);
+ 	if (unlikely(dentry)) {
+@@ -2577,7 +2579,7 @@ struct dentry *d_alloc_parallel(struct dentry *parent,
+ 	}
+ 
+ 	hlist_bl_lock(b);
+-	if (unlikely(READ_ONCE(parent->d_inode->i_dir_seq) != seq)) {
++	if (unlikely(READ_ONCE(parent->d_inode->__i_dir_seq) != seq)) {
+ 		hlist_bl_unlock(b);
+ 		rcu_read_unlock();
+ 		goto retry;
+diff --git a/fs/inode.c b/fs/inode.c
+index 5c7139aa2bda..4ee8239c055f 100644
+--- a/fs/inode.c
++++ b/fs/inode.c
+@@ -158,7 +158,7 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
+ 	inode->i_bdev = NULL;
+ 	inode->i_cdev = NULL;
+ 	inode->i_link = NULL;
+-	inode->i_dir_seq = 0;
++	inode->__i_dir_seq = 0;
+ 	inode->i_rdev = 0;
+ 	inode->dirtied_when = 0;
+ 
+diff --git a/include/linux/fs.h b/include/linux/fs.h
+index 82316863c71f..a29a0b8a1eca 100644
+--- a/include/linux/fs.h
++++ b/include/linux/fs.h
+@@ -699,7 +699,7 @@ struct inode {
+ 		struct block_device	*i_bdev;
+ 		struct cdev		*i_cdev;
+ 		char			*i_link;
+-		unsigned		i_dir_seq;
++		unsigned		__i_dir_seq;
+ 	};
+ 
+ 	__u32			i_generation;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0186-net-Qdisc-use-a-seqlock-instead-seqcount.patch b/debian/patches-rt/0186-net-Qdisc-use-a-seqlock-instead-seqcount.patch
new file mode 100644
index 000000000..a289ccc4f
--- /dev/null
+++ b/debian/patches-rt/0186-net-Qdisc-use-a-seqlock-instead-seqcount.patch
@@ -0,0 +1,299 @@
+From a996bcbd8188409882599175697a464fa6265193 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 14 Sep 2016 17:36:35 +0200
+Subject: [PATCH 186/323] net/Qdisc: use a seqlock instead seqcount
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The seqcount disables preemption on -RT while it is held which can't
+remove. Also we don't want the reader to spin for ages if the writer is
+scheduled out. The seqlock on the other hand will serialize / sleep on
+the lock while writer is active.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/net/gen_stats.h    | 11 ++++++-----
+ include/net/net_seq_lock.h | 24 ++++++++++++++++++++++++
+ include/net/sch_generic.h  | 19 +++++++++++++++++--
+ net/core/gen_estimator.c   |  6 +++---
+ net/core/gen_stats.c       | 12 ++++++------
+ net/sched/sch_api.c        |  2 +-
+ net/sched/sch_generic.c    | 10 ++++++++++
+ 7 files changed, 67 insertions(+), 17 deletions(-)
+ create mode 100644 include/net/net_seq_lock.h
+
+diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h
+index 1424e02cef90..163f8415e5db 100644
+--- a/include/net/gen_stats.h
++++ b/include/net/gen_stats.h
+@@ -6,6 +6,7 @@
+ #include <linux/socket.h>
+ #include <linux/rtnetlink.h>
+ #include <linux/pkt_sched.h>
++#include <net/net_seq_lock.h>
+ 
+ /* Note: this used to be in include/uapi/linux/gen_stats.h */
+ struct gnet_stats_basic_packed {
+@@ -42,15 +43,15 @@ int gnet_stats_start_copy_compat(struct sk_buff *skb, int type,
+ 				 spinlock_t *lock, struct gnet_dump *d,
+ 				 int padattr);
+ 
+-int gnet_stats_copy_basic(const seqcount_t *running,
++int gnet_stats_copy_basic(net_seqlock_t *running,
+ 			  struct gnet_dump *d,
+ 			  struct gnet_stats_basic_cpu __percpu *cpu,
+ 			  struct gnet_stats_basic_packed *b);
+-void __gnet_stats_copy_basic(const seqcount_t *running,
++void __gnet_stats_copy_basic(net_seqlock_t *running,
+ 			     struct gnet_stats_basic_packed *bstats,
+ 			     struct gnet_stats_basic_cpu __percpu *cpu,
+ 			     struct gnet_stats_basic_packed *b);
+-int gnet_stats_copy_basic_hw(const seqcount_t *running,
++int gnet_stats_copy_basic_hw(net_seqlock_t *running,
+ 			     struct gnet_dump *d,
+ 			     struct gnet_stats_basic_cpu __percpu *cpu,
+ 			     struct gnet_stats_basic_packed *b);
+@@ -70,13 +71,13 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
+ 		      struct gnet_stats_basic_cpu __percpu *cpu_bstats,
+ 		      struct net_rate_estimator __rcu **rate_est,
+ 		      spinlock_t *lock,
+-		      seqcount_t *running, struct nlattr *opt);
++		      net_seqlock_t *running, struct nlattr *opt);
+ void gen_kill_estimator(struct net_rate_estimator __rcu **ptr);
+ int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
+ 			  struct gnet_stats_basic_cpu __percpu *cpu_bstats,
+ 			  struct net_rate_estimator __rcu **ptr,
+ 			  spinlock_t *lock,
+-			  seqcount_t *running, struct nlattr *opt);
++			  net_seqlock_t *running, struct nlattr *opt);
+ bool gen_estimator_active(struct net_rate_estimator __rcu **ptr);
+ bool gen_estimator_read(struct net_rate_estimator __rcu **ptr,
+ 			struct gnet_stats_rate_est64 *sample);
+diff --git a/include/net/net_seq_lock.h b/include/net/net_seq_lock.h
+new file mode 100644
+index 000000000000..95a497a72e51
+--- /dev/null
++++ b/include/net/net_seq_lock.h
+@@ -0,0 +1,24 @@
++#ifndef __NET_NET_SEQ_LOCK_H__
++#define __NET_NET_SEQ_LOCK_H__
++
++#ifdef CONFIG_PREEMPT_RT
++# define net_seqlock_t			seqlock_t
++# define net_seq_begin(__r)		read_seqbegin(__r)
++# define net_seq_retry(__r, __s)	read_seqretry(__r, __s)
++
++static inline int try_write_seqlock(seqlock_t *sl)
++{
++	if (spin_trylock(&sl->lock)) {
++		write_seqcount_begin(&sl->seqcount);
++		return 1;
++	}
++	return 0;
++}
++
++#else
++# define net_seqlock_t			seqcount_t
++# define net_seq_begin(__r)		read_seqcount_begin(__r)
++# define net_seq_retry(__r, __s)	read_seqcount_retry(__r, __s)
++#endif
++
++#endif
+diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
+index a62677be7452..8ce663a9b4f4 100644
+--- a/include/net/sch_generic.h
++++ b/include/net/sch_generic.h
+@@ -10,6 +10,7 @@
+ #include <linux/percpu.h>
+ #include <linux/dynamic_queue_limits.h>
+ #include <linux/list.h>
++#include <net/net_seq_lock.h>
+ #include <linux/refcount.h>
+ #include <linux/workqueue.h>
+ #include <linux/mutex.h>
+@@ -101,7 +102,7 @@ struct Qdisc {
+ 	struct sk_buff_head	gso_skb ____cacheline_aligned_in_smp;
+ 	struct qdisc_skb_head	q;
+ 	struct gnet_stats_basic_packed bstats;
+-	seqcount_t		running;
++	net_seqlock_t		running;
+ 	struct gnet_stats_queue	qstats;
+ 	unsigned long		state;
+ 	struct Qdisc            *next_sched;
+@@ -142,7 +143,11 @@ static inline bool qdisc_is_running(struct Qdisc *qdisc)
+ {
+ 	if (qdisc->flags & TCQ_F_NOLOCK)
+ 		return spin_is_locked(&qdisc->seqlock);
++#ifdef CONFIG_PREEMPT_RT
++	return spin_is_locked(&qdisc->running.lock) ? true : false;
++#else
+ 	return (raw_read_seqcount(&qdisc->running) & 1) ? true : false;
++#endif
+ }
+ 
+ static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
+@@ -183,17 +188,27 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc)
+ 	} else if (qdisc_is_running(qdisc)) {
+ 		return false;
+ 	}
++#ifdef CONFIG_PREEMPT_RT
++	if (try_write_seqlock(&qdisc->running))
++		return true;
++	return false;
++#else
+ 	/* Variant of write_seqcount_begin() telling lockdep a trylock
+ 	 * was attempted.
+ 	 */
+ 	raw_write_seqcount_begin(&qdisc->running);
+ 	seqcount_acquire(&qdisc->running.dep_map, 0, 1, _RET_IP_);
+ 	return true;
++#endif
+ }
+ 
+ static inline void qdisc_run_end(struct Qdisc *qdisc)
+ {
++#ifdef CONFIG_PREEMPT_RT
++	write_sequnlock(&qdisc->running);
++#else
+ 	write_seqcount_end(&qdisc->running);
++#endif
+ 	if (qdisc->flags & TCQ_F_NOLOCK) {
+ 		spin_unlock(&qdisc->seqlock);
+ 
+@@ -583,7 +598,7 @@ static inline spinlock_t *qdisc_root_sleeping_lock(const struct Qdisc *qdisc)
+ 	return qdisc_lock(root);
+ }
+ 
+-static inline seqcount_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
++static inline net_seqlock_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
+ {
+ 	struct Qdisc *root = qdisc_root_sleeping(qdisc);
+ 
+diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
+index 8e582e29a41e..e51f4854d8b2 100644
+--- a/net/core/gen_estimator.c
++++ b/net/core/gen_estimator.c
+@@ -42,7 +42,7 @@
+ struct net_rate_estimator {
+ 	struct gnet_stats_basic_packed	*bstats;
+ 	spinlock_t		*stats_lock;
+-	seqcount_t		*running;
++	net_seqlock_t		*running;
+ 	struct gnet_stats_basic_cpu __percpu *cpu_bstats;
+ 	u8			ewma_log;
+ 	u8			intvl_log; /* period : (250ms << intvl_log) */
+@@ -125,7 +125,7 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
+ 		      struct gnet_stats_basic_cpu __percpu *cpu_bstats,
+ 		      struct net_rate_estimator __rcu **rate_est,
+ 		      spinlock_t *lock,
+-		      seqcount_t *running,
++		      net_seqlock_t *running,
+ 		      struct nlattr *opt)
+ {
+ 	struct gnet_estimator *parm = nla_data(opt);
+@@ -226,7 +226,7 @@ int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
+ 			  struct gnet_stats_basic_cpu __percpu *cpu_bstats,
+ 			  struct net_rate_estimator __rcu **rate_est,
+ 			  spinlock_t *lock,
+-			  seqcount_t *running, struct nlattr *opt)
++			  net_seqlock_t *running, struct nlattr *opt)
+ {
+ 	return gen_new_estimator(bstats, cpu_bstats, rate_est,
+ 				 lock, running, opt);
+diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c
+index e491b083b348..ef432cea2e10 100644
+--- a/net/core/gen_stats.c
++++ b/net/core/gen_stats.c
+@@ -137,7 +137,7 @@ __gnet_stats_copy_basic_cpu(struct gnet_stats_basic_packed *bstats,
+ }
+ 
+ void
+-__gnet_stats_copy_basic(const seqcount_t *running,
++__gnet_stats_copy_basic(net_seqlock_t *running,
+ 			struct gnet_stats_basic_packed *bstats,
+ 			struct gnet_stats_basic_cpu __percpu *cpu,
+ 			struct gnet_stats_basic_packed *b)
+@@ -150,15 +150,15 @@ __gnet_stats_copy_basic(const seqcount_t *running,
+ 	}
+ 	do {
+ 		if (running)
+-			seq = read_seqcount_begin(running);
++			seq = net_seq_begin(running);
+ 		bstats->bytes = b->bytes;
+ 		bstats->packets = b->packets;
+-	} while (running && read_seqcount_retry(running, seq));
++	} while (running && net_seq_retry(running, seq));
+ }
+ EXPORT_SYMBOL(__gnet_stats_copy_basic);
+ 
+ static int
+-___gnet_stats_copy_basic(const seqcount_t *running,
++___gnet_stats_copy_basic(net_seqlock_t *running,
+ 			 struct gnet_dump *d,
+ 			 struct gnet_stats_basic_cpu __percpu *cpu,
+ 			 struct gnet_stats_basic_packed *b,
+@@ -204,7 +204,7 @@ ___gnet_stats_copy_basic(const seqcount_t *running,
+  * if the room in the socket buffer was not sufficient.
+  */
+ int
+-gnet_stats_copy_basic(const seqcount_t *running,
++gnet_stats_copy_basic(net_seqlock_t *running,
+ 		      struct gnet_dump *d,
+ 		      struct gnet_stats_basic_cpu __percpu *cpu,
+ 		      struct gnet_stats_basic_packed *b)
+@@ -228,7 +228,7 @@ EXPORT_SYMBOL(gnet_stats_copy_basic);
+  * if the room in the socket buffer was not sufficient.
+  */
+ int
+-gnet_stats_copy_basic_hw(const seqcount_t *running,
++gnet_stats_copy_basic_hw(net_seqlock_t *running,
+ 			 struct gnet_dump *d,
+ 			 struct gnet_stats_basic_cpu __percpu *cpu,
+ 			 struct gnet_stats_basic_packed *b)
+diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
+index 5c2d230790db..a5430619ca5f 100644
+--- a/net/sched/sch_api.c
++++ b/net/sched/sch_api.c
+@@ -1275,7 +1275,7 @@ static struct Qdisc *qdisc_create(struct net_device *dev,
+ 		rcu_assign_pointer(sch->stab, stab);
+ 	}
+ 	if (tca[TCA_RATE]) {
+-		seqcount_t *running;
++		net_seqlock_t *running;
+ 
+ 		err = -EOPNOTSUPP;
+ 		if (sch->flags & TCQ_F_MQROOT) {
+diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
+index ecdd9e83f2f4..73b5aa797645 100644
+--- a/net/sched/sch_generic.c
++++ b/net/sched/sch_generic.c
+@@ -578,7 +578,11 @@ struct Qdisc noop_qdisc = {
+ 	.ops		=	&noop_qdisc_ops,
+ 	.q.lock		=	__SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
+ 	.dev_queue	=	&noop_netdev_queue,
++#ifdef CONFIG_PREEMPT_RT
++	.running	=	__SEQLOCK_UNLOCKED(noop_qdisc.running),
++#else
+ 	.running	=	SEQCNT_ZERO(noop_qdisc.running),
++#endif
+ 	.busylock	=	__SPIN_LOCK_UNLOCKED(noop_qdisc.busylock),
+ 	.gso_skb = {
+ 		.next = (struct sk_buff *)&noop_qdisc.gso_skb,
+@@ -889,9 +893,15 @@ struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
+ 	lockdep_set_class(&sch->seqlock,
+ 			  dev->qdisc_tx_busylock ?: &qdisc_tx_busylock);
+ 
++#ifdef CONFIG_PREEMPT_RT
++	seqlock_init(&sch->running);
++	lockdep_set_class(&sch->running.lock,
++			  dev->qdisc_running_key ?: &qdisc_running_key);
++#else
+ 	seqcount_init(&sch->running);
+ 	lockdep_set_class(&sch->running,
+ 			  dev->qdisc_running_key ?: &qdisc_running_key);
++#endif
+ 
+ 	sch->ops = ops;
+ 	sch->flags = ops->static_flags;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0187-net-Properly-annotate-the-try-lock-for-the-seqlock.patch b/debian/patches-rt/0187-net-Properly-annotate-the-try-lock-for-the-seqlock.patch
new file mode 100644
index 000000000..130a8cb78
--- /dev/null
+++ b/debian/patches-rt/0187-net-Properly-annotate-the-try-lock-for-the-seqlock.patch
@@ -0,0 +1,71 @@
+From 442e014107fc616d529c73b0f0436980b817d021 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 8 Sep 2020 16:57:11 +0200
+Subject: [PATCH 187/323] net: Properly annotate the try-lock for the seqlock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+In patch
+   ("net/Qdisc: use a seqlock instead seqcount")
+
+the seqcount has been replaced with a seqlock to allow to reader to
+boost the preempted writer.
+The try_write_seqlock() acquired the lock with a try-lock but the
+seqcount annotation was "lock".
+
+Opencode write_seqcount_t_begin() and use the try-lock annotation for
+lockdep.
+
+Reported-by: Mike Galbraith <efault@gmx.de>
+Cc: stable-rt@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ include/net/net_seq_lock.h |  9 ---------
+ include/net/sch_generic.h  | 10 +++++++++-
+ 2 files changed, 9 insertions(+), 10 deletions(-)
+
+diff --git a/include/net/net_seq_lock.h b/include/net/net_seq_lock.h
+index 95a497a72e51..67710bace741 100644
+--- a/include/net/net_seq_lock.h
++++ b/include/net/net_seq_lock.h
+@@ -6,15 +6,6 @@
+ # define net_seq_begin(__r)		read_seqbegin(__r)
+ # define net_seq_retry(__r, __s)	read_seqretry(__r, __s)
+ 
+-static inline int try_write_seqlock(seqlock_t *sl)
+-{
+-	if (spin_trylock(&sl->lock)) {
+-		write_seqcount_begin(&sl->seqcount);
+-		return 1;
+-	}
+-	return 0;
+-}
+-
+ #else
+ # define net_seqlock_t			seqcount_t
+ # define net_seq_begin(__r)		read_seqcount_begin(__r)
+diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
+index 8ce663a9b4f4..eee11a1c9321 100644
+--- a/include/net/sch_generic.h
++++ b/include/net/sch_generic.h
+@@ -189,8 +189,16 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc)
+ 		return false;
+ 	}
+ #ifdef CONFIG_PREEMPT_RT
+-	if (try_write_seqlock(&qdisc->running))
++	if (spin_trylock(&qdisc->running.lock)) {
++		seqcount_t *s = &qdisc->running.seqcount.seqcount;
++		/*
++		 * Variant of write_seqcount_t_begin() telling lockdep that a
++		 * trylock was attempted.
++		 */
++		do_raw_write_seqcount_begin(s);
++		seqcount_acquire(&s->dep_map, 0, 1, _RET_IP_);
+ 		return true;
++	}
+ 	return false;
+ #else
+ 	/* Variant of write_seqcount_begin() telling lockdep a trylock
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0188-kconfig-Disable-config-options-which-are-not-RT-comp.patch b/debian/patches-rt/0188-kconfig-Disable-config-options-which-are-not-RT-comp.patch
new file mode 100644
index 000000000..27d06fa44
--- /dev/null
+++ b/debian/patches-rt/0188-kconfig-Disable-config-options-which-are-not-RT-comp.patch
@@ -0,0 +1,43 @@
+From f4fb1a364b1dc97c110e6103ffe75b21e46a0e63 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Sun, 24 Jul 2011 12:11:43 +0200
+Subject: [PATCH 188/323] kconfig: Disable config options which are not RT
+ compatible
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Disable stuff which is known to have issues on RT
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ arch/Kconfig | 1 +
+ mm/Kconfig   | 2 +-
+ 2 files changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/arch/Kconfig b/arch/Kconfig
+index 628e1e7fe302..8bbbca8839e1 100644
+--- a/arch/Kconfig
++++ b/arch/Kconfig
+@@ -37,6 +37,7 @@ config OPROFILE
+ 	tristate "OProfile system profiling"
+ 	depends on PROFILING
+ 	depends on HAVE_OPROFILE
++	depends on !PREEMPT_RT
+ 	select RING_BUFFER
+ 	select RING_BUFFER_ALLOW_SWAP
+ 	help
+diff --git a/mm/Kconfig b/mm/Kconfig
+index 8c49d09da214..c8cbcb5118b0 100644
+--- a/mm/Kconfig
++++ b/mm/Kconfig
+@@ -387,7 +387,7 @@ config NOMMU_INITIAL_TRIM_EXCESS
+ 
+ config TRANSPARENT_HUGEPAGE
+ 	bool "Transparent Hugepage Support"
+-	depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE
++	depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE && !PREEMPT_RT
+ 	select COMPACTION
+ 	select XARRAY_MULTI
+ 	help
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0189-mm-Allow-only-SLUB-on-RT.patch b/debian/patches-rt/0189-mm-Allow-only-SLUB-on-RT.patch
new file mode 100644
index 000000000..9fc3d7351
--- /dev/null
+++ b/debian/patches-rt/0189-mm-Allow-only-SLUB-on-RT.patch
@@ -0,0 +1,47 @@
+From 1da220d86ade67051c7c89743d6d037902c3839d Mon Sep 17 00:00:00 2001
+From: Ingo Molnar <mingo@elte.hu>
+Date: Fri, 3 Jul 2009 08:44:03 -0500
+Subject: [PATCH 189/323] mm: Allow only SLUB on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Memory allocation disables interrupts as part of the allocation and freeing
+process. For -RT it is important that this section remain short and don't
+depend on the size of the request or an internal state of the memory allocator.
+At the beginning the SLAB memory allocator was adopted for RT's needs and it
+required substantial changes. Later, with the addition of the SLUB memory
+allocator we adopted this one as well and the changes were smaller. More
+important, due to the design of the SLUB allocator it performs better and its
+worst case latency was smaller. In the end only SLUB remained supported.
+
+Disable SLAB and SLOB on -RT. Only SLUB is adopted to -RT needs.
+
+Signed-off-by: Ingo Molnar <mingo@elte.hu>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ init/Kconfig | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/init/Kconfig b/init/Kconfig
+index 9807c66b24bb..df8d0d0f800f 100644
+--- a/init/Kconfig
++++ b/init/Kconfig
+@@ -1922,6 +1922,7 @@ choice
+ 
+ config SLAB
+ 	bool "SLAB"
++	depends on !PREEMPT_RT
+ 	select HAVE_HARDENED_USERCOPY_ALLOCATOR
+ 	help
+ 	  The regular slab allocator that is established and known to work
+@@ -1942,6 +1943,7 @@ config SLUB
+ config SLOB
+ 	depends on EXPERT
+ 	bool "SLOB (Simple Allocator)"
++	depends on !PREEMPT_RT
+ 	help
+ 	   SLOB replaces the stock allocator with a drastically simpler
+ 	   allocator. SLOB is generally more space efficient but
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0190-sched-Disable-CONFIG_RT_GROUP_SCHED-on-RT.patch b/debian/patches-rt/0190-sched-Disable-CONFIG_RT_GROUP_SCHED-on-RT.patch
new file mode 100644
index 000000000..eb62300e8
--- /dev/null
+++ b/debian/patches-rt/0190-sched-Disable-CONFIG_RT_GROUP_SCHED-on-RT.patch
@@ -0,0 +1,35 @@
+From 4e23e134063807a9288e9b547e1955a9124ac5b7 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Mon, 18 Jul 2011 17:03:52 +0200
+Subject: [PATCH 190/323] sched: Disable CONFIG_RT_GROUP_SCHED on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Carsten reported problems when running:
+
+  taskset 01 chrt -f 1 sleep 1
+
+from within rc.local on a F15 machine. The task stays running and
+never gets on the run queue because some of the run queues have
+rt_throttled=1 which does not go away. Works nice from a ssh login
+shell. Disabling CONFIG_RT_GROUP_SCHED solves that as well.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ init/Kconfig | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/init/Kconfig b/init/Kconfig
+index df8d0d0f800f..7e9578a0176f 100644
+--- a/init/Kconfig
++++ b/init/Kconfig
+@@ -985,6 +985,7 @@ config CFS_BANDWIDTH
+ config RT_GROUP_SCHED
+ 	bool "Group scheduling for SCHED_RR/FIFO"
+ 	depends on CGROUP_SCHED
++	depends on !PREEMPT_RT
+ 	default n
+ 	help
+ 	  This feature lets you explicitly allocate real CPU bandwidth
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0191-net-core-disable-NET_RX_BUSY_POLL-on-RT.patch b/debian/patches-rt/0191-net-core-disable-NET_RX_BUSY_POLL-on-RT.patch
new file mode 100644
index 000000000..aef82ca64
--- /dev/null
+++ b/debian/patches-rt/0191-net-core-disable-NET_RX_BUSY_POLL-on-RT.patch
@@ -0,0 +1,44 @@
+From 311a1cf04650b065502758f992df44702d23f6cd Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Sat, 27 May 2017 19:02:06 +0200
+Subject: [PATCH 191/323] net/core: disable NET_RX_BUSY_POLL on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+napi_busy_loop() disables preemption and performs a NAPI poll. We can't acquire
+sleeping locks with disabled preemption so we would have to work around this
+and add explicit locking for synchronisation against ksoftirqd.
+Without explicit synchronisation a low priority process would "own" the NAPI
+state (by setting NAPIF_STATE_SCHED) and could be scheduled out (no
+preempt_disable() and BH is preemptible on RT).
+In case a network packages arrives then the interrupt handler would set
+NAPIF_STATE_MISSED and the system would wait until the task owning the NAPI
+would be scheduled in again.
+Should a task with RT priority busy poll then it would consume the CPU instead
+allowing tasks with lower priority to run.
+
+The NET_RX_BUSY_POLL is disabled by default (the system wide sysctls for
+poll/read are set to zero) so disable NET_RX_BUSY_POLL on RT to avoid wrong
+locking context on RT. Should this feature be considered useful on RT systems
+then it could be enabled again with proper locking and synchronisation.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ net/Kconfig | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/net/Kconfig b/net/Kconfig
+index a22c3fb88564..5a17bded7136 100644
+--- a/net/Kconfig
++++ b/net/Kconfig
+@@ -280,7 +280,7 @@ config CGROUP_NET_CLASSID
+ 
+ config NET_RX_BUSY_POLL
+ 	bool
+-	default y
++	default y if !PREEMPT_RT
+ 
+ config BQL
+ 	bool
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0192-efi-Disable-runtime-services-on-RT.patch b/debian/patches-rt/0192-efi-Disable-runtime-services-on-RT.patch
new file mode 100644
index 000000000..ed06b5934
--- /dev/null
+++ b/debian/patches-rt/0192-efi-Disable-runtime-services-on-RT.patch
@@ -0,0 +1,46 @@
+From 6c6afc933fea370e5c90a34ed6b622bcc274af5a Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Thu, 26 Jul 2018 15:03:16 +0200
+Subject: [PATCH 192/323] efi: Disable runtime services on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Based on meassurements the EFI functions get_variable /
+get_next_variable take up to 2us which looks okay.
+The functions get_time, set_time take around 10ms. Those 10ms are too
+much. Even one ms would be too much.
+Ard mentioned that SetVariable might even trigger larger latencies if
+the firware will erase flash blocks on NOR.
+
+The time-functions are used by efi-rtc and can be triggered during
+runtimed (either via explicit read/write or ntp sync).
+
+The variable write could be used by pstore.
+These functions can be disabled without much of a loss. The poweroff /
+reboot hooks may be provided by PSCI.
+
+Disable EFI's runtime wrappers.
+
+This was observed on "EFI v2.60 by SoftIron Overdrive 1000".
+
+Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/firmware/efi/efi.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
+index 332739f3eded..8d390091203f 100644
+--- a/drivers/firmware/efi/efi.c
++++ b/drivers/firmware/efi/efi.c
+@@ -66,7 +66,7 @@ struct mm_struct efi_mm = {
+ 
+ struct workqueue_struct *efi_rts_wq;
+ 
+-static bool disable_runtime;
++static bool disable_runtime = IS_ENABLED(CONFIG_PREEMPT_RT);
+ static int __init setup_noefi(char *arg)
+ {
+ 	disable_runtime = true;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0193-efi-Allow-efi-runtime.patch b/debian/patches-rt/0193-efi-Allow-efi-runtime.patch
new file mode 100644
index 000000000..f52a8c240
--- /dev/null
+++ b/debian/patches-rt/0193-efi-Allow-efi-runtime.patch
@@ -0,0 +1,32 @@
+From 712d19894b0524bdc524334f6d76babef13db194 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Thu, 26 Jul 2018 15:06:10 +0200
+Subject: [PATCH 193/323] efi: Allow efi=runtime
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+In case the command line option "efi=noruntime" is default at built-time, the user
+could overwrite its state by `efi=runtime' and allow it again.
+
+Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/firmware/efi/efi.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
+index 8d390091203f..8589df0e8c1f 100644
+--- a/drivers/firmware/efi/efi.c
++++ b/drivers/firmware/efi/efi.c
+@@ -97,6 +97,9 @@ static int __init parse_efi_cmdline(char *str)
+ 	if (parse_option_str(str, "noruntime"))
+ 		disable_runtime = true;
+ 
++	if (parse_option_str(str, "runtime"))
++		disable_runtime = false;
++
+ 	if (parse_option_str(str, "nosoftreserve"))
+ 		set_bit(EFI_MEM_NO_SOFT_RESERVE, &efi.flags);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0194-rt-Add-local-irq-locks.patch b/debian/patches-rt/0194-rt-Add-local-irq-locks.patch
new file mode 100644
index 000000000..53b3fd552
--- /dev/null
+++ b/debian/patches-rt/0194-rt-Add-local-irq-locks.patch
@@ -0,0 +1,182 @@
+From 0d3e0b0db513aac6e4cd2e2d084b7a76f4d28c44 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Mon, 20 Jun 2011 09:03:47 +0200
+Subject: [PATCH 194/323] rt: Add local irq locks
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Introduce locallock. For !RT this maps to preempt_disable()/
+local_irq_disable() so there is not much that changes. For RT this will
+map to a spinlock. This makes preemption possible and locked "ressource"
+gets the lockdep anotation it wouldn't have otherwise. The locks are
+recursive for owner == current. Also, all locks user migrate_disable()
+which ensures that the task is not migrated to another CPU while the lock
+is held and the owner is preempted.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/local_lock_internal.h | 111 ++++++++++++++++++++++++++--
+ 1 file changed, 103 insertions(+), 8 deletions(-)
+
+diff --git a/include/linux/local_lock_internal.h b/include/linux/local_lock_internal.h
+index 3f02b818625e..1b8ae034946f 100644
+--- a/include/linux/local_lock_internal.h
++++ b/include/linux/local_lock_internal.h
+@@ -7,13 +7,39 @@
+ #include <linux/lockdep.h>
+ 
+ typedef struct {
+-#ifdef CONFIG_DEBUG_LOCK_ALLOC
++#ifdef CONFIG_PREEMPT_RT
++	spinlock_t              lock;
++	struct task_struct      *owner;
++	int                     nestcnt;
++
++#elif defined(CONFIG_DEBUG_LOCK_ALLOC)
+ 	struct lockdep_map	dep_map;
+ 	struct task_struct	*owner;
+ #endif
+ } local_lock_t;
+ 
+-#ifdef CONFIG_DEBUG_LOCK_ALLOC
++#ifdef CONFIG_PREEMPT_RT
++
++#define INIT_LOCAL_LOCK(lockname)	{	\
++	__SPIN_LOCK_UNLOCKED((lockname).lock),	\
++	.owner		= NULL,			\
++	.nestcnt	= 0,			\
++	}
++
++static inline void ___local_lock_init(local_lock_t *l)
++{
++	l->owner = NULL;
++	l->nestcnt = 0;
++}
++
++#define __local_lock_init(l)					\
++do {								\
++	spin_lock_init(&(l)->lock);				\
++	___local_lock_init(l);					\
++} while (0)
++
++#elif defined(CONFIG_DEBUG_LOCK_ALLOC)
++
+ # define LOCAL_LOCK_DEBUG_INIT(lockname)		\
+ 	.dep_map = {					\
+ 		.name = #lockname,			\
+@@ -21,7 +47,33 @@ typedef struct {
+ 		.lock_type = LD_LOCK_PERCPU,		\
+ 	},						\
+ 	.owner = NULL,
++#endif
++
++#ifdef CONFIG_PREEMPT_RT
+ 
++static inline void local_lock_acquire(local_lock_t *l)
++{
++	if (l->owner != current) {
++		spin_lock(&l->lock);
++		DEBUG_LOCKS_WARN_ON(l->owner);
++		DEBUG_LOCKS_WARN_ON(l->nestcnt);
++		l->owner = current;
++	}
++	l->nestcnt++;
++}
++
++static inline void local_lock_release(local_lock_t *l)
++{
++	DEBUG_LOCKS_WARN_ON(l->nestcnt == 0);
++	DEBUG_LOCKS_WARN_ON(l->owner != current);
++	if (--l->nestcnt)
++		return;
++
++	l->owner = NULL;
++	spin_unlock(&l->lock);
++}
++
++#elif defined(CONFIG_DEBUG_LOCK_ALLOC)
+ static inline void local_lock_acquire(local_lock_t *l)
+ {
+ 	lock_map_acquire(&l->dep_map);
+@@ -47,6 +99,47 @@ static inline void local_lock_release(local_lock_t *l) { }
+ static inline void local_lock_debug_init(local_lock_t *l) { }
+ #endif /* !CONFIG_DEBUG_LOCK_ALLOC */
+ 
++#ifdef CONFIG_PREEMPT_RT
++
++#define __local_lock(lock)					\
++	do {							\
++		migrate_disable();				\
++		local_lock_acquire(this_cpu_ptr(lock));		\
++	} while (0)
++
++#define __local_unlock(lock)					\
++	do {							\
++		local_lock_release(this_cpu_ptr(lock));		\
++		migrate_enable();				\
++	} while (0)
++
++#define __local_lock_irq(lock)					\
++	do {							\
++		migrate_disable();				\
++		local_lock_acquire(this_cpu_ptr(lock));		\
++	} while (0)
++
++#define __local_lock_irqsave(lock, flags)			\
++	do {							\
++		migrate_disable();				\
++		flags = 0;					\
++		local_lock_acquire(this_cpu_ptr(lock));		\
++	} while (0)
++
++#define __local_unlock_irq(lock)				\
++	do {							\
++		local_lock_release(this_cpu_ptr(lock));		\
++		migrate_enable();				\
++	} while (0)
++
++#define __local_unlock_irqrestore(lock, flags)			\
++	do {							\
++		local_lock_release(this_cpu_ptr(lock));		\
++		migrate_enable();				\
++	} while (0)
++
++#else
++
+ #define INIT_LOCAL_LOCK(lockname)	{ LOCAL_LOCK_DEBUG_INIT(lockname) }
+ 
+ #define __local_lock_init(lock)					\
+@@ -66,6 +159,12 @@ do {								\
+ 		local_lock_acquire(this_cpu_ptr(lock));		\
+ 	} while (0)
+ 
++#define __local_unlock(lock)					\
++	do {							\
++		local_lock_release(this_cpu_ptr(lock));		\
++		preempt_enable();				\
++	} while (0)
++
+ #define __local_lock_irq(lock)					\
+ 	do {							\
+ 		local_irq_disable();				\
+@@ -78,12 +177,6 @@ do {								\
+ 		local_lock_acquire(this_cpu_ptr(lock));		\
+ 	} while (0)
+ 
+-#define __local_unlock(lock)					\
+-	do {							\
+-		local_lock_release(this_cpu_ptr(lock));		\
+-		preempt_enable();				\
+-	} while (0)
+-
+ #define __local_unlock_irq(lock)				\
+ 	do {							\
+ 		local_lock_release(this_cpu_ptr(lock));		\
+@@ -95,3 +188,5 @@ do {								\
+ 		local_lock_release(this_cpu_ptr(lock));		\
+ 		local_irq_restore(flags);			\
+ 	} while (0)
++
++#endif
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0195-signal-x86-Delay-calling-signals-in-atomic.patch b/debian/patches-rt/0195-signal-x86-Delay-calling-signals-in-atomic.patch
new file mode 100644
index 000000000..af5ab46e8
--- /dev/null
+++ b/debian/patches-rt/0195-signal-x86-Delay-calling-signals-in-atomic.patch
@@ -0,0 +1,140 @@
+From f4ff44284474fd78b52414326c579dcd8196fc47 Mon Sep 17 00:00:00 2001
+From: Oleg Nesterov <oleg@redhat.com>
+Date: Tue, 14 Jul 2015 14:26:34 +0200
+Subject: [PATCH 195/323] signal/x86: Delay calling signals in atomic
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+On x86_64 we must disable preemption before we enable interrupts
+for stack faults, int3 and debugging, because the current task is using
+a per CPU debug stack defined by the IST. If we schedule out, another task
+can come in and use the same stack and cause the stack to be corrupted
+and crash the kernel on return.
+
+When CONFIG_PREEMPT_RT is enabled, spin_locks become mutexes, and
+one of these is the spin lock used in signal handling.
+
+Some of the debug code (int3) causes do_trap() to send a signal.
+This function calls a spin lock that has been converted to a mutex
+and has the possibility to sleep. If this happens, the above issues with
+the corrupted stack is possible.
+
+Instead of calling the signal right away, for PREEMPT_RT and x86_64,
+the signal information is stored on the stacks task_struct and
+TIF_NOTIFY_RESUME is set. Then on exit of the trap, the signal resume
+code will send the signal when preemption is enabled.
+
+[ rostedt: Switched from #ifdef CONFIG_PREEMPT_RT to
+  ARCH_RT_DELAYS_SIGNAL_SEND and added comments to the code. ]
+
+Signed-off-by: Oleg Nesterov <oleg@redhat.com>
+Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+[bigeasy: also needed on 32bit as per Yang Shi <yang.shi@linaro.org>]
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/x86/include/asm/signal.h | 13 +++++++++++++
+ include/linux/sched.h         |  4 ++++
+ kernel/entry/common.c         |  8 ++++++++
+ kernel/signal.c               | 28 ++++++++++++++++++++++++++++
+ 4 files changed, 53 insertions(+)
+
+diff --git a/arch/x86/include/asm/signal.h b/arch/x86/include/asm/signal.h
+index 6fd8410a3910..f3bf2f515edb 100644
+--- a/arch/x86/include/asm/signal.h
++++ b/arch/x86/include/asm/signal.h
+@@ -28,6 +28,19 @@ typedef struct {
+ #define SA_IA32_ABI	0x02000000u
+ #define SA_X32_ABI	0x01000000u
+ 
++/*
++ * Because some traps use the IST stack, we must keep preemption
++ * disabled while calling do_trap(), but do_trap() may call
++ * force_sig_info() which will grab the signal spin_locks for the
++ * task, which in PREEMPT_RT are mutexes.  By defining
++ * ARCH_RT_DELAYS_SIGNAL_SEND the force_sig_info() will set
++ * TIF_NOTIFY_RESUME and set up the signal to be sent on exit of the
++ * trap.
++ */
++#if defined(CONFIG_PREEMPT_RT)
++#define ARCH_RT_DELAYS_SIGNAL_SEND
++#endif
++
+ #ifndef CONFIG_COMPAT
+ typedef sigset_t compat_sigset_t;
+ #endif
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index 3650fdaac4ca..d259126f46cf 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -1001,6 +1001,10 @@ struct task_struct {
+ 	/* Restored if set_restore_sigmask() was used: */
+ 	sigset_t			saved_sigmask;
+ 	struct sigpending		pending;
++#ifdef CONFIG_PREEMPT_RT
++	/* TODO: move me into ->restart_block ? */
++	struct				kernel_siginfo forced_info;
++#endif
+ 	unsigned long			sas_ss_sp;
+ 	size_t				sas_ss_size;
+ 	unsigned int			sas_ss_flags;
+diff --git a/kernel/entry/common.c b/kernel/entry/common.c
+index e6a66de1202a..e6da86039ccf 100644
+--- a/kernel/entry/common.c
++++ b/kernel/entry/common.c
+@@ -160,6 +160,14 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
+ 		if (ti_work & _TIF_NEED_RESCHED)
+ 			schedule();
+ 
++#ifdef ARCH_RT_DELAYS_SIGNAL_SEND
++		if (unlikely(current->forced_info.si_signo)) {
++			struct task_struct *t = current;
++			force_sig_info(&t->forced_info);
++			t->forced_info.si_signo = 0;
++		}
++#endif
++
+ 		if (ti_work & _TIF_UPROBE)
+ 			uprobe_notify_resume(regs);
+ 
+diff --git a/kernel/signal.c b/kernel/signal.c
+index 5ab628e2afc5..e8819aabe3cd 100644
+--- a/kernel/signal.c
++++ b/kernel/signal.c
+@@ -1314,6 +1314,34 @@ force_sig_info_to_task(struct kernel_siginfo *info, struct task_struct *t)
+ 	struct k_sigaction *action;
+ 	int sig = info->si_signo;
+ 
++	/*
++	 * On some archs, PREEMPT_RT has to delay sending a signal from a trap
++	 * since it can not enable preemption, and the signal code's spin_locks
++	 * turn into mutexes. Instead, it must set TIF_NOTIFY_RESUME which will
++	 * send the signal on exit of the trap.
++	 */
++#ifdef ARCH_RT_DELAYS_SIGNAL_SEND
++	if (in_atomic()) {
++		struct task_struct *t = current;
++
++		if (WARN_ON_ONCE(t->forced_info.si_signo))
++			return 0;
++
++		if (is_si_special(info)) {
++			WARN_ON_ONCE(info != SEND_SIG_PRIV);
++			t->forced_info.si_signo = info->si_signo;
++			t->forced_info.si_errno = 0;
++			t->forced_info.si_code = SI_KERNEL;
++			t->forced_info.si_pid = 0;
++			t->forced_info.si_uid = 0;
++		} else {
++			t->forced_info = *info;
++		}
++
++		set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
++		return 0;
++	}
++#endif
+ 	spin_lock_irqsave(&t->sighand->siglock, flags);
+ 	action = &t->sighand->action[sig-1];
+ 	ignored = action->sa.sa_handler == SIG_IGN;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0196-Split-IRQ-off-and-zone-lock-while-freeing-pages-from.patch b/debian/patches-rt/0196-Split-IRQ-off-and-zone-lock-while-freeing-pages-from.patch
new file mode 100644
index 000000000..999298a0e
--- /dev/null
+++ b/debian/patches-rt/0196-Split-IRQ-off-and-zone-lock-while-freeing-pages-from.patch
@@ -0,0 +1,172 @@
+From 1e362e9e053f608c55deb05577371d61d5db1a92 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Mon, 28 May 2018 15:24:20 +0200
+Subject: [PATCH 196/323] Split IRQ-off and zone->lock while freeing pages from
+ PCP list #1
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Split the IRQ-off section while accessing the PCP list from zone->lock
+while freeing pages.
+Introcude  isolate_pcp_pages() which separates the pages from the PCP
+list onto a temporary list and then free the temporary list via
+free_pcppages_bulk().
+
+Signed-off-by: Peter Zijlstra <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/page_alloc.c | 81 +++++++++++++++++++++++++++++++------------------
+ 1 file changed, 51 insertions(+), 30 deletions(-)
+
+diff --git a/mm/page_alloc.c b/mm/page_alloc.c
+index 124ab9324610..0dc0eb767fb6 100644
+--- a/mm/page_alloc.c
++++ b/mm/page_alloc.c
+@@ -1331,7 +1331,7 @@ static inline void prefetch_buddy(struct page *page)
+ }
+ 
+ /*
+- * Frees a number of pages from the PCP lists
++ * Frees a number of pages which have been collected from the pcp lists.
+  * Assumes all pages on list are in same zone, and of same order.
+  * count is the number of pages to free.
+  *
+@@ -1342,14 +1342,40 @@ static inline void prefetch_buddy(struct page *page)
+  * pinned" detection logic.
+  */
+ static void free_pcppages_bulk(struct zone *zone, int count,
+-					struct per_cpu_pages *pcp)
++			       struct list_head *head)
++{
++	bool isolated_pageblocks;
++	struct page *page, *tmp;
++	unsigned long flags;
++
++	spin_lock_irqsave(&zone->lock, flags);
++	isolated_pageblocks = has_isolate_pageblock(zone);
++
++	/*
++	 * Use safe version since after __free_one_page(),
++	 * page->lru.next will not point to original list.
++	 */
++	list_for_each_entry_safe(page, tmp, head, lru) {
++		int mt = get_pcppage_migratetype(page);
++		/* MIGRATE_ISOLATE page should not go to pcplists */
++		VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
++		/* Pageblock could have been isolated meanwhile */
++		if (unlikely(isolated_pageblocks))
++			mt = get_pageblock_migratetype(page);
++
++		__free_one_page(page, page_to_pfn(page), zone, 0, mt, FPI_NONE);
++		trace_mm_page_pcpu_drain(page, 0, mt);
++	}
++	spin_unlock_irqrestore(&zone->lock, flags);
++}
++
++static void isolate_pcp_pages(int count, struct per_cpu_pages *pcp,
++			      struct list_head *dst)
+ {
+ 	int migratetype = 0;
+ 	int batch_free = 0;
+ 	int prefetch_nr = 0;
+-	bool isolated_pageblocks;
+-	struct page *page, *tmp;
+-	LIST_HEAD(head);
++	struct page *page;
+ 
+ 	/*
+ 	 * Ensure proper count is passed which otherwise would stuck in the
+@@ -1386,7 +1412,7 @@ static void free_pcppages_bulk(struct zone *zone, int count,
+ 			if (bulkfree_pcp_prepare(page))
+ 				continue;
+ 
+-			list_add_tail(&page->lru, &head);
++			list_add_tail(&page->lru, dst);
+ 
+ 			/*
+ 			 * We are going to put the page back to the global
+@@ -1401,26 +1427,6 @@ static void free_pcppages_bulk(struct zone *zone, int count,
+ 				prefetch_buddy(page);
+ 		} while (--count && --batch_free && !list_empty(list));
+ 	}
+-
+-	spin_lock(&zone->lock);
+-	isolated_pageblocks = has_isolate_pageblock(zone);
+-
+-	/*
+-	 * Use safe version since after __free_one_page(),
+-	 * page->lru.next will not point to original list.
+-	 */
+-	list_for_each_entry_safe(page, tmp, &head, lru) {
+-		int mt = get_pcppage_migratetype(page);
+-		/* MIGRATE_ISOLATE page should not go to pcplists */
+-		VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
+-		/* Pageblock could have been isolated meanwhile */
+-		if (unlikely(isolated_pageblocks))
+-			mt = get_pageblock_migratetype(page);
+-
+-		__free_one_page(page, page_to_pfn(page), zone, 0, mt, FPI_NONE);
+-		trace_mm_page_pcpu_drain(page, 0, mt);
+-	}
+-	spin_unlock(&zone->lock);
+ }
+ 
+ static void free_one_page(struct zone *zone,
+@@ -2938,13 +2944,18 @@ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
+ {
+ 	unsigned long flags;
+ 	int to_drain, batch;
++	LIST_HEAD(dst);
+ 
+ 	local_irq_save(flags);
+ 	batch = READ_ONCE(pcp->batch);
+ 	to_drain = min(pcp->count, batch);
+ 	if (to_drain > 0)
+-		free_pcppages_bulk(zone, to_drain, pcp);
++		isolate_pcp_pages(to_drain, pcp, &dst);
++
+ 	local_irq_restore(flags);
++
++	if (to_drain > 0)
++		free_pcppages_bulk(zone, to_drain, &dst);
+ }
+ #endif
+ 
+@@ -2960,14 +2971,21 @@ static void drain_pages_zone(unsigned int cpu, struct zone *zone)
+ 	unsigned long flags;
+ 	struct per_cpu_pageset *pset;
+ 	struct per_cpu_pages *pcp;
++	LIST_HEAD(dst);
++	int count;
+ 
+ 	local_irq_save(flags);
+ 	pset = per_cpu_ptr(zone->pageset, cpu);
+ 
+ 	pcp = &pset->pcp;
+-	if (pcp->count)
+-		free_pcppages_bulk(zone, pcp->count, pcp);
++	count = pcp->count;
++	if (count)
++		isolate_pcp_pages(count, pcp, &dst);
++
+ 	local_irq_restore(flags);
++
++	if (count)
++		free_pcppages_bulk(zone, count, &dst);
+ }
+ 
+ /*
+@@ -3196,7 +3214,10 @@ static void free_unref_page_commit(struct page *page, unsigned long pfn)
+ 	pcp->count++;
+ 	if (pcp->count >= pcp->high) {
+ 		unsigned long batch = READ_ONCE(pcp->batch);
+-		free_pcppages_bulk(zone, batch, pcp);
++		LIST_HEAD(dst);
++
++		isolate_pcp_pages(batch, pcp, &dst);
++		free_pcppages_bulk(zone, batch, &dst);
+ 	}
+ }
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0197-Split-IRQ-off-and-zone-lock-while-freeing-pages-from.patch b/debian/patches-rt/0197-Split-IRQ-off-and-zone-lock-while-freeing-pages-from.patch
new file mode 100644
index 000000000..60c805684
--- /dev/null
+++ b/debian/patches-rt/0197-Split-IRQ-off-and-zone-lock-while-freeing-pages-from.patch
@@ -0,0 +1,172 @@
+From 3bb0aee1e418d977b819e6d0632d71cbb7cd1138 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Mon, 28 May 2018 15:24:21 +0200
+Subject: [PATCH 197/323] Split IRQ-off and zone->lock while freeing pages from
+ PCP list #2
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Split the IRQ-off section while accessing the PCP list from zone->lock
+while freeing pages.
+Introcude  isolate_pcp_pages() which separates the pages from the PCP
+list onto a temporary list and then free the temporary list via
+free_pcppages_bulk().
+
+Signed-off-by: Peter Zijlstra <peterz@infradead.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/page_alloc.c | 60 ++++++++++++++++++++++++++++++++++++++++---------
+ 1 file changed, 50 insertions(+), 10 deletions(-)
+
+diff --git a/mm/page_alloc.c b/mm/page_alloc.c
+index 0dc0eb767fb6..a3f1e4c6bdc8 100644
+--- a/mm/page_alloc.c
++++ b/mm/page_alloc.c
+@@ -1341,8 +1341,8 @@ static inline void prefetch_buddy(struct page *page)
+  * And clear the zone's pages_scanned counter, to hold off the "all pages are
+  * pinned" detection logic.
+  */
+-static void free_pcppages_bulk(struct zone *zone, int count,
+-			       struct list_head *head)
++static void free_pcppages_bulk(struct zone *zone, struct list_head *head,
++			       bool zone_retry)
+ {
+ 	bool isolated_pageblocks;
+ 	struct page *page, *tmp;
+@@ -1357,12 +1357,27 @@ static void free_pcppages_bulk(struct zone *zone, int count,
+ 	 */
+ 	list_for_each_entry_safe(page, tmp, head, lru) {
+ 		int mt = get_pcppage_migratetype(page);
++
++		if (page_zone(page) != zone) {
++			/*
++			 * free_unref_page_list() sorts pages by zone. If we end
++			 * up with pages from a different NUMA nodes belonging
++			 * to the same ZONE index then we need to redo with the
++			 * correct ZONE pointer. Skip the page for now, redo it
++			 * on the next iteration.
++			 */
++			WARN_ON_ONCE(zone_retry == false);
++			if (zone_retry)
++				continue;
++		}
++
+ 		/* MIGRATE_ISOLATE page should not go to pcplists */
+ 		VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
+ 		/* Pageblock could have been isolated meanwhile */
+ 		if (unlikely(isolated_pageblocks))
+ 			mt = get_pageblock_migratetype(page);
+ 
++		list_del(&page->lru);
+ 		__free_one_page(page, page_to_pfn(page), zone, 0, mt, FPI_NONE);
+ 		trace_mm_page_pcpu_drain(page, 0, mt);
+ 	}
+@@ -2955,7 +2970,7 @@ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
+ 	local_irq_restore(flags);
+ 
+ 	if (to_drain > 0)
+-		free_pcppages_bulk(zone, to_drain, &dst);
++		free_pcppages_bulk(zone, &dst, false);
+ }
+ #endif
+ 
+@@ -2985,7 +3000,7 @@ static void drain_pages_zone(unsigned int cpu, struct zone *zone)
+ 	local_irq_restore(flags);
+ 
+ 	if (count)
+-		free_pcppages_bulk(zone, count, &dst);
++		free_pcppages_bulk(zone, &dst, false);
+ }
+ 
+ /*
+@@ -3184,7 +3199,8 @@ static bool free_unref_page_prepare(struct page *page, unsigned long pfn)
+ 	return true;
+ }
+ 
+-static void free_unref_page_commit(struct page *page, unsigned long pfn)
++static void free_unref_page_commit(struct page *page, unsigned long pfn,
++				   struct list_head *dst)
+ {
+ 	struct zone *zone = page_zone(page);
+ 	struct per_cpu_pages *pcp;
+@@ -3214,10 +3230,8 @@ static void free_unref_page_commit(struct page *page, unsigned long pfn)
+ 	pcp->count++;
+ 	if (pcp->count >= pcp->high) {
+ 		unsigned long batch = READ_ONCE(pcp->batch);
+-		LIST_HEAD(dst);
+ 
+-		isolate_pcp_pages(batch, pcp, &dst);
+-		free_pcppages_bulk(zone, batch, &dst);
++		isolate_pcp_pages(batch, pcp, dst);
+ 	}
+ }
+ 
+@@ -3228,13 +3242,17 @@ void free_unref_page(struct page *page)
+ {
+ 	unsigned long flags;
+ 	unsigned long pfn = page_to_pfn(page);
++	struct zone *zone = page_zone(page);
++	LIST_HEAD(dst);
+ 
+ 	if (!free_unref_page_prepare(page, pfn))
+ 		return;
+ 
+ 	local_irq_save(flags);
+-	free_unref_page_commit(page, pfn);
++	free_unref_page_commit(page, pfn, &dst);
+ 	local_irq_restore(flags);
++	if (!list_empty(&dst))
++		free_pcppages_bulk(zone, &dst, false);
+ }
+ 
+ /*
+@@ -3245,6 +3263,11 @@ void free_unref_page_list(struct list_head *list)
+ 	struct page *page, *next;
+ 	unsigned long flags, pfn;
+ 	int batch_count = 0;
++	struct list_head dsts[__MAX_NR_ZONES];
++	int i;
++
++	for (i = 0; i < __MAX_NR_ZONES; i++)
++		INIT_LIST_HEAD(&dsts[i]);
+ 
+ 	/* Prepare pages for freeing */
+ 	list_for_each_entry_safe(page, next, list, lru) {
+@@ -3257,10 +3280,12 @@ void free_unref_page_list(struct list_head *list)
+ 	local_irq_save(flags);
+ 	list_for_each_entry_safe(page, next, list, lru) {
+ 		unsigned long pfn = page_private(page);
++		enum zone_type type;
+ 
+ 		set_page_private(page, 0);
+ 		trace_mm_page_free_batched(page);
+-		free_unref_page_commit(page, pfn);
++		type = page_zonenum(page);
++		free_unref_page_commit(page, pfn, &dsts[type]);
+ 
+ 		/*
+ 		 * Guard against excessive IRQ disabled times when we get
+@@ -3273,6 +3298,21 @@ void free_unref_page_list(struct list_head *list)
+ 		}
+ 	}
+ 	local_irq_restore(flags);
++
++	for (i = 0; i < __MAX_NR_ZONES; ) {
++		struct page *page;
++		struct zone *zone;
++
++		if (list_empty(&dsts[i])) {
++			i++;
++			continue;
++		}
++
++		page = list_first_entry(&dsts[i], struct page, lru);
++		zone = page_zone(page);
++
++		free_pcppages_bulk(zone, &dsts[i], true);
++	}
+ }
+ 
+ /*
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0198-mm-SLxB-change-list_lock-to-raw_spinlock_t.patch b/debian/patches-rt/0198-mm-SLxB-change-list_lock-to-raw_spinlock_t.patch
new file mode 100644
index 000000000..903ce7fd5
--- /dev/null
+++ b/debian/patches-rt/0198-mm-SLxB-change-list_lock-to-raw_spinlock_t.patch
@@ -0,0 +1,603 @@
+From 24eecb5c4b97d1a359a8b16be1dae2a499720795 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Mon, 28 May 2018 15:24:22 +0200
+Subject: [PATCH 198/323] mm/SLxB: change list_lock to raw_spinlock_t
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The list_lock is used with used with IRQs off on RT. Make it a raw_spinlock_t
+otherwise the interrupts won't be disabled on -RT.  The locking rules remain
+the same on !RT.
+This patch changes it for SLAB and SLUB since both share the same header
+file for struct kmem_cache_node defintion.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/slab.c | 90 +++++++++++++++++++++++++++----------------------------
+ mm/slab.h |  2 +-
+ mm/slub.c | 50 +++++++++++++++----------------
+ 3 files changed, 71 insertions(+), 71 deletions(-)
+
+diff --git a/mm/slab.c b/mm/slab.c
+index b2cc2cf7d8a3..677c0651ef66 100644
+--- a/mm/slab.c
++++ b/mm/slab.c
+@@ -233,7 +233,7 @@ static void kmem_cache_node_init(struct kmem_cache_node *parent)
+ 	parent->shared = NULL;
+ 	parent->alien = NULL;
+ 	parent->colour_next = 0;
+-	spin_lock_init(&parent->list_lock);
++	raw_spin_lock_init(&parent->list_lock);
+ 	parent->free_objects = 0;
+ 	parent->free_touched = 0;
+ }
+@@ -558,9 +558,9 @@ static noinline void cache_free_pfmemalloc(struct kmem_cache *cachep,
+ 	page_node = page_to_nid(page);
+ 	n = get_node(cachep, page_node);
+ 
+-	spin_lock(&n->list_lock);
++	raw_spin_lock(&n->list_lock);
+ 	free_block(cachep, &objp, 1, page_node, &list);
+-	spin_unlock(&n->list_lock);
++	raw_spin_unlock(&n->list_lock);
+ 
+ 	slabs_destroy(cachep, &list);
+ }
+@@ -698,7 +698,7 @@ static void __drain_alien_cache(struct kmem_cache *cachep,
+ 	struct kmem_cache_node *n = get_node(cachep, node);
+ 
+ 	if (ac->avail) {
+-		spin_lock(&n->list_lock);
++		raw_spin_lock(&n->list_lock);
+ 		/*
+ 		 * Stuff objects into the remote nodes shared array first.
+ 		 * That way we could avoid the overhead of putting the objects
+@@ -709,7 +709,7 @@ static void __drain_alien_cache(struct kmem_cache *cachep,
+ 
+ 		free_block(cachep, ac->entry, ac->avail, node, list);
+ 		ac->avail = 0;
+-		spin_unlock(&n->list_lock);
++		raw_spin_unlock(&n->list_lock);
+ 	}
+ }
+ 
+@@ -782,9 +782,9 @@ static int __cache_free_alien(struct kmem_cache *cachep, void *objp,
+ 		slabs_destroy(cachep, &list);
+ 	} else {
+ 		n = get_node(cachep, page_node);
+-		spin_lock(&n->list_lock);
++		raw_spin_lock(&n->list_lock);
+ 		free_block(cachep, &objp, 1, page_node, &list);
+-		spin_unlock(&n->list_lock);
++		raw_spin_unlock(&n->list_lock);
+ 		slabs_destroy(cachep, &list);
+ 	}
+ 	return 1;
+@@ -825,10 +825,10 @@ static int init_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp)
+ 	 */
+ 	n = get_node(cachep, node);
+ 	if (n) {
+-		spin_lock_irq(&n->list_lock);
++		raw_spin_lock_irq(&n->list_lock);
+ 		n->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount +
+ 				cachep->num;
+-		spin_unlock_irq(&n->list_lock);
++		raw_spin_unlock_irq(&n->list_lock);
+ 
+ 		return 0;
+ 	}
+@@ -907,7 +907,7 @@ static int setup_kmem_cache_node(struct kmem_cache *cachep,
+ 		goto fail;
+ 
+ 	n = get_node(cachep, node);
+-	spin_lock_irq(&n->list_lock);
++	raw_spin_lock_irq(&n->list_lock);
+ 	if (n->shared && force_change) {
+ 		free_block(cachep, n->shared->entry,
+ 				n->shared->avail, node, &list);
+@@ -925,7 +925,7 @@ static int setup_kmem_cache_node(struct kmem_cache *cachep,
+ 		new_alien = NULL;
+ 	}
+ 
+-	spin_unlock_irq(&n->list_lock);
++	raw_spin_unlock_irq(&n->list_lock);
+ 	slabs_destroy(cachep, &list);
+ 
+ 	/*
+@@ -964,7 +964,7 @@ static void cpuup_canceled(long cpu)
+ 		if (!n)
+ 			continue;
+ 
+-		spin_lock_irq(&n->list_lock);
++		raw_spin_lock_irq(&n->list_lock);
+ 
+ 		/* Free limit for this kmem_cache_node */
+ 		n->free_limit -= cachep->batchcount;
+@@ -975,7 +975,7 @@ static void cpuup_canceled(long cpu)
+ 		nc->avail = 0;
+ 
+ 		if (!cpumask_empty(mask)) {
+-			spin_unlock_irq(&n->list_lock);
++			raw_spin_unlock_irq(&n->list_lock);
+ 			goto free_slab;
+ 		}
+ 
+@@ -989,7 +989,7 @@ static void cpuup_canceled(long cpu)
+ 		alien = n->alien;
+ 		n->alien = NULL;
+ 
+-		spin_unlock_irq(&n->list_lock);
++		raw_spin_unlock_irq(&n->list_lock);
+ 
+ 		kfree(shared);
+ 		if (alien) {
+@@ -1173,7 +1173,7 @@ static void __init init_list(struct kmem_cache *cachep, struct kmem_cache_node *
+ 	/*
+ 	 * Do not assume that spinlocks can be initialized via memcpy:
+ 	 */
+-	spin_lock_init(&ptr->list_lock);
++	raw_spin_lock_init(&ptr->list_lock);
+ 
+ 	MAKE_ALL_LISTS(cachep, ptr, nodeid);
+ 	cachep->node[nodeid] = ptr;
+@@ -1344,11 +1344,11 @@ slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
+ 	for_each_kmem_cache_node(cachep, node, n) {
+ 		unsigned long total_slabs, free_slabs, free_objs;
+ 
+-		spin_lock_irqsave(&n->list_lock, flags);
++		raw_spin_lock_irqsave(&n->list_lock, flags);
+ 		total_slabs = n->total_slabs;
+ 		free_slabs = n->free_slabs;
+ 		free_objs = n->free_objects;
+-		spin_unlock_irqrestore(&n->list_lock, flags);
++		raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 
+ 		pr_warn("  node %d: slabs: %ld/%ld, objs: %ld/%ld\n",
+ 			node, total_slabs - free_slabs, total_slabs,
+@@ -2105,7 +2105,7 @@ static void check_spinlock_acquired(struct kmem_cache *cachep)
+ {
+ #ifdef CONFIG_SMP
+ 	check_irq_off();
+-	assert_spin_locked(&get_node(cachep, numa_mem_id())->list_lock);
++	assert_raw_spin_locked(&get_node(cachep, numa_mem_id())->list_lock);
+ #endif
+ }
+ 
+@@ -2113,7 +2113,7 @@ static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
+ {
+ #ifdef CONFIG_SMP
+ 	check_irq_off();
+-	assert_spin_locked(&get_node(cachep, node)->list_lock);
++	assert_raw_spin_locked(&get_node(cachep, node)->list_lock);
+ #endif
+ }
+ 
+@@ -2153,9 +2153,9 @@ static void do_drain(void *arg)
+ 	check_irq_off();
+ 	ac = cpu_cache_get(cachep);
+ 	n = get_node(cachep, node);
+-	spin_lock(&n->list_lock);
++	raw_spin_lock(&n->list_lock);
+ 	free_block(cachep, ac->entry, ac->avail, node, &list);
+-	spin_unlock(&n->list_lock);
++	raw_spin_unlock(&n->list_lock);
+ 	ac->avail = 0;
+ 	slabs_destroy(cachep, &list);
+ }
+@@ -2173,9 +2173,9 @@ static void drain_cpu_caches(struct kmem_cache *cachep)
+ 			drain_alien_cache(cachep, n->alien);
+ 
+ 	for_each_kmem_cache_node(cachep, node, n) {
+-		spin_lock_irq(&n->list_lock);
++		raw_spin_lock_irq(&n->list_lock);
+ 		drain_array_locked(cachep, n->shared, node, true, &list);
+-		spin_unlock_irq(&n->list_lock);
++		raw_spin_unlock_irq(&n->list_lock);
+ 
+ 		slabs_destroy(cachep, &list);
+ 	}
+@@ -2197,10 +2197,10 @@ static int drain_freelist(struct kmem_cache *cache,
+ 	nr_freed = 0;
+ 	while (nr_freed < tofree && !list_empty(&n->slabs_free)) {
+ 
+-		spin_lock_irq(&n->list_lock);
++		raw_spin_lock_irq(&n->list_lock);
+ 		p = n->slabs_free.prev;
+ 		if (p == &n->slabs_free) {
+-			spin_unlock_irq(&n->list_lock);
++			raw_spin_unlock_irq(&n->list_lock);
+ 			goto out;
+ 		}
+ 
+@@ -2213,7 +2213,7 @@ static int drain_freelist(struct kmem_cache *cache,
+ 		 * to the cache.
+ 		 */
+ 		n->free_objects -= cache->num;
+-		spin_unlock_irq(&n->list_lock);
++		raw_spin_unlock_irq(&n->list_lock);
+ 		slab_destroy(cache, page);
+ 		nr_freed++;
+ 	}
+@@ -2649,7 +2649,7 @@ static void cache_grow_end(struct kmem_cache *cachep, struct page *page)
+ 	INIT_LIST_HEAD(&page->slab_list);
+ 	n = get_node(cachep, page_to_nid(page));
+ 
+-	spin_lock(&n->list_lock);
++	raw_spin_lock(&n->list_lock);
+ 	n->total_slabs++;
+ 	if (!page->active) {
+ 		list_add_tail(&page->slab_list, &n->slabs_free);
+@@ -2659,7 +2659,7 @@ static void cache_grow_end(struct kmem_cache *cachep, struct page *page)
+ 
+ 	STATS_INC_GROWN(cachep);
+ 	n->free_objects += cachep->num - page->active;
+-	spin_unlock(&n->list_lock);
++	raw_spin_unlock(&n->list_lock);
+ 
+ 	fixup_objfreelist_debug(cachep, &list);
+ }
+@@ -2825,7 +2825,7 @@ static struct page *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc)
+ {
+ 	struct page *page;
+ 
+-	assert_spin_locked(&n->list_lock);
++	assert_raw_spin_locked(&n->list_lock);
+ 	page = list_first_entry_or_null(&n->slabs_partial, struct page,
+ 					slab_list);
+ 	if (!page) {
+@@ -2852,10 +2852,10 @@ static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep,
+ 	if (!gfp_pfmemalloc_allowed(flags))
+ 		return NULL;
+ 
+-	spin_lock(&n->list_lock);
++	raw_spin_lock(&n->list_lock);
+ 	page = get_first_slab(n, true);
+ 	if (!page) {
+-		spin_unlock(&n->list_lock);
++		raw_spin_unlock(&n->list_lock);
+ 		return NULL;
+ 	}
+ 
+@@ -2864,7 +2864,7 @@ static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep,
+ 
+ 	fixup_slab_list(cachep, n, page, &list);
+ 
+-	spin_unlock(&n->list_lock);
++	raw_spin_unlock(&n->list_lock);
+ 	fixup_objfreelist_debug(cachep, &list);
+ 
+ 	return obj;
+@@ -2923,7 +2923,7 @@ static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
+ 	if (!n->free_objects && (!shared || !shared->avail))
+ 		goto direct_grow;
+ 
+-	spin_lock(&n->list_lock);
++	raw_spin_lock(&n->list_lock);
+ 	shared = READ_ONCE(n->shared);
+ 
+ 	/* See if we can refill from the shared array */
+@@ -2947,7 +2947,7 @@ static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
+ must_grow:
+ 	n->free_objects -= ac->avail;
+ alloc_done:
+-	spin_unlock(&n->list_lock);
++	raw_spin_unlock(&n->list_lock);
+ 	fixup_objfreelist_debug(cachep, &list);
+ 
+ direct_grow:
+@@ -3172,7 +3172,7 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
+ 	BUG_ON(!n);
+ 
+ 	check_irq_off();
+-	spin_lock(&n->list_lock);
++	raw_spin_lock(&n->list_lock);
+ 	page = get_first_slab(n, false);
+ 	if (!page)
+ 		goto must_grow;
+@@ -3190,12 +3190,12 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
+ 
+ 	fixup_slab_list(cachep, n, page, &list);
+ 
+-	spin_unlock(&n->list_lock);
++	raw_spin_unlock(&n->list_lock);
+ 	fixup_objfreelist_debug(cachep, &list);
+ 	return obj;
+ 
+ must_grow:
+-	spin_unlock(&n->list_lock);
++	raw_spin_unlock(&n->list_lock);
+ 	page = cache_grow_begin(cachep, gfp_exact_node(flags), nodeid);
+ 	if (page) {
+ 		/* This slab isn't counted yet so don't update free_objects */
+@@ -3373,7 +3373,7 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
+ 
+ 	check_irq_off();
+ 	n = get_node(cachep, node);
+-	spin_lock(&n->list_lock);
++	raw_spin_lock(&n->list_lock);
+ 	if (n->shared) {
+ 		struct array_cache *shared_array = n->shared;
+ 		int max = shared_array->limit - shared_array->avail;
+@@ -3402,7 +3402,7 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
+ 		STATS_SET_FREEABLE(cachep, i);
+ 	}
+ #endif
+-	spin_unlock(&n->list_lock);
++	raw_spin_unlock(&n->list_lock);
+ 	ac->avail -= batchcount;
+ 	memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
+ 	slabs_destroy(cachep, &list);
+@@ -3831,9 +3831,9 @@ static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
+ 
+ 		node = cpu_to_mem(cpu);
+ 		n = get_node(cachep, node);
+-		spin_lock_irq(&n->list_lock);
++		raw_spin_lock_irq(&n->list_lock);
+ 		free_block(cachep, ac->entry, ac->avail, node, &list);
+-		spin_unlock_irq(&n->list_lock);
++		raw_spin_unlock_irq(&n->list_lock);
+ 		slabs_destroy(cachep, &list);
+ 	}
+ 	free_percpu(prev);
+@@ -3928,9 +3928,9 @@ static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
+ 		return;
+ 	}
+ 
+-	spin_lock_irq(&n->list_lock);
++	raw_spin_lock_irq(&n->list_lock);
+ 	drain_array_locked(cachep, ac, node, false, &list);
+-	spin_unlock_irq(&n->list_lock);
++	raw_spin_unlock_irq(&n->list_lock);
+ 
+ 	slabs_destroy(cachep, &list);
+ }
+@@ -4014,7 +4014,7 @@ void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
+ 
+ 	for_each_kmem_cache_node(cachep, node, n) {
+ 		check_irq_on();
+-		spin_lock_irq(&n->list_lock);
++		raw_spin_lock_irq(&n->list_lock);
+ 
+ 		total_slabs += n->total_slabs;
+ 		free_slabs += n->free_slabs;
+@@ -4023,7 +4023,7 @@ void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
+ 		if (n->shared)
+ 			shared_avail += n->shared->avail;
+ 
+-		spin_unlock_irq(&n->list_lock);
++		raw_spin_unlock_irq(&n->list_lock);
+ 	}
+ 	num_objs = total_slabs * cachep->num;
+ 	active_slabs = total_slabs - free_slabs;
+diff --git a/mm/slab.h b/mm/slab.h
+index 6952e10cf33b..ed5dd6e9e0cc 100644
+--- a/mm/slab.h
++++ b/mm/slab.h
+@@ -543,7 +543,7 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s,
+  * The slab lists for all objects.
+  */
+ struct kmem_cache_node {
+-	spinlock_t list_lock;
++	raw_spinlock_t list_lock;
+ 
+ #ifdef CONFIG_SLAB
+ 	struct list_head slabs_partial;	/* partial list first, better asm code */
+diff --git a/mm/slub.c b/mm/slub.c
+index b0f637519ac9..863554db3323 100644
+--- a/mm/slub.c
++++ b/mm/slub.c
+@@ -1214,7 +1214,7 @@ static noinline int free_debug_processing(
+ 	unsigned long flags;
+ 	int ret = 0;
+ 
+-	spin_lock_irqsave(&n->list_lock, flags);
++	raw_spin_lock_irqsave(&n->list_lock, flags);
+ 	slab_lock(page);
+ 
+ 	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
+@@ -1249,7 +1249,7 @@ static noinline int free_debug_processing(
+ 			 bulk_cnt, cnt);
+ 
+ 	slab_unlock(page);
+-	spin_unlock_irqrestore(&n->list_lock, flags);
++	raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 	if (!ret)
+ 		slab_fix(s, "Object at 0x%p not freed", object);
+ 	return ret;
+@@ -1967,7 +1967,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
+ 	if (!n || !n->nr_partial)
+ 		return NULL;
+ 
+-	spin_lock(&n->list_lock);
++	raw_spin_lock(&n->list_lock);
+ 	list_for_each_entry_safe(page, page2, &n->partial, slab_list) {
+ 		void *t;
+ 
+@@ -1992,7 +1992,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
+ 			break;
+ 
+ 	}
+-	spin_unlock(&n->list_lock);
++	raw_spin_unlock(&n->list_lock);
+ 	return object;
+ }
+ 
+@@ -2246,7 +2246,7 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
+ 			 * that acquire_slab() will see a slab page that
+ 			 * is frozen
+ 			 */
+-			spin_lock(&n->list_lock);
++			raw_spin_lock(&n->list_lock);
+ 		}
+ 	} else {
+ 		m = M_FULL;
+@@ -2258,7 +2258,7 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
+ 			 * slabs from diagnostic functions will not see
+ 			 * any frozen slabs.
+ 			 */
+-			spin_lock(&n->list_lock);
++			raw_spin_lock(&n->list_lock);
+ 		}
+ #endif
+ 	}
+@@ -2283,7 +2283,7 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
+ 		goto redo;
+ 
+ 	if (lock)
+-		spin_unlock(&n->list_lock);
++		raw_spin_unlock(&n->list_lock);
+ 
+ 	if (m == M_PARTIAL)
+ 		stat(s, tail);
+@@ -2323,10 +2323,10 @@ static void unfreeze_partials(struct kmem_cache *s,
+ 		n2 = get_node(s, page_to_nid(page));
+ 		if (n != n2) {
+ 			if (n)
+-				spin_unlock(&n->list_lock);
++				raw_spin_unlock(&n->list_lock);
+ 
+ 			n = n2;
+-			spin_lock(&n->list_lock);
++			raw_spin_lock(&n->list_lock);
+ 		}
+ 
+ 		do {
+@@ -2355,7 +2355,7 @@ static void unfreeze_partials(struct kmem_cache *s,
+ 	}
+ 
+ 	if (n)
+-		spin_unlock(&n->list_lock);
++		raw_spin_unlock(&n->list_lock);
+ 
+ 	while (discard_page) {
+ 		page = discard_page;
+@@ -2520,10 +2520,10 @@ static unsigned long count_partial(struct kmem_cache_node *n,
+ 	unsigned long x = 0;
+ 	struct page *page;
+ 
+-	spin_lock_irqsave(&n->list_lock, flags);
++	raw_spin_lock_irqsave(&n->list_lock, flags);
+ 	list_for_each_entry(page, &n->partial, slab_list)
+ 		x += get_count(page);
+-	spin_unlock_irqrestore(&n->list_lock, flags);
++	raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 	return x;
+ }
+ #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
+@@ -2983,7 +2983,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
+ 
+ 	do {
+ 		if (unlikely(n)) {
+-			spin_unlock_irqrestore(&n->list_lock, flags);
++			raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 			n = NULL;
+ 		}
+ 		prior = page->freelist;
+@@ -3015,7 +3015,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
+ 				 * Otherwise the list_lock will synchronize with
+ 				 * other processors updating the list of slabs.
+ 				 */
+-				spin_lock_irqsave(&n->list_lock, flags);
++				raw_spin_lock_irqsave(&n->list_lock, flags);
+ 
+ 			}
+ 		}
+@@ -3057,7 +3057,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
+ 		add_partial(n, page, DEACTIVATE_TO_TAIL);
+ 		stat(s, FREE_ADD_PARTIAL);
+ 	}
+-	spin_unlock_irqrestore(&n->list_lock, flags);
++	raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 	return;
+ 
+ slab_empty:
+@@ -3072,7 +3072,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
+ 		remove_full(s, n, page);
+ 	}
+ 
+-	spin_unlock_irqrestore(&n->list_lock, flags);
++	raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 	stat(s, FREE_SLAB);
+ 	discard_slab(s, page);
+ }
+@@ -3479,7 +3479,7 @@ static void
+ init_kmem_cache_node(struct kmem_cache_node *n)
+ {
+ 	n->nr_partial = 0;
+-	spin_lock_init(&n->list_lock);
++	raw_spin_lock_init(&n->list_lock);
+ 	INIT_LIST_HEAD(&n->partial);
+ #ifdef CONFIG_SLUB_DEBUG
+ 	atomic_long_set(&n->nr_slabs, 0);
+@@ -3874,7 +3874,7 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
+ 	struct page *page, *h;
+ 
+ 	BUG_ON(irqs_disabled());
+-	spin_lock_irq(&n->list_lock);
++	raw_spin_lock_irq(&n->list_lock);
+ 	list_for_each_entry_safe(page, h, &n->partial, slab_list) {
+ 		if (!page->inuse) {
+ 			remove_partial(n, page);
+@@ -3884,7 +3884,7 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
+ 			  "Objects remaining in %s on __kmem_cache_shutdown()");
+ 		}
+ 	}
+-	spin_unlock_irq(&n->list_lock);
++	raw_spin_unlock_irq(&n->list_lock);
+ 
+ 	list_for_each_entry_safe(page, h, &discard, slab_list)
+ 		discard_slab(s, page);
+@@ -4155,7 +4155,7 @@ int __kmem_cache_shrink(struct kmem_cache *s)
+ 		for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
+ 			INIT_LIST_HEAD(promote + i);
+ 
+-		spin_lock_irqsave(&n->list_lock, flags);
++		raw_spin_lock_irqsave(&n->list_lock, flags);
+ 
+ 		/*
+ 		 * Build lists of slabs to discard or promote.
+@@ -4186,7 +4186,7 @@ int __kmem_cache_shrink(struct kmem_cache *s)
+ 		for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
+ 			list_splice(promote + i, &n->partial);
+ 
+-		spin_unlock_irqrestore(&n->list_lock, flags);
++		raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 
+ 		/* Release empty slabs */
+ 		list_for_each_entry_safe(page, t, &discard, slab_list)
+@@ -4548,7 +4548,7 @@ static int validate_slab_node(struct kmem_cache *s,
+ 	struct page *page;
+ 	unsigned long flags;
+ 
+-	spin_lock_irqsave(&n->list_lock, flags);
++	raw_spin_lock_irqsave(&n->list_lock, flags);
+ 
+ 	list_for_each_entry(page, &n->partial, slab_list) {
+ 		validate_slab(s, page);
+@@ -4570,7 +4570,7 @@ static int validate_slab_node(struct kmem_cache *s,
+ 		       s->name, count, atomic_long_read(&n->nr_slabs));
+ 
+ out:
+-	spin_unlock_irqrestore(&n->list_lock, flags);
++	raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 	return count;
+ }
+ 
+@@ -4749,12 +4749,12 @@ static int list_locations(struct kmem_cache *s, char *buf,
+ 		if (!atomic_long_read(&n->nr_slabs))
+ 			continue;
+ 
+-		spin_lock_irqsave(&n->list_lock, flags);
++		raw_spin_lock_irqsave(&n->list_lock, flags);
+ 		list_for_each_entry(page, &n->partial, slab_list)
+ 			process_slab(&t, s, page, alloc);
+ 		list_for_each_entry(page, &n->full, slab_list)
+ 			process_slab(&t, s, page, alloc);
+-		spin_unlock_irqrestore(&n->list_lock, flags);
++		raw_spin_unlock_irqrestore(&n->list_lock, flags);
+ 	}
+ 
+ 	for (i = 0; i < t.count; i++) {
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0199-mm-SLUB-delay-giving-back-empty-slubs-to-IRQ-enabled.patch b/debian/patches-rt/0199-mm-SLUB-delay-giving-back-empty-slubs-to-IRQ-enabled.patch
new file mode 100644
index 000000000..8af579dea
--- /dev/null
+++ b/debian/patches-rt/0199-mm-SLUB-delay-giving-back-empty-slubs-to-IRQ-enabled.patch
@@ -0,0 +1,223 @@
+From e620c8c3d37a6e6ff999f303521997d2950a71cd Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 21 Jun 2018 17:29:19 +0200
+Subject: [PATCH 199/323] mm/SLUB: delay giving back empty slubs to IRQ enabled
+ regions
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+__free_slab() is invoked with disabled interrupts which increases the
+irq-off time while __free_pages() is doing the work.
+Allow __free_slab() to be invoked with enabled interrupts and move
+everything from interrupts-off invocations to a temporary per-CPU list
+so it can be processed later.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/slub.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++----
+ 1 file changed, 69 insertions(+), 5 deletions(-)
+
+diff --git a/mm/slub.c b/mm/slub.c
+index 863554db3323..faba29039375 100644
+--- a/mm/slub.c
++++ b/mm/slub.c
+@@ -1494,6 +1494,12 @@ static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
+ }
+ #endif /* CONFIG_SLUB_DEBUG */
+ 
++struct slub_free_list {
++	raw_spinlock_t		lock;
++	struct list_head	list;
++};
++static DEFINE_PER_CPU(struct slub_free_list, slub_free_list);
++
+ /*
+  * Hooks for other subsystems that check memory allocations. In a typical
+  * production configuration these hooks all should produce no code at all.
+@@ -1849,6 +1855,16 @@ static void __free_slab(struct kmem_cache *s, struct page *page)
+ 	__free_pages(page, order);
+ }
+ 
++static void free_delayed(struct list_head *h)
++{
++	while (!list_empty(h)) {
++		struct page *page = list_first_entry(h, struct page, lru);
++
++		list_del(&page->lru);
++		__free_slab(page->slab_cache, page);
++	}
++}
++
+ static void rcu_free_slab(struct rcu_head *h)
+ {
+ 	struct page *page = container_of(h, struct page, rcu_head);
+@@ -1860,6 +1876,12 @@ static void free_slab(struct kmem_cache *s, struct page *page)
+ {
+ 	if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {
+ 		call_rcu(&page->rcu_head, rcu_free_slab);
++	} else if (irqs_disabled()) {
++		struct slub_free_list *f = this_cpu_ptr(&slub_free_list);
++
++		raw_spin_lock(&f->lock);
++		list_add(&page->lru, &f->list);
++		raw_spin_unlock(&f->lock);
+ 	} else
+ 		__free_slab(s, page);
+ }
+@@ -2392,14 +2414,21 @@ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
+ 			pobjects = oldpage->pobjects;
+ 			pages = oldpage->pages;
+ 			if (drain && pobjects > slub_cpu_partial(s)) {
++				struct slub_free_list *f;
+ 				unsigned long flags;
++				LIST_HEAD(tofree);
+ 				/*
+ 				 * partial array is full. Move the existing
+ 				 * set to the per node partial list.
+ 				 */
+ 				local_irq_save(flags);
+ 				unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
++				f = this_cpu_ptr(&slub_free_list);
++				raw_spin_lock(&f->lock);
++				list_splice_init(&f->list, &tofree);
++				raw_spin_unlock(&f->lock);
+ 				local_irq_restore(flags);
++				free_delayed(&tofree);
+ 				oldpage = NULL;
+ 				pobjects = 0;
+ 				pages = 0;
+@@ -2465,7 +2494,22 @@ static bool has_cpu_slab(int cpu, void *info)
+ 
+ static void flush_all(struct kmem_cache *s)
+ {
++	LIST_HEAD(tofree);
++	int cpu;
++
+ 	on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1);
++	for_each_online_cpu(cpu) {
++		struct slub_free_list *f;
++
++		if (!has_cpu_slab(cpu, s))
++			continue;
++
++		f = &per_cpu(slub_free_list, cpu);
++		raw_spin_lock_irq(&f->lock);
++		list_splice_init(&f->list, &tofree);
++		raw_spin_unlock_irq(&f->lock);
++		free_delayed(&tofree);
++	}
+ }
+ 
+ /*
+@@ -2662,8 +2706,10 @@ static inline void *get_freelist(struct kmem_cache *s, struct page *page)
+  * already disabled (which is the case for bulk allocation).
+  */
+ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
+-			  unsigned long addr, struct kmem_cache_cpu *c)
++			  unsigned long addr, struct kmem_cache_cpu *c,
++			  struct list_head *to_free)
+ {
++	struct slub_free_list *f;
+ 	void *freelist;
+ 	struct page *page;
+ 
+@@ -2732,6 +2778,13 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
+ 	VM_BUG_ON(!c->page->frozen);
+ 	c->freelist = get_freepointer(s, freelist);
+ 	c->tid = next_tid(c->tid);
++
++out:
++	f = this_cpu_ptr(&slub_free_list);
++	raw_spin_lock(&f->lock);
++	list_splice_init(&f->list, to_free);
++	raw_spin_unlock(&f->lock);
++
+ 	return freelist;
+ 
+ new_slab:
+@@ -2747,7 +2800,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
+ 
+ 	if (unlikely(!freelist)) {
+ 		slab_out_of_memory(s, gfpflags, node);
+-		return NULL;
++		goto out;
+ 	}
+ 
+ 	page = c->page;
+@@ -2760,7 +2813,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
+ 		goto new_slab;	/* Slab failed checks. Next slab needed */
+ 
+ 	deactivate_slab(s, page, get_freepointer(s, freelist), c);
+-	return freelist;
++	goto out;
+ }
+ 
+ /*
+@@ -2772,6 +2825,7 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
+ {
+ 	void *p;
+ 	unsigned long flags;
++	LIST_HEAD(tofree);
+ 
+ 	local_irq_save(flags);
+ #ifdef CONFIG_PREEMPTION
+@@ -2783,8 +2837,9 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
+ 	c = this_cpu_ptr(s->cpu_slab);
+ #endif
+ 
+-	p = ___slab_alloc(s, gfpflags, node, addr, c);
++	p = ___slab_alloc(s, gfpflags, node, addr, c, &tofree);
+ 	local_irq_restore(flags);
++	free_delayed(&tofree);
+ 	return p;
+ }
+ 
+@@ -3282,6 +3337,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
+ 			  void **p)
+ {
+ 	struct kmem_cache_cpu *c;
++	LIST_HEAD(to_free);
+ 	int i;
+ 	struct obj_cgroup *objcg = NULL;
+ 
+@@ -3315,7 +3371,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
+ 			 * of re-populating per CPU c->freelist
+ 			 */
+ 			p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
+-					    _RET_IP_, c);
++					    _RET_IP_, c, &to_free);
+ 			if (unlikely(!p[i]))
+ 				goto error;
+ 
+@@ -3330,6 +3386,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
+ 	}
+ 	c->tid = next_tid(c->tid);
+ 	local_irq_enable();
++	free_delayed(&to_free);
+ 
+ 	/* Clear memory outside IRQ disabled fastpath loop */
+ 	if (unlikely(slab_want_init_on_alloc(flags, s))) {
+@@ -3344,6 +3401,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
+ 	return i;
+ error:
+ 	local_irq_enable();
++	free_delayed(&to_free);
+ 	slab_post_alloc_hook(s, objcg, flags, i, p);
+ 	__kmem_cache_free_bulk(s, i, p);
+ 	return 0;
+@@ -4361,6 +4419,12 @@ void __init kmem_cache_init(void)
+ {
+ 	static __initdata struct kmem_cache boot_kmem_cache,
+ 		boot_kmem_cache_node;
++	int cpu;
++
++	for_each_possible_cpu(cpu) {
++		raw_spin_lock_init(&per_cpu(slub_free_list, cpu).lock);
++		INIT_LIST_HEAD(&per_cpu(slub_free_list, cpu).list);
++	}
+ 
+ 	if (debug_guardpage_minorder())
+ 		slub_max_order = 0;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0200-mm-slub-Always-flush-the-delayed-empty-slubs-in-flus.patch b/debian/patches-rt/0200-mm-slub-Always-flush-the-delayed-empty-slubs-in-flus.patch
new file mode 100644
index 000000000..0fd8180bd
--- /dev/null
+++ b/debian/patches-rt/0200-mm-slub-Always-flush-the-delayed-empty-slubs-in-flus.patch
@@ -0,0 +1,61 @@
+From d903b2377e443ae1df59e15824b683d326e7c24b Mon Sep 17 00:00:00 2001
+From: Kevin Hao <haokexin@gmail.com>
+Date: Mon, 4 May 2020 11:34:07 +0800
+Subject: [PATCH 200/323] mm: slub: Always flush the delayed empty slubs in
+ flush_all()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+After commit f0b231101c94 ("mm/SLUB: delay giving back empty slubs to
+IRQ enabled regions"), when the free_slab() is invoked with the IRQ
+disabled, the empty slubs are moved to a per-CPU list and will be
+freed after IRQ enabled later. But in the current codes, there is
+a check to see if there really has the cpu slub on a specific cpu
+before flushing the delayed empty slubs, this may cause a reference
+of already released kmem_cache in a scenario like below:
+	cpu 0				cpu 1
+  kmem_cache_destroy()
+    flush_all()
+                         --->IPI       flush_cpu_slab()
+                                         flush_slab()
+                                           deactivate_slab()
+                                             discard_slab()
+                                               free_slab()
+                                             c->page = NULL;
+      for_each_online_cpu(cpu)
+        if (!has_cpu_slab(1, s))
+          continue
+        this skip to flush the delayed
+        empty slub released by cpu1
+    kmem_cache_free(kmem_cache, s)
+
+                                       kmalloc()
+                                         __slab_alloc()
+                                            free_delayed()
+                                            __free_slab()
+                                            reference to released kmem_cache
+
+Fixes: f0b231101c94 ("mm/SLUB: delay giving back empty slubs to IRQ enabled regions")
+Signed-off-by: Kevin Hao <haokexin@gmail.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Cc: stable-rt@vger.kernel.org
+---
+ mm/slub.c | 3 ---
+ 1 file changed, 3 deletions(-)
+
+diff --git a/mm/slub.c b/mm/slub.c
+index faba29039375..cb414c1f9ef6 100644
+--- a/mm/slub.c
++++ b/mm/slub.c
+@@ -2501,9 +2501,6 @@ static void flush_all(struct kmem_cache *s)
+ 	for_each_online_cpu(cpu) {
+ 		struct slub_free_list *f;
+ 
+-		if (!has_cpu_slab(cpu, s))
+-			continue;
+-
+ 		f = &per_cpu(slub_free_list, cpu);
+ 		raw_spin_lock_irq(&f->lock);
+ 		list_splice_init(&f->list, &tofree);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0201-mm-slub-Don-t-resize-the-location-tracking-cache-on-.patch b/debian/patches-rt/0201-mm-slub-Don-t-resize-the-location-tracking-cache-on-.patch
new file mode 100644
index 000000000..c233be3ef
--- /dev/null
+++ b/debian/patches-rt/0201-mm-slub-Don-t-resize-the-location-tracking-cache-on-.patch
@@ -0,0 +1,37 @@
+From 6f5d1f04864beb65079068f48faf17c269c8509b Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 26 Feb 2021 17:26:04 +0100
+Subject: [PATCH 201/323] mm: slub: Don't resize the location tracking cache on
+ PREEMPT_RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The location tracking cache has a size of a page and is resized if its
+current size is too small.
+This allocation happens with disabled interrupts and can't happen on
+PREEMPT_RT.
+Should one page be too small, then we have to allocate more at the
+beginning. The only downside is that less callers will be visible.
+
+Cc: stable-rt@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/slub.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/mm/slub.c b/mm/slub.c
+index cb414c1f9ef6..57c598dd7454 100644
+--- a/mm/slub.c
++++ b/mm/slub.c
+@@ -4682,6 +4682,9 @@ static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
+ 	struct location *l;
+ 	int order;
+ 
++	if (IS_ENABLED(CONFIG_PREEMPT_RT) && flags == GFP_ATOMIC)
++		return 0;
++
+ 	order = get_order(sizeof(struct location) * max);
+ 
+ 	l = (void *)__get_free_pages(flags, order);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0202-mm-page_alloc-Use-migrate_disable-in-drain_local_pag.patch b/debian/patches-rt/0202-mm-page_alloc-Use-migrate_disable-in-drain_local_pag.patch
new file mode 100644
index 000000000..486873119
--- /dev/null
+++ b/debian/patches-rt/0202-mm-page_alloc-Use-migrate_disable-in-drain_local_pag.patch
@@ -0,0 +1,39 @@
+From 4c4d7886b6c8d16df841ac103b4742481ad5f014 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Thu, 2 Jul 2020 14:27:23 +0200
+Subject: [PATCH 202/323] mm/page_alloc: Use migrate_disable() in
+ drain_local_pages_wq()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+drain_local_pages_wq() disables preemption to avoid CPU migration during
+CPU hotplug.
+Using migrate_disable() makes the function preemptible on PREEMPT_RT but
+still avoids CPU migrations during CPU-hotplug. On !PREEMPT_RT it
+behaves like preempt_disable().
+
+Use migrate_disable() in drain_local_pages_wq().
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/page_alloc.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/mm/page_alloc.c b/mm/page_alloc.c
+index a3f1e4c6bdc8..508650843235 100644
+--- a/mm/page_alloc.c
++++ b/mm/page_alloc.c
+@@ -3048,9 +3048,9 @@ static void drain_local_pages_wq(struct work_struct *work)
+ 	 * cpu which is allright but we also have to make sure to not move to
+ 	 * a different one.
+ 	 */
+-	preempt_disable();
++	migrate_disable();
+ 	drain_local_pages(drain->zone);
+-	preempt_enable();
++	migrate_enable();
+ }
+ 
+ /*
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0203-mm-page_alloc-rt-friendly-per-cpu-pages.patch b/debian/patches-rt/0203-mm-page_alloc-rt-friendly-per-cpu-pages.patch
new file mode 100644
index 000000000..8102e89d2
--- /dev/null
+++ b/debian/patches-rt/0203-mm-page_alloc-rt-friendly-per-cpu-pages.patch
@@ -0,0 +1,197 @@
+From 9f33cce55eb2594c4602653658103381064572d7 Mon Sep 17 00:00:00 2001
+From: Ingo Molnar <mingo@elte.hu>
+Date: Fri, 3 Jul 2009 08:29:37 -0500
+Subject: [PATCH 203/323] mm: page_alloc: rt-friendly per-cpu pages
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+rt-friendly per-cpu pages: convert the irqs-off per-cpu locking
+method into a preemptible, explicit-per-cpu-locks method.
+
+Contains fixes from:
+	 Peter Zijlstra <a.p.zijlstra@chello.nl>
+	 Thomas Gleixner <tglx@linutronix.de>
+
+Signed-off-by: Ingo Molnar <mingo@elte.hu>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ mm/page_alloc.c | 47 ++++++++++++++++++++++++++++-------------------
+ 1 file changed, 28 insertions(+), 19 deletions(-)
+
+diff --git a/mm/page_alloc.c b/mm/page_alloc.c
+index 508650843235..c5eb7d6844ae 100644
+--- a/mm/page_alloc.c
++++ b/mm/page_alloc.c
+@@ -61,6 +61,7 @@
+ #include <linux/hugetlb.h>
+ #include <linux/sched/rt.h>
+ #include <linux/sched/mm.h>
++#include <linux/local_lock.h>
+ #include <linux/page_owner.h>
+ #include <linux/kthread.h>
+ #include <linux/memcontrol.h>
+@@ -386,6 +387,13 @@ EXPORT_SYMBOL(nr_node_ids);
+ EXPORT_SYMBOL(nr_online_nodes);
+ #endif
+ 
++struct pa_lock {
++	local_lock_t l;
++};
++static DEFINE_PER_CPU(struct pa_lock, pa_lock) = {
++	.l	= INIT_LOCAL_LOCK(l),
++};
++
+ int page_group_by_mobility_disabled __read_mostly;
+ 
+ #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+@@ -1543,11 +1551,11 @@ static void __free_pages_ok(struct page *page, unsigned int order,
+ 		return;
+ 
+ 	migratetype = get_pfnblock_migratetype(page, pfn);
+-	local_irq_save(flags);
++	local_lock_irqsave(&pa_lock.l, flags);
+ 	__count_vm_events(PGFREE, 1 << order);
+ 	free_one_page(page_zone(page), page, pfn, order, migratetype,
+ 		      fpi_flags);
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&pa_lock.l, flags);
+ }
+ 
+ void __free_pages_core(struct page *page, unsigned int order)
+@@ -2961,13 +2969,13 @@ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
+ 	int to_drain, batch;
+ 	LIST_HEAD(dst);
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(&pa_lock.l, flags);
+ 	batch = READ_ONCE(pcp->batch);
+ 	to_drain = min(pcp->count, batch);
+ 	if (to_drain > 0)
+ 		isolate_pcp_pages(to_drain, pcp, &dst);
+ 
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&pa_lock.l, flags);
+ 
+ 	if (to_drain > 0)
+ 		free_pcppages_bulk(zone, &dst, false);
+@@ -2989,7 +2997,7 @@ static void drain_pages_zone(unsigned int cpu, struct zone *zone)
+ 	LIST_HEAD(dst);
+ 	int count;
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(&pa_lock.l, flags);
+ 	pset = per_cpu_ptr(zone->pageset, cpu);
+ 
+ 	pcp = &pset->pcp;
+@@ -2997,7 +3005,7 @@ static void drain_pages_zone(unsigned int cpu, struct zone *zone)
+ 	if (count)
+ 		isolate_pcp_pages(count, pcp, &dst);
+ 
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&pa_lock.l, flags);
+ 
+ 	if (count)
+ 		free_pcppages_bulk(zone, &dst, false);
+@@ -3248,9 +3256,9 @@ void free_unref_page(struct page *page)
+ 	if (!free_unref_page_prepare(page, pfn))
+ 		return;
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(&pa_lock.l, flags);
+ 	free_unref_page_commit(page, pfn, &dst);
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&pa_lock.l, flags);
+ 	if (!list_empty(&dst))
+ 		free_pcppages_bulk(zone, &dst, false);
+ }
+@@ -3277,7 +3285,7 @@ void free_unref_page_list(struct list_head *list)
+ 		set_page_private(page, pfn);
+ 	}
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(&pa_lock.l, flags);
+ 	list_for_each_entry_safe(page, next, list, lru) {
+ 		unsigned long pfn = page_private(page);
+ 		enum zone_type type;
+@@ -3292,12 +3300,12 @@ void free_unref_page_list(struct list_head *list)
+ 		 * a large list of pages to free.
+ 		 */
+ 		if (++batch_count == SWAP_CLUSTER_MAX) {
+-			local_irq_restore(flags);
++			local_unlock_irqrestore(&pa_lock.l, flags);
+ 			batch_count = 0;
+-			local_irq_save(flags);
++			local_lock_irqsave(&pa_lock.l, flags);
+ 		}
+ 	}
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&pa_lock.l, flags);
+ 
+ 	for (i = 0; i < __MAX_NR_ZONES; ) {
+ 		struct page *page;
+@@ -3468,7 +3476,7 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone,
+ 	struct page *page;
+ 	unsigned long flags;
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(&pa_lock.l, flags);
+ 	pcp = &this_cpu_ptr(zone->pageset)->pcp;
+ 	list = &pcp->lists[migratetype];
+ 	page = __rmqueue_pcplist(zone,  migratetype, alloc_flags, pcp, list);
+@@ -3476,7 +3484,7 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone,
+ 		__count_zid_vm_events(PGALLOC, page_zonenum(page), 1);
+ 		zone_statistics(preferred_zone, zone);
+ 	}
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&pa_lock.l, flags);
+ 	return page;
+ }
+ 
+@@ -3510,7 +3518,8 @@ struct page *rmqueue(struct zone *preferred_zone,
+ 	 * allocate greater than order-1 page units with __GFP_NOFAIL.
+ 	 */
+ 	WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));
+-	spin_lock_irqsave(&zone->lock, flags);
++	local_lock_irqsave(&pa_lock.l, flags);
++	spin_lock(&zone->lock);
+ 
+ 	do {
+ 		page = NULL;
+@@ -3536,7 +3545,7 @@ struct page *rmqueue(struct zone *preferred_zone,
+ 
+ 	__count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
+ 	zone_statistics(preferred_zone, zone);
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&pa_lock.l, flags);
+ 
+ out:
+ 	/* Separate test+clear to avoid unnecessary atomics */
+@@ -3549,7 +3558,7 @@ struct page *rmqueue(struct zone *preferred_zone,
+ 	return page;
+ 
+ failed:
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&pa_lock.l, flags);
+ 	return NULL;
+ }
+ 
+@@ -8892,7 +8901,7 @@ void zone_pcp_reset(struct zone *zone)
+ 	struct per_cpu_pageset *pset;
+ 
+ 	/* avoid races with drain_pages()  */
+-	local_irq_save(flags);
++	local_lock_irqsave(&pa_lock.l, flags);
+ 	if (zone->pageset != &boot_pageset) {
+ 		for_each_online_cpu(cpu) {
+ 			pset = per_cpu_ptr(zone->pageset, cpu);
+@@ -8901,7 +8910,7 @@ void zone_pcp_reset(struct zone *zone)
+ 		free_percpu(zone->pageset);
+ 		zone->pageset = &boot_pageset;
+ 	}
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&pa_lock.l, flags);
+ }
+ 
+ #ifdef CONFIG_MEMORY_HOTREMOVE
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0204-mm-slub-Make-object_map_lock-a-raw_spinlock_t.patch b/debian/patches-rt/0204-mm-slub-Make-object_map_lock-a-raw_spinlock_t.patch
new file mode 100644
index 000000000..28c14ea49
--- /dev/null
+++ b/debian/patches-rt/0204-mm-slub-Make-object_map_lock-a-raw_spinlock_t.patch
@@ -0,0 +1,50 @@
+From d2d45bd13ad6112afefb224d46501b76473196eb Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Thu, 16 Jul 2020 18:47:50 +0200
+Subject: [PATCH 204/323] mm/slub: Make object_map_lock a raw_spinlock_t
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The variable object_map is protected by object_map_lock. The lock is always
+acquired in debug code and within already atomic context
+
+Make object_map_lock a raw_spinlock_t.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/slub.c | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/mm/slub.c b/mm/slub.c
+index 57c598dd7454..ac2ddf6a4220 100644
+--- a/mm/slub.c
++++ b/mm/slub.c
+@@ -435,7 +435,7 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
+ 
+ #ifdef CONFIG_SLUB_DEBUG
+ static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
+-static DEFINE_SPINLOCK(object_map_lock);
++static DEFINE_RAW_SPINLOCK(object_map_lock);
+ 
+ /*
+  * Determine a map of object in use on a page.
+@@ -451,7 +451,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page)
+ 
+ 	VM_BUG_ON(!irqs_disabled());
+ 
+-	spin_lock(&object_map_lock);
++	raw_spin_lock(&object_map_lock);
+ 
+ 	bitmap_zero(object_map, page->objects);
+ 
+@@ -464,7 +464,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page)
+ static void put_map(unsigned long *map) __releases(&object_map_lock)
+ {
+ 	VM_BUG_ON(map != object_map);
+-	spin_unlock(&object_map_lock);
++	raw_spin_unlock(&object_map_lock);
+ }
+ 
+ static inline unsigned int size_from_object(struct kmem_cache *s)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0205-slub-Enable-irqs-for-__GFP_WAIT.patch b/debian/patches-rt/0205-slub-Enable-irqs-for-__GFP_WAIT.patch
new file mode 100644
index 000000000..d3496f78e
--- /dev/null
+++ b/debian/patches-rt/0205-slub-Enable-irqs-for-__GFP_WAIT.patch
@@ -0,0 +1,76 @@
+From c0f57e0b6278391f1fec71ccb1e25fe46deade2b Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 9 Jan 2013 12:08:15 +0100
+Subject: [PATCH 205/323] slub: Enable irqs for __GFP_WAIT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+SYSTEM_RUNNING might be too late for enabling interrupts. Allocations
+with GFP_WAIT can happen before that. So use this as an indicator.
+
+[bigeasy: Add warning on RT for allocations in atomic context.
+  Don't enable interrupts on allocations during SYSTEM_SUSPEND. This is done
+  during suspend by ACPI, noticed by Liwei Song <liwei.song@windriver.com>
+]
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ mm/slub.c | 18 +++++++++++++++++-
+ 1 file changed, 17 insertions(+), 1 deletion(-)
+
+diff --git a/mm/slub.c b/mm/slub.c
+index ac2ddf6a4220..00f1d1206dbc 100644
+--- a/mm/slub.c
++++ b/mm/slub.c
+@@ -1750,10 +1750,18 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
+ 	void *start, *p, *next;
+ 	int idx;
+ 	bool shuffle;
++	bool enableirqs = false;
+ 
+ 	flags &= gfp_allowed_mask;
+ 
+ 	if (gfpflags_allow_blocking(flags))
++		enableirqs = true;
++
++#ifdef CONFIG_PREEMPT_RT
++	if (system_state > SYSTEM_BOOTING && system_state < SYSTEM_SUSPEND)
++		enableirqs = true;
++#endif
++	if (enableirqs)
+ 		local_irq_enable();
+ 
+ 	flags |= s->allocflags;
+@@ -1812,7 +1820,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
+ 	page->frozen = 1;
+ 
+ out:
+-	if (gfpflags_allow_blocking(flags))
++	if (enableirqs)
+ 		local_irq_disable();
+ 	if (!page)
+ 		return NULL;
+@@ -2870,6 +2878,10 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s,
+ 	unsigned long tid;
+ 	struct obj_cgroup *objcg = NULL;
+ 
++	if (IS_ENABLED(CONFIG_PREEMPT_RT) && IS_ENABLED(CONFIG_DEBUG_ATOMIC_SLEEP))
++		WARN_ON_ONCE(!preemptible() &&
++			     (system_state > SYSTEM_BOOTING && system_state < SYSTEM_SUSPEND));
++
+ 	s = slab_pre_alloc_hook(s, &objcg, 1, gfpflags);
+ 	if (!s)
+ 		return NULL;
+@@ -3338,6 +3350,10 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
+ 	int i;
+ 	struct obj_cgroup *objcg = NULL;
+ 
++	if (IS_ENABLED(CONFIG_PREEMPT_RT) && IS_ENABLED(CONFIG_DEBUG_ATOMIC_SLEEP))
++		WARN_ON_ONCE(!preemptible() &&
++			     (system_state > SYSTEM_BOOTING && system_state < SYSTEM_SUSPEND));
++
+ 	/* memcg and kmem_cache debug support */
+ 	s = slab_pre_alloc_hook(s, &objcg, size, flags);
+ 	if (unlikely(!s))
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0206-slub-Disable-SLUB_CPU_PARTIAL.patch b/debian/patches-rt/0206-slub-Disable-SLUB_CPU_PARTIAL.patch
new file mode 100644
index 000000000..9f521b566
--- /dev/null
+++ b/debian/patches-rt/0206-slub-Disable-SLUB_CPU_PARTIAL.patch
@@ -0,0 +1,54 @@
+From 8da7619853b38005d113af771657ad188006e1d5 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 15 Apr 2015 19:00:47 +0200
+Subject: [PATCH 206/323] slub: Disable SLUB_CPU_PARTIAL
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:915
+|in_atomic(): 1, irqs_disabled(): 0, pid: 87, name: rcuop/7
+|1 lock held by rcuop/7/87:
+| #0:  (rcu_callback){......}, at: [<ffffffff8112c76a>] rcu_nocb_kthread+0x1ca/0x5d0
+|Preemption disabled at:[<ffffffff811eebd9>] put_cpu_partial+0x29/0x220
+|
+|CPU: 0 PID: 87 Comm: rcuop/7 Tainted: G        W       4.0.0-rt0+ #477
+|Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
+| 000000000007a9fc ffff88013987baf8 ffffffff817441c7 0000000000000007
+| 0000000000000000 ffff88013987bb18 ffffffff810eee51 0000000000000000
+| ffff88013fc10200 ffff88013987bb48 ffffffff8174a1c4 000000000007a9fc
+|Call Trace:
+| [<ffffffff817441c7>] dump_stack+0x4f/0x90
+| [<ffffffff810eee51>] ___might_sleep+0x121/0x1b0
+| [<ffffffff8174a1c4>] rt_spin_lock+0x24/0x60
+| [<ffffffff811a689a>] __free_pages_ok+0xaa/0x540
+| [<ffffffff811a729d>] __free_pages+0x1d/0x30
+| [<ffffffff811eddd5>] __free_slab+0xc5/0x1e0
+| [<ffffffff811edf46>] free_delayed+0x56/0x70
+| [<ffffffff811eecfd>] put_cpu_partial+0x14d/0x220
+| [<ffffffff811efc98>] __slab_free+0x158/0x2c0
+| [<ffffffff811f0021>] kmem_cache_free+0x221/0x2d0
+| [<ffffffff81204d0c>] file_free_rcu+0x2c/0x40
+| [<ffffffff8112c7e3>] rcu_nocb_kthread+0x243/0x5d0
+| [<ffffffff810e951c>] kthread+0xfc/0x120
+| [<ffffffff8174abc8>] ret_from_fork+0x58/0x90
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ init/Kconfig | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/init/Kconfig b/init/Kconfig
+index 7e9578a0176f..c5f276d782de 100644
+--- a/init/Kconfig
++++ b/init/Kconfig
+@@ -2011,7 +2011,7 @@ config SHUFFLE_PAGE_ALLOCATOR
+ 
+ config SLUB_CPU_PARTIAL
+ 	default y
+-	depends on SLUB && SMP
++	depends on SLUB && SMP && !PREEMPT_RT
+ 	bool "SLUB per cpu partial cache"
+ 	help
+ 	  Per cpu partial caches accelerate objects allocation and freeing
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0207-mm-memcontrol-Provide-a-local_lock-for-per-CPU-memcg.patch b/debian/patches-rt/0207-mm-memcontrol-Provide-a-local_lock-for-per-CPU-memcg.patch
new file mode 100644
index 000000000..73fbdfd8d
--- /dev/null
+++ b/debian/patches-rt/0207-mm-memcontrol-Provide-a-local_lock-for-per-CPU-memcg.patch
@@ -0,0 +1,144 @@
+From 7a4ec53aa79ebc416eb752e204669e0d4dc53a06 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 18 Aug 2020 10:30:00 +0200
+Subject: [PATCH 207/323] mm: memcontrol: Provide a local_lock for per-CPU
+ memcg_stock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The interrupts are disabled to ensure CPU-local access to the per-CPU
+variable `memcg_stock'.
+As the code inside the interrupt disabled section acquires regular
+spinlocks, which are converted to 'sleeping' spinlocks on a PREEMPT_RT
+kernel, this conflicts with the RT semantics.
+
+Convert it to a local_lock which allows RT kernels to substitute them with
+a real per CPU lock. On non RT kernels this maps to local_irq_save() as
+before, but provides also lockdep coverage of the critical region.
+No functional change.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/memcontrol.c | 31 ++++++++++++++++++-------------
+ 1 file changed, 18 insertions(+), 13 deletions(-)
+
+diff --git a/mm/memcontrol.c b/mm/memcontrol.c
+index 49566afaef1c..d2a47428831b 100644
+--- a/mm/memcontrol.c
++++ b/mm/memcontrol.c
+@@ -2202,6 +2202,7 @@ void unlock_page_memcg(struct page *page)
+ EXPORT_SYMBOL(unlock_page_memcg);
+ 
+ struct memcg_stock_pcp {
++	local_lock_t lock;
+ 	struct mem_cgroup *cached; /* this never be root cgroup */
+ 	unsigned int nr_pages;
+ 
+@@ -2253,7 +2254,7 @@ static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
+ 	if (nr_pages > MEMCG_CHARGE_BATCH)
+ 		return ret;
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(&memcg_stock.lock, flags);
+ 
+ 	stock = this_cpu_ptr(&memcg_stock);
+ 	if (memcg == stock->cached && stock->nr_pages >= nr_pages) {
+@@ -2261,7 +2262,7 @@ static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
+ 		ret = true;
+ 	}
+ 
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&memcg_stock.lock, flags);
+ 
+ 	return ret;
+ }
+@@ -2296,14 +2297,14 @@ static void drain_local_stock(struct work_struct *dummy)
+ 	 * The only protection from memory hotplug vs. drain_stock races is
+ 	 * that we always operate on local CPU stock here with IRQ disabled
+ 	 */
+-	local_irq_save(flags);
++	local_lock_irqsave(&memcg_stock.lock, flags);
+ 
+ 	stock = this_cpu_ptr(&memcg_stock);
+ 	drain_obj_stock(stock);
+ 	drain_stock(stock);
+ 	clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
+ 
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&memcg_stock.lock, flags);
+ }
+ 
+ /*
+@@ -2315,7 +2316,7 @@ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
+ 	struct memcg_stock_pcp *stock;
+ 	unsigned long flags;
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(&memcg_stock.lock, flags);
+ 
+ 	stock = this_cpu_ptr(&memcg_stock);
+ 	if (stock->cached != memcg) { /* reset if necessary */
+@@ -2328,7 +2329,7 @@ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
+ 	if (stock->nr_pages > MEMCG_CHARGE_BATCH)
+ 		drain_stock(stock);
+ 
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&memcg_stock.lock, flags);
+ }
+ 
+ /*
+@@ -3137,7 +3138,7 @@ static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
+ 	unsigned long flags;
+ 	bool ret = false;
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(&memcg_stock.lock, flags);
+ 
+ 	stock = this_cpu_ptr(&memcg_stock);
+ 	if (objcg == stock->cached_objcg && stock->nr_bytes >= nr_bytes) {
+@@ -3145,7 +3146,7 @@ static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
+ 		ret = true;
+ 	}
+ 
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&memcg_stock.lock, flags);
+ 
+ 	return ret;
+ }
+@@ -3212,7 +3213,7 @@ static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
+ 	struct memcg_stock_pcp *stock;
+ 	unsigned long flags;
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(&memcg_stock.lock, flags);
+ 
+ 	stock = this_cpu_ptr(&memcg_stock);
+ 	if (stock->cached_objcg != objcg) { /* reset if necessary */
+@@ -3226,7 +3227,7 @@ static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
+ 	if (stock->nr_bytes > PAGE_SIZE)
+ 		drain_obj_stock(stock);
+ 
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&memcg_stock.lock, flags);
+ }
+ 
+ int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size)
+@@ -7161,9 +7162,13 @@ static int __init mem_cgroup_init(void)
+ 	cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL,
+ 				  memcg_hotplug_cpu_dead);
+ 
+-	for_each_possible_cpu(cpu)
+-		INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work,
+-			  drain_local_stock);
++	for_each_possible_cpu(cpu) {
++		struct memcg_stock_pcp *stock;
++
++		stock = per_cpu_ptr(&memcg_stock, cpu);
++		INIT_WORK(&stock->work, drain_local_stock);
++		local_lock_init(&stock->lock);
++	}
+ 
+ 	for_each_node(node) {
+ 		struct mem_cgroup_tree_per_node *rtpn;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0208-mm-memcontrol-Don-t-call-schedule_work_on-in-preempt.patch b/debian/patches-rt/0208-mm-memcontrol-Don-t-call-schedule_work_on-in-preempt.patch
new file mode 100644
index 000000000..e1de69b43
--- /dev/null
+++ b/debian/patches-rt/0208-mm-memcontrol-Don-t-call-schedule_work_on-in-preempt.patch
@@ -0,0 +1,74 @@
+From 915ee75a3da5732cf20be8f92b31d3ce33042c5b Mon Sep 17 00:00:00 2001
+From: Yang Shi <yang.shi@windriver.com>
+Date: Wed, 30 Oct 2013 11:48:33 -0700
+Subject: [PATCH 208/323] mm/memcontrol: Don't call schedule_work_on in
+ preemption disabled context
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The following trace is triggered when running ltp oom test cases:
+
+BUG: sleeping function called from invalid context at kernel/rtmutex.c:659
+in_atomic(): 1, irqs_disabled(): 0, pid: 17188, name: oom03
+Preemption disabled at:[<ffffffff8112ba70>] mem_cgroup_reclaim+0x90/0xe0
+
+CPU: 2 PID: 17188 Comm: oom03 Not tainted 3.10.10-rt3 #2
+Hardware name: Intel Corporation Calpella platform/MATXM-CORE-411-B, BIOS 4.6.3 08/18/2010
+ffff88007684d730 ffff880070df9b58 ffffffff8169918d ffff880070df9b70
+ffffffff8106db31 ffff88007688b4a0 ffff880070df9b88 ffffffff8169d9c0
+ffff88007688b4a0 ffff880070df9bc8 ffffffff81059da1 0000000170df9bb0
+Call Trace:
+[<ffffffff8169918d>] dump_stack+0x19/0x1b
+[<ffffffff8106db31>] __might_sleep+0xf1/0x170
+[<ffffffff8169d9c0>] rt_spin_lock+0x20/0x50
+[<ffffffff81059da1>] queue_work_on+0x61/0x100
+[<ffffffff8112b361>] drain_all_stock+0xe1/0x1c0
+[<ffffffff8112ba70>] mem_cgroup_reclaim+0x90/0xe0
+[<ffffffff8112beda>] __mem_cgroup_try_charge+0x41a/0xc40
+[<ffffffff810f1c91>] ? release_pages+0x1b1/0x1f0
+[<ffffffff8106f200>] ? sched_exec+0x40/0xb0
+[<ffffffff8112cc87>] mem_cgroup_charge_common+0x37/0x70
+[<ffffffff8112e2c6>] mem_cgroup_newpage_charge+0x26/0x30
+[<ffffffff8110af68>] handle_pte_fault+0x618/0x840
+[<ffffffff8103ecf6>] ? unpin_current_cpu+0x16/0x70
+[<ffffffff81070f94>] ? migrate_enable+0xd4/0x200
+[<ffffffff8110cde5>] handle_mm_fault+0x145/0x1e0
+[<ffffffff810301e1>] __do_page_fault+0x1a1/0x4c0
+[<ffffffff8169c9eb>] ? preempt_schedule_irq+0x4b/0x70
+[<ffffffff8169e3b7>] ? retint_kernel+0x37/0x40
+[<ffffffff8103053e>] do_page_fault+0xe/0x10
+[<ffffffff8169e4c2>] page_fault+0x22/0x30
+
+So, to prevent schedule_work_on from being called in preempt disabled context,
+replace the pair of get/put_cpu() to get/put_cpu_light().
+
+Signed-off-by: Yang Shi <yang.shi@windriver.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/memcontrol.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/mm/memcontrol.c b/mm/memcontrol.c
+index d2a47428831b..53522a52ff15 100644
+--- a/mm/memcontrol.c
++++ b/mm/memcontrol.c
+@@ -2349,7 +2349,7 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)
+ 	 * as well as workers from this path always operate on the local
+ 	 * per-cpu data. CPU up doesn't touch memcg_stock at all.
+ 	 */
+-	curcpu = get_cpu();
++	curcpu = get_cpu_light();
+ 	for_each_online_cpu(cpu) {
+ 		struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
+ 		struct mem_cgroup *memcg;
+@@ -2372,7 +2372,7 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)
+ 				schedule_work_on(cpu, &stock->work);
+ 		}
+ 	}
+-	put_cpu();
++	put_cpu_light();
+ 	mutex_unlock(&percpu_charge_mutex);
+ }
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0209-mm-memcontrol-Replace-local_irq_disable-with-local-l.patch b/debian/patches-rt/0209-mm-memcontrol-Replace-local_irq_disable-with-local-l.patch
new file mode 100644
index 000000000..143299bc1
--- /dev/null
+++ b/debian/patches-rt/0209-mm-memcontrol-Replace-local_irq_disable-with-local-l.patch
@@ -0,0 +1,123 @@
+From aed289fe7a9923b6c8a98fa08048d56aa97c71c4 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 28 Jan 2015 17:14:16 +0100
+Subject: [PATCH 209/323] mm/memcontrol: Replace local_irq_disable with local
+ locks
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+There are a few local_irq_disable() which then take sleeping locks. This
+patch converts them local locks.
+
+[bigeasy: Move unlock after memcg_check_events() in mem_cgroup_swapout(),
+	pointed out by Matt Fleming <matt@codeblueprint.co.uk>]
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/memcontrol.c | 29 +++++++++++++++++++++--------
+ 1 file changed, 21 insertions(+), 8 deletions(-)
+
+diff --git a/mm/memcontrol.c b/mm/memcontrol.c
+index 53522a52ff15..5bf696318643 100644
+--- a/mm/memcontrol.c
++++ b/mm/memcontrol.c
+@@ -63,6 +63,7 @@
+ #include <net/sock.h>
+ #include <net/ip.h>
+ #include "slab.h"
++#include <linux/local_lock.h>
+ 
+ #include <linux/uaccess.h>
+ 
+@@ -93,6 +94,13 @@ bool cgroup_memory_noswap __read_mostly;
+ static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq);
+ #endif
+ 
++struct event_lock {
++	local_lock_t l;
++};
++static DEFINE_PER_CPU(struct event_lock, event_lock) = {
++	.l      = INIT_LOCAL_LOCK(l),
++};
++
+ /* Whether legacy memory+swap accounting is active */
+ static bool do_memsw_account(void)
+ {
+@@ -5747,12 +5755,12 @@ static int mem_cgroup_move_account(struct page *page,
+ 
+ 	ret = 0;
+ 
+-	local_irq_disable();
++	local_lock_irq(&event_lock.l);
+ 	mem_cgroup_charge_statistics(to, page, nr_pages);
+ 	memcg_check_events(to, page);
+ 	mem_cgroup_charge_statistics(from, page, -nr_pages);
+ 	memcg_check_events(from, page);
+-	local_irq_enable();
++	local_unlock_irq(&event_lock.l);
+ out_unlock:
+ 	unlock_page(page);
+ out:
+@@ -6822,10 +6830,10 @@ int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
+ 	css_get(&memcg->css);
+ 	commit_charge(page, memcg);
+ 
+-	local_irq_disable();
++	local_lock_irq(&event_lock.l);
+ 	mem_cgroup_charge_statistics(memcg, page, nr_pages);
+ 	memcg_check_events(memcg, page);
+-	local_irq_enable();
++	local_unlock_irq(&event_lock.l);
+ 
+ 	/*
+ 	 * Cgroup1's unified memory+swap counter has been charged with the
+@@ -6881,11 +6889,11 @@ static void uncharge_batch(const struct uncharge_gather *ug)
+ 		memcg_oom_recover(ug->memcg);
+ 	}
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(&event_lock.l, flags);
+ 	__count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
+ 	__this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_pages);
+ 	memcg_check_events(ug->memcg, ug->dummy_page);
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&event_lock.l, flags);
+ 
+ 	/* drop reference from uncharge_page */
+ 	css_put(&ug->memcg->css);
+@@ -7039,10 +7047,10 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage)
+ 	css_get(&memcg->css);
+ 	commit_charge(newpage, memcg);
+ 
+-	local_irq_save(flags);
++	local_lock_irqsave(&event_lock.l, flags);
+ 	mem_cgroup_charge_statistics(memcg, newpage, nr_pages);
+ 	memcg_check_events(memcg, newpage);
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&event_lock.l, flags);
+ }
+ 
+ DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key);
+@@ -7217,6 +7225,7 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
+ 	struct mem_cgroup *memcg, *swap_memcg;
+ 	unsigned int nr_entries;
+ 	unsigned short oldid;
++	unsigned long flags;
+ 
+ 	VM_BUG_ON_PAGE(PageLRU(page), page);
+ 	VM_BUG_ON_PAGE(page_count(page), page);
+@@ -7262,9 +7271,13 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
+ 	 * important here to have the interrupts disabled because it is the
+ 	 * only synchronisation we have for updating the per-CPU variables.
+ 	 */
++	local_lock_irqsave(&event_lock.l, flags);
++#ifndef CONFIG_PREEMPT_RT
+ 	VM_BUG_ON(!irqs_disabled());
++#endif
+ 	mem_cgroup_charge_statistics(memcg, page, -nr_entries);
+ 	memcg_check_events(memcg, page);
++	local_unlock_irqrestore(&event_lock.l, flags);
+ 
+ 	css_put(&memcg->css);
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0210-mm-zsmalloc-copy-with-get_cpu_var-and-locking.patch b/debian/patches-rt/0210-mm-zsmalloc-copy-with-get_cpu_var-and-locking.patch
new file mode 100644
index 000000000..f48595a8d
--- /dev/null
+++ b/debian/patches-rt/0210-mm-zsmalloc-copy-with-get_cpu_var-and-locking.patch
@@ -0,0 +1,212 @@
+From 7e86ac4a42c020de9b35b02a3ef02f2fc0dee2ed Mon Sep 17 00:00:00 2001
+From: Mike Galbraith <umgwanakikbuti@gmail.com>
+Date: Tue, 22 Mar 2016 11:16:09 +0100
+Subject: [PATCH 210/323] mm/zsmalloc: copy with get_cpu_var() and locking
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+get_cpu_var() disables preemption and triggers a might_sleep() splat later.
+This is replaced with get_locked_var().
+This bitspinlocks are replaced with a proper mutex which requires a slightly
+larger struct to allocate.
+
+Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
+[bigeasy: replace the bitspin_lock() with a mutex, get_locked_var(). Mike then
+fixed the size magic]
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/zsmalloc.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++----
+ 1 file changed, 79 insertions(+), 6 deletions(-)
+
+diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
+index c18dc8e61d35..7dad2ff3e778 100644
+--- a/mm/zsmalloc.c
++++ b/mm/zsmalloc.c
+@@ -57,6 +57,7 @@
+ #include <linux/wait.h>
+ #include <linux/pagemap.h>
+ #include <linux/fs.h>
++#include <linux/local_lock.h>
+ 
+ #define ZSPAGE_MAGIC	0x58
+ 
+@@ -77,6 +78,20 @@
+ 
+ #define ZS_HANDLE_SIZE (sizeof(unsigned long))
+ 
++#ifdef CONFIG_PREEMPT_RT
++
++struct zsmalloc_handle {
++	unsigned long addr;
++	struct mutex lock;
++};
++
++#define ZS_HANDLE_ALLOC_SIZE (sizeof(struct zsmalloc_handle))
++
++#else
++
++#define ZS_HANDLE_ALLOC_SIZE (sizeof(unsigned long))
++#endif
++
+ /*
+  * Object location (<PFN>, <obj_idx>) is encoded as
+  * a single (unsigned long) handle value.
+@@ -293,6 +308,7 @@ struct zspage {
+ };
+ 
+ struct mapping_area {
++	local_lock_t lock;
+ 	char *vm_buf; /* copy buffer for objects that span pages */
+ 	char *vm_addr; /* address of kmap_atomic()'ed pages */
+ 	enum zs_mapmode vm_mm; /* mapping mode */
+@@ -322,7 +338,7 @@ static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {}
+ 
+ static int create_cache(struct zs_pool *pool)
+ {
+-	pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE,
++	pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_ALLOC_SIZE,
+ 					0, 0, NULL);
+ 	if (!pool->handle_cachep)
+ 		return 1;
+@@ -346,9 +362,26 @@ static void destroy_cache(struct zs_pool *pool)
+ 
+ static unsigned long cache_alloc_handle(struct zs_pool *pool, gfp_t gfp)
+ {
+-	return (unsigned long)kmem_cache_alloc(pool->handle_cachep,
+-			gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
++	void *p;
++
++	p = kmem_cache_alloc(pool->handle_cachep,
++			     gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
++#ifdef CONFIG_PREEMPT_RT
++	if (p) {
++		struct zsmalloc_handle *zh = p;
++
++		mutex_init(&zh->lock);
++	}
++#endif
++	return (unsigned long)p;
++}
++
++#ifdef CONFIG_PREEMPT_RT
++static struct zsmalloc_handle *zs_get_pure_handle(unsigned long handle)
++{
++	return (void *)(handle &~((1 << OBJ_TAG_BITS) - 1));
+ }
++#endif
+ 
+ static void cache_free_handle(struct zs_pool *pool, unsigned long handle)
+ {
+@@ -368,12 +401,18 @@ static void cache_free_zspage(struct zs_pool *pool, struct zspage *zspage)
+ 
+ static void record_obj(unsigned long handle, unsigned long obj)
+ {
++#ifdef CONFIG_PREEMPT_RT
++	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
++
++	WRITE_ONCE(zh->addr, obj);
++#else
+ 	/*
+ 	 * lsb of @obj represents handle lock while other bits
+ 	 * represent object value the handle is pointing so
+ 	 * updating shouldn't do store tearing.
+ 	 */
+ 	WRITE_ONCE(*(unsigned long *)handle, obj);
++#endif
+ }
+ 
+ /* zpool driver */
+@@ -455,7 +494,10 @@ MODULE_ALIAS("zpool-zsmalloc");
+ #endif /* CONFIG_ZPOOL */
+ 
+ /* per-cpu VM mapping areas for zspage accesses that cross page boundaries */
+-static DEFINE_PER_CPU(struct mapping_area, zs_map_area);
++static DEFINE_PER_CPU(struct mapping_area, zs_map_area) = {
++	/* XXX remove this and use a spin_lock_t in pin_tag() */
++	.lock	= INIT_LOCAL_LOCK(lock),
++};
+ 
+ static bool is_zspage_isolated(struct zspage *zspage)
+ {
+@@ -865,7 +907,13 @@ static unsigned long location_to_obj(struct page *page, unsigned int obj_idx)
+ 
+ static unsigned long handle_to_obj(unsigned long handle)
+ {
++#ifdef CONFIG_PREEMPT_RT
++	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
++
++	return zh->addr;
++#else
+ 	return *(unsigned long *)handle;
++#endif
+ }
+ 
+ static unsigned long obj_to_head(struct page *page, void *obj)
+@@ -879,22 +927,46 @@ static unsigned long obj_to_head(struct page *page, void *obj)
+ 
+ static inline int testpin_tag(unsigned long handle)
+ {
++#ifdef CONFIG_PREEMPT_RT
++	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
++
++	return mutex_is_locked(&zh->lock);
++#else
+ 	return bit_spin_is_locked(HANDLE_PIN_BIT, (unsigned long *)handle);
++#endif
+ }
+ 
+ static inline int trypin_tag(unsigned long handle)
+ {
++#ifdef CONFIG_PREEMPT_RT
++	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
++
++	return mutex_trylock(&zh->lock);
++#else
+ 	return bit_spin_trylock(HANDLE_PIN_BIT, (unsigned long *)handle);
++#endif
+ }
+ 
+ static void pin_tag(unsigned long handle) __acquires(bitlock)
+ {
++#ifdef CONFIG_PREEMPT_RT
++	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
++
++	return mutex_lock(&zh->lock);
++#else
+ 	bit_spin_lock(HANDLE_PIN_BIT, (unsigned long *)handle);
++#endif
+ }
+ 
+ static void unpin_tag(unsigned long handle) __releases(bitlock)
+ {
++#ifdef CONFIG_PREEMPT_RT
++	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
++
++	return mutex_unlock(&zh->lock);
++#else
+ 	bit_spin_unlock(HANDLE_PIN_BIT, (unsigned long *)handle);
++#endif
+ }
+ 
+ static void reset_page(struct page *page)
+@@ -1278,7 +1350,8 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
+ 	class = pool->size_class[class_idx];
+ 	off = (class->size * obj_idx) & ~PAGE_MASK;
+ 
+-	area = &get_cpu_var(zs_map_area);
++	local_lock(&zs_map_area.lock);
++	area = this_cpu_ptr(&zs_map_area);
+ 	area->vm_mm = mm;
+ 	if (off + class->size <= PAGE_SIZE) {
+ 		/* this object is contained entirely within a page */
+@@ -1332,7 +1405,7 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
+ 
+ 		__zs_unmap_object(area, pages, off, class->size);
+ 	}
+-	put_cpu_var(zs_map_area);
++	local_unlock(&zs_map_area.lock);
+ 
+ 	migrate_read_unlock(zspage);
+ 	unpin_tag(handle);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0211-mm-zswap-Use-local-lock-to-protect-per-CPU-data.patch b/debian/patches-rt/0211-mm-zswap-Use-local-lock-to-protect-per-CPU-data.patch
new file mode 100644
index 000000000..772cff44a
--- /dev/null
+++ b/debian/patches-rt/0211-mm-zswap-Use-local-lock-to-protect-per-CPU-data.patch
@@ -0,0 +1,150 @@
+From 5bfa3eb76d50818c90253df970e7afbc747211c2 Mon Sep 17 00:00:00 2001
+From: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
+Date: Tue, 25 Jun 2019 11:28:04 -0300
+Subject: [PATCH 211/323] mm/zswap: Use local lock to protect per-CPU data
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+zwap uses per-CPU compression. The per-CPU data pointer is acquired with
+get_cpu_ptr() which implicitly disables preemption. It allocates
+memory inside the preempt disabled region which conflicts with the
+PREEMPT_RT semantics.
+
+Replace the implicit preemption control with an explicit local lock.
+This allows RT kernels to substitute it with a real per CPU lock, which
+serializes the access but keeps the code section preemptible. On non RT
+kernels this maps to preempt_disable() as before, i.e. no functional
+change.
+
+[bigeasy: Use local_lock(), additional hunks, patch description]
+
+Cc: Seth Jennings <sjenning@redhat.com>
+Cc: Dan Streetman <ddstreet@ieee.org>
+Cc: Vitaly Wool <vitaly.wool@konsulko.com>
+Cc: Andrew Morton <akpm@linux-foundation.org>
+Cc: linux-mm@kvack.org
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ mm/zswap.c | 43 ++++++++++++++++++++++++++++---------------
+ 1 file changed, 28 insertions(+), 15 deletions(-)
+
+diff --git a/mm/zswap.c b/mm/zswap.c
+index fbb782924ccc..b24f761b9241 100644
+--- a/mm/zswap.c
++++ b/mm/zswap.c
+@@ -18,6 +18,7 @@
+ #include <linux/highmem.h>
+ #include <linux/slab.h>
+ #include <linux/spinlock.h>
++#include <linux/local_lock.h>
+ #include <linux/types.h>
+ #include <linux/atomic.h>
+ #include <linux/frontswap.h>
+@@ -387,27 +388,37 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
+ /*********************************
+ * per-cpu code
+ **********************************/
+-static DEFINE_PER_CPU(u8 *, zswap_dstmem);
++struct zswap_comp {
++	/* Used for per-CPU dstmem and tfm */
++	local_lock_t lock;
++	u8 *dstmem;
++};
++
++static DEFINE_PER_CPU(struct zswap_comp, zswap_comp) = {
++	.lock = INIT_LOCAL_LOCK(lock),
++};
+ 
+ static int zswap_dstmem_prepare(unsigned int cpu)
+ {
++	struct zswap_comp *zcomp;
+ 	u8 *dst;
+ 
+ 	dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
+ 	if (!dst)
+ 		return -ENOMEM;
+ 
+-	per_cpu(zswap_dstmem, cpu) = dst;
++	zcomp = per_cpu_ptr(&zswap_comp, cpu);
++	zcomp->dstmem = dst;
+ 	return 0;
+ }
+ 
+ static int zswap_dstmem_dead(unsigned int cpu)
+ {
+-	u8 *dst;
++	struct zswap_comp *zcomp;
+ 
+-	dst = per_cpu(zswap_dstmem, cpu);
+-	kfree(dst);
+-	per_cpu(zswap_dstmem, cpu) = NULL;
++	zcomp = per_cpu_ptr(&zswap_comp, cpu);
++	kfree(zcomp->dstmem);
++	zcomp->dstmem = NULL;
+ 
+ 	return 0;
+ }
+@@ -919,10 +930,11 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
+ 		dlen = PAGE_SIZE;
+ 		src = (u8 *)zhdr + sizeof(struct zswap_header);
+ 		dst = kmap_atomic(page);
+-		tfm = *get_cpu_ptr(entry->pool->tfm);
++		local_lock(&zswap_comp.lock);
++		tfm = *this_cpu_ptr(entry->pool->tfm);
+ 		ret = crypto_comp_decompress(tfm, src, entry->length,
+ 					     dst, &dlen);
+-		put_cpu_ptr(entry->pool->tfm);
++		local_unlock(&zswap_comp.lock);
+ 		kunmap_atomic(dst);
+ 		BUG_ON(ret);
+ 		BUG_ON(dlen != PAGE_SIZE);
+@@ -1074,12 +1086,12 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
+ 	}
+ 
+ 	/* compress */
+-	dst = get_cpu_var(zswap_dstmem);
+-	tfm = *get_cpu_ptr(entry->pool->tfm);
++	local_lock(&zswap_comp.lock);
++	dst = *this_cpu_ptr(&zswap_comp.dstmem);
++	tfm = *this_cpu_ptr(entry->pool->tfm);
+ 	src = kmap_atomic(page);
+ 	ret = crypto_comp_compress(tfm, src, PAGE_SIZE, dst, &dlen);
+ 	kunmap_atomic(src);
+-	put_cpu_ptr(entry->pool->tfm);
+ 	if (ret) {
+ 		ret = -EINVAL;
+ 		goto put_dstmem;
+@@ -1103,7 +1115,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
+ 	memcpy(buf, &zhdr, hlen);
+ 	memcpy(buf + hlen, dst, dlen);
+ 	zpool_unmap_handle(entry->pool->zpool, handle);
+-	put_cpu_var(zswap_dstmem);
++	local_unlock(&zswap_comp.lock);
+ 
+ 	/* populate entry */
+ 	entry->offset = offset;
+@@ -1131,7 +1143,7 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
+ 	return 0;
+ 
+ put_dstmem:
+-	put_cpu_var(zswap_dstmem);
++	local_unlock(&zswap_comp.lock);
+ 	zswap_pool_put(entry->pool);
+ freepage:
+ 	zswap_entry_cache_free(entry);
+@@ -1176,9 +1188,10 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
+ 	if (zpool_evictable(entry->pool->zpool))
+ 		src += sizeof(struct zswap_header);
+ 	dst = kmap_atomic(page);
+-	tfm = *get_cpu_ptr(entry->pool->tfm);
++	local_lock(&zswap_comp.lock);
++	tfm = *this_cpu_ptr(entry->pool->tfm);
+ 	ret = crypto_comp_decompress(tfm, src, entry->length, dst, &dlen);
+-	put_cpu_ptr(entry->pool->tfm);
++	local_unlock(&zswap_comp.lock);
+ 	kunmap_atomic(dst);
+ 	zpool_unmap_handle(entry->pool->zpool, entry->handle);
+ 	BUG_ON(ret);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0212-x86-kvm-Require-const-tsc-for-RT.patch b/debian/patches-rt/0212-x86-kvm-Require-const-tsc-for-RT.patch
new file mode 100644
index 000000000..461bb6d81
--- /dev/null
+++ b/debian/patches-rt/0212-x86-kvm-Require-const-tsc-for-RT.patch
@@ -0,0 +1,38 @@
+From 6ef3a23d8f37d55fa94b9f1212830a3b8018c76f Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Sun, 6 Nov 2011 12:26:18 +0100
+Subject: [PATCH 212/323] x86: kvm Require const tsc for RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Non constant TSC is a nightmare on bare metal already, but with
+virtualization it becomes a complete disaster because the workarounds
+are horrible latency wise. That's also a preliminary for running RT in
+a guest on top of a RT host.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ arch/x86/kvm/x86.c | 8 ++++++++
+ 1 file changed, 8 insertions(+)
+
+diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
+index 13e4699a0744..21a1aa76eb23 100644
+--- a/arch/x86/kvm/x86.c
++++ b/arch/x86/kvm/x86.c
+@@ -8167,6 +8167,14 @@ int kvm_arch_init(void *opaque)
+ 		goto out;
+ 	}
+ 
++#ifdef CONFIG_PREEMPT_RT
++	if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) {
++		pr_err("RT requires X86_FEATURE_CONSTANT_TSC\n");
++		r = -EOPNOTSUPP;
++		goto out;
++	}
++#endif
++
+ 	r = -ENOMEM;
+ 	x86_fpu_cache = kmem_cache_create("x86_fpu", sizeof(struct fpu),
+ 					  __alignof__(struct fpu), SLAB_ACCOUNT,
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0213-wait.h-include-atomic.h.patch b/debian/patches-rt/0213-wait.h-include-atomic.h.patch
new file mode 100644
index 000000000..1d060be29
--- /dev/null
+++ b/debian/patches-rt/0213-wait.h-include-atomic.h.patch
@@ -0,0 +1,42 @@
+From 25ddd3a9a10e8b30e5c6ff85e57532a5f20ffa9d Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 28 Oct 2013 12:19:57 +0100
+Subject: [PATCH 213/323] wait.h: include atomic.h
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+|  CC      init/main.o
+|In file included from include/linux/mmzone.h:9:0,
+|                 from include/linux/gfp.h:4,
+|                 from include/linux/kmod.h:22,
+|                 from include/linux/module.h:13,
+|                 from init/main.c:15:
+|include/linux/wait.h: In function ‘wait_on_atomic_t’:
+|include/linux/wait.h:982:2: error: implicit declaration of function ‘atomic_read’ [-Werror=implicit-function-declaration]
+|  if (atomic_read(val) == 0)
+|  ^
+
+This pops up on ARM. Non-RT gets its atomic.h include from spinlock.h
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/wait.h | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/include/linux/wait.h b/include/linux/wait.h
+index 1663e47681a3..20aae69387aa 100644
+--- a/include/linux/wait.h
++++ b/include/linux/wait.h
+@@ -10,6 +10,7 @@
+ 
+ #include <asm/current.h>
+ #include <uapi/linux/wait.h>
++#include <linux/atomic.h>
+ 
+ typedef struct wait_queue_entry wait_queue_entry_t;
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0214-sched-Limit-the-number-of-task-migrations-per-batch.patch b/debian/patches-rt/0214-sched-Limit-the-number-of-task-migrations-per-batch.patch
new file mode 100644
index 000000000..c157da12c
--- /dev/null
+++ b/debian/patches-rt/0214-sched-Limit-the-number-of-task-migrations-per-batch.patch
@@ -0,0 +1,33 @@
+From a178dbd2a3f8eeedf39cde9582a29bc95f335b17 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Mon, 6 Jun 2011 12:12:51 +0200
+Subject: [PATCH 214/323] sched: Limit the number of task migrations per batch
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Put an upper limit on the number of tasks which are migrated per batch
+to avoid large latencies.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ kernel/sched/core.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index aaeed4b14278..3d7e9ecbd376 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -65,7 +65,11 @@ const_debug unsigned int sysctl_sched_features =
+  * Number of tasks to iterate in a single balance run.
+  * Limited because this is done with IRQs disabled.
+  */
++#ifdef CONFIG_PREEMPT_RT
++const_debug unsigned int sysctl_sched_nr_migrate = 8;
++#else
+ const_debug unsigned int sysctl_sched_nr_migrate = 32;
++#endif
+ 
+ /*
+  * period over which we measure -rt task CPU usage in us.
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0215-sched-Move-mmdrop-to-RCU-on-RT.patch b/debian/patches-rt/0215-sched-Move-mmdrop-to-RCU-on-RT.patch
new file mode 100644
index 000000000..caf0a9bc6
--- /dev/null
+++ b/debian/patches-rt/0215-sched-Move-mmdrop-to-RCU-on-RT.patch
@@ -0,0 +1,115 @@
+From e29feec1bad5cc39575600e68d6f5523b17c189a Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Mon, 6 Jun 2011 12:20:33 +0200
+Subject: [PATCH 215/323] sched: Move mmdrop to RCU on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Takes sleeping locks and calls into the memory allocator, so nothing
+we want to do in task switch and oder atomic contexts.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/mm_types.h |  4 ++++
+ include/linux/sched/mm.h | 11 +++++++++++
+ kernel/fork.c            | 13 +++++++++++++
+ kernel/sched/core.c      |  7 ++++++-
+ 4 files changed, 34 insertions(+), 1 deletion(-)
+
+diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
+index 4eb38918da8f..2a83d965b00e 100644
+--- a/include/linux/mm_types.h
++++ b/include/linux/mm_types.h
+@@ -12,6 +12,7 @@
+ #include <linux/completion.h>
+ #include <linux/cpumask.h>
+ #include <linux/uprobes.h>
++#include <linux/rcupdate.h>
+ #include <linux/page-flags-layout.h>
+ #include <linux/workqueue.h>
+ #include <linux/seqlock.h>
+@@ -570,6 +571,9 @@ struct mm_struct {
+ 		bool tlb_flush_batched;
+ #endif
+ 		struct uprobes_state uprobes_state;
++#ifdef CONFIG_PREEMPT_RT
++		struct rcu_head delayed_drop;
++#endif
+ #ifdef CONFIG_HUGETLB_PAGE
+ 		atomic_long_t hugetlb_usage;
+ #endif
+diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
+index e3e5e149b00e..6d39ad0f55bb 100644
+--- a/include/linux/sched/mm.h
++++ b/include/linux/sched/mm.h
+@@ -49,6 +49,17 @@ static inline void mmdrop(struct mm_struct *mm)
+ 		__mmdrop(mm);
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT
++extern void __mmdrop_delayed(struct rcu_head *rhp);
++static inline void mmdrop_delayed(struct mm_struct *mm)
++{
++	if (atomic_dec_and_test(&mm->mm_count))
++		call_rcu(&mm->delayed_drop, __mmdrop_delayed);
++}
++#else
++# define mmdrop_delayed(mm)    mmdrop(mm)
++#endif
++
+ /**
+  * mmget() - Pin the address space associated with a &struct mm_struct.
+  * @mm: The address space to pin.
+diff --git a/kernel/fork.c b/kernel/fork.c
+index 32b9d7205ac1..078058436f2f 100644
+--- a/kernel/fork.c
++++ b/kernel/fork.c
+@@ -691,6 +691,19 @@ void __mmdrop(struct mm_struct *mm)
+ }
+ EXPORT_SYMBOL_GPL(__mmdrop);
+ 
++#ifdef CONFIG_PREEMPT_RT
++/*
++ * RCU callback for delayed mm drop. Not strictly rcu, but we don't
++ * want another facility to make this work.
++ */
++void __mmdrop_delayed(struct rcu_head *rhp)
++{
++	struct mm_struct *mm = container_of(rhp, struct mm_struct, delayed_drop);
++
++	__mmdrop(mm);
++}
++#endif
++
+ static void mmdrop_async_fn(struct work_struct *work)
+ {
+ 	struct mm_struct *mm;
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 3d7e9ecbd376..5e5d28f5d970 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -4269,9 +4269,13 @@ static struct rq *finish_task_switch(struct task_struct *prev)
+ 	 *   provided by mmdrop(),
+ 	 * - a sync_core for SYNC_CORE.
+ 	 */
++	/*
++	 * We use mmdrop_delayed() here so we don't have to do the
++	 * full __mmdrop() when we are the last user.
++	 */
+ 	if (mm) {
+ 		membarrier_mm_sync_core_before_usermode(mm);
+-		mmdrop(mm);
++		mmdrop_delayed(mm);
+ 	}
+ 	if (unlikely(prev_state == TASK_DEAD)) {
+ 		if (prev->sched_class->task_dead)
+@@ -7264,6 +7268,7 @@ void sched_setnuma(struct task_struct *p, int nid)
+ #endif /* CONFIG_NUMA_BALANCING */
+ 
+ #ifdef CONFIG_HOTPLUG_CPU
++
+ /*
+  * Ensure that the idle task is using init_mm right before its CPU goes
+  * offline.
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0216-kernel-sched-move-stack-kprobe-clean-up-to-__put_tas.patch b/debian/patches-rt/0216-kernel-sched-move-stack-kprobe-clean-up-to-__put_tas.patch
new file mode 100644
index 000000000..c420a7438
--- /dev/null
+++ b/debian/patches-rt/0216-kernel-sched-move-stack-kprobe-clean-up-to-__put_tas.patch
@@ -0,0 +1,81 @@
+From 0d19bdfa59a3f9976aacac9944e5c2519f1a508b Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 21 Nov 2016 19:31:08 +0100
+Subject: [PATCH 216/323] kernel/sched: move stack + kprobe clean up to
+ __put_task_struct()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+There is no need to free the stack before the task struct (except for reasons
+mentioned in commit 68f24b08ee89 ("sched/core: Free the stack early if
+CONFIG_THREAD_INFO_IN_TASK")). This also comes handy on -RT because we can't
+free memory in preempt disabled region.
+vfree_atomic() delays the memory cleanup to a worker. Since we move everything
+to the RCU callback, we can also free it immediately.
+
+Cc: stable-rt@vger.kernel.org #for kprobe_flush_task()
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/fork.c       | 12 +++++++++++-
+ kernel/sched/core.c |  9 ---------
+ 2 files changed, 11 insertions(+), 10 deletions(-)
+
+diff --git a/kernel/fork.c b/kernel/fork.c
+index 078058436f2f..2a11bf5f9e30 100644
+--- a/kernel/fork.c
++++ b/kernel/fork.c
+@@ -42,6 +42,7 @@
+ #include <linux/mmu_notifier.h>
+ #include <linux/fs.h>
+ #include <linux/mm.h>
++#include <linux/kprobes.h>
+ #include <linux/vmacache.h>
+ #include <linux/nsproxy.h>
+ #include <linux/capability.h>
+@@ -288,7 +289,7 @@ static inline void free_thread_stack(struct task_struct *tsk)
+ 			return;
+ 		}
+ 
+-		vfree_atomic(tsk->stack);
++		vfree(tsk->stack);
+ 		return;
+ 	}
+ #endif
+@@ -745,6 +746,15 @@ void __put_task_struct(struct task_struct *tsk)
+ 	WARN_ON(refcount_read(&tsk->usage));
+ 	WARN_ON(tsk == current);
+ 
++	/*
++	 * Remove function-return probe instances associated with this
++	 * task and put them back on the free list.
++	 */
++	kprobe_flush_task(tsk);
++
++	/* Task is done with its stack. */
++	put_task_stack(tsk);
++
+ 	io_uring_free(tsk);
+ 	cgroup_free(tsk);
+ 	task_numa_free(tsk, true);
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 5e5d28f5d970..81bc9efbd191 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -4281,15 +4281,6 @@ static struct rq *finish_task_switch(struct task_struct *prev)
+ 		if (prev->sched_class->task_dead)
+ 			prev->sched_class->task_dead(prev);
+ 
+-		/*
+-		 * Remove function-return probe instances associated with this
+-		 * task and put them back on the free list.
+-		 */
+-		kprobe_flush_task(prev);
+-
+-		/* Task is done with its stack. */
+-		put_task_stack(prev);
+-
+ 		put_task_struct_rcu_user(prev);
+ 	}
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0217-sched-Do-not-account-rcu_preempt_depth-on-RT-in-migh.patch b/debian/patches-rt/0217-sched-Do-not-account-rcu_preempt_depth-on-RT-in-migh.patch
new file mode 100644
index 000000000..71686f72d
--- /dev/null
+++ b/debian/patches-rt/0217-sched-Do-not-account-rcu_preempt_depth-on-RT-in-migh.patch
@@ -0,0 +1,57 @@
+From 55d4bd8636745b8d1b987b6561ae2b14cebace78 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 7 Jun 2011 09:19:06 +0200
+Subject: [PATCH 217/323] sched: Do not account rcu_preempt_depth on RT in
+ might_sleep()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+RT changes the rcu_preempt_depth semantics, so we cannot check for it
+in might_sleep().
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/rcupdate.h | 7 +++++++
+ kernel/sched/core.c      | 2 +-
+ 2 files changed, 8 insertions(+), 1 deletion(-)
+
+diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
+index bb9681309e0d..cbeea5c61a3a 100644
+--- a/include/linux/rcupdate.h
++++ b/include/linux/rcupdate.h
+@@ -54,6 +54,11 @@ void __rcu_read_unlock(void);
+  * types of kernel builds, the rcu_read_lock() nesting depth is unknowable.
+  */
+ #define rcu_preempt_depth() (current->rcu_read_lock_nesting)
++#ifndef CONFIG_PREEMPT_RT
++#define sched_rcu_preempt_depth()	rcu_preempt_depth()
++#else
++static inline int sched_rcu_preempt_depth(void) { return 0; }
++#endif
+ 
+ #else /* #ifdef CONFIG_PREEMPT_RCU */
+ 
+@@ -79,6 +84,8 @@ static inline int rcu_preempt_depth(void)
+ 	return 0;
+ }
+ 
++#define sched_rcu_preempt_depth()	rcu_preempt_depth()
++
+ #endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+ 
+ /* Internal to kernel */
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 81bc9efbd191..2f689b4fa68b 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -7878,7 +7878,7 @@ void __init sched_init(void)
+ #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+ static inline int preempt_count_equals(int preempt_offset)
+ {
+-	int nested = preempt_count() + rcu_preempt_depth();
++	int nested = preempt_count() + sched_rcu_preempt_depth();
+ 
+ 	return (nested == preempt_offset);
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0218-sched-Disable-TTWU_QUEUE-on-RT.patch b/debian/patches-rt/0218-sched-Disable-TTWU_QUEUE-on-RT.patch
new file mode 100644
index 000000000..77eb3b029
--- /dev/null
+++ b/debian/patches-rt/0218-sched-Disable-TTWU_QUEUE-on-RT.patch
@@ -0,0 +1,38 @@
+From 5b867d72795af288909e6370aabef927a70c8d78 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 13 Sep 2011 16:42:35 +0200
+Subject: [PATCH 218/323] sched: Disable TTWU_QUEUE on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The queued remote wakeup mechanism can introduce rather large
+latencies if the number of migrated tasks is high. Disable it for RT.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ kernel/sched/features.h | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/kernel/sched/features.h b/kernel/sched/features.h
+index f1bf5e12d889..402fd37fb340 100644
+--- a/kernel/sched/features.h
++++ b/kernel/sched/features.h
+@@ -45,11 +45,16 @@ SCHED_FEAT(DOUBLE_TICK, false)
+  */
+ SCHED_FEAT(NONTASK_CAPACITY, true)
+ 
++#ifdef CONFIG_PREEMPT_RT
++SCHED_FEAT(TTWU_QUEUE, false)
++#else
++
+ /*
+  * Queue remote wakeups on the target CPU and process them
+  * using the scheduler IPI. Reduces rq->lock contention/bounces.
+  */
+ SCHED_FEAT(TTWU_QUEUE, true)
++#endif
+ 
+ /*
+  * When doing wakeups, attempt to limit superfluous scans of the LLC domain.
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0219-softirq-Check-preemption-after-reenabling-interrupts.patch b/debian/patches-rt/0219-softirq-Check-preemption-after-reenabling-interrupts.patch
new file mode 100644
index 000000000..173c118c2
--- /dev/null
+++ b/debian/patches-rt/0219-softirq-Check-preemption-after-reenabling-interrupts.patch
@@ -0,0 +1,151 @@
+From c63275b524df4d3556c7cf1690bc874d4a8cd72e Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Sun, 13 Nov 2011 17:17:09 +0100
+Subject: [PATCH 219/323] softirq: Check preemption after reenabling interrupts
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+raise_softirq_irqoff() disables interrupts and wakes the softirq
+daemon, but after reenabling interrupts there is no preemption check,
+so the execution of the softirq thread might be delayed arbitrarily.
+
+In principle we could add that check to local_irq_enable/restore, but
+that's overkill as the rasie_softirq_irqoff() sections are the only
+ones which show this behaviour.
+
+Reported-by: Carsten Emde <cbe@osadl.org>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/preempt.h | 3 +++
+ lib/irq_poll.c          | 5 +++++
+ net/core/dev.c          | 7 +++++++
+ 3 files changed, 15 insertions(+)
+
+diff --git a/include/linux/preempt.h b/include/linux/preempt.h
+index 5ceac863e729..fb140e00f74d 100644
+--- a/include/linux/preempt.h
++++ b/include/linux/preempt.h
+@@ -190,8 +190,10 @@ do { \
+ 
+ #ifdef CONFIG_PREEMPT_RT
+ # define preempt_enable_no_resched() sched_preempt_enable_no_resched()
++# define preempt_check_resched_rt() preempt_check_resched()
+ #else
+ # define preempt_enable_no_resched() preempt_enable()
++# define preempt_check_resched_rt() barrier();
+ #endif
+ 
+ #define preemptible()	(preempt_count() == 0 && !irqs_disabled())
+@@ -262,6 +264,7 @@ do { \
+ #define preempt_disable_notrace()		barrier()
+ #define preempt_enable_no_resched_notrace()	barrier()
+ #define preempt_enable_notrace()		barrier()
++#define preempt_check_resched_rt()		barrier()
+ #define preemptible()				0
+ 
+ #endif /* CONFIG_PREEMPT_COUNT */
+diff --git a/lib/irq_poll.c b/lib/irq_poll.c
+index 2f17b488d58e..7557bf7ecf1f 100644
+--- a/lib/irq_poll.c
++++ b/lib/irq_poll.c
+@@ -37,6 +37,7 @@ void irq_poll_sched(struct irq_poll *iop)
+ 	list_add_tail(&iop->list, this_cpu_ptr(&blk_cpu_iopoll));
+ 	raise_softirq_irqoff(IRQ_POLL_SOFTIRQ);
+ 	local_irq_restore(flags);
++	preempt_check_resched_rt();
+ }
+ EXPORT_SYMBOL(irq_poll_sched);
+ 
+@@ -72,6 +73,7 @@ void irq_poll_complete(struct irq_poll *iop)
+ 	local_irq_save(flags);
+ 	__irq_poll_complete(iop);
+ 	local_irq_restore(flags);
++	preempt_check_resched_rt();
+ }
+ EXPORT_SYMBOL(irq_poll_complete);
+ 
+@@ -96,6 +98,7 @@ static void __latent_entropy irq_poll_softirq(struct softirq_action *h)
+ 		}
+ 
+ 		local_irq_enable();
++		preempt_check_resched_rt();
+ 
+ 		/* Even though interrupts have been re-enabled, this
+ 		 * access is safe because interrupts can only add new
+@@ -133,6 +136,7 @@ static void __latent_entropy irq_poll_softirq(struct softirq_action *h)
+ 		__raise_softirq_irqoff(IRQ_POLL_SOFTIRQ);
+ 
+ 	local_irq_enable();
++	preempt_check_resched_rt();
+ }
+ 
+ /**
+@@ -196,6 +200,7 @@ static int irq_poll_cpu_dead(unsigned int cpu)
+ 			 this_cpu_ptr(&blk_cpu_iopoll));
+ 	__raise_softirq_irqoff(IRQ_POLL_SOFTIRQ);
+ 	local_irq_enable();
++	preempt_check_resched_rt();
+ 
+ 	return 0;
+ }
+diff --git a/net/core/dev.c b/net/core/dev.c
+index 3fc27b52bf42..3f23ac2ad497 100644
+--- a/net/core/dev.c
++++ b/net/core/dev.c
+@@ -3052,6 +3052,7 @@ static void __netif_reschedule(struct Qdisc *q)
+ 	sd->output_queue_tailp = &q->next_sched;
+ 	raise_softirq_irqoff(NET_TX_SOFTIRQ);
+ 	local_irq_restore(flags);
++	preempt_check_resched_rt();
+ }
+ 
+ void __netif_schedule(struct Qdisc *q)
+@@ -3114,6 +3115,7 @@ void __dev_kfree_skb_irq(struct sk_buff *skb, enum skb_free_reason reason)
+ 	__this_cpu_write(softnet_data.completion_queue, skb);
+ 	raise_softirq_irqoff(NET_TX_SOFTIRQ);
+ 	local_irq_restore(flags);
++	preempt_check_resched_rt();
+ }
+ EXPORT_SYMBOL(__dev_kfree_skb_irq);
+ 
+@@ -4596,6 +4598,7 @@ static int enqueue_to_backlog(struct sk_buff *skb, int cpu,
+ 	rps_unlock(sd);
+ 
+ 	local_irq_restore(flags);
++	preempt_check_resched_rt();
+ 
+ 	atomic_long_inc(&skb->dev->rx_dropped);
+ 	kfree_skb(skb);
+@@ -6348,12 +6351,14 @@ static void net_rps_action_and_irq_enable(struct softnet_data *sd)
+ 		sd->rps_ipi_list = NULL;
+ 
+ 		local_irq_enable();
++		preempt_check_resched_rt();
+ 
+ 		/* Send pending IPI's to kick RPS processing on remote cpus. */
+ 		net_rps_send_ipi(remsd);
+ 	} else
+ #endif
+ 		local_irq_enable();
++	preempt_check_resched_rt();
+ }
+ 
+ static bool sd_has_rps_ipi_waiting(struct softnet_data *sd)
+@@ -6431,6 +6436,7 @@ void __napi_schedule(struct napi_struct *n)
+ 	local_irq_save(flags);
+ 	____napi_schedule(this_cpu_ptr(&softnet_data), n);
+ 	local_irq_restore(flags);
++	preempt_check_resched_rt();
+ }
+ EXPORT_SYMBOL(__napi_schedule);
+ 
+@@ -10962,6 +10968,7 @@ static int dev_cpu_dead(unsigned int oldcpu)
+ 
+ 	raise_softirq_irqoff(NET_TX_SOFTIRQ);
+ 	local_irq_enable();
++	preempt_check_resched_rt();
+ 
+ #ifdef CONFIG_RPS
+ 	remsd = oldsd->rps_ipi_list;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0220-softirq-Disable-softirq-stacks-for-RT.patch b/debian/patches-rt/0220-softirq-Disable-softirq-stacks-for-RT.patch
new file mode 100644
index 000000000..90e5f9abf
--- /dev/null
+++ b/debian/patches-rt/0220-softirq-Disable-softirq-stacks-for-RT.patch
@@ -0,0 +1,168 @@
+From 539938b186e370ddf9bfc1d68703cfddf80a3f42 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Mon, 18 Jul 2011 13:59:17 +0200
+Subject: [PATCH 220/323] softirq: Disable softirq stacks for RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Disable extra stacks for softirqs. We want to preempt softirqs and
+having them on special IRQ-stack does not make this easier.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ arch/powerpc/kernel/irq.c     | 2 ++
+ arch/powerpc/kernel/misc_32.S | 2 ++
+ arch/powerpc/kernel/misc_64.S | 2 ++
+ arch/sh/kernel/irq.c          | 2 ++
+ arch/sparc/kernel/irq_64.c    | 2 ++
+ arch/x86/kernel/irq_32.c      | 2 ++
+ arch/x86/kernel/irq_64.c      | 2 ++
+ include/linux/interrupt.h     | 2 +-
+ 8 files changed, 15 insertions(+), 1 deletion(-)
+
+diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
+index e8a548447dd6..5ad4f27cba10 100644
+--- a/arch/powerpc/kernel/irq.c
++++ b/arch/powerpc/kernel/irq.c
+@@ -753,10 +753,12 @@ void *mcheckirq_ctx[NR_CPUS] __read_mostly;
+ void *softirq_ctx[NR_CPUS] __read_mostly;
+ void *hardirq_ctx[NR_CPUS] __read_mostly;
+ 
++#ifndef CONFIG_PREEMPT_RT
+ void do_softirq_own_stack(void)
+ {
+ 	call_do_softirq(softirq_ctx[smp_processor_id()]);
+ }
++#endif
+ 
+ irq_hw_number_t virq_to_hw(unsigned int virq)
+ {
+diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
+index 717e658b90fd..08ee95ad6593 100644
+--- a/arch/powerpc/kernel/misc_32.S
++++ b/arch/powerpc/kernel/misc_32.S
+@@ -31,6 +31,7 @@
+  * We store the saved ksp_limit in the unused part
+  * of the STACK_FRAME_OVERHEAD
+  */
++#ifndef CONFIG_PREEMPT_RT
+ _GLOBAL(call_do_softirq)
+ 	mflr	r0
+ 	stw	r0,4(r1)
+@@ -46,6 +47,7 @@ _GLOBAL(call_do_softirq)
+ 	stw	r10,THREAD+KSP_LIMIT(r2)
+ 	mtlr	r0
+ 	blr
++#endif
+ 
+ /*
+  * void call_do_irq(struct pt_regs *regs, void *sp);
+diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
+index 070465825c21..a6b33f7b3264 100644
+--- a/arch/powerpc/kernel/misc_64.S
++++ b/arch/powerpc/kernel/misc_64.S
+@@ -27,6 +27,7 @@
+ 
+ 	.text
+ 
++#ifndef CONFIG_PREEMPT_RT
+ _GLOBAL(call_do_softirq)
+ 	mflr	r0
+ 	std	r0,16(r1)
+@@ -37,6 +38,7 @@ _GLOBAL(call_do_softirq)
+ 	ld	r0,16(r1)
+ 	mtlr	r0
+ 	blr
++#endif
+ 
+ _GLOBAL(call_do_irq)
+ 	mflr	r0
+diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
+index ab5f790b0cd2..5db7af565dec 100644
+--- a/arch/sh/kernel/irq.c
++++ b/arch/sh/kernel/irq.c
+@@ -148,6 +148,7 @@ void irq_ctx_exit(int cpu)
+ 	hardirq_ctx[cpu] = NULL;
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT
+ void do_softirq_own_stack(void)
+ {
+ 	struct thread_info *curctx;
+@@ -175,6 +176,7 @@ void do_softirq_own_stack(void)
+ 		  "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
+ 	);
+ }
++#endif
+ #else
+ static inline void handle_one_irq(unsigned int irq)
+ {
+diff --git a/arch/sparc/kernel/irq_64.c b/arch/sparc/kernel/irq_64.c
+index 3ec9f1402aad..eb21682abfcb 100644
+--- a/arch/sparc/kernel/irq_64.c
++++ b/arch/sparc/kernel/irq_64.c
+@@ -854,6 +854,7 @@ void __irq_entry handler_irq(int pil, struct pt_regs *regs)
+ 	set_irq_regs(old_regs);
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT
+ void do_softirq_own_stack(void)
+ {
+ 	void *orig_sp, *sp = softirq_stack[smp_processor_id()];
+@@ -868,6 +869,7 @@ void do_softirq_own_stack(void)
+ 	__asm__ __volatile__("mov %0, %%sp"
+ 			     : : "r" (orig_sp));
+ }
++#endif
+ 
+ #ifdef CONFIG_HOTPLUG_CPU
+ void fixup_irqs(void)
+diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
+index 0b79efc87be5..93c6b88b382a 100644
+--- a/arch/x86/kernel/irq_32.c
++++ b/arch/x86/kernel/irq_32.c
+@@ -131,6 +131,7 @@ int irq_init_percpu_irqstack(unsigned int cpu)
+ 	return 0;
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT
+ void do_softirq_own_stack(void)
+ {
+ 	struct irq_stack *irqstk;
+@@ -147,6 +148,7 @@ void do_softirq_own_stack(void)
+ 
+ 	call_on_stack(__do_softirq, isp);
+ }
++#endif
+ 
+ void __handle_irq(struct irq_desc *desc, struct pt_regs *regs)
+ {
+diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
+index 440eed558558..7cfc4e6b7c94 100644
+--- a/arch/x86/kernel/irq_64.c
++++ b/arch/x86/kernel/irq_64.c
+@@ -72,7 +72,9 @@ int irq_init_percpu_irqstack(unsigned int cpu)
+ 	return map_irq_stack(cpu);
+ }
+ 
++#ifndef CONFIG_PREEMPT_RT
+ void do_softirq_own_stack(void)
+ {
+ 	run_on_irqstack_cond(__do_softirq, NULL);
+ }
++#endif
+diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
+index a1c64d969532..7f185482ea22 100644
+--- a/include/linux/interrupt.h
++++ b/include/linux/interrupt.h
+@@ -564,7 +564,7 @@ struct softirq_action
+ asmlinkage void do_softirq(void);
+ asmlinkage void __do_softirq(void);
+ 
+-#ifdef __ARCH_HAS_DO_SOFTIRQ
++#if defined(__ARCH_HAS_DO_SOFTIRQ) && !defined(CONFIG_PREEMPT_RT)
+ void do_softirq_own_stack(void);
+ #else
+ static inline void do_softirq_own_stack(void)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0221-net-core-use-local_bh_disable-in-netif_rx_ni.patch b/debian/patches-rt/0221-net-core-use-local_bh_disable-in-netif_rx_ni.patch
new file mode 100644
index 000000000..aeba8e9de
--- /dev/null
+++ b/debian/patches-rt/0221-net-core-use-local_bh_disable-in-netif_rx_ni.patch
@@ -0,0 +1,41 @@
+From 3f41204b42e2804a8eff4dbae9f811c5112a5e49 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 16 Jun 2017 19:03:16 +0200
+Subject: [PATCH 221/323] net/core: use local_bh_disable() in netif_rx_ni()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+In 2004 netif_rx_ni() gained a preempt_disable() section around
+netif_rx() and its do_softirq() + testing for it. The do_softirq() part
+is required because netif_rx() raises the softirq but does not invoke
+it. The preempt_disable() is required to remain on the same CPU which added the
+skb to the per-CPU list.
+All this can be avoided be putting this into a local_bh_disable()ed
+section. The local_bh_enable() part will invoke do_softirq() if
+required.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ net/core/dev.c | 6 ++----
+ 1 file changed, 2 insertions(+), 4 deletions(-)
+
+diff --git a/net/core/dev.c b/net/core/dev.c
+index 3f23ac2ad497..f973f53c7a1f 100644
+--- a/net/core/dev.c
++++ b/net/core/dev.c
+@@ -4870,11 +4870,9 @@ int netif_rx_ni(struct sk_buff *skb)
+ 
+ 	trace_netif_rx_ni_entry(skb);
+ 
+-	preempt_disable();
++	local_bh_disable();
+ 	err = netif_rx_internal(skb);
+-	if (local_softirq_pending())
+-		do_softirq();
+-	preempt_enable();
++	local_bh_enable();
+ 	trace_netif_rx_ni_exit(err);
+ 
+ 	return err;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0222-pid.h-include-atomic.h.patch b/debian/patches-rt/0222-pid.h-include-atomic.h.patch
new file mode 100644
index 000000000..159e5afbe
--- /dev/null
+++ b/debian/patches-rt/0222-pid.h-include-atomic.h.patch
@@ -0,0 +1,43 @@
+From 281d6228df38fdd331290ccf7753daee6ee7e520 Mon Sep 17 00:00:00 2001
+From: Grygorii Strashko <Grygorii.Strashko@linaro.org>
+Date: Tue, 21 Jul 2015 19:43:56 +0300
+Subject: [PATCH 222/323] pid.h: include atomic.h
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+This patch fixes build error:
+  CC      kernel/pid_namespace.o
+In file included from kernel/pid_namespace.c:11:0:
+include/linux/pid.h: In function 'get_pid':
+include/linux/pid.h:78:3: error: implicit declaration of function 'atomic_inc' [-Werror=implicit-function-declaration]
+   atomic_inc(&pid->count);
+   ^
+which happens when
+ CONFIG_PROVE_LOCKING=n
+ CONFIG_DEBUG_SPINLOCK=n
+ CONFIG_DEBUG_MUTEXES=n
+ CONFIG_DEBUG_LOCK_ALLOC=n
+ CONFIG_PID_NS=y
+
+Vanilla gets this via spinlock.h.
+
+Signed-off-by: Grygorii Strashko <Grygorii.Strashko@linaro.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/pid.h | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/include/linux/pid.h b/include/linux/pid.h
+index fa10acb8d6a4..2f86f84e9fc1 100644
+--- a/include/linux/pid.h
++++ b/include/linux/pid.h
+@@ -3,6 +3,7 @@
+ #define _LINUX_PID_H
+ 
+ #include <linux/rculist.h>
++#include <linux/atomic.h>
+ #include <linux/wait.h>
+ #include <linux/refcount.h>
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0223-ptrace-fix-ptrace-vs-tasklist_lock-race.patch b/debian/patches-rt/0223-ptrace-fix-ptrace-vs-tasklist_lock-race.patch
new file mode 100644
index 000000000..efff232da
--- /dev/null
+++ b/debian/patches-rt/0223-ptrace-fix-ptrace-vs-tasklist_lock-race.patch
@@ -0,0 +1,166 @@
+From 2b742ac53e22db703a46b21ff3817c797b7cb071 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Thu, 29 Aug 2013 18:21:04 +0200
+Subject: [PATCH 223/323] ptrace: fix ptrace vs tasklist_lock race
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+As explained by Alexander Fyodorov <halcy@yandex.ru>:
+
+|read_lock(&tasklist_lock) in ptrace_stop() is converted to mutex on RT kernel,
+|and it can remove __TASK_TRACED from task->state (by moving  it to
+|task->saved_state). If parent does wait() on child followed by a sys_ptrace
+|call, the following race can happen:
+|
+|- child sets __TASK_TRACED in ptrace_stop()
+|- parent does wait() which eventually calls wait_task_stopped() and returns
+|  child's pid
+|- child blocks on read_lock(&tasklist_lock) in ptrace_stop() and moves
+|  __TASK_TRACED flag to saved_state
+|- parent calls sys_ptrace, which calls ptrace_check_attach() and wait_task_inactive()
+
+The patch is based on his initial patch where an additional check is
+added in case the __TASK_TRACED moved to ->saved_state. The pi_lock is
+taken in case the caller is interrupted between looking into ->state and
+->saved_state.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/sched.h | 49 +++++++++++++++++++++++++++++++++++++++----
+ kernel/ptrace.c       |  9 +++++++-
+ kernel/sched/core.c   | 17 +++++++++++++--
+ 3 files changed, 68 insertions(+), 7 deletions(-)
+
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index d259126f46cf..bd0c9c633438 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -112,12 +112,8 @@ struct io_uring_task;
+ 					 __TASK_TRACED | EXIT_DEAD | EXIT_ZOMBIE | \
+ 					 TASK_PARKED)
+ 
+-#define task_is_traced(task)		((task->state & __TASK_TRACED) != 0)
+-
+ #define task_is_stopped(task)		((task->state & __TASK_STOPPED) != 0)
+ 
+-#define task_is_stopped_or_traced(task)	((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0)
+-
+ #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+ 
+ /*
+@@ -1886,6 +1882,51 @@ static inline int test_tsk_need_resched(struct task_struct *tsk)
+ 	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
+ }
+ 
++static inline bool __task_is_stopped_or_traced(struct task_struct *task)
++{
++	if (task->state & (__TASK_STOPPED | __TASK_TRACED))
++		return true;
++#ifdef CONFIG_PREEMPT_RT
++	if (task->saved_state & (__TASK_STOPPED | __TASK_TRACED))
++		return true;
++#endif
++	return false;
++}
++
++static inline bool task_is_stopped_or_traced(struct task_struct *task)
++{
++	bool traced_stopped;
++
++#ifdef CONFIG_PREEMPT_RT
++	unsigned long flags;
++
++	raw_spin_lock_irqsave(&task->pi_lock, flags);
++	traced_stopped = __task_is_stopped_or_traced(task);
++	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
++#else
++	traced_stopped = __task_is_stopped_or_traced(task);
++#endif
++	return traced_stopped;
++}
++
++static inline bool task_is_traced(struct task_struct *task)
++{
++	bool traced = false;
++
++	if (task->state & __TASK_TRACED)
++		return true;
++#ifdef CONFIG_PREEMPT_RT
++	/* in case the task is sleeping on tasklist_lock */
++	raw_spin_lock_irq(&task->pi_lock);
++	if (task->state & __TASK_TRACED)
++		traced = true;
++	else if (task->saved_state & __TASK_TRACED)
++		traced = true;
++	raw_spin_unlock_irq(&task->pi_lock);
++#endif
++	return traced;
++}
++
+ /*
+  * cond_resched() and cond_resched_lock(): latency reduction via
+  * explicit rescheduling in places that are safe. The return
+diff --git a/kernel/ptrace.c b/kernel/ptrace.c
+index aab480e24bd6..71acb6341e63 100644
+--- a/kernel/ptrace.c
++++ b/kernel/ptrace.c
+@@ -196,7 +196,14 @@ static bool ptrace_freeze_traced(struct task_struct *task)
+ 	spin_lock_irq(&task->sighand->siglock);
+ 	if (task_is_traced(task) && !looks_like_a_spurious_pid(task) &&
+ 	    !__fatal_signal_pending(task)) {
+-		task->state = __TASK_TRACED;
++		unsigned long flags;
++
++		raw_spin_lock_irqsave(&task->pi_lock, flags);
++		if (task->state & __TASK_TRACED)
++			task->state = __TASK_TRACED;
++		else
++			task->saved_state = __TASK_TRACED;
++		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+ 		ret = true;
+ 	}
+ 	spin_unlock_irq(&task->sighand->siglock);
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 2f689b4fa68b..8ac1f0526476 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -2587,6 +2587,18 @@ int migrate_swap(struct task_struct *cur, struct task_struct *p,
+ }
+ #endif /* CONFIG_NUMA_BALANCING */
+ 
++static bool check_task_state(struct task_struct *p, long match_state)
++{
++	bool match = false;
++
++	raw_spin_lock_irq(&p->pi_lock);
++	if (p->state == match_state || p->saved_state == match_state)
++		match = true;
++	raw_spin_unlock_irq(&p->pi_lock);
++
++	return match;
++}
++
+ /*
+  * wait_task_inactive - wait for a thread to unschedule.
+  *
+@@ -2631,7 +2643,7 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state)
+ 		 * is actually now running somewhere else!
+ 		 */
+ 		while (task_running(rq, p)) {
+-			if (match_state && unlikely(p->state != match_state))
++			if (match_state && !check_task_state(p, match_state))
+ 				return 0;
+ 			cpu_relax();
+ 		}
+@@ -2646,7 +2658,8 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state)
+ 		running = task_running(rq, p);
+ 		queued = task_on_rq_queued(p);
+ 		ncsw = 0;
+-		if (!match_state || p->state == match_state)
++		if (!match_state || p->state == match_state ||
++		    p->saved_state == match_state)
+ 			ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
+ 		task_rq_unlock(rq, p, &rf);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0224-ptrace-fix-ptrace_unfreeze_traced-race-with-rt-lock.patch b/debian/patches-rt/0224-ptrace-fix-ptrace_unfreeze_traced-race-with-rt-lock.patch
new file mode 100644
index 000000000..4e61137e3
--- /dev/null
+++ b/debian/patches-rt/0224-ptrace-fix-ptrace_unfreeze_traced-race-with-rt-lock.patch
@@ -0,0 +1,65 @@
+From 10d5d8e25cce1695bb99f7149038d97b9a160201 Mon Sep 17 00:00:00 2001
+From: Oleg Nesterov <oleg@redhat.com>
+Date: Tue, 3 Nov 2020 12:39:01 +0100
+Subject: [PATCH 224/323] ptrace: fix ptrace_unfreeze_traced() race with
+ rt-lock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The patch "ptrace: fix ptrace vs tasklist_lock race" changed
+ptrace_freeze_traced() to take task->saved_state into account, but
+ptrace_unfreeze_traced() has the same problem and needs a similar fix:
+it should check/update both ->state and ->saved_state.
+
+Reported-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+Fixes: "ptrace: fix ptrace vs tasklist_lock race"
+Signed-off-by: Oleg Nesterov <oleg@redhat.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Cc: stable-rt@vger.kernel.org
+---
+ kernel/ptrace.c | 23 +++++++++++++++--------
+ 1 file changed, 15 insertions(+), 8 deletions(-)
+
+diff --git a/kernel/ptrace.c b/kernel/ptrace.c
+index 71acb6341e63..fb5d1a19507d 100644
+--- a/kernel/ptrace.c
++++ b/kernel/ptrace.c
+@@ -213,8 +213,8 @@ static bool ptrace_freeze_traced(struct task_struct *task)
+ 
+ static void ptrace_unfreeze_traced(struct task_struct *task)
+ {
+-	if (task->state != __TASK_TRACED)
+-		return;
++	unsigned long flags;
++	bool frozen = true;
+ 
+ 	WARN_ON(!task->ptrace || task->parent != current);
+ 
+@@ -223,12 +223,19 @@ static void ptrace_unfreeze_traced(struct task_struct *task)
+ 	 * Recheck state under the lock to close this race.
+ 	 */
+ 	spin_lock_irq(&task->sighand->siglock);
+-	if (task->state == __TASK_TRACED) {
+-		if (__fatal_signal_pending(task))
+-			wake_up_state(task, __TASK_TRACED);
+-		else
+-			task->state = TASK_TRACED;
+-	}
++
++	raw_spin_lock_irqsave(&task->pi_lock, flags);
++	if (task->state == __TASK_TRACED)
++		task->state = TASK_TRACED;
++	else if (task->saved_state == __TASK_TRACED)
++		task->saved_state = TASK_TRACED;
++	else
++		frozen = false;
++	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
++
++	if (frozen && __fatal_signal_pending(task))
++		wake_up_state(task, __TASK_TRACED);
++
+ 	spin_unlock_irq(&task->sighand->siglock);
+ }
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0225-kernel-sched-add-put-get-_cpu_light.patch b/debian/patches-rt/0225-kernel-sched-add-put-get-_cpu_light.patch
new file mode 100644
index 000000000..6a6e0620c
--- /dev/null
+++ b/debian/patches-rt/0225-kernel-sched-add-put-get-_cpu_light.patch
@@ -0,0 +1,28 @@
+From f5e1368135f9f3d520828544dc31762f19f43848 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Sat, 27 May 2017 19:02:06 +0200
+Subject: [PATCH 225/323] kernel/sched: add {put|get}_cpu_light()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/smp.h | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/include/linux/smp.h b/include/linux/smp.h
+index 04f44e0aa2e0..cae66815f9e2 100644
+--- a/include/linux/smp.h
++++ b/include/linux/smp.h
+@@ -239,6 +239,9 @@ static inline int get_boot_cpu_id(void)
+ #define get_cpu()		({ preempt_disable(); __smp_processor_id(); })
+ #define put_cpu()		preempt_enable()
+ 
++#define get_cpu_light()		({ migrate_disable(); __smp_processor_id(); })
++#define put_cpu_light()		migrate_enable()
++
+ /*
+  * Callback to arch code if there's nosmp or maxcpus=0 on the
+  * boot command line:
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0226-trace-Add-migrate-disabled-counter-to-tracing-output.patch b/debian/patches-rt/0226-trace-Add-migrate-disabled-counter-to-tracing-output.patch
new file mode 100644
index 000000000..23ba35a68
--- /dev/null
+++ b/debian/patches-rt/0226-trace-Add-migrate-disabled-counter-to-tracing-output.patch
@@ -0,0 +1,123 @@
+From 61f802c21cb2e063c6e8b39e9f497f2d38440b5a Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Sun, 17 Jul 2011 21:56:42 +0200
+Subject: [PATCH 226/323] trace: Add migrate-disabled counter to tracing output
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/trace_events.h |  2 ++
+ kernel/trace/trace.c         | 26 +++++++++++++++++++-------
+ kernel/trace/trace_events.c  |  1 +
+ kernel/trace/trace_output.c  |  5 +++++
+ 4 files changed, 27 insertions(+), 7 deletions(-)
+
+diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
+index 2fea9fcd4d4e..2151524a10f0 100644
+--- a/include/linux/trace_events.h
++++ b/include/linux/trace_events.h
+@@ -69,6 +69,7 @@ struct trace_entry {
+ 	unsigned char		flags;
+ 	unsigned char		preempt_count;
+ 	int			pid;
++	unsigned char		migrate_disable;
+ };
+ 
+ #define TRACE_EVENT_TYPE_MAX						\
+@@ -157,6 +158,7 @@ static inline void tracing_generic_entry_update(struct trace_entry *entry,
+ 						unsigned int trace_ctx)
+ {
+ 	entry->preempt_count		= trace_ctx & 0xff;
++	entry->migrate_disable		= (trace_ctx >> 8) & 0xff;
+ 	entry->pid			= current->pid;
+ 	entry->type			= type;
+ 	entry->flags =			trace_ctx >> 16;
+diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
+index 5d6730589823..02dffb1862b8 100644
+--- a/kernel/trace/trace.c
++++ b/kernel/trace/trace.c
+@@ -2575,6 +2575,15 @@ enum print_line_t trace_handle_return(struct trace_seq *s)
+ }
+ EXPORT_SYMBOL_GPL(trace_handle_return);
+ 
++static unsigned short migration_disable_value(void)
++{
++#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
++	return current->migration_disabled;
++#else
++	return 0;
++#endif
++}
++
+ unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
+ {
+ 	unsigned int trace_flags = irqs_status;
+@@ -2593,7 +2602,8 @@ unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
+ 		trace_flags |= TRACE_FLAG_NEED_RESCHED;
+ 	if (test_preempt_need_resched())
+ 		trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
+-	return (trace_flags << 16) | (pc & 0xff);
++	return (trace_flags << 16) | (pc & 0xff) |
++		(migration_disable_value() & 0xff) << 8;
+ }
+ 
+ struct ring_buffer_event *
+@@ -3856,9 +3866,10 @@ static void print_lat_help_header(struct seq_file *m)
+ 		    "#                  | / _----=> need-resched    \n"
+ 		    "#                  || / _---=> hardirq/softirq \n"
+ 		    "#                  ||| / _--=> preempt-depth   \n"
+-		    "#                  |||| /     delay            \n"
+-		    "#  cmd     pid     ||||| time  |   caller      \n"
+-		    "#     \\   /        |||||  \\    |   /         \n");
++		    "#                  |||| / _-=> migrate-disable \n"
++		    "#                  ||||| /     delay           \n"
++		    "#  cmd     pid     |||||| time  |   caller     \n"
++		    "#     \\   /        ||||||  \\    |    /       \n");
+ }
+ 
+ static void print_event_info(struct array_buffer *buf, struct seq_file *m)
+@@ -3896,9 +3907,10 @@ static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file
+ 	seq_printf(m, "#                            %.*s / _----=> need-resched\n", prec, space);
+ 	seq_printf(m, "#                            %.*s| / _---=> hardirq/softirq\n", prec, space);
+ 	seq_printf(m, "#                            %.*s|| / _--=> preempt-depth\n", prec, space);
+-	seq_printf(m, "#                            %.*s||| /     delay\n", prec, space);
+-	seq_printf(m, "#           TASK-PID  %.*s CPU#  ||||   TIMESTAMP  FUNCTION\n", prec, "     TGID   ");
+-	seq_printf(m, "#              | |    %.*s   |   ||||      |         |\n", prec, "       |    ");
++	seq_printf(m, "#                            %.*s||| / _-=> migrate-disable\n", prec, space);
++	seq_printf(m, "#                            %.*s|||| /     delay\n", prec, space);
++	seq_printf(m, "#           TASK-PID  %.*s CPU#  |||||  TIMESTAMP  FUNCTION\n", prec, "     TGID   ");
++	seq_printf(m, "#              | |    %.*s   |   |||||     |         |\n", prec, "       |    ");
+ }
+ 
+ void
+diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
+index df64b92c5edc..636fb7df3714 100644
+--- a/kernel/trace/trace_events.c
++++ b/kernel/trace/trace_events.c
+@@ -184,6 +184,7 @@ static int trace_define_common_fields(void)
+ 	__common_field(unsigned char, flags);
+ 	__common_field(unsigned char, preempt_count);
+ 	__common_field(int, pid);
++	__common_field(unsigned char, migrate_disable);
+ 
+ 	return ret;
+ }
+diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
+index 94b0991717b6..b3619b21217c 100644
+--- a/kernel/trace/trace_output.c
++++ b/kernel/trace/trace_output.c
+@@ -497,6 +497,11 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
+ 	else
+ 		trace_seq_putc(s, '.');
+ 
++	if (entry->migrate_disable)
++		trace_seq_printf(s, "%x", entry->migrate_disable);
++	else
++		trace_seq_putc(s, '.');
++
+ 	return !trace_seq_has_overflowed(s);
+ }
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0227-locking-don-t-check-for-__LINUX_SPINLOCK_TYPES_H-on-.patch b/debian/patches-rt/0227-locking-don-t-check-for-__LINUX_SPINLOCK_TYPES_H-on-.patch
new file mode 100644
index 000000000..aeea997ea
--- /dev/null
+++ b/debian/patches-rt/0227-locking-don-t-check-for-__LINUX_SPINLOCK_TYPES_H-on-.patch
@@ -0,0 +1,166 @@
+From d9e2f0098c8afde2f68ff94ea5dcdf818bc454d9 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 4 Aug 2017 17:40:42 +0200
+Subject: [PATCH 227/323] locking: don't check for __LINUX_SPINLOCK_TYPES_H on
+ -RT archs
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Upstream uses arch_spinlock_t within spinlock_t and requests that
+spinlock_types.h header file is included first.
+On -RT we have the rt_mutex with its raw_lock wait_lock which needs
+architectures' spinlock_types.h header file for its definition. However
+we need rt_mutex first because it is used to build the spinlock_t so
+that check does not work for us.
+Therefore I am dropping that check.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/alpha/include/asm/spinlock_types.h   | 4 ----
+ arch/arm/include/asm/spinlock_types.h     | 4 ----
+ arch/arm64/include/asm/spinlock_types.h   | 4 ----
+ arch/hexagon/include/asm/spinlock_types.h | 4 ----
+ arch/ia64/include/asm/spinlock_types.h    | 4 ----
+ arch/powerpc/include/asm/spinlock_types.h | 4 ----
+ arch/s390/include/asm/spinlock_types.h    | 4 ----
+ arch/sh/include/asm/spinlock_types.h      | 4 ----
+ arch/xtensa/include/asm/spinlock_types.h  | 4 ----
+ 9 files changed, 36 deletions(-)
+
+diff --git a/arch/alpha/include/asm/spinlock_types.h b/arch/alpha/include/asm/spinlock_types.h
+index 1d5716bc060b..6883bc952d22 100644
+--- a/arch/alpha/include/asm/spinlock_types.h
++++ b/arch/alpha/include/asm/spinlock_types.h
+@@ -2,10 +2,6 @@
+ #ifndef _ALPHA_SPINLOCK_TYPES_H
+ #define _ALPHA_SPINLOCK_TYPES_H
+ 
+-#ifndef __LINUX_SPINLOCK_TYPES_H
+-# error "please don't include this file directly"
+-#endif
+-
+ typedef struct {
+ 	volatile unsigned int lock;
+ } arch_spinlock_t;
+diff --git a/arch/arm/include/asm/spinlock_types.h b/arch/arm/include/asm/spinlock_types.h
+index 5976958647fe..a37c0803954b 100644
+--- a/arch/arm/include/asm/spinlock_types.h
++++ b/arch/arm/include/asm/spinlock_types.h
+@@ -2,10 +2,6 @@
+ #ifndef __ASM_SPINLOCK_TYPES_H
+ #define __ASM_SPINLOCK_TYPES_H
+ 
+-#ifndef __LINUX_SPINLOCK_TYPES_H
+-# error "please don't include this file directly"
+-#endif
+-
+ #define TICKET_SHIFT	16
+ 
+ typedef struct {
+diff --git a/arch/arm64/include/asm/spinlock_types.h b/arch/arm64/include/asm/spinlock_types.h
+index 18782f0c4721..6672b05350b4 100644
+--- a/arch/arm64/include/asm/spinlock_types.h
++++ b/arch/arm64/include/asm/spinlock_types.h
+@@ -5,10 +5,6 @@
+ #ifndef __ASM_SPINLOCK_TYPES_H
+ #define __ASM_SPINLOCK_TYPES_H
+ 
+-#if !defined(__LINUX_SPINLOCK_TYPES_H) && !defined(__ASM_SPINLOCK_H)
+-# error "please don't include this file directly"
+-#endif
+-
+ #include <asm-generic/qspinlock_types.h>
+ #include <asm-generic/qrwlock_types.h>
+ 
+diff --git a/arch/hexagon/include/asm/spinlock_types.h b/arch/hexagon/include/asm/spinlock_types.h
+index 19d233497ba5..de72fb23016d 100644
+--- a/arch/hexagon/include/asm/spinlock_types.h
++++ b/arch/hexagon/include/asm/spinlock_types.h
+@@ -8,10 +8,6 @@
+ #ifndef _ASM_SPINLOCK_TYPES_H
+ #define _ASM_SPINLOCK_TYPES_H
+ 
+-#ifndef __LINUX_SPINLOCK_TYPES_H
+-# error "please don't include this file directly"
+-#endif
+-
+ typedef struct {
+ 	volatile unsigned int lock;
+ } arch_spinlock_t;
+diff --git a/arch/ia64/include/asm/spinlock_types.h b/arch/ia64/include/asm/spinlock_types.h
+index 6e345fefcdca..681408d6816f 100644
+--- a/arch/ia64/include/asm/spinlock_types.h
++++ b/arch/ia64/include/asm/spinlock_types.h
+@@ -2,10 +2,6 @@
+ #ifndef _ASM_IA64_SPINLOCK_TYPES_H
+ #define _ASM_IA64_SPINLOCK_TYPES_H
+ 
+-#ifndef __LINUX_SPINLOCK_TYPES_H
+-# error "please don't include this file directly"
+-#endif
+-
+ typedef struct {
+ 	volatile unsigned int lock;
+ } arch_spinlock_t;
+diff --git a/arch/powerpc/include/asm/spinlock_types.h b/arch/powerpc/include/asm/spinlock_types.h
+index c5d742f18021..cc6922a011ba 100644
+--- a/arch/powerpc/include/asm/spinlock_types.h
++++ b/arch/powerpc/include/asm/spinlock_types.h
+@@ -2,10 +2,6 @@
+ #ifndef _ASM_POWERPC_SPINLOCK_TYPES_H
+ #define _ASM_POWERPC_SPINLOCK_TYPES_H
+ 
+-#ifndef __LINUX_SPINLOCK_TYPES_H
+-# error "please don't include this file directly"
+-#endif
+-
+ #ifdef CONFIG_PPC_QUEUED_SPINLOCKS
+ #include <asm-generic/qspinlock_types.h>
+ #include <asm-generic/qrwlock_types.h>
+diff --git a/arch/s390/include/asm/spinlock_types.h b/arch/s390/include/asm/spinlock_types.h
+index cfed272e4fd5..8e28e8176ec8 100644
+--- a/arch/s390/include/asm/spinlock_types.h
++++ b/arch/s390/include/asm/spinlock_types.h
+@@ -2,10 +2,6 @@
+ #ifndef __ASM_SPINLOCK_TYPES_H
+ #define __ASM_SPINLOCK_TYPES_H
+ 
+-#ifndef __LINUX_SPINLOCK_TYPES_H
+-# error "please don't include this file directly"
+-#endif
+-
+ typedef struct {
+ 	int lock;
+ } __attribute__ ((aligned (4))) arch_spinlock_t;
+diff --git a/arch/sh/include/asm/spinlock_types.h b/arch/sh/include/asm/spinlock_types.h
+index e82369f286a2..22ca9a98bbb8 100644
+--- a/arch/sh/include/asm/spinlock_types.h
++++ b/arch/sh/include/asm/spinlock_types.h
+@@ -2,10 +2,6 @@
+ #ifndef __ASM_SH_SPINLOCK_TYPES_H
+ #define __ASM_SH_SPINLOCK_TYPES_H
+ 
+-#ifndef __LINUX_SPINLOCK_TYPES_H
+-# error "please don't include this file directly"
+-#endif
+-
+ typedef struct {
+ 	volatile unsigned int lock;
+ } arch_spinlock_t;
+diff --git a/arch/xtensa/include/asm/spinlock_types.h b/arch/xtensa/include/asm/spinlock_types.h
+index 64c9389254f1..dc846323b1cd 100644
+--- a/arch/xtensa/include/asm/spinlock_types.h
++++ b/arch/xtensa/include/asm/spinlock_types.h
+@@ -2,10 +2,6 @@
+ #ifndef __ASM_SPINLOCK_TYPES_H
+ #define __ASM_SPINLOCK_TYPES_H
+ 
+-#if !defined(__LINUX_SPINLOCK_TYPES_H) && !defined(__ASM_SPINLOCK_H)
+-# error "please don't include this file directly"
+-#endif
+-
+ #include <asm-generic/qspinlock_types.h>
+ #include <asm-generic/qrwlock_types.h>
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0228-locking-Make-spinlock_t-and-rwlock_t-a-RCU-section-o.patch b/debian/patches-rt/0228-locking-Make-spinlock_t-and-rwlock_t-a-RCU-section-o.patch
new file mode 100644
index 000000000..77ce72c24
--- /dev/null
+++ b/debian/patches-rt/0228-locking-Make-spinlock_t-and-rwlock_t-a-RCU-section-o.patch
@@ -0,0 +1,126 @@
+From 166485c3d38dd51a1a9a35edb7b2d3c1054a2418 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 19 Nov 2019 09:25:04 +0100
+Subject: [PATCH 228/323] locking: Make spinlock_t and rwlock_t a RCU section
+ on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+On !RT a locked spinlock_t and rwlock_t disables preemption which
+implies a RCU read section. There is code that relies on that behaviour.
+
+Add an explicit RCU read section on RT while a sleeping lock (a lock
+which would disables preemption on !RT) acquired.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/locking/rtmutex.c   | 6 ++++++
+ kernel/locking/rwlock-rt.c | 6 ++++++
+ 2 files changed, 12 insertions(+)
+
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index 2fe178651254..31b374d36d04 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -1136,6 +1136,7 @@ void __lockfunc rt_spin_lock(spinlock_t *lock)
+ {
+ 	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+ 	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
++	rcu_read_lock();
+ 	migrate_disable();
+ }
+ EXPORT_SYMBOL(rt_spin_lock);
+@@ -1150,6 +1151,7 @@ void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass)
+ {
+ 	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+ 	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
++	rcu_read_lock();
+ 	migrate_disable();
+ }
+ EXPORT_SYMBOL(rt_spin_lock_nested);
+@@ -1159,6 +1161,7 @@ void __lockfunc rt_spin_lock_nest_lock(spinlock_t *lock,
+ {
+ 	spin_acquire_nest(&lock->dep_map, 0, 0, nest_lock, _RET_IP_);
+ 	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
++	rcu_read_lock();
+ 	migrate_disable();
+ }
+ EXPORT_SYMBOL(rt_spin_lock_nest_lock);
+@@ -1169,6 +1172,7 @@ void __lockfunc rt_spin_unlock(spinlock_t *lock)
+ 	/* NOTE: we always pass in '1' for nested, for simplicity */
+ 	spin_release(&lock->dep_map, _RET_IP_);
+ 	migrate_enable();
++	rcu_read_unlock();
+ 	rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock);
+ }
+ EXPORT_SYMBOL(rt_spin_unlock);
+@@ -1198,6 +1202,7 @@ int __lockfunc rt_spin_trylock(spinlock_t *lock)
+ 	ret = __rt_mutex_trylock(&lock->lock);
+ 	if (ret) {
+ 		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
++		rcu_read_lock();
+ 		migrate_disable();
+ 	}
+ 	return ret;
+@@ -1212,6 +1217,7 @@ int __lockfunc rt_spin_trylock_bh(spinlock_t *lock)
+ 	ret = __rt_mutex_trylock(&lock->lock);
+ 	if (ret) {
+ 		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
++		rcu_read_lock();
+ 		migrate_disable();
+ 	} else {
+ 		local_bh_enable();
+diff --git a/kernel/locking/rwlock-rt.c b/kernel/locking/rwlock-rt.c
+index 16be7111aae7..3d2d1f14b513 100644
+--- a/kernel/locking/rwlock-rt.c
++++ b/kernel/locking/rwlock-rt.c
+@@ -270,6 +270,7 @@ int __lockfunc rt_read_trylock(rwlock_t *rwlock)
+ 	ret = __read_rt_trylock(rwlock);
+ 	if (ret) {
+ 		rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_);
++		rcu_read_lock();
+ 		migrate_disable();
+ 	}
+ 	return ret;
+@@ -283,6 +284,7 @@ int __lockfunc rt_write_trylock(rwlock_t *rwlock)
+ 	ret = __write_rt_trylock(rwlock);
+ 	if (ret) {
+ 		rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
++		rcu_read_lock();
+ 		migrate_disable();
+ 	}
+ 	return ret;
+@@ -293,6 +295,7 @@ void __lockfunc rt_read_lock(rwlock_t *rwlock)
+ {
+ 	rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_);
+ 	__read_rt_lock(rwlock);
++	rcu_read_lock();
+ 	migrate_disable();
+ }
+ EXPORT_SYMBOL(rt_read_lock);
+@@ -301,6 +304,7 @@ void __lockfunc rt_write_lock(rwlock_t *rwlock)
+ {
+ 	rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
+ 	__write_rt_lock(rwlock);
++	rcu_read_lock();
+ 	migrate_disable();
+ }
+ EXPORT_SYMBOL(rt_write_lock);
+@@ -309,6 +313,7 @@ void __lockfunc rt_read_unlock(rwlock_t *rwlock)
+ {
+ 	rwlock_release(&rwlock->dep_map, _RET_IP_);
+ 	migrate_enable();
++	rcu_read_unlock();
+ 	__read_rt_unlock(rwlock);
+ }
+ EXPORT_SYMBOL(rt_read_unlock);
+@@ -317,6 +322,7 @@ void __lockfunc rt_write_unlock(rwlock_t *rwlock)
+ {
+ 	rwlock_release(&rwlock->dep_map, _RET_IP_);
+ 	migrate_enable();
++	rcu_read_unlock();
+ 	__write_rt_unlock(rwlock);
+ }
+ EXPORT_SYMBOL(rt_write_unlock);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0229-mm-vmalloc-Another-preempt-disable-region-which-suck.patch b/debian/patches-rt/0229-mm-vmalloc-Another-preempt-disable-region-which-suck.patch
new file mode 100644
index 000000000..c699a1ab7
--- /dev/null
+++ b/debian/patches-rt/0229-mm-vmalloc-Another-preempt-disable-region-which-suck.patch
@@ -0,0 +1,73 @@
+From 61aced1d729a22bbaf66e1f68806e04058bafb3f Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 12 Jul 2011 11:39:36 +0200
+Subject: [PATCH 229/323] mm/vmalloc: Another preempt disable region which
+ sucks
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Avoid the preempt disable version of get_cpu_var(). The inner-lock should
+provide enough serialisation.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ mm/vmalloc.c | 13 ++++++++-----
+ 1 file changed, 8 insertions(+), 5 deletions(-)
+
+diff --git a/mm/vmalloc.c b/mm/vmalloc.c
+index d6a4794fa8ca..8113e4f0d2f2 100644
+--- a/mm/vmalloc.c
++++ b/mm/vmalloc.c
+@@ -1542,7 +1542,7 @@ static void *new_vmap_block(unsigned int order, gfp_t gfp_mask)
+ 	struct vmap_block *vb;
+ 	struct vmap_area *va;
+ 	unsigned long vb_idx;
+-	int node, err;
++	int node, err, cpu;
+ 	void *vaddr;
+ 
+ 	node = numa_node_id();
+@@ -1579,11 +1579,12 @@ static void *new_vmap_block(unsigned int order, gfp_t gfp_mask)
+ 		return ERR_PTR(err);
+ 	}
+ 
+-	vbq = &get_cpu_var(vmap_block_queue);
++	cpu = get_cpu_light();
++	vbq = this_cpu_ptr(&vmap_block_queue);
+ 	spin_lock(&vbq->lock);
+ 	list_add_tail_rcu(&vb->free_list, &vbq->free);
+ 	spin_unlock(&vbq->lock);
+-	put_cpu_var(vmap_block_queue);
++	put_cpu_light();
+ 
+ 	return vaddr;
+ }
+@@ -1648,6 +1649,7 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
+ 	struct vmap_block *vb;
+ 	void *vaddr = NULL;
+ 	unsigned int order;
++	int cpu;
+ 
+ 	BUG_ON(offset_in_page(size));
+ 	BUG_ON(size > PAGE_SIZE*VMAP_MAX_ALLOC);
+@@ -1662,7 +1664,8 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
+ 	order = get_order(size);
+ 
+ 	rcu_read_lock();
+-	vbq = &get_cpu_var(vmap_block_queue);
++	cpu = get_cpu_light();
++	vbq = this_cpu_ptr(&vmap_block_queue);
+ 	list_for_each_entry_rcu(vb, &vbq->free, free_list) {
+ 		unsigned long pages_off;
+ 
+@@ -1685,7 +1688,7 @@ static void *vb_alloc(unsigned long size, gfp_t gfp_mask)
+ 		break;
+ 	}
+ 
+-	put_cpu_var(vmap_block_queue);
++	put_cpu_light();
+ 	rcu_read_unlock();
+ 
+ 	/* Allocate new block if nothing was found */
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0230-block-mq-do-not-invoke-preempt_disable.patch b/debian/patches-rt/0230-block-mq-do-not-invoke-preempt_disable.patch
new file mode 100644
index 000000000..d1f8234d5
--- /dev/null
+++ b/debian/patches-rt/0230-block-mq-do-not-invoke-preempt_disable.patch
@@ -0,0 +1,40 @@
+From 0470292c7761cc1cd2847e60b43b202b1be7ee29 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 14 Jul 2015 14:26:34 +0200
+Subject: [PATCH 230/323] block/mq: do not invoke preempt_disable()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+preempt_disable() and get_cpu() don't play well together with the sleeping
+locks it tries to allocate later.
+It seems to be enough to replace it with get_cpu_light() and migrate_disable().
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ block/blk-mq.c | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/block/blk-mq.c b/block/blk-mq.c
+index a6618bf45992..37466b3a4ba5 100644
+--- a/block/blk-mq.c
++++ b/block/blk-mq.c
+@@ -1575,14 +1575,14 @@ static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async,
+ 		return;
+ 
+ 	if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
+-		int cpu = get_cpu();
++		int cpu = get_cpu_light();
+ 		if (cpumask_test_cpu(cpu, hctx->cpumask)) {
+ 			__blk_mq_run_hw_queue(hctx);
+-			put_cpu();
++			put_cpu_light();
+ 			return;
+ 		}
+ 
+-		put_cpu();
++		put_cpu_light();
+ 	}
+ 
+ 	kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0231-md-raid5-Make-raid5_percpu-handling-RT-aware.patch b/debian/patches-rt/0231-md-raid5-Make-raid5_percpu-handling-RT-aware.patch
new file mode 100644
index 000000000..33a40d5fc
--- /dev/null
+++ b/debian/patches-rt/0231-md-raid5-Make-raid5_percpu-handling-RT-aware.patch
@@ -0,0 +1,69 @@
+From 4af1829664e98b9b3ec542a03ee30aeee8f47f6c Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 6 Apr 2010 16:51:31 +0200
+Subject: [PATCH 231/323] md: raid5: Make raid5_percpu handling RT aware
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+__raid_run_ops() disables preemption with get_cpu() around the access
+to the raid5_percpu variables. That causes scheduling while atomic
+spews on RT.
+
+Serialize the access to the percpu data with a lock and keep the code
+preemptible.
+
+Reported-by: Udo van den Heuvel <udovdh@xs4all.nl>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Udo van den Heuvel <udovdh@xs4all.nl>
+---
+ drivers/md/raid5.c | 7 +++++--
+ drivers/md/raid5.h | 1 +
+ 2 files changed, 6 insertions(+), 2 deletions(-)
+
+diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
+index 9f114b9d8dc6..7e0eb8defeaf 100644
+--- a/drivers/md/raid5.c
++++ b/drivers/md/raid5.c
+@@ -2218,8 +2218,9 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
+ 	struct raid5_percpu *percpu;
+ 	unsigned long cpu;
+ 
+-	cpu = get_cpu();
++	cpu = get_cpu_light();
+ 	percpu = per_cpu_ptr(conf->percpu, cpu);
++	spin_lock(&percpu->lock);
+ 	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
+ 		ops_run_biofill(sh);
+ 		overlap_clear++;
+@@ -2278,7 +2279,8 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
+ 			if (test_and_clear_bit(R5_Overlap, &dev->flags))
+ 				wake_up(&sh->raid_conf->wait_for_overlap);
+ 		}
+-	put_cpu();
++	spin_unlock(&percpu->lock);
++	put_cpu_light();
+ }
+ 
+ static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
+@@ -7108,6 +7110,7 @@ static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
+ 			__func__, cpu);
+ 		return -ENOMEM;
+ 	}
++	spin_lock_init(&per_cpu_ptr(conf->percpu, cpu)->lock);
+ 	return 0;
+ }
+ 
+diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
+index 5c05acf20e1f..665fe138ab4f 100644
+--- a/drivers/md/raid5.h
++++ b/drivers/md/raid5.h
+@@ -635,6 +635,7 @@ struct r5conf {
+ 	int			recovery_disabled;
+ 	/* per cpu variables */
+ 	struct raid5_percpu {
++		spinlock_t	lock;		/* Protection for -RT */
+ 		struct page	*spare_page; /* Used when checking P/Q in raid6 */
+ 		void		*scribble;  /* space for constructing buffer
+ 					     * lists and performing address
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0232-scsi-fcoe-Make-RT-aware.patch b/debian/patches-rt/0232-scsi-fcoe-Make-RT-aware.patch
new file mode 100644
index 000000000..dbe99481a
--- /dev/null
+++ b/debian/patches-rt/0232-scsi-fcoe-Make-RT-aware.patch
@@ -0,0 +1,116 @@
+From a2eaf0c262e1151f5978da03d033819e82104cce Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Sat, 12 Nov 2011 14:00:48 +0100
+Subject: [PATCH 232/323] scsi/fcoe: Make RT aware.
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Do not disable preemption while taking sleeping locks. All user look safe
+for migrate_diable() only.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ drivers/scsi/fcoe/fcoe.c      | 16 ++++++++--------
+ drivers/scsi/fcoe/fcoe_ctlr.c |  4 ++--
+ drivers/scsi/libfc/fc_exch.c  |  4 ++--
+ 3 files changed, 12 insertions(+), 12 deletions(-)
+
+diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c
+index 30afcbbe1f86..4ae5b8152ece 100644
+--- a/drivers/scsi/fcoe/fcoe.c
++++ b/drivers/scsi/fcoe/fcoe.c
+@@ -1452,11 +1452,11 @@ static int fcoe_rcv(struct sk_buff *skb, struct net_device *netdev,
+ static int fcoe_alloc_paged_crc_eof(struct sk_buff *skb, int tlen)
+ {
+ 	struct fcoe_percpu_s *fps;
+-	int rc;
++	int rc, cpu = get_cpu_light();
+ 
+-	fps = &get_cpu_var(fcoe_percpu);
++	fps = &per_cpu(fcoe_percpu, cpu);
+ 	rc = fcoe_get_paged_crc_eof(skb, tlen, fps);
+-	put_cpu_var(fcoe_percpu);
++	put_cpu_light();
+ 
+ 	return rc;
+ }
+@@ -1641,11 +1641,11 @@ static inline int fcoe_filter_frames(struct fc_lport *lport,
+ 		return 0;
+ 	}
+ 
+-	stats = per_cpu_ptr(lport->stats, get_cpu());
++	stats = per_cpu_ptr(lport->stats, get_cpu_light());
+ 	stats->InvalidCRCCount++;
+ 	if (stats->InvalidCRCCount < 5)
+ 		printk(KERN_WARNING "fcoe: dropping frame with CRC error\n");
+-	put_cpu();
++	put_cpu_light();
+ 	return -EINVAL;
+ }
+ 
+@@ -1686,7 +1686,7 @@ static void fcoe_recv_frame(struct sk_buff *skb)
+ 	 */
+ 	hp = (struct fcoe_hdr *) skb_network_header(skb);
+ 
+-	stats = per_cpu_ptr(lport->stats, get_cpu());
++	stats = per_cpu_ptr(lport->stats, get_cpu_light());
+ 	if (unlikely(FC_FCOE_DECAPS_VER(hp) != FC_FCOE_VER)) {
+ 		if (stats->ErrorFrames < 5)
+ 			printk(KERN_WARNING "fcoe: FCoE version "
+@@ -1718,13 +1718,13 @@ static void fcoe_recv_frame(struct sk_buff *skb)
+ 		goto drop;
+ 
+ 	if (!fcoe_filter_frames(lport, fp)) {
+-		put_cpu();
++		put_cpu_light();
+ 		fc_exch_recv(lport, fp);
+ 		return;
+ 	}
+ drop:
+ 	stats->ErrorFrames++;
+-	put_cpu();
++	put_cpu_light();
+ 	kfree_skb(skb);
+ }
+ 
+diff --git a/drivers/scsi/fcoe/fcoe_ctlr.c b/drivers/scsi/fcoe/fcoe_ctlr.c
+index a2d60ad2a683..3fdc403bc7d8 100644
+--- a/drivers/scsi/fcoe/fcoe_ctlr.c
++++ b/drivers/scsi/fcoe/fcoe_ctlr.c
+@@ -830,7 +830,7 @@ static unsigned long fcoe_ctlr_age_fcfs(struct fcoe_ctlr *fip)
+ 
+ 	INIT_LIST_HEAD(&del_list);
+ 
+-	stats = per_cpu_ptr(fip->lp->stats, get_cpu());
++	stats = per_cpu_ptr(fip->lp->stats, get_cpu_light());
+ 
+ 	list_for_each_entry_safe(fcf, next, &fip->fcfs, list) {
+ 		deadline = fcf->time + fcf->fka_period + fcf->fka_period / 2;
+@@ -866,7 +866,7 @@ static unsigned long fcoe_ctlr_age_fcfs(struct fcoe_ctlr *fip)
+ 				sel_time = fcf->time;
+ 		}
+ 	}
+-	put_cpu();
++	put_cpu_light();
+ 
+ 	list_for_each_entry_safe(fcf, next, &del_list, list) {
+ 		/* Removes fcf from current list */
+diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
+index 4261380af97b..65160eaaa929 100644
+--- a/drivers/scsi/libfc/fc_exch.c
++++ b/drivers/scsi/libfc/fc_exch.c
+@@ -826,10 +826,10 @@ static struct fc_exch *fc_exch_em_alloc(struct fc_lport *lport,
+ 	}
+ 	memset(ep, 0, sizeof(*ep));
+ 
+-	cpu = get_cpu();
++	cpu = get_cpu_light();
+ 	pool = per_cpu_ptr(mp->pool, cpu);
+ 	spin_lock_bh(&pool->lock);
+-	put_cpu();
++	put_cpu_light();
+ 
+ 	/* peek cache of free slot */
+ 	if (pool->left != FC_XID_UNKNOWN) {
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0233-sunrpc-Make-svc_xprt_do_enqueue-use-get_cpu_light.patch b/debian/patches-rt/0233-sunrpc-Make-svc_xprt_do_enqueue-use-get_cpu_light.patch
new file mode 100644
index 000000000..22b2f6973
--- /dev/null
+++ b/debian/patches-rt/0233-sunrpc-Make-svc_xprt_do_enqueue-use-get_cpu_light.patch
@@ -0,0 +1,60 @@
+From 971df27cc65fb6805b2253bd66e81bd244887ecc Mon Sep 17 00:00:00 2001
+From: Mike Galbraith <umgwanakikbuti@gmail.com>
+Date: Wed, 18 Feb 2015 16:05:28 +0100
+Subject: [PATCH 233/323] sunrpc: Make svc_xprt_do_enqueue() use
+ get_cpu_light()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+|BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:915
+|in_atomic(): 1, irqs_disabled(): 0, pid: 3194, name: rpc.nfsd
+|Preemption disabled at:[<ffffffffa06bf0bb>] svc_xprt_received+0x4b/0xc0 [sunrpc]
+|CPU: 6 PID: 3194 Comm: rpc.nfsd Not tainted 3.18.7-rt1 #9
+|Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.404 11/06/2014
+| ffff880409630000 ffff8800d9a33c78 ffffffff815bdeb5 0000000000000002
+| 0000000000000000 ffff8800d9a33c98 ffffffff81073c86 ffff880408dd6008
+| ffff880408dd6000 ffff8800d9a33cb8 ffffffff815c3d84 ffff88040b3ac000
+|Call Trace:
+| [<ffffffff815bdeb5>] dump_stack+0x4f/0x9e
+| [<ffffffff81073c86>] __might_sleep+0xe6/0x150
+| [<ffffffff815c3d84>] rt_spin_lock+0x24/0x50
+| [<ffffffffa06beec0>] svc_xprt_do_enqueue+0x80/0x230 [sunrpc]
+| [<ffffffffa06bf0bb>] svc_xprt_received+0x4b/0xc0 [sunrpc]
+| [<ffffffffa06c03ed>] svc_add_new_perm_xprt+0x6d/0x80 [sunrpc]
+| [<ffffffffa06b2693>] svc_addsock+0x143/0x200 [sunrpc]
+| [<ffffffffa072e69c>] write_ports+0x28c/0x340 [nfsd]
+| [<ffffffffa072d2ac>] nfsctl_transaction_write+0x4c/0x80 [nfsd]
+| [<ffffffff8117ee83>] vfs_write+0xb3/0x1d0
+| [<ffffffff8117f889>] SyS_write+0x49/0xb0
+| [<ffffffff815c4556>] system_call_fastpath+0x16/0x1b
+
+Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ net/sunrpc/svc_xprt.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
+index 06e503466c32..16bd1278a989 100644
+--- a/net/sunrpc/svc_xprt.c
++++ b/net/sunrpc/svc_xprt.c
+@@ -422,7 +422,7 @@ void svc_xprt_do_enqueue(struct svc_xprt *xprt)
+ 	if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
+ 		return;
+ 
+-	cpu = get_cpu();
++	cpu = get_cpu_light();
+ 	pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
+ 
+ 	atomic_long_inc(&pool->sp_stats.packets);
+@@ -446,7 +446,7 @@ void svc_xprt_do_enqueue(struct svc_xprt *xprt)
+ 	rqstp = NULL;
+ out_unlock:
+ 	rcu_read_unlock();
+-	put_cpu();
++	put_cpu_light();
+ 	trace_svc_xprt_do_enqueue(xprt, rqstp);
+ }
+ EXPORT_SYMBOL_GPL(svc_xprt_do_enqueue);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0234-rt-Introduce-cpu_chill.patch b/debian/patches-rt/0234-rt-Introduce-cpu_chill.patch
new file mode 100644
index 000000000..f2a8eeee5
--- /dev/null
+++ b/debian/patches-rt/0234-rt-Introduce-cpu_chill.patch
@@ -0,0 +1,122 @@
+From 38e8018fba96ecd6e7c7a47e18ed06324fd1d0e2 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 7 Mar 2012 20:51:03 +0100
+Subject: [PATCH 234/323] rt: Introduce cpu_chill()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Retry loops on RT might loop forever when the modifying side was
+preempted. Add cpu_chill() to replace cpu_relax(). cpu_chill()
+defaults to cpu_relax() for non RT. On RT it puts the looping task to
+sleep for a tick so the preempted task can make progress.
+
+Steven Rostedt changed it to use a hrtimer instead of msleep():
+|
+|Ulrich Obergfell pointed out that cpu_chill() calls msleep() which is woken
+|up by the ksoftirqd running the TIMER softirq. But as the cpu_chill() is
+|called from softirq context, it may block the ksoftirqd() from running, in
+|which case, it may never wake up the msleep() causing the deadlock.
+
++ bigeasy later changed to schedule_hrtimeout()
+|If a task calls cpu_chill() and gets woken up by a regular or spurious
+|wakeup and has a signal pending, then it exits the sleep loop in
+|do_nanosleep() and sets up the restart block. If restart->nanosleep.type is
+|not TI_NONE then this results in accessing a stale user pointer from a
+|previously interrupted syscall and a copy to user based on the stale
+|pointer or a BUG() when 'type' is not supported in nanosleep_copyout().
+
++ bigeasy: add PF_NOFREEZE:
+| [....] Waiting for /dev to be fully populated...
+| =====================================
+| [ BUG: udevd/229 still has locks held! ]
+| 3.12.11-rt17 #23 Not tainted
+| -------------------------------------
+| 1 lock held by udevd/229:
+|  #0:  (&type->i_mutex_dir_key#2){+.+.+.}, at: lookup_slow+0x28/0x98
+|
+| stack backtrace:
+| CPU: 0 PID: 229 Comm: udevd Not tainted 3.12.11-rt17 #23
+| (unwind_backtrace+0x0/0xf8) from (show_stack+0x10/0x14)
+| (show_stack+0x10/0x14) from (dump_stack+0x74/0xbc)
+| (dump_stack+0x74/0xbc) from (do_nanosleep+0x120/0x160)
+| (do_nanosleep+0x120/0x160) from (hrtimer_nanosleep+0x90/0x110)
+| (hrtimer_nanosleep+0x90/0x110) from (cpu_chill+0x30/0x38)
+| (cpu_chill+0x30/0x38) from (dentry_kill+0x158/0x1ec)
+| (dentry_kill+0x158/0x1ec) from (dput+0x74/0x15c)
+| (dput+0x74/0x15c) from (lookup_real+0x4c/0x50)
+| (lookup_real+0x4c/0x50) from (__lookup_hash+0x34/0x44)
+| (__lookup_hash+0x34/0x44) from (lookup_slow+0x38/0x98)
+| (lookup_slow+0x38/0x98) from (path_lookupat+0x208/0x7fc)
+| (path_lookupat+0x208/0x7fc) from (filename_lookup+0x20/0x60)
+| (filename_lookup+0x20/0x60) from (user_path_at_empty+0x50/0x7c)
+| (user_path_at_empty+0x50/0x7c) from (user_path_at+0x14/0x1c)
+| (user_path_at+0x14/0x1c) from (vfs_fstatat+0x48/0x94)
+| (vfs_fstatat+0x48/0x94) from (SyS_stat64+0x14/0x30)
+| (SyS_stat64+0x14/0x30) from (ret_fast_syscall+0x0/0x48)
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/delay.h |  6 ++++++
+ kernel/time/hrtimer.c | 30 ++++++++++++++++++++++++++++++
+ 2 files changed, 36 insertions(+)
+
+diff --git a/include/linux/delay.h b/include/linux/delay.h
+index 1d0e2ce6b6d9..02b37178b54f 100644
+--- a/include/linux/delay.h
++++ b/include/linux/delay.h
+@@ -76,4 +76,10 @@ static inline void fsleep(unsigned long usecs)
+ 		msleep(DIV_ROUND_UP(usecs, 1000));
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT
++extern void cpu_chill(void);
++#else
++# define cpu_chill()	cpu_relax()
++#endif
++
+ #endif /* defined(_LINUX_DELAY_H) */
+diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
+index ede09dda36e9..9dcc6215599f 100644
+--- a/kernel/time/hrtimer.c
++++ b/kernel/time/hrtimer.c
+@@ -2054,6 +2054,36 @@ SYSCALL_DEFINE2(nanosleep_time32, struct old_timespec32 __user *, rqtp,
+ }
+ #endif
+ 
++#ifdef CONFIG_PREEMPT_RT
++/*
++ * Sleep for 1 ms in hope whoever holds what we want will let it go.
++ */
++void cpu_chill(void)
++{
++	unsigned int freeze_flag = current->flags & PF_NOFREEZE;
++	struct task_struct *self = current;
++	ktime_t chill_time;
++
++	raw_spin_lock_irq(&self->pi_lock);
++	self->saved_state = self->state;
++	__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
++	raw_spin_unlock_irq(&self->pi_lock);
++
++	chill_time = ktime_set(0, NSEC_PER_MSEC);
++
++	current->flags |= PF_NOFREEZE;
++	schedule_hrtimeout(&chill_time, HRTIMER_MODE_REL_HARD);
++	if (!freeze_flag)
++		current->flags &= ~PF_NOFREEZE;
++
++	raw_spin_lock_irq(&self->pi_lock);
++	__set_current_state_no_track(self->saved_state);
++	self->saved_state = TASK_RUNNING;
++	raw_spin_unlock_irq(&self->pi_lock);
++}
++EXPORT_SYMBOL(cpu_chill);
++#endif
++
+ /*
+  * Functions related to boot-time initialization:
+  */
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0235-fs-namespace-Use-cpu_chill-in-trylock-loops.patch b/debian/patches-rt/0235-fs-namespace-Use-cpu_chill-in-trylock-loops.patch
new file mode 100644
index 000000000..046c48516
--- /dev/null
+++ b/debian/patches-rt/0235-fs-namespace-Use-cpu_chill-in-trylock-loops.patch
@@ -0,0 +1,44 @@
+From e174bc8c285602601d09d4e7997654e66a18bc87 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 7 Mar 2012 21:00:34 +0100
+Subject: [PATCH 235/323] fs: namespace: Use cpu_chill() in trylock loops
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Retry loops on RT might loop forever when the modifying side was
+preempted. Use cpu_chill() instead of cpu_relax() to let the system
+make progress.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ fs/namespace.c | 8 ++++++--
+ 1 file changed, 6 insertions(+), 2 deletions(-)
+
+diff --git a/fs/namespace.c b/fs/namespace.c
+index 046b084136c5..6a550e342d6b 100644
+--- a/fs/namespace.c
++++ b/fs/namespace.c
+@@ -14,6 +14,7 @@
+ #include <linux/mnt_namespace.h>
+ #include <linux/user_namespace.h>
+ #include <linux/namei.h>
++#include <linux/delay.h>
+ #include <linux/security.h>
+ #include <linux/cred.h>
+ #include <linux/idr.h>
+@@ -321,8 +322,11 @@ int __mnt_want_write(struct vfsmount *m)
+ 	 * incremented count after it has set MNT_WRITE_HOLD.
+ 	 */
+ 	smp_mb();
+-	while (READ_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD)
+-		cpu_relax();
++	while (READ_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD) {
++		preempt_enable();
++		cpu_chill();
++		preempt_disable();
++	}
+ 	/*
+ 	 * After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will
+ 	 * be set to match its requirements. So we must not load that until
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0236-net-Use-skbufhead-with-raw-lock.patch b/debian/patches-rt/0236-net-Use-skbufhead-with-raw-lock.patch
new file mode 100644
index 000000000..48d95d023
--- /dev/null
+++ b/debian/patches-rt/0236-net-Use-skbufhead-with-raw-lock.patch
@@ -0,0 +1,74 @@
+From d58fbc3fc363cee50de0ac64be0b90fd2666956a Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 12 Jul 2011 15:38:34 +0200
+Subject: [PATCH 236/323] net: Use skbufhead with raw lock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Use the rps lock as rawlock so we can keep irq-off regions. It looks low
+latency. However we can't kfree() from this context therefore we defer this
+to the softirq and use the tofree_queue list for it (similar to process_queue).
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/skbuff.h | 7 +++++++
+ net/core/dev.c         | 6 +++---
+ 2 files changed, 10 insertions(+), 3 deletions(-)
+
+diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
+index a210f1995862..af89bd5e7d56 100644
+--- a/include/linux/skbuff.h
++++ b/include/linux/skbuff.h
+@@ -296,6 +296,7 @@ struct sk_buff_head {
+ 
+ 	__u32		qlen;
+ 	spinlock_t	lock;
++	raw_spinlock_t	raw_lock;
+ };
+ 
+ struct sk_buff;
+@@ -1892,6 +1893,12 @@ static inline void skb_queue_head_init(struct sk_buff_head *list)
+ 	__skb_queue_head_init(list);
+ }
+ 
++static inline void skb_queue_head_init_raw(struct sk_buff_head *list)
++{
++	raw_spin_lock_init(&list->raw_lock);
++	__skb_queue_head_init(list);
++}
++
+ static inline void skb_queue_head_init_class(struct sk_buff_head *list,
+ 		struct lock_class_key *class)
+ {
+diff --git a/net/core/dev.c b/net/core/dev.c
+index f973f53c7a1f..895eb42bb5d6 100644
+--- a/net/core/dev.c
++++ b/net/core/dev.c
+@@ -221,14 +221,14 @@ static inline struct hlist_head *dev_index_hash(struct net *net, int ifindex)
+ static inline void rps_lock(struct softnet_data *sd)
+ {
+ #ifdef CONFIG_RPS
+-	spin_lock(&sd->input_pkt_queue.lock);
++	raw_spin_lock(&sd->input_pkt_queue.raw_lock);
+ #endif
+ }
+ 
+ static inline void rps_unlock(struct softnet_data *sd)
+ {
+ #ifdef CONFIG_RPS
+-	spin_unlock(&sd->input_pkt_queue.lock);
++	raw_spin_unlock(&sd->input_pkt_queue.raw_lock);
+ #endif
+ }
+ 
+@@ -11296,7 +11296,7 @@ static int __init net_dev_init(void)
+ 
+ 		INIT_WORK(flush, flush_backlog);
+ 
+-		skb_queue_head_init(&sd->input_pkt_queue);
++		skb_queue_head_init_raw(&sd->input_pkt_queue);
+ 		skb_queue_head_init(&sd->process_queue);
+ #ifdef CONFIG_XFRM_OFFLOAD
+ 		skb_queue_head_init(&sd->xfrm_backlog);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0237-net-Dequeue-in-dev_cpu_dead-without-the-lock.patch b/debian/patches-rt/0237-net-Dequeue-in-dev_cpu_dead-without-the-lock.patch
new file mode 100644
index 000000000..36e0d28d2
--- /dev/null
+++ b/debian/patches-rt/0237-net-Dequeue-in-dev_cpu_dead-without-the-lock.patch
@@ -0,0 +1,37 @@
+From 95dbb10c81619c9a35a63f73dadd7379d95fdec0 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 16 Sep 2020 16:15:39 +0200
+Subject: [PATCH 237/323] net: Dequeue in dev_cpu_dead() without the lock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Upstream uses skb_dequeue() to acquire lock of `input_pkt_queue'. The reason is
+to synchronize against a remote CPU which still thinks that the CPU is online
+enqueues packets to this CPU.
+There are no guarantees that the packet is enqueued before the callback is run,
+it just hope.
+RT however complains about an not initialized lock because it uses another lock
+for `input_pkt_queue' due to the IRQ-off nature of the context.
+
+Use the unlocked dequeue version for `input_pkt_queue'.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ net/core/dev.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/net/core/dev.c b/net/core/dev.c
+index 895eb42bb5d6..c55993848233 100644
+--- a/net/core/dev.c
++++ b/net/core/dev.c
+@@ -10980,7 +10980,7 @@ static int dev_cpu_dead(unsigned int oldcpu)
+ 		netif_rx_ni(skb);
+ 		input_queue_head_incr(oldsd);
+ 	}
+-	while ((skb = skb_dequeue(&oldsd->input_pkt_queue))) {
++	while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) {
+ 		netif_rx_ni(skb);
+ 		input_queue_head_incr(oldsd);
+ 	}
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0238-net-dev-always-take-qdisc-s-busylock-in-__dev_xmit_s.patch b/debian/patches-rt/0238-net-dev-always-take-qdisc-s-busylock-in-__dev_xmit_s.patch
new file mode 100644
index 000000000..fe05e1e78
--- /dev/null
+++ b/debian/patches-rt/0238-net-dev-always-take-qdisc-s-busylock-in-__dev_xmit_s.patch
@@ -0,0 +1,42 @@
+From 3a7ff2036ac29effdf8fc39fc7ea9610f98ca5e4 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 30 Mar 2016 13:36:29 +0200
+Subject: [PATCH 238/323] net: dev: always take qdisc's busylock in
+ __dev_xmit_skb()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The root-lock is dropped before dev_hard_start_xmit() is invoked and after
+setting the __QDISC___STATE_RUNNING bit. If this task is now pushed away
+by a task with a higher priority then the task with the higher priority
+won't be able to submit packets to the NIC directly instead they will be
+enqueued into the Qdisc. The NIC will remain idle until the task(s) with
+higher priority leave the CPU and the task with lower priority gets back
+and finishes the job.
+
+If we take always the busylock we ensure that the RT task can boost the
+low-prio task and submit the packet.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ net/core/dev.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/net/core/dev.c b/net/core/dev.c
+index c55993848233..c3b4e5e320ca 100644
+--- a/net/core/dev.c
++++ b/net/core/dev.c
+@@ -3796,7 +3796,11 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
+ 	 * This permits qdisc->running owner to get the lock more
+ 	 * often and dequeue packets faster.
+ 	 */
++#ifdef CONFIG_PREEMPT_RT
++	contended = true;
++#else
+ 	contended = qdisc_is_running(q);
++#endif
+ 	if (unlikely(contended))
+ 		spin_lock(&q->busylock);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0239-irqwork-push-most-work-into-softirq-context.patch b/debian/patches-rt/0239-irqwork-push-most-work-into-softirq-context.patch
new file mode 100644
index 000000000..1ac41992f
--- /dev/null
+++ b/debian/patches-rt/0239-irqwork-push-most-work-into-softirq-context.patch
@@ -0,0 +1,189 @@
+From 57453ffdf0bcba3fa27ca0b19f622ea371c2c686 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 23 Jun 2015 15:32:51 +0200
+Subject: [PATCH 239/323] irqwork: push most work into softirq context
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Initially we defered all irqwork into softirq because we didn't want the
+latency spikes if perf or another user was busy and delayed the RT task.
+The NOHZ trigger (nohz_full_kick_work) was the first user that did not work
+as expected if it did not run in the original irqwork context so we had to
+bring it back somehow for it. push_irq_work_func is the second one that
+requires this.
+
+This patch adds the IRQ_WORK_HARD_IRQ which makes sure the callback runs
+in raw-irq context. Everything else is defered into softirq context. Without
+-RT we have the orignal behavior.
+
+This patch incorporates tglx orignal work which revoked a little bringing back
+the arch_irq_work_raise() if possible and a few fixes from Steven Rostedt and
+Mike Galbraith,
+
+[bigeasy: melt tglx's irq_work_tick_soft() which splits irq_work_tick() into a
+          hard and soft variant]
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/irq_work.h |  6 +++++
+ kernel/irq_work.c        | 58 +++++++++++++++++++++++++++++++---------
+ kernel/sched/topology.c  |  1 +
+ kernel/time/timer.c      |  2 ++
+ 4 files changed, 55 insertions(+), 12 deletions(-)
+
+diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
+index 30823780c192..f941f2d7d71c 100644
+--- a/include/linux/irq_work.h
++++ b/include/linux/irq_work.h
+@@ -55,4 +55,10 @@ static inline void irq_work_run(void) { }
+ static inline void irq_work_single(void *arg) { }
+ #endif
+ 
++#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT)
++void irq_work_tick_soft(void);
++#else
++static inline void irq_work_tick_soft(void) { }
++#endif
++
+ #endif /* _LINUX_IRQ_WORK_H */
+diff --git a/kernel/irq_work.c b/kernel/irq_work.c
+index eca83965b631..8183d30e1bb1 100644
+--- a/kernel/irq_work.c
++++ b/kernel/irq_work.c
+@@ -18,6 +18,7 @@
+ #include <linux/cpu.h>
+ #include <linux/notifier.h>
+ #include <linux/smp.h>
++#include <linux/interrupt.h>
+ #include <asm/processor.h>
+ 
+ 
+@@ -52,13 +53,19 @@ void __weak arch_irq_work_raise(void)
+ /* Enqueue on current CPU, work must already be claimed and preempt disabled */
+ static void __irq_work_queue_local(struct irq_work *work)
+ {
++	struct llist_head *list;
++	bool lazy_work, realtime = IS_ENABLED(CONFIG_PREEMPT_RT);
++
++	lazy_work = atomic_read(&work->flags) & IRQ_WORK_LAZY;
++
+ 	/* If the work is "lazy", handle it from next tick if any */
+-	if (atomic_read(&work->flags) & IRQ_WORK_LAZY) {
+-		if (llist_add(&work->llnode, this_cpu_ptr(&lazy_list)) &&
+-		    tick_nohz_tick_stopped())
+-			arch_irq_work_raise();
+-	} else {
+-		if (llist_add(&work->llnode, this_cpu_ptr(&raised_list)))
++	if (lazy_work || (realtime && !(atomic_read(&work->flags) & IRQ_WORK_HARD_IRQ)))
++		list = this_cpu_ptr(&lazy_list);
++	else
++		list = this_cpu_ptr(&raised_list);
++
++	if (llist_add(&work->llnode, list)) {
++		if (!lazy_work || tick_nohz_tick_stopped())
+ 			arch_irq_work_raise();
+ 	}
+ }
+@@ -102,7 +109,13 @@ bool irq_work_queue_on(struct irq_work *work, int cpu)
+ 	if (cpu != smp_processor_id()) {
+ 		/* Arch remote IPI send/receive backend aren't NMI safe */
+ 		WARN_ON_ONCE(in_nmi());
+-		__smp_call_single_queue(cpu, &work->llnode);
++
++		if (IS_ENABLED(CONFIG_PREEMPT_RT) && !(atomic_read(&work->flags) & IRQ_WORK_HARD_IRQ)) {
++			if (llist_add(&work->llnode, &per_cpu(lazy_list, cpu)))
++				arch_send_call_function_single_ipi(cpu);
++		} else {
++			__smp_call_single_queue(cpu, &work->llnode);
++		}
+ 	} else {
+ 		__irq_work_queue_local(work);
+ 	}
+@@ -120,9 +133,8 @@ bool irq_work_needs_cpu(void)
+ 	raised = this_cpu_ptr(&raised_list);
+ 	lazy = this_cpu_ptr(&lazy_list);
+ 
+-	if (llist_empty(raised) || arch_irq_work_has_interrupt())
+-		if (llist_empty(lazy))
+-			return false;
++	if (llist_empty(raised) && llist_empty(lazy))
++		return false;
+ 
+ 	/* All work should have been flushed before going offline */
+ 	WARN_ON_ONCE(cpu_is_offline(smp_processor_id()));
+@@ -160,8 +172,12 @@ static void irq_work_run_list(struct llist_head *list)
+ 	struct irq_work *work, *tmp;
+ 	struct llist_node *llnode;
+ 
++#ifndef CONFIG_PREEMPT_RT
++	/*
++	 * nort: On RT IRQ-work may run in SOFTIRQ context.
++	 */
+ 	BUG_ON(!irqs_disabled());
+-
++#endif
+ 	if (llist_empty(list))
+ 		return;
+ 
+@@ -177,7 +193,16 @@ static void irq_work_run_list(struct llist_head *list)
+ void irq_work_run(void)
+ {
+ 	irq_work_run_list(this_cpu_ptr(&raised_list));
+-	irq_work_run_list(this_cpu_ptr(&lazy_list));
++	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
++		/*
++		 * NOTE: we raise softirq via IPI for safety,
++		 * and execute in irq_work_tick() to move the
++		 * overhead from hard to soft irq context.
++		 */
++		if (!llist_empty(this_cpu_ptr(&lazy_list)))
++			raise_softirq(TIMER_SOFTIRQ);
++	} else
++		irq_work_run_list(this_cpu_ptr(&lazy_list));
+ }
+ EXPORT_SYMBOL_GPL(irq_work_run);
+ 
+@@ -187,8 +212,17 @@ void irq_work_tick(void)
+ 
+ 	if (!llist_empty(raised) && !arch_irq_work_has_interrupt())
+ 		irq_work_run_list(raised);
++
++	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
++		irq_work_run_list(this_cpu_ptr(&lazy_list));
++}
++
++#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT)
++void irq_work_tick_soft(void)
++{
+ 	irq_work_run_list(this_cpu_ptr(&lazy_list));
+ }
++#endif
+ 
+ /*
+  * Synchronize against the irq_work @entry, ensures the entry is not
+diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
+index ff2c6d3ba6c7..2f1bea4f7dba 100644
+--- a/kernel/sched/topology.c
++++ b/kernel/sched/topology.c
+@@ -514,6 +514,7 @@ static int init_rootdomain(struct root_domain *rd)
+ 	rd->rto_cpu = -1;
+ 	raw_spin_lock_init(&rd->rto_lock);
+ 	init_irq_work(&rd->rto_push_work, rto_push_irq_work_func);
++	atomic_or(IRQ_WORK_HARD_IRQ, &rd->rto_push_work.flags);
+ #endif
+ 
+ 	init_dl_bw(&rd->dl_bw);
+diff --git a/kernel/time/timer.c b/kernel/time/timer.c
+index a4fdc7cfb723..1cad0efd635c 100644
+--- a/kernel/time/timer.c
++++ b/kernel/time/timer.c
+@@ -1770,6 +1770,8 @@ static __latent_entropy void run_timer_softirq(struct softirq_action *h)
+ {
+ 	struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+ 
++	irq_work_tick_soft();
++
+ 	__run_timers(base);
+ 	if (IS_ENABLED(CONFIG_NO_HZ_COMMON))
+ 		__run_timers(this_cpu_ptr(&timer_bases[BASE_DEF]));
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0240-x86-crypto-Reduce-preempt-disabled-regions.patch b/debian/patches-rt/0240-x86-crypto-Reduce-preempt-disabled-regions.patch
new file mode 100644
index 000000000..b84653cfb
--- /dev/null
+++ b/debian/patches-rt/0240-x86-crypto-Reduce-preempt-disabled-regions.patch
@@ -0,0 +1,118 @@
+From 523f64f1a87e6454e46f5e25ae797b6a7050a6a8 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Mon, 14 Nov 2011 18:19:27 +0100
+Subject: [PATCH 240/323] x86: crypto: Reduce preempt disabled regions
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Restrict the preempt disabled regions to the actual floating point
+operations and enable preemption for the administrative actions.
+
+This is necessary on RT to avoid that kfree and other operations are
+called with preemption disabled.
+
+Reported-and-tested-by: Carsten Emde <cbe@osadl.org>
+Signed-off-by: Peter Zijlstra <peterz@infradead.org>
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ arch/x86/crypto/aesni-intel_glue.c | 22 ++++++++++++----------
+ 1 file changed, 12 insertions(+), 10 deletions(-)
+
+diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
+index be891fdf8d17..29c716ed103f 100644
+--- a/arch/x86/crypto/aesni-intel_glue.c
++++ b/arch/x86/crypto/aesni-intel_glue.c
+@@ -379,14 +379,14 @@ static int ecb_encrypt(struct skcipher_request *req)
+ 
+ 	err = skcipher_walk_virt(&walk, req, true);
+ 
+-	kernel_fpu_begin();
+ 	while ((nbytes = walk.nbytes)) {
++		kernel_fpu_begin();
+ 		aesni_ecb_enc(ctx, walk.dst.virt.addr, walk.src.virt.addr,
+ 			      nbytes & AES_BLOCK_MASK);
++		kernel_fpu_end();
+ 		nbytes &= AES_BLOCK_SIZE - 1;
+ 		err = skcipher_walk_done(&walk, nbytes);
+ 	}
+-	kernel_fpu_end();
+ 
+ 	return err;
+ }
+@@ -401,14 +401,14 @@ static int ecb_decrypt(struct skcipher_request *req)
+ 
+ 	err = skcipher_walk_virt(&walk, req, true);
+ 
+-	kernel_fpu_begin();
+ 	while ((nbytes = walk.nbytes)) {
++		kernel_fpu_begin();
+ 		aesni_ecb_dec(ctx, walk.dst.virt.addr, walk.src.virt.addr,
+ 			      nbytes & AES_BLOCK_MASK);
++		kernel_fpu_end();
+ 		nbytes &= AES_BLOCK_SIZE - 1;
+ 		err = skcipher_walk_done(&walk, nbytes);
+ 	}
+-	kernel_fpu_end();
+ 
+ 	return err;
+ }
+@@ -423,14 +423,14 @@ static int cbc_encrypt(struct skcipher_request *req)
+ 
+ 	err = skcipher_walk_virt(&walk, req, true);
+ 
+-	kernel_fpu_begin();
+ 	while ((nbytes = walk.nbytes)) {
++		kernel_fpu_begin();
+ 		aesni_cbc_enc(ctx, walk.dst.virt.addr, walk.src.virt.addr,
+ 			      nbytes & AES_BLOCK_MASK, walk.iv);
++		kernel_fpu_end();
+ 		nbytes &= AES_BLOCK_SIZE - 1;
+ 		err = skcipher_walk_done(&walk, nbytes);
+ 	}
+-	kernel_fpu_end();
+ 
+ 	return err;
+ }
+@@ -445,14 +445,14 @@ static int cbc_decrypt(struct skcipher_request *req)
+ 
+ 	err = skcipher_walk_virt(&walk, req, true);
+ 
+-	kernel_fpu_begin();
+ 	while ((nbytes = walk.nbytes)) {
++		kernel_fpu_begin();
+ 		aesni_cbc_dec(ctx, walk.dst.virt.addr, walk.src.virt.addr,
+ 			      nbytes & AES_BLOCK_MASK, walk.iv);
++		kernel_fpu_end();
+ 		nbytes &= AES_BLOCK_SIZE - 1;
+ 		err = skcipher_walk_done(&walk, nbytes);
+ 	}
+-	kernel_fpu_end();
+ 
+ 	return err;
+ }
+@@ -500,18 +500,20 @@ static int ctr_crypt(struct skcipher_request *req)
+ 
+ 	err = skcipher_walk_virt(&walk, req, true);
+ 
+-	kernel_fpu_begin();
+ 	while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
++		kernel_fpu_begin();
+ 		aesni_ctr_enc_tfm(ctx, walk.dst.virt.addr, walk.src.virt.addr,
+ 			              nbytes & AES_BLOCK_MASK, walk.iv);
++		kernel_fpu_end();
+ 		nbytes &= AES_BLOCK_SIZE - 1;
+ 		err = skcipher_walk_done(&walk, nbytes);
+ 	}
+ 	if (walk.nbytes) {
++		kernel_fpu_begin();
+ 		ctr_crypt_final(ctx, &walk);
++		kernel_fpu_end();
+ 		err = skcipher_walk_done(&walk, 0);
+ 	}
+-	kernel_fpu_end();
+ 
+ 	return err;
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0241-crypto-Reduce-preempt-disabled-regions-more-algos.patch b/debian/patches-rt/0241-crypto-Reduce-preempt-disabled-regions-more-algos.patch
new file mode 100644
index 000000000..f02d88086
--- /dev/null
+++ b/debian/patches-rt/0241-crypto-Reduce-preempt-disabled-regions-more-algos.patch
@@ -0,0 +1,240 @@
+From e9bc715aa25df5aa654a5243e90ee31fb1b1e010 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 21 Feb 2014 17:24:04 +0100
+Subject: [PATCH 241/323] crypto: Reduce preempt disabled regions, more algos
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Don Estabrook reported
+| kernel: WARNING: CPU: 2 PID: 858 at kernel/sched/core.c:2428 migrate_disable+0xed/0x100()
+| kernel: WARNING: CPU: 2 PID: 858 at kernel/sched/core.c:2462 migrate_enable+0x17b/0x200()
+| kernel: WARNING: CPU: 3 PID: 865 at kernel/sched/core.c:2428 migrate_disable+0xed/0x100()
+
+and his backtrace showed some crypto functions which looked fine.
+
+The problem is the following sequence:
+
+glue_xts_crypt_128bit()
+{
+	blkcipher_walk_virt(); /* normal migrate_disable() */
+
+	glue_fpu_begin(); /* get atomic */
+
+	while (nbytes) {
+		__glue_xts_crypt_128bit();
+		blkcipher_walk_done(); /* with nbytes = 0, migrate_enable()
+					* while we are atomic */
+	};
+	glue_fpu_end() /* no longer atomic */
+}
+
+and this is why the counter get out of sync and the warning is printed.
+The other problem is that we are non-preemptible between
+glue_fpu_begin() and glue_fpu_end() and the latency grows. To fix this,
+I shorten the FPU off region and ensure blkcipher_walk_done() is called
+with preemption enabled. This might hurt the performance because we now
+enable/disable the FPU state more often but we gain lower latency and
+the bug is gone.
+
+Reported-by: Don Estabrook <don.estabrook@gmail.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/x86/crypto/cast5_avx_glue.c | 21 +++++++++------------
+ arch/x86/crypto/glue_helper.c    | 26 +++++++++++++++-----------
+ 2 files changed, 24 insertions(+), 23 deletions(-)
+
+diff --git a/arch/x86/crypto/cast5_avx_glue.c b/arch/x86/crypto/cast5_avx_glue.c
+index 384ccb00f9e1..2f8df8ef8644 100644
+--- a/arch/x86/crypto/cast5_avx_glue.c
++++ b/arch/x86/crypto/cast5_avx_glue.c
+@@ -46,7 +46,7 @@ static inline void cast5_fpu_end(bool fpu_enabled)
+ 
+ static int ecb_crypt(struct skcipher_request *req, bool enc)
+ {
+-	bool fpu_enabled = false;
++	bool fpu_enabled;
+ 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ 	struct cast5_ctx *ctx = crypto_skcipher_ctx(tfm);
+ 	struct skcipher_walk walk;
+@@ -61,7 +61,7 @@ static int ecb_crypt(struct skcipher_request *req, bool enc)
+ 		u8 *wsrc = walk.src.virt.addr;
+ 		u8 *wdst = walk.dst.virt.addr;
+ 
+-		fpu_enabled = cast5_fpu_begin(fpu_enabled, &walk, nbytes);
++		fpu_enabled = cast5_fpu_begin(false, &walk, nbytes);
+ 
+ 		/* Process multi-block batch */
+ 		if (nbytes >= bsize * CAST5_PARALLEL_BLOCKS) {
+@@ -90,10 +90,9 @@ static int ecb_crypt(struct skcipher_request *req, bool enc)
+ 		} while (nbytes >= bsize);
+ 
+ done:
++		cast5_fpu_end(fpu_enabled);
+ 		err = skcipher_walk_done(&walk, nbytes);
+ 	}
+-
+-	cast5_fpu_end(fpu_enabled);
+ 	return err;
+ }
+ 
+@@ -197,7 +196,7 @@ static int cbc_decrypt(struct skcipher_request *req)
+ {
+ 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ 	struct cast5_ctx *ctx = crypto_skcipher_ctx(tfm);
+-	bool fpu_enabled = false;
++	bool fpu_enabled;
+ 	struct skcipher_walk walk;
+ 	unsigned int nbytes;
+ 	int err;
+@@ -205,12 +204,11 @@ static int cbc_decrypt(struct skcipher_request *req)
+ 	err = skcipher_walk_virt(&walk, req, false);
+ 
+ 	while ((nbytes = walk.nbytes)) {
+-		fpu_enabled = cast5_fpu_begin(fpu_enabled, &walk, nbytes);
++		fpu_enabled = cast5_fpu_begin(false, &walk, nbytes);
+ 		nbytes = __cbc_decrypt(ctx, &walk);
++		cast5_fpu_end(fpu_enabled);
+ 		err = skcipher_walk_done(&walk, nbytes);
+ 	}
+-
+-	cast5_fpu_end(fpu_enabled);
+ 	return err;
+ }
+ 
+@@ -277,7 +275,7 @@ static int ctr_crypt(struct skcipher_request *req)
+ {
+ 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ 	struct cast5_ctx *ctx = crypto_skcipher_ctx(tfm);
+-	bool fpu_enabled = false;
++	bool fpu_enabled;
+ 	struct skcipher_walk walk;
+ 	unsigned int nbytes;
+ 	int err;
+@@ -285,13 +283,12 @@ static int ctr_crypt(struct skcipher_request *req)
+ 	err = skcipher_walk_virt(&walk, req, false);
+ 
+ 	while ((nbytes = walk.nbytes) >= CAST5_BLOCK_SIZE) {
+-		fpu_enabled = cast5_fpu_begin(fpu_enabled, &walk, nbytes);
++		fpu_enabled = cast5_fpu_begin(false, &walk, nbytes);
+ 		nbytes = __ctr_crypt(&walk, ctx);
++		cast5_fpu_end(fpu_enabled);
+ 		err = skcipher_walk_done(&walk, nbytes);
+ 	}
+ 
+-	cast5_fpu_end(fpu_enabled);
+-
+ 	if (walk.nbytes) {
+ 		ctr_crypt_final(&walk, ctx);
+ 		err = skcipher_walk_done(&walk, 0);
+diff --git a/arch/x86/crypto/glue_helper.c b/arch/x86/crypto/glue_helper.c
+index d3d91a0abf88..6d0774721514 100644
+--- a/arch/x86/crypto/glue_helper.c
++++ b/arch/x86/crypto/glue_helper.c
+@@ -24,7 +24,7 @@ int glue_ecb_req_128bit(const struct common_glue_ctx *gctx,
+ 	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
+ 	const unsigned int bsize = 128 / 8;
+ 	struct skcipher_walk walk;
+-	bool fpu_enabled = false;
++	bool fpu_enabled;
+ 	unsigned int nbytes;
+ 	int err;
+ 
+@@ -37,7 +37,7 @@ int glue_ecb_req_128bit(const struct common_glue_ctx *gctx,
+ 		unsigned int i;
+ 
+ 		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
+-					     &walk, fpu_enabled, nbytes);
++					     &walk, false, nbytes);
+ 		for (i = 0; i < gctx->num_funcs; i++) {
+ 			func_bytes = bsize * gctx->funcs[i].num_blocks;
+ 
+@@ -55,10 +55,9 @@ int glue_ecb_req_128bit(const struct common_glue_ctx *gctx,
+ 			if (nbytes < bsize)
+ 				break;
+ 		}
++		glue_fpu_end(fpu_enabled);
+ 		err = skcipher_walk_done(&walk, nbytes);
+ 	}
+-
+-	glue_fpu_end(fpu_enabled);
+ 	return err;
+ }
+ EXPORT_SYMBOL_GPL(glue_ecb_req_128bit);
+@@ -101,7 +100,7 @@ int glue_cbc_decrypt_req_128bit(const struct common_glue_ctx *gctx,
+ 	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
+ 	const unsigned int bsize = 128 / 8;
+ 	struct skcipher_walk walk;
+-	bool fpu_enabled = false;
++	bool fpu_enabled;
+ 	unsigned int nbytes;
+ 	int err;
+ 
+@@ -115,7 +114,7 @@ int glue_cbc_decrypt_req_128bit(const struct common_glue_ctx *gctx,
+ 		u128 last_iv;
+ 
+ 		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
+-					     &walk, fpu_enabled, nbytes);
++					     &walk, false, nbytes);
+ 		/* Start of the last block. */
+ 		src += nbytes / bsize - 1;
+ 		dst += nbytes / bsize - 1;
+@@ -148,10 +147,10 @@ int glue_cbc_decrypt_req_128bit(const struct common_glue_ctx *gctx,
+ done:
+ 		u128_xor(dst, dst, (u128 *)walk.iv);
+ 		*(u128 *)walk.iv = last_iv;
++		glue_fpu_end(fpu_enabled);
+ 		err = skcipher_walk_done(&walk, nbytes);
+ 	}
+ 
+-	glue_fpu_end(fpu_enabled);
+ 	return err;
+ }
+ EXPORT_SYMBOL_GPL(glue_cbc_decrypt_req_128bit);
+@@ -162,7 +161,7 @@ int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
+ 	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
+ 	const unsigned int bsize = 128 / 8;
+ 	struct skcipher_walk walk;
+-	bool fpu_enabled = false;
++	bool fpu_enabled;
+ 	unsigned int nbytes;
+ 	int err;
+ 
+@@ -176,7 +175,7 @@ int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
+ 		le128 ctrblk;
+ 
+ 		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
+-					     &walk, fpu_enabled, nbytes);
++					     &walk, false, nbytes);
+ 
+ 		be128_to_le128(&ctrblk, (be128 *)walk.iv);
+ 
+@@ -202,11 +201,10 @@ int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
+ 		}
+ 
+ 		le128_to_be128((be128 *)walk.iv, &ctrblk);
++		glue_fpu_end(fpu_enabled);
+ 		err = skcipher_walk_done(&walk, nbytes);
+ 	}
+ 
+-	glue_fpu_end(fpu_enabled);
+-
+ 	if (nbytes) {
+ 		le128 ctrblk;
+ 		u128 tmp;
+@@ -306,8 +304,14 @@ int glue_xts_req_128bit(const struct common_glue_ctx *gctx,
+ 	tweak_fn(tweak_ctx, walk.iv, walk.iv);
+ 
+ 	while (nbytes) {
++		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
++					     &walk, fpu_enabled,
++					     nbytes < bsize ? bsize : nbytes);
+ 		nbytes = __glue_xts_req_128bit(gctx, crypt_ctx, &walk);
+ 
++		glue_fpu_end(fpu_enabled);
++		fpu_enabled = false;
++
+ 		err = skcipher_walk_done(&walk, nbytes);
+ 		nbytes = walk.nbytes;
+ 	}
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0242-crypto-limit-more-FPU-enabled-sections.patch b/debian/patches-rt/0242-crypto-limit-more-FPU-enabled-sections.patch
new file mode 100644
index 000000000..9f98cd223
--- /dev/null
+++ b/debian/patches-rt/0242-crypto-limit-more-FPU-enabled-sections.patch
@@ -0,0 +1,74 @@
+From dd8a48342b4ff4b80a32a4ae49115db93ad069c1 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Thu, 30 Nov 2017 13:40:10 +0100
+Subject: [PATCH 242/323] crypto: limit more FPU-enabled sections
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Those crypto drivers use SSE/AVX/… for their crypto work and in order to
+do so in kernel they need to enable the "FPU" in kernel mode which
+disables preemption.
+There are two problems with the way they are used:
+- the while loop which processes X bytes may create latency spikes and
+  should be avoided or limited.
+- the cipher-walk-next part may allocate/free memory and may use
+  kmap_atomic().
+
+The whole kernel_fpu_begin()/end() processing isn't probably that cheap.
+It most likely makes sense to process as much of those as possible in one
+go. The new *_fpu_sched_rt() schedules only if a RT task is pending.
+
+Probably we should measure the performance those ciphers in pure SW
+mode and with this optimisations to see if it makes sense to keep them
+for RT.
+
+This kernel_fpu_resched() makes the code more preemptible which might hurt
+performance.
+
+Cc: stable-rt@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/x86/include/asm/fpu/api.h |  1 +
+ arch/x86/kernel/fpu/core.c     | 12 ++++++++++++
+ 2 files changed, 13 insertions(+)
+
+diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
+index ad2fee785310..d31b0886592a 100644
+--- a/arch/x86/include/asm/fpu/api.h
++++ b/arch/x86/include/asm/fpu/api.h
+@@ -28,6 +28,7 @@ extern void kernel_fpu_begin_mask(unsigned int kfpu_mask);
+ extern void kernel_fpu_end(void);
+ extern bool irq_fpu_usable(void);
+ extern void fpregs_mark_activate(void);
++extern void kernel_fpu_resched(void);
+ 
+ /* Code that is unaware of kernel_fpu_begin_mask() can use this */
+ static inline void kernel_fpu_begin(void)
+diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
+index 835b948095cd..8cfc2f972fe5 100644
+--- a/arch/x86/kernel/fpu/core.c
++++ b/arch/x86/kernel/fpu/core.c
+@@ -144,6 +144,18 @@ void kernel_fpu_end(void)
+ }
+ EXPORT_SYMBOL_GPL(kernel_fpu_end);
+ 
++void kernel_fpu_resched(void)
++{
++	WARN_ON_FPU(!this_cpu_read(in_kernel_fpu));
++
++	if (should_resched(PREEMPT_OFFSET)) {
++		kernel_fpu_end();
++		cond_resched();
++		kernel_fpu_begin();
++	}
++}
++EXPORT_SYMBOL_GPL(kernel_fpu_resched);
++
+ /*
+  * Save the FPU state (mark it for reload if necessary):
+  *
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0243-panic-skip-get_random_bytes-for-RT_FULL-in-init_oops.patch b/debian/patches-rt/0243-panic-skip-get_random_bytes-for-RT_FULL-in-init_oops.patch
new file mode 100644
index 000000000..fbcd9407a
--- /dev/null
+++ b/debian/patches-rt/0243-panic-skip-get_random_bytes-for-RT_FULL-in-init_oops.patch
@@ -0,0 +1,34 @@
+From e0a748983b07205d9f2f52230c897f49a2c84c8d Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 14 Jul 2015 14:26:34 +0200
+Subject: [PATCH 243/323] panic: skip get_random_bytes for RT_FULL in
+ init_oops_id
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Disable on -RT. If this is invoked from irq-context we will have problems
+to acquire the sleeping lock.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ kernel/panic.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/kernel/panic.c b/kernel/panic.c
+index 5a1a4bf2feb3..aa36078657be 100644
+--- a/kernel/panic.c
++++ b/kernel/panic.c
+@@ -621,9 +621,11 @@ static u64 oops_id;
+ 
+ static int init_oops_id(void)
+ {
++#ifndef CONFIG_PREEMPT_RT
+ 	if (!oops_id)
+ 		get_random_bytes(&oops_id, sizeof(oops_id));
+ 	else
++#endif
+ 		oops_id++;
+ 
+ 	return 0;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0244-x86-stackprotector-Avoid-random-pool-on-rt.patch b/debian/patches-rt/0244-x86-stackprotector-Avoid-random-pool-on-rt.patch
new file mode 100644
index 000000000..c8e46ef39
--- /dev/null
+++ b/debian/patches-rt/0244-x86-stackprotector-Avoid-random-pool-on-rt.patch
@@ -0,0 +1,51 @@
+From f7c4220e56be1d8fc2bc339984fb5919ee02cf4f Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 16 Dec 2010 14:25:18 +0100
+Subject: [PATCH 244/323] x86: stackprotector: Avoid random pool on rt
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+CPU bringup calls into the random pool to initialize the stack
+canary. During boot that works nicely even on RT as the might sleep
+checks are disabled. During CPU hotplug the might sleep checks
+trigger. Making the locks in random raw is a major PITA, so avoid the
+call on RT is the only sensible solution. This is basically the same
+randomness which we get during boot where the random pool has no
+entropy and we rely on the TSC randomnness.
+
+Reported-by: Carsten Emde <carsten.emde@osadl.org>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ arch/x86/include/asm/stackprotector.h | 8 +++++++-
+ 1 file changed, 7 insertions(+), 1 deletion(-)
+
+diff --git a/arch/x86/include/asm/stackprotector.h b/arch/x86/include/asm/stackprotector.h
+index 7fb482f0f25b..3df0a95c9e13 100644
+--- a/arch/x86/include/asm/stackprotector.h
++++ b/arch/x86/include/asm/stackprotector.h
+@@ -65,7 +65,7 @@
+  */
+ static __always_inline void boot_init_stack_canary(void)
+ {
+-	u64 canary;
++	u64 canary = 0;
+ 	u64 tsc;
+ 
+ #ifdef CONFIG_X86_64
+@@ -76,8 +76,14 @@ static __always_inline void boot_init_stack_canary(void)
+ 	 * of randomness. The TSC only matters for very early init,
+ 	 * there it already has some randomness on most systems. Later
+ 	 * on during the bootup the random pool has true entropy too.
++	 * For preempt-rt we need to weaken the randomness a bit, as
++	 * we can't call into the random generator from atomic context
++	 * due to locking constraints. We just leave canary
++	 * uninitialized and use the TSC based randomness on top of it.
+ 	 */
++#ifndef CONFIG_PREEMPT_RT
+ 	get_random_bytes(&canary, sizeof(canary));
++#endif
+ 	tsc = rdtsc();
+ 	canary += tsc + (tsc << 32UL);
+ 	canary &= CANARY_MASK;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0245-net-Remove-preemption-disabling-in-netif_rx.patch b/debian/patches-rt/0245-net-Remove-preemption-disabling-in-netif_rx.patch
new file mode 100644
index 000000000..88ffbf8ad
--- /dev/null
+++ b/debian/patches-rt/0245-net-Remove-preemption-disabling-in-netif_rx.patch
@@ -0,0 +1,68 @@
+From ceda0e136831589d22c9bd35844b3fafcc722e7c Mon Sep 17 00:00:00 2001
+From: Priyanka Jain <Priyanka.Jain@freescale.com>
+Date: Thu, 17 May 2012 09:35:11 +0530
+Subject: [PATCH 245/323] net: Remove preemption disabling in netif_rx()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+1)enqueue_to_backlog() (called from netif_rx) should be
+  bind to a particluar CPU. This can be achieved by
+  disabling migration. No need to disable preemption
+
+2)Fixes crash "BUG: scheduling while atomic: ksoftirqd"
+  in case of RT.
+  If preemption is disabled, enqueue_to_backog() is called
+  in atomic context. And if backlog exceeds its count,
+  kfree_skb() is called. But in RT, kfree_skb() might
+  gets scheduled out, so it expects non atomic context.
+
+-Replace preempt_enable(), preempt_disable() with
+ migrate_enable(), migrate_disable() respectively
+-Replace get_cpu(), put_cpu() with get_cpu_light(),
+ put_cpu_light() respectively
+
+Signed-off-by: Priyanka Jain <Priyanka.Jain@freescale.com>
+Acked-by: Rajan Srivastava <Rajan.Srivastava@freescale.com>
+Cc: <rostedt@goodmis.orgn>
+Link: http://lkml.kernel.org/r/1337227511-2271-1-git-send-email-Priyanka.Jain@freescale.com
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+[bigeasy: Remove assumption about migrate_disable() from the description.]
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ net/core/dev.c | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/net/core/dev.c b/net/core/dev.c
+index c3b4e5e320ca..fb00a777f559 100644
+--- a/net/core/dev.c
++++ b/net/core/dev.c
+@@ -4818,7 +4818,7 @@ static int netif_rx_internal(struct sk_buff *skb)
+ 		struct rps_dev_flow voidflow, *rflow = &voidflow;
+ 		int cpu;
+ 
+-		preempt_disable();
++		migrate_disable();
+ 		rcu_read_lock();
+ 
+ 		cpu = get_rps_cpu(skb->dev, skb, &rflow);
+@@ -4828,14 +4828,14 @@ static int netif_rx_internal(struct sk_buff *skb)
+ 		ret = enqueue_to_backlog(skb, cpu, &rflow->last_qtail);
+ 
+ 		rcu_read_unlock();
+-		preempt_enable();
++		migrate_enable();
+ 	} else
+ #endif
+ 	{
+ 		unsigned int qtail;
+ 
+-		ret = enqueue_to_backlog(skb, get_cpu(), &qtail);
+-		put_cpu();
++		ret = enqueue_to_backlog(skb, get_cpu_light(), &qtail);
++		put_cpu_light();
+ 	}
+ 	return ret;
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0246-lockdep-Make-it-RT-aware.patch b/debian/patches-rt/0246-lockdep-Make-it-RT-aware.patch
new file mode 100644
index 000000000..6c7174f34
--- /dev/null
+++ b/debian/patches-rt/0246-lockdep-Make-it-RT-aware.patch
@@ -0,0 +1,78 @@
+From 9d9c323e950c13cde64d5ae87dd12e0e3b81abd8 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Sun, 17 Jul 2011 18:51:23 +0200
+Subject: [PATCH 246/323] lockdep: Make it RT aware
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+teach lockdep that we don't really do softirqs on -RT.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/irqflags.h | 23 +++++++++++++++--------
+ kernel/locking/lockdep.c |  2 ++
+ 2 files changed, 17 insertions(+), 8 deletions(-)
+
+diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
+index 3ed4e8771b64..a437b2e70d37 100644
+--- a/include/linux/irqflags.h
++++ b/include/linux/irqflags.h
+@@ -71,14 +71,6 @@ do {						\
+ do {						\
+ 	__this_cpu_dec(hardirq_context);	\
+ } while (0)
+-# define lockdep_softirq_enter()		\
+-do {						\
+-	current->softirq_context++;		\
+-} while (0)
+-# define lockdep_softirq_exit()			\
+-do {						\
+-	current->softirq_context--;		\
+-} while (0)
+ 
+ # define lockdep_hrtimer_enter(__hrtimer)		\
+ ({							\
+@@ -140,6 +132,21 @@ do {						\
+ # define lockdep_irq_work_exit(__work)		do { } while (0)
+ #endif
+ 
++#if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PREEMPT_RT)
++# define lockdep_softirq_enter()		\
++do {						\
++	current->softirq_context++;		\
++} while (0)
++# define lockdep_softirq_exit()			\
++do {						\
++	current->softirq_context--;		\
++} while (0)
++
++#else
++# define lockdep_softirq_enter()		do { } while (0)
++# define lockdep_softirq_exit()			do { } while (0)
++#endif
++
+ #if defined(CONFIG_IRQSOFF_TRACER) || \
+ 	defined(CONFIG_PREEMPT_TRACER)
+  extern void stop_critical_timings(void);
+diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
+index 7471d85f54ae..4fb9e6301018 100644
+--- a/kernel/locking/lockdep.c
++++ b/kernel/locking/lockdep.c
+@@ -5414,6 +5414,7 @@ static noinstr void check_flags(unsigned long flags)
+ 		}
+ 	}
+ 
++#ifndef CONFIG_PREEMPT_RT
+ 	/*
+ 	 * We dont accurately track softirq state in e.g.
+ 	 * hardirq contexts (such as on 4KSTACKS), so only
+@@ -5428,6 +5429,7 @@ static noinstr void check_flags(unsigned long flags)
+ 			DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
+ 		}
+ 	}
++#endif
+ 
+ 	if (!debug_locks)
+ 		print_irqtrace_events(current);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0247-lockdep-selftest-Only-do-hardirq-context-test-for-ra.patch b/debian/patches-rt/0247-lockdep-selftest-Only-do-hardirq-context-test-for-ra.patch
new file mode 100644
index 000000000..c4ca02928
--- /dev/null
+++ b/debian/patches-rt/0247-lockdep-selftest-Only-do-hardirq-context-test-for-ra.patch
@@ -0,0 +1,62 @@
+From 98d28c479e8b02a795109f6bc0b6aa1da54f6ede Mon Sep 17 00:00:00 2001
+From: Yong Zhang <yong.zhang@windriver.com>
+Date: Mon, 16 Apr 2012 15:01:56 +0800
+Subject: [PATCH 247/323] lockdep: selftest: Only do hardirq context test for
+ raw spinlock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+On -rt there is no softirq context any more and rwlock is sleepable,
+disable softirq context test and rwlock+irq test.
+
+Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
+Cc: Yong Zhang <yong.zhang@windriver.com>
+Link: http://lkml.kernel.org/r/1334559716-18447-3-git-send-email-yong.zhang0@gmail.com
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ lib/locking-selftest.c | 23 +++++++++++++++++++++++
+ 1 file changed, 23 insertions(+)
+
+diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
+index 76c52b0b76d3..663c071bc445 100644
+--- a/lib/locking-selftest.c
++++ b/lib/locking-selftest.c
+@@ -2456,6 +2456,7 @@ void locking_selftest(void)
+ 
+ 	printk("  --------------------------------------------------------------------------\n");
+ 
++#ifndef CONFIG_PREEMPT_RT
+ 	/*
+ 	 * irq-context testcases:
+ 	 */
+@@ -2470,6 +2471,28 @@ void locking_selftest(void)
+ 	DO_TESTCASE_6x2x2RW("irq read-recursion #2", irq_read_recursion2);
+ 	DO_TESTCASE_6x2x2RW("irq read-recursion #3", irq_read_recursion3);
+ 
++#else
++	/* On -rt, we only do hardirq context test for raw spinlock */
++	DO_TESTCASE_1B("hard-irqs-on + irq-safe-A", irqsafe1_hard_spin, 12);
++	DO_TESTCASE_1B("hard-irqs-on + irq-safe-A", irqsafe1_hard_spin, 21);
++
++	DO_TESTCASE_1B("hard-safe-A + irqs-on", irqsafe2B_hard_spin, 12);
++	DO_TESTCASE_1B("hard-safe-A + irqs-on", irqsafe2B_hard_spin, 21);
++
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 123);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 132);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 213);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 231);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 312);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #1", irqsafe3_hard_spin, 321);
++
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 123);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 132);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 213);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 231);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 312);
++	DO_TESTCASE_1B("hard-safe-A + unsafe-B #2", irqsafe4_hard_spin, 321);
++#endif
+ 	ww_tests();
+ 
+ 	force_read_lock_recursive = 0;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0248-lockdep-selftest-fix-warnings-due-to-missing-PREEMPT.patch b/debian/patches-rt/0248-lockdep-selftest-fix-warnings-due-to-missing-PREEMPT.patch
new file mode 100644
index 000000000..dbb683c42
--- /dev/null
+++ b/debian/patches-rt/0248-lockdep-selftest-fix-warnings-due-to-missing-PREEMPT.patch
@@ -0,0 +1,149 @@
+From c10790e859050b8a0a251e2e57b7fffb9ffa75df Mon Sep 17 00:00:00 2001
+From: Josh Cartwright <josh.cartwright@ni.com>
+Date: Wed, 28 Jan 2015 13:08:45 -0600
+Subject: [PATCH 248/323] lockdep: selftest: fix warnings due to missing
+ PREEMPT_RT conditionals
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+"lockdep: Selftest: Only do hardirq context test for raw spinlock"
+disabled the execution of certain tests with PREEMPT_RT, but did
+not prevent the tests from still being defined.  This leads to warnings
+like:
+
+  ./linux/lib/locking-selftest.c:574:1: warning: 'irqsafe1_hard_rlock_12' defined but not used [-Wunused-function]
+  ./linux/lib/locking-selftest.c:574:1: warning: 'irqsafe1_hard_rlock_21' defined but not used [-Wunused-function]
+  ./linux/lib/locking-selftest.c:577:1: warning: 'irqsafe1_hard_wlock_12' defined but not used [-Wunused-function]
+  ./linux/lib/locking-selftest.c:577:1: warning: 'irqsafe1_hard_wlock_21' defined but not used [-Wunused-function]
+  ./linux/lib/locking-selftest.c:580:1: warning: 'irqsafe1_soft_spin_12' defined but not used [-Wunused-function]
+  ...
+
+Fixed by wrapping the test definitions in #ifndef CONFIG_PREEMPT_RT
+conditionals.
+
+Signed-off-by: Josh Cartwright <josh.cartwright@ni.com>
+Signed-off-by: Xander Huff <xander.huff@ni.com>
+Acked-by: Gratian Crisan <gratian.crisan@ni.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ lib/locking-selftest.c | 28 ++++++++++++++++++++++++++++
+ 1 file changed, 28 insertions(+)
+
+diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
+index 663c071bc445..98c376b02dff 100644
+--- a/lib/locking-selftest.c
++++ b/lib/locking-selftest.c
+@@ -787,6 +787,8 @@ GENERATE_TESTCASE(init_held_rtmutex);
+ #include "locking-selftest-spin-hardirq.h"
+ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_hard_spin)
+ 
++#ifndef CONFIG_PREEMPT_RT
++
+ #include "locking-selftest-rlock-hardirq.h"
+ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_hard_rlock)
+ 
+@@ -802,9 +804,12 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_soft_rlock)
+ #include "locking-selftest-wlock-softirq.h"
+ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe1_soft_wlock)
+ 
++#endif
++
+ #undef E1
+ #undef E2
+ 
++#ifndef CONFIG_PREEMPT_RT
+ /*
+  * Enabling hardirqs with a softirq-safe lock held:
+  */
+@@ -837,6 +842,8 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2A_rlock)
+ #undef E1
+ #undef E2
+ 
++#endif
++
+ /*
+  * Enabling irqs with an irq-safe lock held:
+  */
+@@ -860,6 +867,8 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2A_rlock)
+ #include "locking-selftest-spin-hardirq.h"
+ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_hard_spin)
+ 
++#ifndef CONFIG_PREEMPT_RT
++
+ #include "locking-selftest-rlock-hardirq.h"
+ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_hard_rlock)
+ 
+@@ -875,6 +884,8 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_soft_rlock)
+ #include "locking-selftest-wlock-softirq.h"
+ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_soft_wlock)
+ 
++#endif
++
+ #undef E1
+ #undef E2
+ 
+@@ -906,6 +917,8 @@ GENERATE_PERMUTATIONS_2_EVENTS(irqsafe2B_soft_wlock)
+ #include "locking-selftest-spin-hardirq.h"
+ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_hard_spin)
+ 
++#ifndef CONFIG_PREEMPT_RT
++
+ #include "locking-selftest-rlock-hardirq.h"
+ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_hard_rlock)
+ 
+@@ -921,6 +934,8 @@ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_soft_rlock)
+ #include "locking-selftest-wlock-softirq.h"
+ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_soft_wlock)
+ 
++#endif
++
+ #undef E1
+ #undef E2
+ #undef E3
+@@ -954,6 +969,8 @@ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe3_soft_wlock)
+ #include "locking-selftest-spin-hardirq.h"
+ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_hard_spin)
+ 
++#ifndef CONFIG_PREEMPT_RT
++
+ #include "locking-selftest-rlock-hardirq.h"
+ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_hard_rlock)
+ 
+@@ -969,10 +986,14 @@ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_soft_rlock)
+ #include "locking-selftest-wlock-softirq.h"
+ GENERATE_PERMUTATIONS_3_EVENTS(irqsafe4_soft_wlock)
+ 
++#endif
++
+ #undef E1
+ #undef E2
+ #undef E3
+ 
++#ifndef CONFIG_PREEMPT_RT
++
+ /*
+  * read-lock / write-lock irq inversion.
+  *
+@@ -1162,6 +1183,11 @@ GENERATE_PERMUTATIONS_3_EVENTS(W1W2_R2R3_R3W1)
+ #undef E1
+ #undef E2
+ #undef E3
++
++#endif
++
++#ifndef CONFIG_PREEMPT_RT
++
+ /*
+  * read-lock / write-lock recursion that is actually safe.
+  */
+@@ -1208,6 +1234,8 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion_soft_wlock)
+ #undef E2
+ #undef E3
+ 
++#endif
++
+ /*
+  * read-lock / write-lock recursion that is unsafe.
+  */
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0249-lockdep-disable-self-test.patch b/debian/patches-rt/0249-lockdep-disable-self-test.patch
new file mode 100644
index 000000000..bd19a4f00
--- /dev/null
+++ b/debian/patches-rt/0249-lockdep-disable-self-test.patch
@@ -0,0 +1,35 @@
+From da32b1f1c20ebd096acfb511cf3a608169d210c7 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 17 Oct 2017 16:36:18 +0200
+Subject: [PATCH 249/323] lockdep: disable self-test
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The self-test wasn't always 100% accurate for RT. We disabled a few
+tests which failed because they had a different semantic for RT. Some
+still reported false positives. Now the selftest locks up the system
+during boot and it needs to be investigated…
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ lib/Kconfig.debug | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
+index 24ca61cf86dd..70172d5ab82a 100644
+--- a/lib/Kconfig.debug
++++ b/lib/Kconfig.debug
+@@ -1373,7 +1373,7 @@ config DEBUG_ATOMIC_SLEEP
+ 
+ config DEBUG_LOCKING_API_SELFTESTS
+ 	bool "Locking API boot-time self-tests"
+-	depends on DEBUG_KERNEL
++	depends on DEBUG_KERNEL && !PREEMPT_RT
+ 	help
+ 	  Say Y here if you want the kernel to run a short self-test during
+ 	  bootup. The self-test checks whether common types of locking bugs
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0250-drm-radeon-i915-Use-preempt_disable-enable_rt-where-.patch b/debian/patches-rt/0250-drm-radeon-i915-Use-preempt_disable-enable_rt-where-.patch
new file mode 100644
index 000000000..c0e7434f2
--- /dev/null
+++ b/debian/patches-rt/0250-drm-radeon-i915-Use-preempt_disable-enable_rt-where-.patch
@@ -0,0 +1,61 @@
+From 2c69acb6875156b092516fc81bd2a05b96973c2b Mon Sep 17 00:00:00 2001
+From: Mike Galbraith <umgwanakikbuti@gmail.com>
+Date: Sat, 27 Feb 2016 08:09:11 +0100
+Subject: [PATCH 250/323] drm,radeon,i915: Use preempt_disable/enable_rt()
+ where recommended
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+DRM folks identified the spots, so use them.
+
+Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
+Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Cc: linux-rt-users <linux-rt-users@vger.kernel.org>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ drivers/gpu/drm/i915/i915_irq.c         | 2 ++
+ drivers/gpu/drm/radeon/radeon_display.c | 2 ++
+ 2 files changed, 4 insertions(+)
+
+diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
+index 759f523c6a6b..7339a42ab2b8 100644
+--- a/drivers/gpu/drm/i915/i915_irq.c
++++ b/drivers/gpu/drm/i915/i915_irq.c
+@@ -847,6 +847,7 @@ static bool i915_get_crtc_scanoutpos(struct drm_crtc *_crtc,
+ 	spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
+ 
+ 	/* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */
++	preempt_disable_rt();
+ 
+ 	/* Get optional system timestamp before query. */
+ 	if (stime)
+@@ -898,6 +899,7 @@ static bool i915_get_crtc_scanoutpos(struct drm_crtc *_crtc,
+ 		*etime = ktime_get();
+ 
+ 	/* preempt_enable_rt() should go right here in PREEMPT_RT patchset. */
++	preempt_enable_rt();
+ 
+ 	spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
+ 
+diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
+index 71bdafac9210..95ce311f434b 100644
+--- a/drivers/gpu/drm/radeon/radeon_display.c
++++ b/drivers/gpu/drm/radeon/radeon_display.c
+@@ -1823,6 +1823,7 @@ int radeon_get_crtc_scanoutpos(struct drm_device *dev, unsigned int pipe,
+ 	struct radeon_device *rdev = dev->dev_private;
+ 
+ 	/* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */
++	preempt_disable_rt();
+ 
+ 	/* Get optional system timestamp before query. */
+ 	if (stime)
+@@ -1915,6 +1916,7 @@ int radeon_get_crtc_scanoutpos(struct drm_device *dev, unsigned int pipe,
+ 		*etime = ktime_get();
+ 
+ 	/* preempt_enable_rt() should go right here in PREEMPT_RT patchset. */
++	preempt_enable_rt();
+ 
+ 	/* Decode into vertical and horizontal scanout position. */
+ 	*vpos = position & 0x1fff;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0251-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch b/debian/patches-rt/0251-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch
new file mode 100644
index 000000000..dd9329591
--- /dev/null
+++ b/debian/patches-rt/0251-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch
@@ -0,0 +1,80 @@
+From 940e64f8d4b797c592e6736a1fae0d0ff2087e95 Mon Sep 17 00:00:00 2001
+From: Mike Galbraith <umgwanakikbuti@gmail.com>
+Date: Sat, 27 Feb 2016 09:01:42 +0100
+Subject: [PATCH 251/323] drm/i915: Don't disable interrupts on PREEMPT_RT
+ during atomic updates
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Commit
+   8d7849db3eab7 ("drm/i915: Make sprite updates atomic")
+
+started disabling interrupts across atomic updates. This breaks on PREEMPT_RT
+because within this section the code attempt to acquire spinlock_t locks which
+are sleeping locks on PREEMPT_RT.
+
+According to the comment the interrupts are disabled to avoid random delays and
+not required for protection or synchronisation.
+
+Don't disable interrupts on PREEMPT_RT during atomic updates.
+
+[bigeasy: drop local locks, commit message]
+
+Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/gpu/drm/i915/display/intel_sprite.c | 15 ++++++++++-----
+ 1 file changed, 10 insertions(+), 5 deletions(-)
+
+diff --git a/drivers/gpu/drm/i915/display/intel_sprite.c b/drivers/gpu/drm/i915/display/intel_sprite.c
+index 12f7128b777f..a65061e3e1d3 100644
+--- a/drivers/gpu/drm/i915/display/intel_sprite.c
++++ b/drivers/gpu/drm/i915/display/intel_sprite.c
+@@ -118,7 +118,8 @@ void intel_pipe_update_start(const struct intel_crtc_state *new_crtc_state)
+ 			"PSR idle timed out 0x%x, atomic update may fail\n",
+ 			psr_status);
+ 
+-	local_irq_disable();
++	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
++		local_irq_disable();
+ 
+ 	crtc->debug.min_vbl = min;
+ 	crtc->debug.max_vbl = max;
+@@ -143,11 +144,13 @@ void intel_pipe_update_start(const struct intel_crtc_state *new_crtc_state)
+ 			break;
+ 		}
+ 
+-		local_irq_enable();
++		if (!IS_ENABLED(CONFIG_PREEMPT_RT))
++			local_irq_enable();
+ 
+ 		timeout = schedule_timeout(timeout);
+ 
+-		local_irq_disable();
++		if (!IS_ENABLED(CONFIG_PREEMPT_RT))
++			local_irq_disable();
+ 	}
+ 
+ 	finish_wait(wq, &wait);
+@@ -180,7 +183,8 @@ void intel_pipe_update_start(const struct intel_crtc_state *new_crtc_state)
+ 	return;
+ 
+ irq_disable:
+-	local_irq_disable();
++	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
++		local_irq_disable();
+ }
+ 
+ /**
+@@ -218,7 +222,8 @@ void intel_pipe_update_end(struct intel_crtc_state *new_crtc_state)
+ 		new_crtc_state->uapi.event = NULL;
+ 	}
+ 
+-	local_irq_enable();
++	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
++		local_irq_enable();
+ 
+ 	if (intel_vgpu_active(dev_priv))
+ 		return;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0252-drm-i915-disable-tracing-on-RT.patch b/debian/patches-rt/0252-drm-i915-disable-tracing-on-RT.patch
new file mode 100644
index 000000000..833c9d37f
--- /dev/null
+++ b/debian/patches-rt/0252-drm-i915-disable-tracing-on-RT.patch
@@ -0,0 +1,47 @@
+From 0e88cde8cbd40cc7e519bccaf1ba847de2d9bd02 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Thu, 6 Dec 2018 09:52:20 +0100
+Subject: [PATCH 252/323] drm/i915: disable tracing on -RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Luca Abeni reported this:
+| BUG: scheduling while atomic: kworker/u8:2/15203/0x00000003
+| CPU: 1 PID: 15203 Comm: kworker/u8:2 Not tainted 4.19.1-rt3 #10
+| Call Trace:
+|  rt_spin_lock+0x3f/0x50
+|  gen6_read32+0x45/0x1d0 [i915]
+|  g4x_get_vblank_counter+0x36/0x40 [i915]
+|  trace_event_raw_event_i915_pipe_update_start+0x7d/0xf0 [i915]
+
+The tracing events use trace_i915_pipe_update_start() among other events
+use functions acquire spin locks. A few trace points use
+intel_get_crtc_scanline(), others use ->get_vblank_counter() wich also
+might acquire a sleeping lock.
+
+Based on this I don't see any other way than disable trace points on RT.
+
+Cc: stable-rt@vger.kernel.org
+Reported-by: Luca Abeni <lucabe72@gmail.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/gpu/drm/i915/i915_trace.h | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h
+index a4addcc64978..0ba5a0a0fd25 100644
+--- a/drivers/gpu/drm/i915/i915_trace.h
++++ b/drivers/gpu/drm/i915/i915_trace.h
+@@ -2,6 +2,10 @@
+ #if !defined(_I915_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ)
+ #define _I915_TRACE_H_
+ 
++#ifdef CONFIG_PREEMPT_RT
++#define NOTRACE
++#endif
++
+ #include <linux/stringify.h>
+ #include <linux/types.h>
+ #include <linux/tracepoint.h>
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0253-drm-i915-skip-DRM_I915_LOW_LEVEL_TRACEPOINTS-with-NO.patch b/debian/patches-rt/0253-drm-i915-skip-DRM_I915_LOW_LEVEL_TRACEPOINTS-with-NO.patch
new file mode 100644
index 000000000..9aa6af966
--- /dev/null
+++ b/debian/patches-rt/0253-drm-i915-skip-DRM_I915_LOW_LEVEL_TRACEPOINTS-with-NO.patch
@@ -0,0 +1,33 @@
+From 2c550981e43f1612f6999bbc04634e0d6eb16760 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 19 Dec 2018 10:47:02 +0100
+Subject: [PATCH 253/323] drm/i915: skip DRM_I915_LOW_LEVEL_TRACEPOINTS with
+ NOTRACE
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The order of the header files is important. If this header file is
+included after tracepoint.h was included then the NOTRACE here becomes a
+nop. Currently this happens for two .c files which use the tracepoitns
+behind DRM_I915_LOW_LEVEL_TRACEPOINTS.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/gpu/drm/i915/i915_trace.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h
+index 0ba5a0a0fd25..396b6598694d 100644
+--- a/drivers/gpu/drm/i915/i915_trace.h
++++ b/drivers/gpu/drm/i915/i915_trace.h
+@@ -782,7 +782,7 @@ DEFINE_EVENT(i915_request, i915_request_add,
+ 	    TP_ARGS(rq)
+ );
+ 
+-#if defined(CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS)
++#if defined(CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS) && !defined(NOTRACE)
+ DEFINE_EVENT(i915_request, i915_request_submit,
+ 	     TP_PROTO(struct i915_request *rq),
+ 	     TP_ARGS(rq)
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0254-drm-i915-gt-Only-disable-interrupts-for-the-timeline.patch b/debian/patches-rt/0254-drm-i915-gt-Only-disable-interrupts-for-the-timeline.patch
new file mode 100644
index 000000000..722c5567e
--- /dev/null
+++ b/debian/patches-rt/0254-drm-i915-gt-Only-disable-interrupts-for-the-timeline.patch
@@ -0,0 +1,52 @@
+From 63884dc87002ed5187007558a7356e7a4f570e75 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 7 Jul 2020 12:25:11 +0200
+Subject: [PATCH 254/323] drm/i915/gt: Only disable interrupts for the timeline
+ lock on !force-threaded
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+According to commit
+    d67739268cf0e ("drm/i915/gt: Mark up the nested engine-pm timeline lock as irqsafe")
+
+the intrrupts are disabled the code may be called from an interrupt
+handler and from preemptible context.
+With `force_irqthreads' set the timeline mutex is never observed in IRQ
+context so it is not neede to disable interrupts.
+
+Disable only interrupts if not in `force_irqthreads' mode.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/gpu/drm/i915/gt/intel_engine_pm.c | 8 +++++---
+ 1 file changed, 5 insertions(+), 3 deletions(-)
+
+diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+index f7b2e07e2229..313d8a28e776 100644
+--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
++++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+@@ -60,9 +60,10 @@ static int __engine_unpark(struct intel_wakeref *wf)
+ 
+ static inline unsigned long __timeline_mark_lock(struct intel_context *ce)
+ {
+-	unsigned long flags;
++	unsigned long flags = 0;
+ 
+-	local_irq_save(flags);
++	if (!force_irqthreads)
++		local_irq_save(flags);
+ 	mutex_acquire(&ce->timeline->mutex.dep_map, 2, 0, _THIS_IP_);
+ 
+ 	return flags;
+@@ -72,7 +73,8 @@ static inline void __timeline_mark_unlock(struct intel_context *ce,
+ 					  unsigned long flags)
+ {
+ 	mutex_release(&ce->timeline->mutex.dep_map, _THIS_IP_);
+-	local_irq_restore(flags);
++	if (!force_irqthreads)
++		local_irq_restore(flags);
+ }
+ 
+ #else
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0255-cpuset-Convert-callback_lock-to-raw_spinlock_t.patch b/debian/patches-rt/0255-cpuset-Convert-callback_lock-to-raw_spinlock_t.patch
new file mode 100644
index 000000000..bb6e6895a
--- /dev/null
+++ b/debian/patches-rt/0255-cpuset-Convert-callback_lock-to-raw_spinlock_t.patch
@@ -0,0 +1,367 @@
+From ebc27a7d1ceef838efef4feecd2bcb490552f0ec Mon Sep 17 00:00:00 2001
+From: Mike Galbraith <efault@gmx.de>
+Date: Sun, 8 Jan 2017 09:32:25 +0100
+Subject: [PATCH 255/323] cpuset: Convert callback_lock to raw_spinlock_t
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The two commits below add up to a cpuset might_sleep() splat for RT:
+
+8447a0fee974 cpuset: convert callback_mutex to a spinlock
+344736f29b35 cpuset: simplify cpuset_node_allowed API
+
+BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:995
+in_atomic(): 0, irqs_disabled(): 1, pid: 11718, name: cset
+CPU: 135 PID: 11718 Comm: cset Tainted: G            E   4.10.0-rt1-rt #4
+Hardware name: Intel Corporation BRICKLAND/BRICKLAND, BIOS BRHSXSD1.86B.0056.R01.1409242327 09/24/2014
+Call Trace:
+ ? dump_stack+0x5c/0x81
+ ? ___might_sleep+0xf4/0x170
+ ? rt_spin_lock+0x1c/0x50
+ ? __cpuset_node_allowed+0x66/0xc0
+ ? ___slab_alloc+0x390/0x570 <disables IRQs>
+ ? anon_vma_fork+0x8f/0x140
+ ? copy_page_range+0x6cf/0xb00
+ ? anon_vma_fork+0x8f/0x140
+ ? __slab_alloc.isra.74+0x5a/0x81
+ ? anon_vma_fork+0x8f/0x140
+ ? kmem_cache_alloc+0x1b5/0x1f0
+ ? anon_vma_fork+0x8f/0x140
+ ? copy_process.part.35+0x1670/0x1ee0
+ ? _do_fork+0xdd/0x3f0
+ ? _do_fork+0xdd/0x3f0
+ ? do_syscall_64+0x61/0x170
+ ? entry_SYSCALL64_slow_path+0x25/0x25
+
+The later ensured that a NUMA box WILL take callback_lock in atomic
+context by removing the allocator and reclaim path __GFP_HARDWALL
+usage which prevented such contexts from taking callback_mutex.
+
+One option would be to reinstate __GFP_HARDWALL protections for
+RT, however, as the 8447a0fee974 changelog states:
+
+The callback_mutex is only used to synchronize reads/updates of cpusets'
+flags and cpu/node masks. These operations should always proceed fast so
+there's no reason why we can't use a spinlock instead of the mutex.
+
+Cc: stable-rt@vger.kernel.org
+Signed-off-by: Mike Galbraith <efault@gmx.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ kernel/cgroup/cpuset.c | 82 +++++++++++++++++++++---------------------
+ 1 file changed, 41 insertions(+), 41 deletions(-)
+
+diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
+index 195f9cccab20..fd371215b81f 100644
+--- a/kernel/cgroup/cpuset.c
++++ b/kernel/cgroup/cpuset.c
+@@ -368,7 +368,7 @@ void cpuset_unlock(void)
+ 	mutex_unlock(&cpuset_mutex);
+ }
+ 
+-static DEFINE_SPINLOCK(callback_lock);
++static DEFINE_RAW_SPINLOCK(callback_lock);
+ 
+ static struct workqueue_struct *cpuset_migrate_mm_wq;
+ 
+@@ -1316,7 +1316,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
+ 	 * Newly added CPUs will be removed from effective_cpus and
+ 	 * newly deleted ones will be added back to effective_cpus.
+ 	 */
+-	spin_lock_irq(&callback_lock);
++	raw_spin_lock_irq(&callback_lock);
+ 	if (adding) {
+ 		cpumask_or(parent->subparts_cpus,
+ 			   parent->subparts_cpus, tmp->addmask);
+@@ -1338,7 +1338,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
+ 
+ 	if (cpuset->partition_root_state != new_prs)
+ 		cpuset->partition_root_state = new_prs;
+-	spin_unlock_irq(&callback_lock);
++	raw_spin_unlock_irq(&callback_lock);
+ 
+ 	return cmd == partcmd_update;
+ }
+@@ -1441,7 +1441,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
+ 			continue;
+ 		rcu_read_unlock();
+ 
+-		spin_lock_irq(&callback_lock);
++		raw_spin_lock_irq(&callback_lock);
+ 
+ 		cpumask_copy(cp->effective_cpus, tmp->new_cpus);
+ 		if (cp->nr_subparts_cpus && (new_prs != PRS_ENABLED)) {
+@@ -1475,7 +1475,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
+ 		if (new_prs != cp->partition_root_state)
+ 			cp->partition_root_state = new_prs;
+ 
+-		spin_unlock_irq(&callback_lock);
++		raw_spin_unlock_irq(&callback_lock);
+ 
+ 		WARN_ON(!is_in_v2_mode() &&
+ 			!cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
+@@ -1603,7 +1603,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
+ 			return -EINVAL;
+ 	}
+ 
+-	spin_lock_irq(&callback_lock);
++	raw_spin_lock_irq(&callback_lock);
+ 	cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
+ 
+ 	/*
+@@ -1613,7 +1613,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
+ 		cpumask_and(cs->subparts_cpus, cs->subparts_cpus, cs->cpus_allowed);
+ 		cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus);
+ 	}
+-	spin_unlock_irq(&callback_lock);
++	raw_spin_unlock_irq(&callback_lock);
+ 
+ 	update_cpumasks_hier(cs, &tmp);
+ 
+@@ -1807,9 +1807,9 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
+ 			continue;
+ 		rcu_read_unlock();
+ 
+-		spin_lock_irq(&callback_lock);
++		raw_spin_lock_irq(&callback_lock);
+ 		cp->effective_mems = *new_mems;
+-		spin_unlock_irq(&callback_lock);
++		raw_spin_unlock_irq(&callback_lock);
+ 
+ 		WARN_ON(!is_in_v2_mode() &&
+ 			!nodes_equal(cp->mems_allowed, cp->effective_mems));
+@@ -1877,9 +1877,9 @@ static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
+ 	if (retval < 0)
+ 		goto done;
+ 
+-	spin_lock_irq(&callback_lock);
++	raw_spin_lock_irq(&callback_lock);
+ 	cs->mems_allowed = trialcs->mems_allowed;
+-	spin_unlock_irq(&callback_lock);
++	raw_spin_unlock_irq(&callback_lock);
+ 
+ 	/* use trialcs->mems_allowed as a temp variable */
+ 	update_nodemasks_hier(cs, &trialcs->mems_allowed);
+@@ -1970,9 +1970,9 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
+ 	spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
+ 			|| (is_spread_page(cs) != is_spread_page(trialcs)));
+ 
+-	spin_lock_irq(&callback_lock);
++	raw_spin_lock_irq(&callback_lock);
+ 	cs->flags = trialcs->flags;
+-	spin_unlock_irq(&callback_lock);
++	raw_spin_unlock_irq(&callback_lock);
+ 
+ 	if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
+ 		rebuild_sched_domains_locked();
+@@ -2058,9 +2058,9 @@ static int update_prstate(struct cpuset *cs, int new_prs)
+ 	rebuild_sched_domains_locked();
+ out:
+ 	if (!err) {
+-		spin_lock_irq(&callback_lock);
++		raw_spin_lock_irq(&callback_lock);
+ 		cs->partition_root_state = new_prs;
+-		spin_unlock_irq(&callback_lock);
++		raw_spin_unlock_irq(&callback_lock);
+ 	}
+ 
+ 	free_cpumasks(NULL, &tmpmask);
+@@ -2527,7 +2527,7 @@ static int cpuset_common_seq_show(struct seq_file *sf, void *v)
+ 	cpuset_filetype_t type = seq_cft(sf)->private;
+ 	int ret = 0;
+ 
+-	spin_lock_irq(&callback_lock);
++	raw_spin_lock_irq(&callback_lock);
+ 
+ 	switch (type) {
+ 	case FILE_CPULIST:
+@@ -2549,7 +2549,7 @@ static int cpuset_common_seq_show(struct seq_file *sf, void *v)
+ 		ret = -EINVAL;
+ 	}
+ 
+-	spin_unlock_irq(&callback_lock);
++	raw_spin_unlock_irq(&callback_lock);
+ 	return ret;
+ }
+ 
+@@ -2862,14 +2862,14 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
+ 
+ 	cpuset_inc();
+ 
+-	spin_lock_irq(&callback_lock);
++	raw_spin_lock_irq(&callback_lock);
+ 	if (is_in_v2_mode()) {
+ 		cpumask_copy(cs->effective_cpus, parent->effective_cpus);
+ 		cs->effective_mems = parent->effective_mems;
+ 		cs->use_parent_ecpus = true;
+ 		parent->child_ecpus_count++;
+ 	}
+-	spin_unlock_irq(&callback_lock);
++	raw_spin_unlock_irq(&callback_lock);
+ 
+ 	if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags))
+ 		goto out_unlock;
+@@ -2896,12 +2896,12 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
+ 	}
+ 	rcu_read_unlock();
+ 
+-	spin_lock_irq(&callback_lock);
++	raw_spin_lock_irq(&callback_lock);
+ 	cs->mems_allowed = parent->mems_allowed;
+ 	cs->effective_mems = parent->mems_allowed;
+ 	cpumask_copy(cs->cpus_allowed, parent->cpus_allowed);
+ 	cpumask_copy(cs->effective_cpus, parent->cpus_allowed);
+-	spin_unlock_irq(&callback_lock);
++	raw_spin_unlock_irq(&callback_lock);
+ out_unlock:
+ 	mutex_unlock(&cpuset_mutex);
+ 	put_online_cpus();
+@@ -2957,7 +2957,7 @@ static void cpuset_css_free(struct cgroup_subsys_state *css)
+ static void cpuset_bind(struct cgroup_subsys_state *root_css)
+ {
+ 	mutex_lock(&cpuset_mutex);
+-	spin_lock_irq(&callback_lock);
++	raw_spin_lock_irq(&callback_lock);
+ 
+ 	if (is_in_v2_mode()) {
+ 		cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask);
+@@ -2968,7 +2968,7 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css)
+ 		top_cpuset.mems_allowed = top_cpuset.effective_mems;
+ 	}
+ 
+-	spin_unlock_irq(&callback_lock);
++	raw_spin_unlock_irq(&callback_lock);
+ 	mutex_unlock(&cpuset_mutex);
+ }
+ 
+@@ -3063,12 +3063,12 @@ hotplug_update_tasks_legacy(struct cpuset *cs,
+ {
+ 	bool is_empty;
+ 
+-	spin_lock_irq(&callback_lock);
++	raw_spin_lock_irq(&callback_lock);
+ 	cpumask_copy(cs->cpus_allowed, new_cpus);
+ 	cpumask_copy(cs->effective_cpus, new_cpus);
+ 	cs->mems_allowed = *new_mems;
+ 	cs->effective_mems = *new_mems;
+-	spin_unlock_irq(&callback_lock);
++	raw_spin_unlock_irq(&callback_lock);
+ 
+ 	/*
+ 	 * Don't call update_tasks_cpumask() if the cpuset becomes empty,
+@@ -3105,10 +3105,10 @@ hotplug_update_tasks(struct cpuset *cs,
+ 	if (nodes_empty(*new_mems))
+ 		*new_mems = parent_cs(cs)->effective_mems;
+ 
+-	spin_lock_irq(&callback_lock);
++	raw_spin_lock_irq(&callback_lock);
+ 	cpumask_copy(cs->effective_cpus, new_cpus);
+ 	cs->effective_mems = *new_mems;
+-	spin_unlock_irq(&callback_lock);
++	raw_spin_unlock_irq(&callback_lock);
+ 
+ 	if (cpus_updated)
+ 		update_tasks_cpumask(cs);
+@@ -3175,10 +3175,10 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
+ 	if (is_partition_root(cs) && (cpumask_empty(&new_cpus) ||
+ 	   (parent->partition_root_state == PRS_ERROR))) {
+ 		if (cs->nr_subparts_cpus) {
+-			spin_lock_irq(&callback_lock);
++			raw_spin_lock_irq(&callback_lock);
+ 			cs->nr_subparts_cpus = 0;
+ 			cpumask_clear(cs->subparts_cpus);
+-			spin_unlock_irq(&callback_lock);
++			raw_spin_unlock_irq(&callback_lock);
+ 			compute_effective_cpumask(&new_cpus, cs, parent);
+ 		}
+ 
+@@ -3192,9 +3192,9 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
+ 		     cpumask_empty(&new_cpus)) {
+ 			update_parent_subparts_cpumask(cs, partcmd_disable,
+ 						       NULL, tmp);
+-			spin_lock_irq(&callback_lock);
++			raw_spin_lock_irq(&callback_lock);
+ 			cs->partition_root_state = PRS_ERROR;
+-			spin_unlock_irq(&callback_lock);
++			raw_spin_unlock_irq(&callback_lock);
+ 		}
+ 		cpuset_force_rebuild();
+ 	}
+@@ -3274,7 +3274,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
+ 
+ 	/* synchronize cpus_allowed to cpu_active_mask */
+ 	if (cpus_updated) {
+-		spin_lock_irq(&callback_lock);
++		raw_spin_lock_irq(&callback_lock);
+ 		if (!on_dfl)
+ 			cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
+ 		/*
+@@ -3294,17 +3294,17 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
+ 			}
+ 		}
+ 		cpumask_copy(top_cpuset.effective_cpus, &new_cpus);
+-		spin_unlock_irq(&callback_lock);
++		raw_spin_unlock_irq(&callback_lock);
+ 		/* we don't mess with cpumasks of tasks in top_cpuset */
+ 	}
+ 
+ 	/* synchronize mems_allowed to N_MEMORY */
+ 	if (mems_updated) {
+-		spin_lock_irq(&callback_lock);
++		raw_spin_lock_irq(&callback_lock);
+ 		if (!on_dfl)
+ 			top_cpuset.mems_allowed = new_mems;
+ 		top_cpuset.effective_mems = new_mems;
+-		spin_unlock_irq(&callback_lock);
++		raw_spin_unlock_irq(&callback_lock);
+ 		update_tasks_nodemask(&top_cpuset);
+ 	}
+ 
+@@ -3408,11 +3408,11 @@ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
+ {
+ 	unsigned long flags;
+ 
+-	spin_lock_irqsave(&callback_lock, flags);
++	raw_spin_lock_irqsave(&callback_lock, flags);
+ 	rcu_read_lock();
+ 	guarantee_online_cpus(task_cs(tsk), pmask);
+ 	rcu_read_unlock();
+-	spin_unlock_irqrestore(&callback_lock, flags);
++	raw_spin_unlock_irqrestore(&callback_lock, flags);
+ }
+ 
+ /**
+@@ -3473,11 +3473,11 @@ nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
+ 	nodemask_t mask;
+ 	unsigned long flags;
+ 
+-	spin_lock_irqsave(&callback_lock, flags);
++	raw_spin_lock_irqsave(&callback_lock, flags);
+ 	rcu_read_lock();
+ 	guarantee_online_mems(task_cs(tsk), &mask);
+ 	rcu_read_unlock();
+-	spin_unlock_irqrestore(&callback_lock, flags);
++	raw_spin_unlock_irqrestore(&callback_lock, flags);
+ 
+ 	return mask;
+ }
+@@ -3569,14 +3569,14 @@ bool __cpuset_node_allowed(int node, gfp_t gfp_mask)
+ 		return true;
+ 
+ 	/* Not hardwall and node outside mems_allowed: scan up cpusets */
+-	spin_lock_irqsave(&callback_lock, flags);
++	raw_spin_lock_irqsave(&callback_lock, flags);
+ 
+ 	rcu_read_lock();
+ 	cs = nearest_hardwall_ancestor(task_cs(current));
+ 	allowed = node_isset(node, cs->mems_allowed);
+ 	rcu_read_unlock();
+ 
+-	spin_unlock_irqrestore(&callback_lock, flags);
++	raw_spin_unlock_irqrestore(&callback_lock, flags);
+ 	return allowed;
+ }
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0256-x86-Allow-to-enable-RT.patch b/debian/patches-rt/0256-x86-Allow-to-enable-RT.patch
new file mode 100644
index 000000000..50535647c
--- /dev/null
+++ b/debian/patches-rt/0256-x86-Allow-to-enable-RT.patch
@@ -0,0 +1,28 @@
+From 6ab508c3cdd4fa46f17f940bd56007189d4984e6 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 7 Aug 2019 18:15:38 +0200
+Subject: [PATCH 256/323] x86: Allow to enable RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Allow to select RT.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/x86/Kconfig | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
+index 54e5284a6ae1..c72d66a0e840 100644
+--- a/arch/x86/Kconfig
++++ b/arch/x86/Kconfig
+@@ -27,6 +27,7 @@ config X86_64
+ 	# Options that are inherently 64-bit kernel only:
+ 	select ARCH_HAS_GIGANTIC_PAGE
+ 	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
++	select ARCH_SUPPORTS_RT
+ 	select ARCH_USE_CMPXCHG_LOCKREF
+ 	select HAVE_ARCH_SOFT_DIRTY
+ 	select MODULES_USE_ELF_RELA
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0257-mm-scatterlist-Do-not-disable-irqs-on-RT.patch b/debian/patches-rt/0257-mm-scatterlist-Do-not-disable-irqs-on-RT.patch
new file mode 100644
index 000000000..c97153016
--- /dev/null
+++ b/debian/patches-rt/0257-mm-scatterlist-Do-not-disable-irqs-on-RT.patch
@@ -0,0 +1,30 @@
+From 767e9014ec3dbfeee9323cfcc34acac5315c262e Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 3 Jul 2009 08:44:34 -0500
+Subject: [PATCH 257/323] mm/scatterlist: Do not disable irqs on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+For -RT it is enough to keep pagefault disabled (which is currently handled by
+kmap_atomic()).
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ lib/scatterlist.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/lib/scatterlist.c b/lib/scatterlist.c
+index a59778946404..907f59045998 100644
+--- a/lib/scatterlist.c
++++ b/lib/scatterlist.c
+@@ -892,7 +892,7 @@ void sg_miter_stop(struct sg_mapping_iter *miter)
+ 			flush_kernel_dcache_page(miter->page);
+ 
+ 		if (miter->__flags & SG_MITER_ATOMIC) {
+-			WARN_ON_ONCE(preemptible());
++			WARN_ON_ONCE(!pagefault_disabled());
+ 			kunmap_atomic(miter->addr);
+ 		} else
+ 			kunmap(miter->page);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0258-sched-Add-support-for-lazy-preemption.patch b/debian/patches-rt/0258-sched-Add-support-for-lazy-preemption.patch
new file mode 100644
index 000000000..12d064860
--- /dev/null
+++ b/debian/patches-rt/0258-sched-Add-support-for-lazy-preemption.patch
@@ -0,0 +1,691 @@
+From e8b4a64bf2eb6ff6330544895c0f69696059ffda Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 26 Oct 2012 18:50:54 +0100
+Subject: [PATCH 258/323] sched: Add support for lazy preemption
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+It has become an obsession to mitigate the determinism vs. throughput
+loss of RT. Looking at the mainline semantics of preemption points
+gives a hint why RT sucks throughput wise for ordinary SCHED_OTHER
+tasks. One major issue is the wakeup of tasks which are right away
+preempting the waking task while the waking task holds a lock on which
+the woken task will block right after having preempted the wakee. In
+mainline this is prevented due to the implicit preemption disable of
+spin/rw_lock held regions. On RT this is not possible due to the fully
+preemptible nature of sleeping spinlocks.
+
+Though for a SCHED_OTHER task preempting another SCHED_OTHER task this
+is really not a correctness issue. RT folks are concerned about
+SCHED_FIFO/RR tasks preemption and not about the purely fairness
+driven SCHED_OTHER preemption latencies.
+
+So I introduced a lazy preemption mechanism which only applies to
+SCHED_OTHER tasks preempting another SCHED_OTHER task. Aside of the
+existing preempt_count each tasks sports now a preempt_lazy_count
+which is manipulated on lock acquiry and release. This is slightly
+incorrect as for lazyness reasons I coupled this on
+migrate_disable/enable so some other mechanisms get the same treatment
+(e.g. get_cpu_light).
+
+Now on the scheduler side instead of setting NEED_RESCHED this sets
+NEED_RESCHED_LAZY in case of a SCHED_OTHER/SCHED_OTHER preemption and
+therefor allows to exit the waking task the lock held region before
+the woken task preempts. That also works better for cross CPU wakeups
+as the other side can stay in the adaptive spinning loop.
+
+For RT class preemption there is no change. This simply sets
+NEED_RESCHED and forgoes the lazy preemption counter.
+
+ Initial test do not expose any observable latency increasement, but
+history shows that I've been proven wrong before :)
+
+The lazy preemption mode is per default on, but with
+CONFIG_SCHED_DEBUG enabled it can be disabled via:
+
+ # echo NO_PREEMPT_LAZY >/sys/kernel/debug/sched_features
+
+and reenabled via
+
+ # echo PREEMPT_LAZY >/sys/kernel/debug/sched_features
+
+The test results so far are very machine and workload dependent, but
+there is a clear trend that it enhances the non RT workload
+performance.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/preempt.h      | 54 ++++++++++++++++++++++--
+ include/linux/sched.h        | 38 +++++++++++++++++
+ include/linux/thread_info.h  | 12 +++++-
+ include/linux/trace_events.h |  5 ++-
+ kernel/Kconfig.preempt       |  6 +++
+ kernel/sched/core.c          | 82 +++++++++++++++++++++++++++++++++++-
+ kernel/sched/fair.c          | 16 +++----
+ kernel/sched/features.h      |  3 ++
+ kernel/sched/sched.h         |  9 ++++
+ kernel/trace/trace.c         | 50 +++++++++++++---------
+ kernel/trace/trace_events.c  |  1 +
+ kernel/trace/trace_output.c  | 14 +++++-
+ 12 files changed, 254 insertions(+), 36 deletions(-)
+
+diff --git a/include/linux/preempt.h b/include/linux/preempt.h
+index fb140e00f74d..af39859f02ee 100644
+--- a/include/linux/preempt.h
++++ b/include/linux/preempt.h
+@@ -174,6 +174,20 @@ extern void preempt_count_sub(int val);
+ #define preempt_count_inc() preempt_count_add(1)
+ #define preempt_count_dec() preempt_count_sub(1)
+ 
++#ifdef CONFIG_PREEMPT_LAZY
++#define add_preempt_lazy_count(val)	do { preempt_lazy_count() += (val); } while (0)
++#define sub_preempt_lazy_count(val)	do { preempt_lazy_count() -= (val); } while (0)
++#define inc_preempt_lazy_count()	add_preempt_lazy_count(1)
++#define dec_preempt_lazy_count()	sub_preempt_lazy_count(1)
++#define preempt_lazy_count()		(current_thread_info()->preempt_lazy_count)
++#else
++#define add_preempt_lazy_count(val)	do { } while (0)
++#define sub_preempt_lazy_count(val)	do { } while (0)
++#define inc_preempt_lazy_count()	do { } while (0)
++#define dec_preempt_lazy_count()	do { } while (0)
++#define preempt_lazy_count()		(0)
++#endif
++
+ #ifdef CONFIG_PREEMPT_COUNT
+ 
+ #define preempt_disable() \
+@@ -182,6 +196,12 @@ do { \
+ 	barrier(); \
+ } while (0)
+ 
++#define preempt_lazy_disable() \
++do { \
++	inc_preempt_lazy_count(); \
++	barrier(); \
++} while (0)
++
+ #define sched_preempt_enable_no_resched() \
+ do { \
+ 	barrier(); \
+@@ -219,6 +239,18 @@ do { \
+ 		__preempt_schedule(); \
+ } while (0)
+ 
++/*
++ * open code preempt_check_resched() because it is not exported to modules and
++ * used by local_unlock() or bpf_enable_instrumentation().
++ */
++#define preempt_lazy_enable() \
++do { \
++	dec_preempt_lazy_count(); \
++	barrier(); \
++	if (should_resched(0)) \
++		__preempt_schedule(); \
++} while (0)
++
+ #else /* !CONFIG_PREEMPTION */
+ #define preempt_enable() \
+ do { \
+@@ -226,6 +258,12 @@ do { \
+ 	preempt_count_dec(); \
+ } while (0)
+ 
++#define preempt_lazy_enable() \
++do { \
++	dec_preempt_lazy_count(); \
++	barrier(); \
++} while (0)
++
+ #define preempt_enable_notrace() \
+ do { \
+ 	barrier(); \
+@@ -267,6 +305,9 @@ do { \
+ #define preempt_check_resched_rt()		barrier()
+ #define preemptible()				0
+ 
++#define preempt_lazy_disable()			barrier()
++#define preempt_lazy_enable()			barrier()
++
+ #endif /* CONFIG_PREEMPT_COUNT */
+ 
+ #ifdef MODULE
+@@ -285,7 +326,7 @@ do { \
+ } while (0)
+ #define preempt_fold_need_resched() \
+ do { \
+-	if (tif_need_resched()) \
++	if (tif_need_resched_now()) \
+ 		set_preempt_need_resched(); \
+ } while (0)
+ 
+@@ -413,8 +454,15 @@ extern void migrate_enable(void);
+ 
+ #else
+ 
+-static inline void migrate_disable(void) { }
+-static inline void migrate_enable(void) { }
++static inline void migrate_disable(void)
++{
++	preempt_lazy_disable();
++}
++
++static inline void migrate_enable(void)
++{
++	preempt_lazy_enable();
++}
+ 
+ #endif /* CONFIG_SMP */
+ 
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index bd0c9c633438..665a17e4f69b 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -1882,6 +1882,44 @@ static inline int test_tsk_need_resched(struct task_struct *tsk)
+ 	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
+ }
+ 
++#ifdef CONFIG_PREEMPT_LAZY
++static inline void set_tsk_need_resched_lazy(struct task_struct *tsk)
++{
++	set_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY);
++}
++
++static inline void clear_tsk_need_resched_lazy(struct task_struct *tsk)
++{
++	clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY);
++}
++
++static inline int test_tsk_need_resched_lazy(struct task_struct *tsk)
++{
++	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY));
++}
++
++static inline int need_resched_lazy(void)
++{
++	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
++}
++
++static inline int need_resched_now(void)
++{
++	return test_thread_flag(TIF_NEED_RESCHED);
++}
++
++#else
++static inline void clear_tsk_need_resched_lazy(struct task_struct *tsk) { }
++static inline int need_resched_lazy(void) { return 0; }
++
++static inline int need_resched_now(void)
++{
++	return test_thread_flag(TIF_NEED_RESCHED);
++}
++
++#endif
++
++
+ static inline bool __task_is_stopped_or_traced(struct task_struct *task)
+ {
+ 	if (task->state & (__TASK_STOPPED | __TASK_TRACED))
+diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
+index f3040b0b4b23..3cb02ced141b 100644
+--- a/include/linux/thread_info.h
++++ b/include/linux/thread_info.h
+@@ -110,7 +110,17 @@ static inline int test_ti_thread_flag(struct thread_info *ti, int flag)
+ #define test_thread_flag(flag) \
+ 	test_ti_thread_flag(current_thread_info(), flag)
+ 
+-#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED)
++#ifdef CONFIG_PREEMPT_LAZY
++#define tif_need_resched()	(test_thread_flag(TIF_NEED_RESCHED) || \
++				 test_thread_flag(TIF_NEED_RESCHED_LAZY))
++#define tif_need_resched_now()	(test_thread_flag(TIF_NEED_RESCHED))
++#define tif_need_resched_lazy()	test_thread_flag(TIF_NEED_RESCHED_LAZY))
++
++#else
++#define tif_need_resched()	test_thread_flag(TIF_NEED_RESCHED)
++#define tif_need_resched_now()	test_thread_flag(TIF_NEED_RESCHED)
++#define tif_need_resched_lazy()	0
++#endif
+ 
+ #ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
+ static inline int arch_within_stack_frames(const void * const stack,
+diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
+index 2151524a10f0..e7afd9fe35e5 100644
+--- a/include/linux/trace_events.h
++++ b/include/linux/trace_events.h
+@@ -70,6 +70,7 @@ struct trace_entry {
+ 	unsigned char		preempt_count;
+ 	int			pid;
+ 	unsigned char		migrate_disable;
++	unsigned char		preempt_lazy_count;
+ };
+ 
+ #define TRACE_EVENT_TYPE_MAX						\
+@@ -159,9 +160,10 @@ static inline void tracing_generic_entry_update(struct trace_entry *entry,
+ {
+ 	entry->preempt_count		= trace_ctx & 0xff;
+ 	entry->migrate_disable		= (trace_ctx >> 8) & 0xff;
++	entry->preempt_lazy_count	= (trace_ctx >> 16) & 0xff;
+ 	entry->pid			= current->pid;
+ 	entry->type			= type;
+-	entry->flags =			trace_ctx >> 16;
++	entry->flags			= trace_ctx >> 24;
+ }
+ 
+ unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status);
+@@ -174,6 +176,7 @@ enum trace_flag_type {
+ 	TRACE_FLAG_SOFTIRQ		= 0x10,
+ 	TRACE_FLAG_PREEMPT_RESCHED	= 0x20,
+ 	TRACE_FLAG_NMI			= 0x40,
++	TRACE_FLAG_NEED_RESCHED_LAZY	= 0x80,
+ };
+ 
+ #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
+diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
+index cbe3aa495519..b5cd1e278eb5 100644
+--- a/kernel/Kconfig.preempt
++++ b/kernel/Kconfig.preempt
+@@ -1,5 +1,11 @@
+ # SPDX-License-Identifier: GPL-2.0-only
+ 
++config HAVE_PREEMPT_LAZY
++	bool
++
++config PREEMPT_LAZY
++	def_bool y if HAVE_PREEMPT_LAZY && PREEMPT_RT
++
+ choice
+ 	prompt "Preemption Model"
+ 	default PREEMPT_NONE
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 8ac1f0526476..c847d17e3b04 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -656,6 +656,48 @@ void resched_curr(struct rq *rq)
+ 		trace_sched_wake_idle_without_ipi(cpu);
+ }
+ 
++#ifdef CONFIG_PREEMPT_LAZY
++
++static int tsk_is_polling(struct task_struct *p)
++{
++#ifdef TIF_POLLING_NRFLAG
++	return test_tsk_thread_flag(p, TIF_POLLING_NRFLAG);
++#else
++	return 0;
++#endif
++}
++
++void resched_curr_lazy(struct rq *rq)
++{
++	struct task_struct *curr = rq->curr;
++	int cpu;
++
++	if (!sched_feat(PREEMPT_LAZY)) {
++		resched_curr(rq);
++		return;
++	}
++
++	lockdep_assert_held(&rq->lock);
++
++	if (test_tsk_need_resched(curr))
++		return;
++
++	if (test_tsk_need_resched_lazy(curr))
++		return;
++
++	set_tsk_need_resched_lazy(curr);
++
++	cpu = cpu_of(rq);
++	if (cpu == smp_processor_id())
++		return;
++
++	/* NEED_RESCHED_LAZY must be visible before we test polling */
++	smp_mb();
++	if (!tsk_is_polling(curr))
++		smp_send_reschedule(cpu);
++}
++#endif
++
+ void resched_cpu(int cpu)
+ {
+ 	struct rq *rq = cpu_rq(cpu);
+@@ -1772,6 +1814,7 @@ void migrate_disable(void)
+ 	preempt_disable();
+ 	this_rq()->nr_pinned++;
+ 	p->migration_disabled = 1;
++	preempt_lazy_disable();
+ 	preempt_enable();
+ }
+ EXPORT_SYMBOL_GPL(migrate_disable);
+@@ -1800,6 +1843,7 @@ void migrate_enable(void)
+ 	barrier();
+ 	p->migration_disabled = 0;
+ 	this_rq()->nr_pinned--;
++	preempt_lazy_enable();
+ 	preempt_enable();
+ 
+ 	trace_sched_migrate_enable_tp(p);
+@@ -3822,6 +3866,9 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p)
+ 	p->on_cpu = 0;
+ #endif
+ 	init_task_preempt_count(p);
++#ifdef CONFIG_HAVE_PREEMPT_LAZY
++	task_thread_info(p)->preempt_lazy_count = 0;
++#endif
+ #ifdef CONFIG_SMP
+ 	plist_node_init(&p->pushable_tasks, MAX_PRIO);
+ 	RB_CLEAR_NODE(&p->pushable_dl_tasks);
+@@ -5101,6 +5148,7 @@ static void __sched notrace __schedule(bool preempt, bool spinning_lock)
+ 
+ 	next = pick_next_task(rq, prev, &rf);
+ 	clear_tsk_need_resched(prev);
++	clear_tsk_need_resched_lazy(prev);
+ 	clear_preempt_need_resched();
+ 
+ 	if (likely(prev != next)) {
+@@ -5300,6 +5348,30 @@ static void __sched notrace preempt_schedule_common(void)
+ 	} while (need_resched());
+ }
+ 
++#ifdef CONFIG_PREEMPT_LAZY
++/*
++ * If TIF_NEED_RESCHED is then we allow to be scheduled away since this is
++ * set by a RT task. Oterwise we try to avoid beeing scheduled out as long as
++ * preempt_lazy_count counter >0.
++ */
++static __always_inline int preemptible_lazy(void)
++{
++	if (test_thread_flag(TIF_NEED_RESCHED))
++		return 1;
++	if (current_thread_info()->preempt_lazy_count)
++		return 0;
++	return 1;
++}
++
++#else
++
++static inline int preemptible_lazy(void)
++{
++	return 1;
++}
++
++#endif
++
+ #ifdef CONFIG_PREEMPTION
+ /*
+  * This is the entry point to schedule() from in-kernel preemption
+@@ -5313,7 +5385,8 @@ asmlinkage __visible void __sched notrace preempt_schedule(void)
+ 	 */
+ 	if (likely(!preemptible()))
+ 		return;
+-
++	if (!preemptible_lazy())
++		return;
+ 	preempt_schedule_common();
+ }
+ NOKPROBE_SYMBOL(preempt_schedule);
+@@ -5353,6 +5426,9 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
+ 	if (likely(!preemptible()))
+ 		return;
+ 
++	if (!preemptible_lazy())
++		return;
++
+ 	do {
+ 		/*
+ 		 * Because the function tracer can trace preempt_count_sub()
+@@ -7175,7 +7251,9 @@ void __init init_idle(struct task_struct *idle, int cpu)
+ 
+ 	/* Set the preempt count _outside_ the spinlocks! */
+ 	init_idle_preempt_count(idle, cpu);
+-
++#ifdef CONFIG_HAVE_PREEMPT_LAZY
++	task_thread_info(idle)->preempt_lazy_count = 0;
++#endif
+ 	/*
+ 	 * The idle tasks have their own, simple scheduling class:
+ 	 */
+diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
+index 73a89fbd81be..f4928e5b6611 100644
+--- a/kernel/sched/fair.c
++++ b/kernel/sched/fair.c
+@@ -4570,7 +4570,7 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
+ 	ideal_runtime = sched_slice(cfs_rq, curr);
+ 	delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
+ 	if (delta_exec > ideal_runtime) {
+-		resched_curr(rq_of(cfs_rq));
++		resched_curr_lazy(rq_of(cfs_rq));
+ 		/*
+ 		 * The current task ran long enough, ensure it doesn't get
+ 		 * re-elected due to buddy favours.
+@@ -4594,7 +4594,7 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
+ 		return;
+ 
+ 	if (delta > ideal_runtime)
+-		resched_curr(rq_of(cfs_rq));
++		resched_curr_lazy(rq_of(cfs_rq));
+ }
+ 
+ static void
+@@ -4737,7 +4737,7 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
+ 	 * validating it and just reschedule.
+ 	 */
+ 	if (queued) {
+-		resched_curr(rq_of(cfs_rq));
++		resched_curr_lazy(rq_of(cfs_rq));
+ 		return;
+ 	}
+ 	/*
+@@ -4874,7 +4874,7 @@ static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec)
+ 	 * hierarchy can be throttled
+ 	 */
+ 	if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr))
+-		resched_curr(rq_of(cfs_rq));
++		resched_curr_lazy(rq_of(cfs_rq));
+ }
+ 
+ static __always_inline
+@@ -5609,7 +5609,7 @@ static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
+ 
+ 		if (delta < 0) {
+ 			if (rq->curr == p)
+-				resched_curr(rq);
++				resched_curr_lazy(rq);
+ 			return;
+ 		}
+ 		hrtick_start(rq, delta);
+@@ -7218,7 +7218,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
+ 	return;
+ 
+ preempt:
+-	resched_curr(rq);
++	resched_curr_lazy(rq);
+ 	/*
+ 	 * Only set the backward buddy when the current task is still
+ 	 * on the rq. This can happen when a wakeup gets interleaved
+@@ -11059,7 +11059,7 @@ static void task_fork_fair(struct task_struct *p)
+ 		 * 'current' within the tree based on its new key value.
+ 		 */
+ 		swap(curr->vruntime, se->vruntime);
+-		resched_curr(rq);
++		resched_curr_lazy(rq);
+ 	}
+ 
+ 	se->vruntime -= cfs_rq->min_vruntime;
+@@ -11086,7 +11086,7 @@ prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
+ 	 */
+ 	if (rq->curr == p) {
+ 		if (p->prio > oldprio)
+-			resched_curr(rq);
++			resched_curr_lazy(rq);
+ 	} else
+ 		check_preempt_curr(rq, p, 0);
+ }
+diff --git a/kernel/sched/features.h b/kernel/sched/features.h
+index 402fd37fb340..bc2466af142e 100644
+--- a/kernel/sched/features.h
++++ b/kernel/sched/features.h
+@@ -47,6 +47,9 @@ SCHED_FEAT(NONTASK_CAPACITY, true)
+ 
+ #ifdef CONFIG_PREEMPT_RT
+ SCHED_FEAT(TTWU_QUEUE, false)
++# ifdef CONFIG_PREEMPT_LAZY
++SCHED_FEAT(PREEMPT_LAZY, true)
++# endif
+ #else
+ 
+ /*
+diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
+index d4bfc51358d3..ad854a670701 100644
+--- a/kernel/sched/sched.h
++++ b/kernel/sched/sched.h
+@@ -1997,6 +1997,15 @@ extern void reweight_task(struct task_struct *p, int prio);
+ extern void resched_curr(struct rq *rq);
+ extern void resched_cpu(int cpu);
+ 
++#ifdef CONFIG_PREEMPT_LAZY
++extern void resched_curr_lazy(struct rq *rq);
++#else
++static inline void resched_curr_lazy(struct rq *rq)
++{
++	resched_curr(rq);
++}
++#endif
++
+ extern struct rt_bandwidth def_rt_bandwidth;
+ extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime);
+ 
+diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
+index 02dffb1862b8..7caae85af03d 100644
+--- a/kernel/trace/trace.c
++++ b/kernel/trace/trace.c
+@@ -2602,8 +2602,16 @@ unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
+ 		trace_flags |= TRACE_FLAG_NEED_RESCHED;
+ 	if (test_preempt_need_resched())
+ 		trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
+-	return (trace_flags << 16) | (pc & 0xff) |
+-		(migration_disable_value() & 0xff) << 8;
++
++#ifdef CONFIG_PREEMPT_LAZY
++	if (need_resched_lazy())
++		trace_flags |= TRACE_FLAG_NEED_RESCHED_LAZY;
++#endif
++
++	return (pc & 0xff) |
++		(migration_disable_value() & 0xff) << 8 |
++		(preempt_lazy_count() & 0xff) << 16 |
++		(trace_flags << 24);
+ }
+ 
+ struct ring_buffer_event *
+@@ -3861,15 +3869,17 @@ unsigned long trace_total_entries(struct trace_array *tr)
+ 
+ static void print_lat_help_header(struct seq_file *m)
+ {
+-	seq_puts(m, "#                    _------=> CPU#            \n"
+-		    "#                   / _-----=> irqs-off        \n"
+-		    "#                  | / _----=> need-resched    \n"
+-		    "#                  || / _---=> hardirq/softirq \n"
+-		    "#                  ||| / _--=> preempt-depth   \n"
+-		    "#                  |||| / _-=> migrate-disable \n"
+-		    "#                  ||||| /     delay           \n"
+-		    "#  cmd     pid     |||||| time  |   caller     \n"
+-		    "#     \\   /        ||||||  \\    |    /       \n");
++	seq_puts(m, "#                    _--------=> CPU#            \n"
++		    "#                   / _-------=> irqs-off        \n"
++		    "#                  | / _------=> need-resched    \n"
++		    "#                  || / _-----=> need-resched-lazy\n"
++		    "#                  ||| / _----=> hardirq/softirq \n"
++		    "#                  |||| / _---=> preempt-depth   \n"
++		    "#                  ||||| / _--=> preempt-lazy-depth\n"
++		    "#                  |||||| / _-=> migrate-disable \n"
++		    "#                  ||||||| /     delay           \n"
++		    "#  cmd     pid     |||||||| time  |   caller     \n"
++		    "#     \\   /        ||||||||  \\    |    /       \n");
+ }
+ 
+ static void print_event_info(struct array_buffer *buf, struct seq_file *m)
+@@ -3903,14 +3913,16 @@ static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file
+ 
+ 	print_event_info(buf, m);
+ 
+-	seq_printf(m, "#                            %.*s  _-----=> irqs-off\n", prec, space);
+-	seq_printf(m, "#                            %.*s / _----=> need-resched\n", prec, space);
+-	seq_printf(m, "#                            %.*s| / _---=> hardirq/softirq\n", prec, space);
+-	seq_printf(m, "#                            %.*s|| / _--=> preempt-depth\n", prec, space);
+-	seq_printf(m, "#                            %.*s||| / _-=> migrate-disable\n", prec, space);
+-	seq_printf(m, "#                            %.*s|||| /     delay\n", prec, space);
+-	seq_printf(m, "#           TASK-PID  %.*s CPU#  |||||  TIMESTAMP  FUNCTION\n", prec, "     TGID   ");
+-	seq_printf(m, "#              | |    %.*s   |   |||||     |         |\n", prec, "       |    ");
++	seq_printf(m, "#                            %.*s  _-------=> irqs-off\n", prec, space);
++	seq_printf(m, "#                            %.*s / _------=> need-resched\n", prec, space);
++	seq_printf(m, "#                            %.*s| / _-----=> need-resched-lazy\n", prec, space);
++	seq_printf(m, "#                            %.*s|| / _----=> hardirq/softirq\n", prec, space);
++	seq_printf(m, "#                            %.*s||| / _---=> preempt-depth\n", prec, space);
++	seq_printf(m, "#                            %.*s|||| / _--=> preempt-lazy-depth\n", prec, space);
++	seq_printf(m, "#                            %.*s||||| / _-=> migrate-disable\n", prec, space);
++	seq_printf(m, "#                            %.*s|||||| /     delay\n", prec, space);
++	seq_printf(m, "#           TASK-PID  %.*s CPU#  |||||||  TIMESTAMP  FUNCTION\n", prec, "     TGID   ");
++	seq_printf(m, "#              | |    %.*s   |   |||||||      |         |\n", prec, "       |    ");
+ }
+ 
+ void
+diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
+index 636fb7df3714..245b8289ecdf 100644
+--- a/kernel/trace/trace_events.c
++++ b/kernel/trace/trace_events.c
+@@ -185,6 +185,7 @@ static int trace_define_common_fields(void)
+ 	__common_field(unsigned char, preempt_count);
+ 	__common_field(int, pid);
+ 	__common_field(unsigned char, migrate_disable);
++	__common_field(unsigned char, preempt_lazy_count);
+ 
+ 	return ret;
+ }
+diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
+index b3619b21217c..5a71964ade3a 100644
+--- a/kernel/trace/trace_output.c
++++ b/kernel/trace/trace_output.c
+@@ -451,6 +451,7 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
+ {
+ 	char hardsoft_irq;
+ 	char need_resched;
++	char need_resched_lazy;
+ 	char irqs_off;
+ 	int hardirq;
+ 	int softirq;
+@@ -481,6 +482,9 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
+ 		break;
+ 	}
+ 
++	need_resched_lazy =
++		(entry->flags & TRACE_FLAG_NEED_RESCHED_LAZY) ? 'L' : '.';
++
+ 	hardsoft_irq =
+ 		(nmi && hardirq)     ? 'Z' :
+ 		nmi                  ? 'z' :
+@@ -489,14 +493,20 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
+ 		softirq              ? 's' :
+ 		                       '.' ;
+ 
+-	trace_seq_printf(s, "%c%c%c",
+-			 irqs_off, need_resched, hardsoft_irq);
++	trace_seq_printf(s, "%c%c%c%c",
++			 irqs_off, need_resched, need_resched_lazy,
++			 hardsoft_irq);
+ 
+ 	if (entry->preempt_count)
+ 		trace_seq_printf(s, "%x", entry->preempt_count);
+ 	else
+ 		trace_seq_putc(s, '.');
+ 
++	if (entry->preempt_lazy_count)
++		trace_seq_printf(s, "%x", entry->preempt_lazy_count);
++	else
++		trace_seq_putc(s, '.');
++
+ 	if (entry->migrate_disable)
+ 		trace_seq_printf(s, "%x", entry->migrate_disable);
+ 	else
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0259-x86-entry-Use-should_resched-in-idtentry_exit_cond_r.patch b/debian/patches-rt/0259-x86-entry-Use-should_resched-in-idtentry_exit_cond_r.patch
new file mode 100644
index 000000000..44c4cc8c2
--- /dev/null
+++ b/debian/patches-rt/0259-x86-entry-Use-should_resched-in-idtentry_exit_cond_r.patch
@@ -0,0 +1,35 @@
+From 367fe43dc09205ecc5fcdca95276fc481e7ccd9f Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 30 Jun 2020 11:45:14 +0200
+Subject: [PATCH 259/323] x86/entry: Use should_resched() in
+ idtentry_exit_cond_resched()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The TIF_NEED_RESCHED bit is inlined on x86 into the preemption counter.
+By using should_resched(0) instead of need_resched() the same check can
+be performed which uses the same variable as 'preempt_count()` which was
+issued before.
+
+Use should_resched(0) instead need_resched().
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/entry/common.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/kernel/entry/common.c b/kernel/entry/common.c
+index e6da86039ccf..f32250adb681 100644
+--- a/kernel/entry/common.c
++++ b/kernel/entry/common.c
+@@ -371,7 +371,7 @@ void irqentry_exit_cond_resched(void)
+ 		rcu_irq_exit_check_preempt();
+ 		if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
+ 			WARN_ON_ONCE(!on_thread_stack());
+-		if (need_resched())
++		if (should_resched(0))
+ 			preempt_schedule_irq();
+ 	}
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0260-x86-Support-for-lazy-preemption.patch b/debian/patches-rt/0260-x86-Support-for-lazy-preemption.patch
new file mode 100644
index 000000000..1b4da37ab
--- /dev/null
+++ b/debian/patches-rt/0260-x86-Support-for-lazy-preemption.patch
@@ -0,0 +1,171 @@
+From 3e75dc5bbc430b2a1db27fe101ed508b067af7b0 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 1 Nov 2012 11:03:47 +0100
+Subject: [PATCH 260/323] x86: Support for lazy preemption
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Implement the x86 pieces for lazy preempt.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ arch/x86/Kconfig                   |  1 +
+ arch/x86/include/asm/preempt.h     | 33 +++++++++++++++++++++++++++++-
+ arch/x86/include/asm/thread_info.h | 11 ++++++++++
+ include/linux/entry-common.h       |  6 +++---
+ kernel/entry/common.c              |  2 +-
+ 5 files changed, 48 insertions(+), 5 deletions(-)
+
+diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
+index c72d66a0e840..b9f68b01a8c8 100644
+--- a/arch/x86/Kconfig
++++ b/arch/x86/Kconfig
+@@ -213,6 +213,7 @@ config X86
+ 	select HAVE_PCI
+ 	select HAVE_PERF_REGS
+ 	select HAVE_PERF_USER_STACK_DUMP
++	select HAVE_PREEMPT_LAZY
+ 	select MMU_GATHER_RCU_TABLE_FREE		if PARAVIRT
+ 	select HAVE_POSIX_CPU_TIMERS_TASK_WORK
+ 	select HAVE_REGS_AND_STACK_ACCESS_API
+diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
+index 50e0c0ab7b97..afe37a8c6c24 100644
+--- a/arch/x86/include/asm/preempt.h
++++ b/arch/x86/include/asm/preempt.h
+@@ -89,17 +89,48 @@ static __always_inline void __preempt_count_sub(int val)
+  * a decrement which hits zero means we have no preempt_count and should
+  * reschedule.
+  */
+-static __always_inline bool __preempt_count_dec_and_test(void)
++static __always_inline bool ____preempt_count_dec_and_test(void)
+ {
+ 	return GEN_UNARY_RMWcc("decl", __preempt_count, e, __percpu_arg([var]));
+ }
+ 
++static __always_inline bool __preempt_count_dec_and_test(void)
++{
++	if (____preempt_count_dec_and_test())
++		return true;
++#ifdef CONFIG_PREEMPT_LAZY
++	if (preempt_count())
++		return false;
++	if (current_thread_info()->preempt_lazy_count)
++		return false;
++	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
++#else
++	return false;
++#endif
++}
++
+ /*
+  * Returns true when we need to resched and can (barring IRQ state).
+  */
+ static __always_inline bool should_resched(int preempt_offset)
+ {
++#ifdef CONFIG_PREEMPT_LAZY
++	u32 tmp;
++	tmp = raw_cpu_read_4(__preempt_count);
++	if (tmp == preempt_offset)
++		return true;
++
++	/* preempt count == 0 ? */
++	tmp &= ~PREEMPT_NEED_RESCHED;
++	if (tmp != preempt_offset)
++		return false;
++	/* XXX PREEMPT_LOCK_OFFSET */
++	if (current_thread_info()->preempt_lazy_count)
++		return false;
++	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
++#else
+ 	return unlikely(raw_cpu_read_4(__preempt_count) == preempt_offset);
++#endif
+ }
+ 
+ #ifdef CONFIG_PREEMPTION
+diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
+index 012c8ee93b67..d77e99ba7610 100644
+--- a/arch/x86/include/asm/thread_info.h
++++ b/arch/x86/include/asm/thread_info.h
+@@ -56,17 +56,24 @@ struct task_struct;
+ struct thread_info {
+ 	unsigned long		flags;		/* low level flags */
+ 	u32			status;		/* thread synchronous flags */
++	int			preempt_lazy_count;	/* 0 => lazy preemptable
++							  <0 => BUG */
+ };
+ 
+ #define INIT_THREAD_INFO(tsk)			\
+ {						\
+ 	.flags		= 0,			\
++	.preempt_lazy_count = 0,		\
+ }
+ 
+ #else /* !__ASSEMBLY__ */
+ 
+ #include <asm/asm-offsets.h>
+ 
++#define GET_THREAD_INFO(reg) \
++	_ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \
++	_ASM_SUB $(THREAD_SIZE),reg ;
++
+ #endif
+ 
+ /*
+@@ -103,6 +110,7 @@ struct thread_info {
+ #define TIF_SYSCALL_TRACEPOINT	28	/* syscall tracepoint instrumentation */
+ #define TIF_ADDR32		29	/* 32-bit address space on 64 bits */
+ #define TIF_X32			30	/* 32-bit native x86-64 binary */
++#define TIF_NEED_RESCHED_LAZY	31	/* lazy rescheduling necessary */
+ 
+ #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
+ #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
+@@ -124,6 +132,7 @@ struct thread_info {
+ #define _TIF_IA32		(1 << TIF_IA32)
+ #define _TIF_NOTIFY_SIGNAL	(1 << TIF_NOTIFY_SIGNAL)
+ #define _TIF_SLD		(1 << TIF_SLD)
++#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)
+ #define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
+ #define _TIF_IO_BITMAP		(1 << TIF_IO_BITMAP)
+ #define _TIF_FORCED_TF		(1 << TIF_FORCED_TF)
+@@ -156,6 +165,8 @@ struct thread_info {
+ 
+ #define _TIF_WORK_CTXSW_NEXT	(_TIF_WORK_CTXSW)
+ 
++#define _TIF_NEED_RESCHED_MASK	(_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
++
+ #define STACK_WARN		(THREAD_SIZE/8)
+ 
+ /*
+diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
+index 46c42479f950..b902af13d05f 100644
+--- a/include/linux/entry-common.h
++++ b/include/linux/entry-common.h
+@@ -67,9 +67,9 @@
+ # define ARCH_EXIT_TO_USER_MODE_WORK		(0)
+ #endif
+ 
+-#define EXIT_TO_USER_MODE_WORK						\
+-	(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE |		\
+-	 _TIF_NEED_RESCHED | _TIF_PATCH_PENDING | _TIF_NOTIFY_SIGNAL |	\
++#define EXIT_TO_USER_MODE_WORK						    \
++	(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE |		    \
++	 _TIF_NEED_RESCHED_MASK | _TIF_PATCH_PENDING | _TIF_NOTIFY_SIGNAL | \
+ 	 ARCH_EXIT_TO_USER_MODE_WORK)
+ 
+ /**
+diff --git a/kernel/entry/common.c b/kernel/entry/common.c
+index f32250adb681..cdf97ea30b4c 100644
+--- a/kernel/entry/common.c
++++ b/kernel/entry/common.c
+@@ -157,7 +157,7 @@ static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
+ 
+ 		local_irq_enable_exit_to_user(ti_work);
+ 
+-		if (ti_work & _TIF_NEED_RESCHED)
++		if (ti_work & _TIF_NEED_RESCHED_MASK)
+ 			schedule();
+ 
+ #ifdef ARCH_RT_DELAYS_SIGNAL_SEND
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0261-arm-Add-support-for-lazy-preemption.patch b/debian/patches-rt/0261-arm-Add-support-for-lazy-preemption.patch
new file mode 100644
index 000000000..18012c8d8
--- /dev/null
+++ b/debian/patches-rt/0261-arm-Add-support-for-lazy-preemption.patch
@@ -0,0 +1,153 @@
+From 125d4e163b1aa93781f9cf4673f729053af2bc53 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 31 Oct 2012 12:04:11 +0100
+Subject: [PATCH 261/323] arm: Add support for lazy preemption
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Implement the arm pieces for lazy preempt.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ arch/arm/Kconfig                   |  1 +
+ arch/arm/include/asm/thread_info.h |  5 ++++-
+ arch/arm/kernel/asm-offsets.c      |  1 +
+ arch/arm/kernel/entry-armv.S       | 19 ++++++++++++++++---
+ arch/arm/kernel/entry-common.S     |  1 +
+ arch/arm/kernel/signal.c           |  3 ++-
+ 6 files changed, 25 insertions(+), 5 deletions(-)
+
+diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
+index c01251683018..ee2cbe8ad502 100644
+--- a/arch/arm/Kconfig
++++ b/arch/arm/Kconfig
+@@ -107,6 +107,7 @@ config ARM
+ 	select HAVE_PERF_EVENTS
+ 	select HAVE_PERF_REGS
+ 	select HAVE_PERF_USER_STACK_DUMP
++	select HAVE_PREEMPT_LAZY
+ 	select MMU_GATHER_RCU_TABLE_FREE if SMP && ARM_LPAE
+ 	select HAVE_REGS_AND_STACK_ACCESS_API
+ 	select HAVE_RSEQ
+diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
+index fcccf35f5cf9..3b981ad0c322 100644
+--- a/arch/arm/include/asm/thread_info.h
++++ b/arch/arm/include/asm/thread_info.h
+@@ -46,6 +46,7 @@ struct cpu_context_save {
+ struct thread_info {
+ 	unsigned long		flags;		/* low level flags */
+ 	int			preempt_count;	/* 0 => preemptable, <0 => bug */
++	int			preempt_lazy_count; /* 0 => preemptable, <0 => bug */
+ 	mm_segment_t		addr_limit;	/* address limit */
+ 	struct task_struct	*task;		/* main task structure */
+ 	__u32			cpu;		/* cpu */
+@@ -134,6 +135,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp *,
+ #define TIF_NOTIFY_RESUME	2	/* callback before returning to user */
+ #define TIF_UPROBE		3	/* breakpointed or singlestepping */
+ #define TIF_NOTIFY_SIGNAL	4	/* signal notifications exist */
++#define TIF_NEED_RESCHED_LAZY	5
+ 
+ #define TIF_USING_IWMMXT	17
+ #define TIF_MEMDIE		18	/* is terminating due to OOM killer */
+@@ -143,10 +145,10 @@ extern int vfp_restore_user_hwstate(struct user_vfp *,
+ #define TIF_SYSCALL_TRACEPOINT	22	/* syscall tracepoint instrumentation */
+ #define TIF_SECCOMP		23	/* seccomp syscall filtering active */
+ 
+-
+ #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
+ #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
+ #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
++#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)
+ #define _TIF_UPROBE		(1 << TIF_UPROBE)
+ #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
+ #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
+@@ -164,6 +166,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp *,
+  */
+ #define _TIF_WORK_MASK		(_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
+ 				 _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
++				 _TIF_NEED_RESCHED_LAZY | \
+ 				 _TIF_NOTIFY_SIGNAL)
+ 
+ #endif /* __KERNEL__ */
+diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
+index 70993af22d80..024c65c3a0f2 100644
+--- a/arch/arm/kernel/asm-offsets.c
++++ b/arch/arm/kernel/asm-offsets.c
+@@ -43,6 +43,7 @@ int main(void)
+   BLANK();
+   DEFINE(TI_FLAGS,		offsetof(struct thread_info, flags));
+   DEFINE(TI_PREEMPT,		offsetof(struct thread_info, preempt_count));
++  DEFINE(TI_PREEMPT_LAZY,	offsetof(struct thread_info, preempt_lazy_count));
+   DEFINE(TI_ADDR_LIMIT,		offsetof(struct thread_info, addr_limit));
+   DEFINE(TI_TASK,		offsetof(struct thread_info, task));
+   DEFINE(TI_CPU,		offsetof(struct thread_info, cpu));
+diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
+index 030351d169aa..d6086559168d 100644
+--- a/arch/arm/kernel/entry-armv.S
++++ b/arch/arm/kernel/entry-armv.S
+@@ -206,11 +206,18 @@ __irq_svc:
+ 
+ #ifdef CONFIG_PREEMPTION
+ 	ldr	r8, [tsk, #TI_PREEMPT]		@ get preempt count
+-	ldr	r0, [tsk, #TI_FLAGS]		@ get flags
+ 	teq	r8, #0				@ if preempt count != 0
++	bne	1f				@ return from exeption
++	ldr	r0, [tsk, #TI_FLAGS]		@ get flags
++	tst	r0, #_TIF_NEED_RESCHED		@ if NEED_RESCHED is set
++	blne	svc_preempt			@ preempt!
++
++	ldr	r8, [tsk, #TI_PREEMPT_LAZY]	@ get preempt lazy count
++	teq	r8, #0				@ if preempt lazy count != 0
+ 	movne	r0, #0				@ force flags to 0
+-	tst	r0, #_TIF_NEED_RESCHED
++	tst	r0, #_TIF_NEED_RESCHED_LAZY
+ 	blne	svc_preempt
++1:
+ #endif
+ 
+ 	svc_exit r5, irq = 1			@ return from exception
+@@ -225,8 +232,14 @@ svc_preempt:
+ 1:	bl	preempt_schedule_irq		@ irq en/disable is done inside
+ 	ldr	r0, [tsk, #TI_FLAGS]		@ get new tasks TI_FLAGS
+ 	tst	r0, #_TIF_NEED_RESCHED
++	bne	1b
++	tst	r0, #_TIF_NEED_RESCHED_LAZY
+ 	reteq	r8				@ go again
+-	b	1b
++	ldr	r0, [tsk, #TI_PREEMPT_LAZY]	@ get preempt lazy count
++	teq	r0, #0				@ if preempt lazy count != 0
++	beq	1b
++	ret	r8				@ go again
++
+ #endif
+ 
+ __und_fault:
+diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
+index 9b3c737575e9..a30b1a1cc4d1 100644
+--- a/arch/arm/kernel/entry-common.S
++++ b/arch/arm/kernel/entry-common.S
+@@ -92,6 +92,7 @@ __ret_fast_syscall:
+ 	ldr	r1, [tsk, #TI_FLAGS]		@ re-check for syscall tracing
+ 	movs	r1, r1, lsl #16
+ 	beq	no_work_pending
++do_slower_path:
+  UNWIND(.fnend		)
+ ENDPROC(ret_fast_syscall)
+ 
+diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
+index a3a38d0a4c85..f04ccf19ab1f 100644
+--- a/arch/arm/kernel/signal.c
++++ b/arch/arm/kernel/signal.c
+@@ -649,7 +649,8 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
+ 	 */
+ 	trace_hardirqs_off();
+ 	do {
+-		if (likely(thread_flags & _TIF_NEED_RESCHED)) {
++		if (likely(thread_flags & (_TIF_NEED_RESCHED |
++					   _TIF_NEED_RESCHED_LAZY))) {
+ 			schedule();
+ 		} else {
+ 			if (unlikely(!user_mode(regs)))
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0262-powerpc-Add-support-for-lazy-preemption.patch b/debian/patches-rt/0262-powerpc-Add-support-for-lazy-preemption.patch
new file mode 100644
index 000000000..259c9928b
--- /dev/null
+++ b/debian/patches-rt/0262-powerpc-Add-support-for-lazy-preemption.patch
@@ -0,0 +1,267 @@
+From 8e5e88a7528b5f0b0f2b9835deaf8b6db693500f Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 1 Nov 2012 10:14:11 +0100
+Subject: [PATCH 262/323] powerpc: Add support for lazy preemption
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Implement the powerpc pieces for lazy preempt.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ arch/powerpc/Kconfig                   |  1 +
+ arch/powerpc/include/asm/thread_info.h | 16 ++++++++++++----
+ arch/powerpc/kernel/asm-offsets.c      |  1 +
+ arch/powerpc/kernel/entry_32.S         | 23 ++++++++++++++++-------
+ arch/powerpc/kernel/exceptions-64e.S   | 16 ++++++++++++----
+ arch/powerpc/kernel/syscall_64.c       | 10 +++++++---
+ 6 files changed, 49 insertions(+), 18 deletions(-)
+
+diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
+index b3ab6c2d9f66..6d8ce54ad6dd 100644
+--- a/arch/powerpc/Kconfig
++++ b/arch/powerpc/Kconfig
+@@ -230,6 +230,7 @@ config PPC
+ 	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !HAVE_HARDLOCKUP_DETECTOR_ARCH
+ 	select HAVE_PERF_REGS
+ 	select HAVE_PERF_USER_STACK_DUMP
++	select HAVE_PREEMPT_LAZY
+ 	select MMU_GATHER_RCU_TABLE_FREE
+ 	select MMU_GATHER_PAGE_SIZE
+ 	select HAVE_REGS_AND_STACK_ACCESS_API
+diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
+index ff31d2fa2140..23bfe231fda3 100644
+--- a/arch/powerpc/include/asm/thread_info.h
++++ b/arch/powerpc/include/asm/thread_info.h
+@@ -54,6 +54,8 @@
+ struct thread_info {
+ 	int		preempt_count;		/* 0 => preemptable,
+ 						   <0 => BUG */
++	int             preempt_lazy_count;	/* 0 => preemptable,
++						   <0 => BUG */
+ 	unsigned long	local_flags;		/* private flags for thread */
+ #ifdef CONFIG_LIVEPATCH
+ 	unsigned long *livepatch_sp;
+@@ -104,11 +106,12 @@ void arch_setup_new_exec(void);
+ #define TIF_SINGLESTEP		8	/* singlestepping active */
+ #define TIF_NOHZ		9	/* in adaptive nohz mode */
+ #define TIF_SECCOMP		10	/* secure computing */
+-#define TIF_RESTOREALL		11	/* Restore all regs (implies NOERROR) */
+-#define TIF_NOERROR		12	/* Force successful syscall return */
++
++#define TIF_NEED_RESCHED_LAZY	11	/* lazy rescheduling necessary */
++#define TIF_SYSCALL_TRACEPOINT	12	/* syscall tracepoint instrumentation */
++
+ #define TIF_NOTIFY_RESUME	13	/* callback before returning to user */
+ #define TIF_UPROBE		14	/* breakpointed or single-stepping */
+-#define TIF_SYSCALL_TRACEPOINT	15	/* syscall tracepoint instrumentation */
+ #define TIF_EMULATE_STACK_STORE	16	/* Is an instruction emulation
+ 						for stack store? */
+ #define TIF_MEMDIE		17	/* is terminating due to OOM killer */
+@@ -117,6 +120,9 @@ void arch_setup_new_exec(void);
+ #endif
+ #define TIF_POLLING_NRFLAG	19	/* true if poll_idle() is polling TIF_NEED_RESCHED */
+ #define TIF_32BIT		20	/* 32 bit binary */
++#define TIF_RESTOREALL		21	/* Restore all regs (implies NOERROR) */
++#define TIF_NOERROR		22	/* Force successful syscall return */
++
+ 
+ /* as above, but as bit values */
+ #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
+@@ -137,6 +143,7 @@ void arch_setup_new_exec(void);
+ #define _TIF_SYSCALL_TRACEPOINT	(1<<TIF_SYSCALL_TRACEPOINT)
+ #define _TIF_EMULATE_STACK_STORE	(1<<TIF_EMULATE_STACK_STORE)
+ #define _TIF_NOHZ		(1<<TIF_NOHZ)
++#define _TIF_NEED_RESCHED_LAZY	(1<<TIF_NEED_RESCHED_LAZY)
+ #define _TIF_SYSCALL_EMU	(1<<TIF_SYSCALL_EMU)
+ #define _TIF_SYSCALL_DOTRACE	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
+ 				 _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \
+@@ -145,8 +152,9 @@ void arch_setup_new_exec(void);
+ #define _TIF_USER_WORK_MASK	(_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
+ 				 _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
+ 				 _TIF_RESTORE_TM | _TIF_PATCH_PENDING | \
+-				 _TIF_NOTIFY_SIGNAL)
++				 _TIF_NEED_RESCHED_LAZY | _TIF_NOTIFY_SIGNAL)
+ #define _TIF_PERSYSCALL_MASK	(_TIF_RESTOREALL|_TIF_NOERROR)
++#define _TIF_NEED_RESCHED_MASK	(_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
+ 
+ /* Bits in local_flags */
+ /* Don't move TLF_NAPPING without adjusting the code in entry_32.S */
+diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
+index 5c125255571c..597379121407 100644
+--- a/arch/powerpc/kernel/asm-offsets.c
++++ b/arch/powerpc/kernel/asm-offsets.c
+@@ -189,6 +189,7 @@ int main(void)
+ 	OFFSET(TI_FLAGS, thread_info, flags);
+ 	OFFSET(TI_LOCAL_FLAGS, thread_info, local_flags);
+ 	OFFSET(TI_PREEMPT, thread_info, preempt_count);
++	OFFSET(TI_PREEMPT_LAZY, thread_info, preempt_lazy_count);
+ 
+ #ifdef CONFIG_PPC64
+ 	OFFSET(DCACHEL1BLOCKSIZE, ppc64_caches, l1d.block_size);
+diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
+index 459f5d00b990..fc9517a97640 100644
+--- a/arch/powerpc/kernel/entry_32.S
++++ b/arch/powerpc/kernel/entry_32.S
+@@ -414,7 +414,9 @@ ret_from_syscall:
+ 	mtmsr	r10
+ 	lwz	r9,TI_FLAGS(r2)
+ 	li	r8,-MAX_ERRNO
+-	andi.	r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
++	lis	r0,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)@h
++	ori	r0,r0, (_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)@l
++	and.	r0,r9,r0
+ 	bne-	syscall_exit_work
+ 	cmplw	0,r3,r8
+ 	blt+	syscall_exit_cont
+@@ -530,13 +532,13 @@ syscall_dotrace:
+ 	b	syscall_dotrace_cont
+ 
+ syscall_exit_work:
+-	andi.	r0,r9,_TIF_RESTOREALL
++	andis.	r0,r9,_TIF_RESTOREALL@h
+ 	beq+	0f
+ 	REST_NVGPRS(r1)
+ 	b	2f
+ 0:	cmplw	0,r3,r8
+ 	blt+	1f
+-	andi.	r0,r9,_TIF_NOERROR
++	andis.	r0,r9,_TIF_NOERROR@h
+ 	bne-	1f
+ 	lwz	r11,_CCR(r1)			/* Load CR */
+ 	neg	r3,r3
+@@ -545,12 +547,12 @@ syscall_exit_work:
+ 
+ 1:	stw	r6,RESULT(r1)	/* Save result */
+ 	stw	r3,GPR3(r1)	/* Update return value */
+-2:	andi.	r0,r9,(_TIF_PERSYSCALL_MASK)
++2:	andis.	r0,r9,(_TIF_PERSYSCALL_MASK)@h
+ 	beq	4f
+ 
+ 	/* Clear per-syscall TIF flags if any are set.  */
+ 
+-	li	r11,_TIF_PERSYSCALL_MASK
++	lis	r11,(_TIF_PERSYSCALL_MASK)@h
+ 	addi	r12,r2,TI_FLAGS
+ 3:	lwarx	r8,0,r12
+ 	andc	r8,r8,r11
+@@ -927,7 +929,14 @@ resume_kernel:
+ 	cmpwi	0,r0,0		/* if non-zero, just restore regs and return */
+ 	bne	restore_kuap
+ 	andi.	r8,r8,_TIF_NEED_RESCHED
++	bne+	1f
++	lwz	r0,TI_PREEMPT_LAZY(r2)
++	cmpwi	0,r0,0          /* if non-zero, just restore regs and return */
++	bne	restore_kuap
++	lwz	r0,TI_FLAGS(r2)
++	andi.	r0,r0,_TIF_NEED_RESCHED_LAZY
+ 	beq+	restore_kuap
++1:
+ 	lwz	r3,_MSR(r1)
+ 	andi.	r0,r3,MSR_EE	/* interrupts off? */
+ 	beq	restore_kuap	/* don't schedule if so */
+@@ -1248,7 +1257,7 @@ global_dbcr0:
+ #endif /* !(CONFIG_4xx || CONFIG_BOOKE) */
+ 
+ do_work:			/* r10 contains MSR_KERNEL here */
+-	andi.	r0,r9,_TIF_NEED_RESCHED
++	andi.	r0,r9,_TIF_NEED_RESCHED_MASK
+ 	beq	do_user_signal
+ 
+ do_resched:			/* r10 contains MSR_KERNEL here */
+@@ -1267,7 +1276,7 @@ recheck:
+ 	LOAD_REG_IMMEDIATE(r10,MSR_KERNEL)
+ 	mtmsr	r10		/* disable interrupts */
+ 	lwz	r9,TI_FLAGS(r2)
+-	andi.	r0,r9,_TIF_NEED_RESCHED
++	andi.	r0,r9,_TIF_NEED_RESCHED_MASK
+ 	bne-	do_resched
+ 	andi.	r0,r9,_TIF_USER_WORK_MASK
+ 	beq	restore_user
+diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
+index f579ce46eef2..715ff292a8f8 100644
+--- a/arch/powerpc/kernel/exceptions-64e.S
++++ b/arch/powerpc/kernel/exceptions-64e.S
+@@ -1080,7 +1080,7 @@ _GLOBAL(ret_from_except_lite)
+ 	li	r10, -1
+ 	mtspr	SPRN_DBSR,r10
+ 	b	restore
+-1:	andi.	r0,r4,_TIF_NEED_RESCHED
++1:	andi.	r0,r4,_TIF_NEED_RESCHED_MASK
+ 	beq	2f
+ 	bl	restore_interrupts
+ 	SCHEDULE_USER
+@@ -1132,12 +1132,20 @@ resume_kernel:
+ 	bne-	0b
+ 1:
+ 
+-#ifdef CONFIG_PREEMPT
++#ifdef CONFIG_PREEMPTION
+ 	/* Check if we need to preempt */
++	lwz	r8,TI_PREEMPT(r9)
++	cmpwi	0,r8,0		/* if non-zero, just restore regs and return */
++	bne	restore
+ 	andi.	r0,r4,_TIF_NEED_RESCHED
++	bne+	check_count
++
++	andi.	r0,r4,_TIF_NEED_RESCHED_LAZY
+ 	beq+	restore
++	lwz	r8,TI_PREEMPT_LAZY(r9)
++
+ 	/* Check that preempt_count() == 0 and interrupts are enabled */
+-	lwz	r8,TI_PREEMPT(r9)
++check_count:
+ 	cmpwi	cr0,r8,0
+ 	bne	restore
+ 	ld	r0,SOFTE(r1)
+@@ -1158,7 +1166,7 @@ resume_kernel:
+ 	 * interrupted after loading SRR0/1.
+ 	 */
+ 	wrteei	0
+-#endif /* CONFIG_PREEMPT */
++#endif /* CONFIG_PREEMPTION */
+ 
+ restore:
+ 	/*
+diff --git a/arch/powerpc/kernel/syscall_64.c b/arch/powerpc/kernel/syscall_64.c
+index 310bcd768cd5..ae3212dcf562 100644
+--- a/arch/powerpc/kernel/syscall_64.c
++++ b/arch/powerpc/kernel/syscall_64.c
+@@ -193,7 +193,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
+ 	ti_flags = READ_ONCE(*ti_flagsp);
+ 	while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) {
+ 		local_irq_enable();
+-		if (ti_flags & _TIF_NEED_RESCHED) {
++		if (ti_flags & _TIF_NEED_RESCHED_MASK) {
+ 			schedule();
+ 		} else {
+ 			/*
+@@ -277,7 +277,7 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
+ 	ti_flags = READ_ONCE(*ti_flagsp);
+ 	while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) {
+ 		local_irq_enable(); /* returning to user: may enable */
+-		if (ti_flags & _TIF_NEED_RESCHED) {
++		if (ti_flags & _TIF_NEED_RESCHED_MASK) {
+ 			schedule();
+ 		} else {
+ 			if (ti_flags & _TIF_SIGPENDING)
+@@ -361,11 +361,15 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
+ 		/* Returning to a kernel context with local irqs enabled. */
+ 		WARN_ON_ONCE(!(regs->msr & MSR_EE));
+ again:
+-		if (IS_ENABLED(CONFIG_PREEMPT)) {
++		if (IS_ENABLED(CONFIG_PREEMPTION)) {
+ 			/* Return to preemptible kernel context */
+ 			if (unlikely(*ti_flagsp & _TIF_NEED_RESCHED)) {
+ 				if (preempt_count() == 0)
+ 					preempt_schedule_irq();
++			} else if (unlikely(*ti_flagsp & _TIF_NEED_RESCHED_LAZY)) {
++				if ((preempt_count() == 0) &&
++				    (current_thread_info()->preempt_lazy_count == 0))
++					preempt_schedule_irq();
+ 			}
+ 		}
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0263-arch-arm64-Add-lazy-preempt-support.patch b/debian/patches-rt/0263-arch-arm64-Add-lazy-preempt-support.patch
new file mode 100644
index 000000000..bf46cf898
--- /dev/null
+++ b/debian/patches-rt/0263-arch-arm64-Add-lazy-preempt-support.patch
@@ -0,0 +1,168 @@
+From 7499fc472caecd0270f69d5857ca8a53cc6dad83 Mon Sep 17 00:00:00 2001
+From: Anders Roxell <anders.roxell@linaro.org>
+Date: Thu, 14 May 2015 17:52:17 +0200
+Subject: [PATCH 263/323] arch/arm64: Add lazy preempt support
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+arm64 is missing support for PREEMPT_RT. The main feature which is
+lacking is support for lazy preemption. The arch-specific entry code,
+thread information structure definitions, and associated data tables
+have to be extended to provide this support. Then the Kconfig file has
+to be extended to indicate the support is available, and also to
+indicate that support for full RT preemption is now available.
+
+Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ arch/arm64/Kconfig                   |  1 +
+ arch/arm64/include/asm/preempt.h     | 25 ++++++++++++++++++++++++-
+ arch/arm64/include/asm/thread_info.h |  6 +++++-
+ arch/arm64/kernel/asm-offsets.c      |  1 +
+ arch/arm64/kernel/entry.S            | 13 +++++++++++--
+ arch/arm64/kernel/signal.c           |  2 +-
+ 6 files changed, 43 insertions(+), 5 deletions(-)
+
+diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
+index 13cf137da999..7681d7b65c7d 100644
+--- a/arch/arm64/Kconfig
++++ b/arch/arm64/Kconfig
+@@ -173,6 +173,7 @@ config ARM64
+ 	select HAVE_PERF_EVENTS
+ 	select HAVE_PERF_REGS
+ 	select HAVE_PERF_USER_STACK_DUMP
++	select HAVE_PREEMPT_LAZY
+ 	select HAVE_REGS_AND_STACK_ACCESS_API
+ 	select HAVE_FUNCTION_ARG_ACCESS_API
+ 	select HAVE_FUTEX_CMPXCHG if FUTEX
+diff --git a/arch/arm64/include/asm/preempt.h b/arch/arm64/include/asm/preempt.h
+index f1486b32502c..7a5770d825b9 100644
+--- a/arch/arm64/include/asm/preempt.h
++++ b/arch/arm64/include/asm/preempt.h
+@@ -70,13 +70,36 @@ static inline bool __preempt_count_dec_and_test(void)
+ 	 * interrupt occurring between the non-atomic READ_ONCE/WRITE_ONCE
+ 	 * pair.
+ 	 */
+-	return !pc || !READ_ONCE(ti->preempt_count);
++	if (!pc || !READ_ONCE(ti->preempt_count))
++		return true;
++#ifdef CONFIG_PREEMPT_LAZY
++	if ((pc & ~PREEMPT_NEED_RESCHED))
++		return false;
++	if (current_thread_info()->preempt_lazy_count)
++		return false;
++	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
++#else
++	return false;
++#endif
+ }
+ 
+ static inline bool should_resched(int preempt_offset)
+ {
++#ifdef CONFIG_PREEMPT_LAZY
++	u64 pc = READ_ONCE(current_thread_info()->preempt_count);
++	if (pc == preempt_offset)
++		return true;
++
++	if ((pc & ~PREEMPT_NEED_RESCHED) != preempt_offset)
++		return false;
++
++	if (current_thread_info()->preempt_lazy_count)
++		return false;
++	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
++#else
+ 	u64 pc = READ_ONCE(current_thread_info()->preempt_count);
+ 	return pc == preempt_offset;
++#endif
+ }
+ 
+ #ifdef CONFIG_PREEMPTION
+diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
+index cdcf307764aa..6eb36a2126e8 100644
+--- a/arch/arm64/include/asm/thread_info.h
++++ b/arch/arm64/include/asm/thread_info.h
+@@ -29,6 +29,7 @@ struct thread_info {
+ #ifdef CONFIG_ARM64_SW_TTBR0_PAN
+ 	u64			ttbr0;		/* saved TTBR0_EL1 */
+ #endif
++	int			preempt_lazy_count;	/* 0 => preemptable, <0 => bug */
+ 	union {
+ 		u64		preempt_count;	/* 0 => preemptible, <0 => bug */
+ 		struct {
+@@ -74,6 +75,7 @@ void arch_release_task_struct(struct task_struct *tsk);
+ #define TIF_SYSCALL_TRACEPOINT	10	/* syscall tracepoint for ftrace */
+ #define TIF_SECCOMP		11	/* syscall secure computing */
+ #define TIF_SYSCALL_EMU		12	/* syscall emulation active */
++#define TIF_NEED_RESCHED_LAZY	13
+ #define TIF_MEMDIE		18	/* is terminating due to OOM killer */
+ #define TIF_FREEZE		19
+ #define TIF_RESTORE_SIGMASK	20
+@@ -99,13 +101,15 @@ void arch_release_task_struct(struct task_struct *tsk);
+ #define _TIF_32BIT		(1 << TIF_32BIT)
+ #define _TIF_SVE		(1 << TIF_SVE)
+ #define _TIF_MTE_ASYNC_FAULT	(1 << TIF_MTE_ASYNC_FAULT)
++#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)
+ #define _TIF_NOTIFY_SIGNAL	(1 << TIF_NOTIFY_SIGNAL)
+ 
+ #define _TIF_WORK_MASK		(_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
+ 				 _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \
+ 				 _TIF_UPROBE | _TIF_FSCHECK | _TIF_MTE_ASYNC_FAULT | \
+-				 _TIF_NOTIFY_SIGNAL)
++				 _TIF_NEED_RESCHED_LAZY | _TIF_NOTIFY_SIGNAL)
+ 
++#define _TIF_NEED_RESCHED_MASK	(_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
+ #define _TIF_SYSCALL_WORK	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
+ 				 _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
+ 				 _TIF_SYSCALL_EMU)
+diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
+index 7d32fc959b1a..b2f29bd2ae87 100644
+--- a/arch/arm64/kernel/asm-offsets.c
++++ b/arch/arm64/kernel/asm-offsets.c
+@@ -30,6 +30,7 @@ int main(void)
+   BLANK();
+   DEFINE(TSK_TI_FLAGS,		offsetof(struct task_struct, thread_info.flags));
+   DEFINE(TSK_TI_PREEMPT,	offsetof(struct task_struct, thread_info.preempt_count));
++  DEFINE(TSK_TI_PREEMPT_LAZY,	offsetof(struct task_struct, thread_info.preempt_lazy_count));
+   DEFINE(TSK_TI_ADDR_LIMIT,	offsetof(struct task_struct, thread_info.addr_limit));
+ #ifdef CONFIG_ARM64_SW_TTBR0_PAN
+   DEFINE(TSK_TI_TTBR0,		offsetof(struct task_struct, thread_info.ttbr0));
+diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
+index a94acea770c7..0bfa079043f8 100644
+--- a/arch/arm64/kernel/entry.S
++++ b/arch/arm64/kernel/entry.S
+@@ -523,9 +523,18 @@ alternative_if ARM64_HAS_IRQ_PRIO_MASKING
+ 	mrs	x0, daif
+ 	orr	x24, x24, x0
+ alternative_else_nop_endif
+-	cbnz	x24, 1f				// preempt count != 0 || NMI return path
+-	bl	arm64_preempt_schedule_irq	// irq en/disable is done inside
++
++	cbz     x24, 1f                                 // (need_resched + count) == 0
++	cbnz    w24, 2f                                 // count != 0
++
++	ldr     w24, [tsk, #TSK_TI_PREEMPT_LAZY]        // get preempt lazy count
++	cbnz    w24, 2f                                 // preempt lazy count != 0
++
++	ldr     x0, [tsk, #TSK_TI_FLAGS]                // get flags
++	tbz     x0, #TIF_NEED_RESCHED_LAZY, 2f          // needs rescheduling?
+ 1:
++	bl      arm64_preempt_schedule_irq              // irq en/disable is done inside
++2:
+ #endif
+ 
+ 	mov	x0, sp
+diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
+index b6fbbd527dd7..94eed0dc3afc 100644
+--- a/arch/arm64/kernel/signal.c
++++ b/arch/arm64/kernel/signal.c
+@@ -921,7 +921,7 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
+ 		/* Check valid user FS if needed */
+ 		addr_limit_user_check();
+ 
+-		if (thread_flags & _TIF_NEED_RESCHED) {
++		if (thread_flags & _TIF_NEED_RESCHED_MASK) {
+ 			/* Unmask Debug and SError for the next task */
+ 			local_daif_restore(DAIF_PROCCTX_NOIRQ);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0264-jump-label-disable-if-stop_machine-is-used.patch b/debian/patches-rt/0264-jump-label-disable-if-stop_machine-is-used.patch
new file mode 100644
index 000000000..168745160
--- /dev/null
+++ b/debian/patches-rt/0264-jump-label-disable-if-stop_machine-is-used.patch
@@ -0,0 +1,42 @@
+From 915e18f01ac0c97a6dc374b940a96a105bf57c62 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Wed, 8 Jul 2015 17:14:48 +0200
+Subject: [PATCH 264/323] jump-label: disable if stop_machine() is used
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Some architectures are using stop_machine() while switching the opcode which
+leads to latency spikes.
+The architectures which use stop_machine() atm:
+- ARM stop machine
+- s390 stop machine
+
+The architecures which use other sorcery:
+- MIPS
+- X86
+- powerpc
+- sparc
+- arm64
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+[bigeasy: only ARM for now]
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/arm/Kconfig | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
+index ee2cbe8ad502..73c55cb2f296 100644
+--- a/arch/arm/Kconfig
++++ b/arch/arm/Kconfig
+@@ -67,7 +67,7 @@ config ARM
+ 	select HARDIRQS_SW_RESEND
+ 	select HAVE_ARCH_AUDITSYSCALL if AEABI && !OABI_COMPAT
+ 	select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6
+-	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
++	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU && !PREEMPT_RT
+ 	select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU
+ 	select HAVE_ARCH_MMAP_RND_BITS if MMU
+ 	select HAVE_ARCH_SECCOMP
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0265-leds-trigger-disable-CPU-trigger-on-RT.patch b/debian/patches-rt/0265-leds-trigger-disable-CPU-trigger-on-RT.patch
new file mode 100644
index 000000000..87bc1d736
--- /dev/null
+++ b/debian/patches-rt/0265-leds-trigger-disable-CPU-trigger-on-RT.patch
@@ -0,0 +1,40 @@
+From 524ea188033506aaa1b70534af78b30fe718ae98 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Thu, 23 Jan 2014 14:45:59 +0100
+Subject: [PATCH 265/323] leds: trigger: disable CPU trigger on -RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+as it triggers:
+|CPU: 0 PID: 0 Comm: swapper Not tainted 3.12.8-rt10 #141
+|[<c0014aa4>] (unwind_backtrace+0x0/0xf8) from [<c0012788>] (show_stack+0x1c/0x20)
+|[<c0012788>] (show_stack+0x1c/0x20) from [<c043c8dc>] (dump_stack+0x20/0x2c)
+|[<c043c8dc>] (dump_stack+0x20/0x2c) from [<c004c5e8>] (__might_sleep+0x13c/0x170)
+|[<c004c5e8>] (__might_sleep+0x13c/0x170) from [<c043f270>] (__rt_spin_lock+0x28/0x38)
+|[<c043f270>] (__rt_spin_lock+0x28/0x38) from [<c043fa00>] (rt_read_lock+0x68/0x7c)
+|[<c043fa00>] (rt_read_lock+0x68/0x7c) from [<c036cf74>] (led_trigger_event+0x2c/0x5c)
+|[<c036cf74>] (led_trigger_event+0x2c/0x5c) from [<c036e0bc>] (ledtrig_cpu+0x54/0x5c)
+|[<c036e0bc>] (ledtrig_cpu+0x54/0x5c) from [<c000ffd8>] (arch_cpu_idle_exit+0x18/0x1c)
+|[<c000ffd8>] (arch_cpu_idle_exit+0x18/0x1c) from [<c00590b8>] (cpu_startup_entry+0xa8/0x234)
+|[<c00590b8>] (cpu_startup_entry+0xa8/0x234) from [<c043b2cc>] (rest_init+0xb8/0xe0)
+|[<c043b2cc>] (rest_init+0xb8/0xe0) from [<c061ebe0>] (start_kernel+0x2c4/0x380)
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/leds/trigger/Kconfig | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
+index ce9429ca6dde..29ccbd6acf43 100644
+--- a/drivers/leds/trigger/Kconfig
++++ b/drivers/leds/trigger/Kconfig
+@@ -64,6 +64,7 @@ config LEDS_TRIGGER_BACKLIGHT
+ 
+ config LEDS_TRIGGER_CPU
+ 	bool "LED CPU Trigger"
++	depends on !PREEMPT_RT
+ 	help
+ 	  This allows LEDs to be controlled by active CPUs. This shows
+ 	  the active CPUs across an array of LEDs so you can see which
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0266-tty-serial-omap-Make-the-locking-RT-aware.patch b/debian/patches-rt/0266-tty-serial-omap-Make-the-locking-RT-aware.patch
new file mode 100644
index 000000000..e926c5ed8
--- /dev/null
+++ b/debian/patches-rt/0266-tty-serial-omap-Make-the-locking-RT-aware.patch
@@ -0,0 +1,49 @@
+From c436953e83166f6588469c76032a7038a50cc585 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Thu, 28 Jul 2011 13:32:57 +0200
+Subject: [PATCH 266/323] tty/serial/omap: Make the locking RT aware
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The lock is a sleeping lock and local_irq_save() is not the
+optimsation we are looking for. Redo it to make it work on -RT and
+non-RT.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ drivers/tty/serial/omap-serial.c | 12 ++++--------
+ 1 file changed, 4 insertions(+), 8 deletions(-)
+
+diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
+index 84e8158088cd..342005ed5ebf 100644
+--- a/drivers/tty/serial/omap-serial.c
++++ b/drivers/tty/serial/omap-serial.c
+@@ -1311,13 +1311,10 @@ serial_omap_console_write(struct console *co, const char *s,
+ 
+ 	pm_runtime_get_sync(up->dev);
+ 
+-	local_irq_save(flags);
+-	if (up->port.sysrq)
+-		locked = 0;
+-	else if (oops_in_progress)
+-		locked = spin_trylock(&up->port.lock);
++	if (up->port.sysrq || oops_in_progress)
++		locked = spin_trylock_irqsave(&up->port.lock, flags);
+ 	else
+-		spin_lock(&up->port.lock);
++		spin_lock_irqsave(&up->port.lock, flags);
+ 
+ 	/*
+ 	 * First save the IER then disable the interrupts
+@@ -1346,8 +1343,7 @@ serial_omap_console_write(struct console *co, const char *s,
+ 	pm_runtime_mark_last_busy(up->dev);
+ 	pm_runtime_put_autosuspend(up->dev);
+ 	if (locked)
+-		spin_unlock(&up->port.lock);
+-	local_irq_restore(flags);
++		spin_unlock_irqrestore(&up->port.lock, flags);
+ }
+ 
+ static int __init
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0267-tty-serial-pl011-Make-the-locking-work-on-RT.patch b/debian/patches-rt/0267-tty-serial-pl011-Make-the-locking-work-on-RT.patch
new file mode 100644
index 000000000..73b68ab8d
--- /dev/null
+++ b/debian/patches-rt/0267-tty-serial-pl011-Make-the-locking-work-on-RT.patch
@@ -0,0 +1,60 @@
+From 822739997ff16caa50f619a00344655f21d65a4b Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Tue, 8 Jan 2013 21:36:51 +0100
+Subject: [PATCH 267/323] tty/serial/pl011: Make the locking work on RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The lock is a sleeping lock and local_irq_save() is not the optimsation
+we are looking for. Redo it to make it work on -RT and non-RT.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ drivers/tty/serial/amba-pl011.c | 17 +++++++++++------
+ 1 file changed, 11 insertions(+), 6 deletions(-)
+
+diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
+index d4a93a94b4ca..275c625e3eb9 100644
+--- a/drivers/tty/serial/amba-pl011.c
++++ b/drivers/tty/serial/amba-pl011.c
+@@ -2207,18 +2207,24 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
+ {
+ 	struct uart_amba_port *uap = amba_ports[co->index];
+ 	unsigned int old_cr = 0, new_cr;
+-	unsigned long flags;
++	unsigned long flags = 0;
+ 	int locked = 1;
+ 
+ 	clk_enable(uap->clk);
+ 
+-	local_irq_save(flags);
++	/*
++	 * local_irq_save(flags);
++	 *
++	 * This local_irq_save() is nonsense. If we come in via sysrq
++	 * handling then interrupts are already disabled. Aside of
++	 * that the port.sysrq check is racy on SMP regardless.
++	*/
+ 	if (uap->port.sysrq)
+ 		locked = 0;
+ 	else if (oops_in_progress)
+-		locked = spin_trylock(&uap->port.lock);
++		locked = spin_trylock_irqsave(&uap->port.lock, flags);
+ 	else
+-		spin_lock(&uap->port.lock);
++		spin_lock_irqsave(&uap->port.lock, flags);
+ 
+ 	/*
+ 	 *	First save the CR then disable the interrupts
+@@ -2244,8 +2250,7 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
+ 		pl011_write(old_cr, uap, REG_CR);
+ 
+ 	if (locked)
+-		spin_unlock(&uap->port.lock);
+-	local_irq_restore(flags);
++		spin_unlock_irqrestore(&uap->port.lock, flags);
+ 
+ 	clk_disable(uap->clk);
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0268-ARM-enable-irq-in-translation-section-permission-fau.patch b/debian/patches-rt/0268-ARM-enable-irq-in-translation-section-permission-fau.patch
new file mode 100644
index 000000000..35e0764d9
--- /dev/null
+++ b/debian/patches-rt/0268-ARM-enable-irq-in-translation-section-permission-fau.patch
@@ -0,0 +1,95 @@
+From 0a5ad9dd4773a61fe0f0d6928ef603081390df21 Mon Sep 17 00:00:00 2001
+From: "Yadi.hu" <yadi.hu@windriver.com>
+Date: Wed, 10 Dec 2014 10:32:09 +0800
+Subject: [PATCH 268/323] ARM: enable irq in translation/section permission
+ fault handlers
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Probably happens on all ARM, with
+CONFIG_PREEMPT_RT
+CONFIG_DEBUG_ATOMIC_SLEEP
+
+This simple program....
+
+int main() {
+   *((char*)0xc0001000) = 0;
+};
+
+[ 512.742724] BUG: sleeping function called from invalid context at kernel/rtmutex.c:658
+[ 512.743000] in_atomic(): 0, irqs_disabled(): 128, pid: 994, name: a
+[ 512.743217] INFO: lockdep is turned off.
+[ 512.743360] irq event stamp: 0
+[ 512.743482] hardirqs last enabled at (0): [< (null)>] (null)
+[ 512.743714] hardirqs last disabled at (0): [<c0426370>] copy_process+0x3b0/0x11c0
+[ 512.744013] softirqs last enabled at (0): [<c0426370>] copy_process+0x3b0/0x11c0
+[ 512.744303] softirqs last disabled at (0): [< (null)>] (null)
+[ 512.744631] [<c041872c>] (unwind_backtrace+0x0/0x104)
+[ 512.745001] [<c09af0c4>] (dump_stack+0x20/0x24)
+[ 512.745355] [<c0462490>] (__might_sleep+0x1dc/0x1e0)
+[ 512.745717] [<c09b6770>] (rt_spin_lock+0x34/0x6c)
+[ 512.746073] [<c0441bf0>] (do_force_sig_info+0x34/0xf0)
+[ 512.746457] [<c0442668>] (force_sig_info+0x18/0x1c)
+[ 512.746829] [<c041d880>] (__do_user_fault+0x9c/0xd8)
+[ 512.747185] [<c041d938>] (do_bad_area+0x7c/0x94)
+[ 512.747536] [<c041d990>] (do_sect_fault+0x40/0x48)
+[ 512.747898] [<c040841c>] (do_DataAbort+0x40/0xa0)
+[ 512.748181] Exception stack(0xecaa1fb0 to 0xecaa1ff8)
+
+Oxc0000000 belongs to kernel address space, user task can not be
+allowed to access it. For above condition, correct result is that
+test case should receive a “segment fault” and exits but not stacks.
+
+the root cause is commit 02fe2845d6a8 ("avoid enabling interrupts in
+prefetch/data abort handlers"),it deletes irq enable block in Data
+abort assemble code and move them into page/breakpiont/alignment fault
+handlers instead. But author does not enable irq in translation/section
+permission fault handlers. ARM disables irq when it enters exception/
+interrupt mode, if kernel doesn't enable irq, it would be still disabled
+during translation/section permission fault.
+
+We see the above splat because do_force_sig_info is still called with
+IRQs off, and that code eventually does a:
+
+        spin_lock_irqsave(&t->sighand->siglock, flags);
+
+As this is architecture independent code, and we've not seen any other
+need for other arch to have the siglock converted to raw lock, we can
+conclude that we should enable irq for ARM translation/section
+permission exception.
+
+Signed-off-by: Yadi.hu <yadi.hu@windriver.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/arm/mm/fault.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
+index af5177801fb1..1de016008e2e 100644
+--- a/arch/arm/mm/fault.c
++++ b/arch/arm/mm/fault.c
+@@ -400,6 +400,9 @@ do_translation_fault(unsigned long addr, unsigned int fsr,
+ 	if (addr < TASK_SIZE)
+ 		return do_page_fault(addr, fsr, regs);
+ 
++	if (interrupts_enabled(regs))
++		local_irq_enable();
++
+ 	if (user_mode(regs))
+ 		goto bad_area;
+ 
+@@ -470,6 +473,9 @@ do_translation_fault(unsigned long addr, unsigned int fsr,
+ static int
+ do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
+ {
++	if (interrupts_enabled(regs))
++		local_irq_enable();
++
+ 	do_bad_area(addr, fsr, regs);
+ 	return 0;
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0269-genirq-update-irq_set_irqchip_state-documentation.patch b/debian/patches-rt/0269-genirq-update-irq_set_irqchip_state-documentation.patch
new file mode 100644
index 000000000..aae472078
--- /dev/null
+++ b/debian/patches-rt/0269-genirq-update-irq_set_irqchip_state-documentation.patch
@@ -0,0 +1,32 @@
+From 0eeda295a1e21ff716f482a4115822e9789e305f Mon Sep 17 00:00:00 2001
+From: Josh Cartwright <joshc@ni.com>
+Date: Thu, 11 Feb 2016 11:54:00 -0600
+Subject: [PATCH 269/323] genirq: update irq_set_irqchip_state documentation
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+On -rt kernels, the use of migrate_disable()/migrate_enable() is
+sufficient to guarantee a task isn't moved to another CPU.  Update the
+irq_set_irqchip_state() documentation to reflect this.
+
+Signed-off-by: Josh Cartwright <joshc@ni.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/irq/manage.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
+index 5ec167fb77b9..228699d9c85c 100644
+--- a/kernel/irq/manage.c
++++ b/kernel/irq/manage.c
+@@ -2756,7 +2756,7 @@ EXPORT_SYMBOL_GPL(irq_get_irqchip_state);
+  *	This call sets the internal irqchip state of an interrupt,
+  *	depending on the value of @which.
+  *
+- *	This function should be called with preemption disabled if the
++ *	This function should be called with migration disabled if the
+  *	interrupt controller has per-cpu registers.
+  */
+ int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0270-KVM-arm-arm64-downgrade-preempt_disable-d-region-to-.patch b/debian/patches-rt/0270-KVM-arm-arm64-downgrade-preempt_disable-d-region-to-.patch
new file mode 100644
index 000000000..e9a9de0ad
--- /dev/null
+++ b/debian/patches-rt/0270-KVM-arm-arm64-downgrade-preempt_disable-d-region-to-.patch
@@ -0,0 +1,59 @@
+From bbb0b6e29c89355e0fb77bef3b06badef0ccc946 Mon Sep 17 00:00:00 2001
+From: Josh Cartwright <joshc@ni.com>
+Date: Thu, 11 Feb 2016 11:54:01 -0600
+Subject: [PATCH 270/323] KVM: arm/arm64: downgrade preempt_disable()d region
+ to migrate_disable()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+kvm_arch_vcpu_ioctl_run() disables the use of preemption when updating
+the vgic and timer states to prevent the calling task from migrating to
+another CPU.  It does so to prevent the task from writing to the
+incorrect per-CPU GIC distributor registers.
+
+On -rt kernels, it's possible to maintain the same guarantee with the
+use of migrate_{disable,enable}(), with the added benefit that the
+migrate-disabled region is preemptible.  Update
+kvm_arch_vcpu_ioctl_run() to do so.
+
+Cc: Christoffer Dall <christoffer.dall@linaro.org>
+Reported-by: Manish Jaggi <Manish.Jaggi@caviumnetworks.com>
+Signed-off-by: Josh Cartwright <joshc@ni.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/arm64/kvm/arm.c | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
+index 4d63fcd7574b..06fced951e75 100644
+--- a/arch/arm64/kvm/arm.c
++++ b/arch/arm64/kvm/arm.c
+@@ -708,7 +708,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
+ 		 * involves poking the GIC, which must be done in a
+ 		 * non-preemptible context.
+ 		 */
+-		preempt_disable();
++		migrate_disable();
+ 
+ 		kvm_pmu_flush_hwstate(vcpu);
+ 
+@@ -757,7 +757,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
+ 				kvm_timer_sync_user(vcpu);
+ 			kvm_vgic_sync_hwstate(vcpu);
+ 			local_irq_enable();
+-			preempt_enable();
++			migrate_enable();
+ 			continue;
+ 		}
+ 
+@@ -829,7 +829,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
+ 		/* Exit types that need handling before we can be preempted */
+ 		handle_exit_early(vcpu, ret);
+ 
+-		preempt_enable();
++		migrate_enable();
+ 
+ 		/*
+ 		 * The ARMv8 architecture doesn't give the hypervisor
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0271-arm64-fpsimd-Delay-freeing-memory-in-fpsimd_flush_th.patch b/debian/patches-rt/0271-arm64-fpsimd-Delay-freeing-memory-in-fpsimd_flush_th.patch
new file mode 100644
index 000000000..733617e78
--- /dev/null
+++ b/debian/patches-rt/0271-arm64-fpsimd-Delay-freeing-memory-in-fpsimd_flush_th.patch
@@ -0,0 +1,66 @@
+From d0fe894184b649a8d383fa8d2db7ae3233b04428 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 25 Jul 2018 14:02:38 +0200
+Subject: [PATCH 271/323] arm64: fpsimd: Delay freeing memory in
+ fpsimd_flush_thread()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+fpsimd_flush_thread() invokes kfree() via sve_free() within a preempt disabled
+section which is not working on -RT.
+
+Delay freeing of memory until preemption is enabled again.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/arm64/kernel/fpsimd.c | 14 +++++++++++++-
+ 1 file changed, 13 insertions(+), 1 deletion(-)
+
+diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
+index a9bbfb800ec2..aa631771e0dc 100644
+--- a/arch/arm64/kernel/fpsimd.c
++++ b/arch/arm64/kernel/fpsimd.c
+@@ -226,6 +226,16 @@ static void sve_free(struct task_struct *task)
+ 	__sve_free(task);
+ }
+ 
++static void *sve_free_atomic(struct task_struct *task)
++{
++	void *sve_state = task->thread.sve_state;
++
++	WARN_ON(test_tsk_thread_flag(task, TIF_SVE));
++
++	task->thread.sve_state = NULL;
++	return sve_state;
++}
++
+ /*
+  * TIF_SVE controls whether a task can use SVE without trapping while
+  * in userspace, and also the way a task's FPSIMD/SVE state is stored
+@@ -1022,6 +1032,7 @@ void fpsimd_thread_switch(struct task_struct *next)
+ void fpsimd_flush_thread(void)
+ {
+ 	int vl, supported_vl;
++	void *mem = NULL;
+ 
+ 	if (!system_supports_fpsimd())
+ 		return;
+@@ -1034,7 +1045,7 @@ void fpsimd_flush_thread(void)
+ 
+ 	if (system_supports_sve()) {
+ 		clear_thread_flag(TIF_SVE);
+-		sve_free(current);
++		mem = sve_free_atomic(current);
+ 
+ 		/*
+ 		 * Reset the task vector length as required.
+@@ -1068,6 +1079,7 @@ void fpsimd_flush_thread(void)
+ 	}
+ 
+ 	put_cpu_fpsimd_context();
++	kfree(mem);
+ }
+ 
+ /*
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0272-x86-Enable-RT-also-on-32bit.patch b/debian/patches-rt/0272-x86-Enable-RT-also-on-32bit.patch
new file mode 100644
index 000000000..e7c39e069
--- /dev/null
+++ b/debian/patches-rt/0272-x86-Enable-RT-also-on-32bit.patch
@@ -0,0 +1,34 @@
+From b4def70f635385c0a02c2261e1915671363eeccd Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Thu, 7 Nov 2019 17:49:20 +0100
+Subject: [PATCH 272/323] x86: Enable RT also on 32bit
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/x86/Kconfig | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
+index b9f68b01a8c8..ca79a831f611 100644
+--- a/arch/x86/Kconfig
++++ b/arch/x86/Kconfig
+@@ -27,7 +27,6 @@ config X86_64
+ 	# Options that are inherently 64-bit kernel only:
+ 	select ARCH_HAS_GIGANTIC_PAGE
+ 	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
+-	select ARCH_SUPPORTS_RT
+ 	select ARCH_USE_CMPXCHG_LOCKREF
+ 	select HAVE_ARCH_SOFT_DIRTY
+ 	select MODULES_USE_ELF_RELA
+@@ -96,6 +95,7 @@ config X86
+ 	select ARCH_SUPPORTS_ACPI
+ 	select ARCH_SUPPORTS_ATOMIC_RMW
+ 	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
++	select ARCH_SUPPORTS_RT
+ 	select ARCH_USE_BUILTIN_BSWAP
+ 	select ARCH_USE_QUEUED_RWLOCKS
+ 	select ARCH_USE_QUEUED_SPINLOCKS
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0273-ARM-Allow-to-enable-RT.patch b/debian/patches-rt/0273-ARM-Allow-to-enable-RT.patch
new file mode 100644
index 000000000..9392f0977
--- /dev/null
+++ b/debian/patches-rt/0273-ARM-Allow-to-enable-RT.patch
@@ -0,0 +1,36 @@
+From 98a5d5b92ddcd0df7aa708accc20a07b6008d86a Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 11 Oct 2019 13:14:29 +0200
+Subject: [PATCH 273/323] ARM: Allow to enable RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Allow to select RT.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/arm/Kconfig | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
+index 73c55cb2f296..adf9347724ed 100644
+--- a/arch/arm/Kconfig
++++ b/arch/arm/Kconfig
+@@ -32,6 +32,7 @@ config ARM
+ 	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
+ 	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
+ 	select ARCH_SUPPORTS_ATOMIC_RMW
++	select ARCH_SUPPORTS_RT if HAVE_POSIX_CPU_TIMERS_TASK_WORK
+ 	select ARCH_USE_BUILTIN_BSWAP
+ 	select ARCH_USE_CMPXCHG_LOCKREF
+ 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
+@@ -123,6 +124,7 @@ config ARM
+ 	select OLD_SIGSUSPEND3
+ 	select PCI_SYSCALL if PCI
+ 	select PERF_USE_VMALLOC
++	select HAVE_POSIX_CPU_TIMERS_TASK_WORK if !KVM
+ 	select RTC_LIB
+ 	select SET_FS
+ 	select SYS_SUPPORTS_APM_EMULATION
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0274-ARM64-Allow-to-enable-RT.patch b/debian/patches-rt/0274-ARM64-Allow-to-enable-RT.patch
new file mode 100644
index 000000000..5176f9521
--- /dev/null
+++ b/debian/patches-rt/0274-ARM64-Allow-to-enable-RT.patch
@@ -0,0 +1,36 @@
+From 27aef9eb166603124a97edf3a14035b406f36096 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 11 Oct 2019 13:14:35 +0200
+Subject: [PATCH 274/323] ARM64: Allow to enable RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Allow to select RT.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/arm64/Kconfig | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
+index 7681d7b65c7d..ab8b86b23190 100644
+--- a/arch/arm64/Kconfig
++++ b/arch/arm64/Kconfig
+@@ -76,6 +76,7 @@ config ARM64
+ 	select ARCH_SUPPORTS_ATOMIC_RMW
+ 	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG)
+ 	select ARCH_SUPPORTS_NUMA_BALANCING
++	select ARCH_SUPPORTS_RT if HAVE_POSIX_CPU_TIMERS_TASK_WORK
+ 	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
+ 	select ARCH_WANT_DEFAULT_BPF_JIT
+ 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
+@@ -195,6 +196,7 @@ config ARM64
+ 	select PCI_DOMAINS_GENERIC if PCI
+ 	select PCI_ECAM if (ACPI && PCI)
+ 	select PCI_SYSCALL if PCI
++	select HAVE_POSIX_CPU_TIMERS_TASK_WORK if !KVM
+ 	select POWER_RESET
+ 	select POWER_SUPPLY
+ 	select SET_FS
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0275-powerpc-traps-Use-PREEMPT_RT.patch b/debian/patches-rt/0275-powerpc-traps-Use-PREEMPT_RT.patch
new file mode 100644
index 000000000..75ece9602
--- /dev/null
+++ b/debian/patches-rt/0275-powerpc-traps-Use-PREEMPT_RT.patch
@@ -0,0 +1,39 @@
+From 25b6e91e812b8fe81cda3732be60b3d8402fee43 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 26 Jul 2019 11:30:49 +0200
+Subject: [PATCH 275/323] powerpc: traps: Use PREEMPT_RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Add PREEMPT_RT to the backtrace if enabled.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/powerpc/kernel/traps.c | 7 ++++++-
+ 1 file changed, 6 insertions(+), 1 deletion(-)
+
+diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
+index d39a4a6b4ddf..75a6c83299ad 100644
+--- a/arch/powerpc/kernel/traps.c
++++ b/arch/powerpc/kernel/traps.c
+@@ -259,12 +259,17 @@ static char *get_mmu_str(void)
+ 
+ static int __die(const char *str, struct pt_regs *regs, long err)
+ {
++	const char *pr = "";
++
+ 	printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
+ 
++	if (IS_ENABLED(CONFIG_PREEMPTION))
++		pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT";
++
+ 	printk("%s PAGE_SIZE=%luK%s%s%s%s%s%s %s\n",
+ 	       IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? "LE" : "BE",
+ 	       PAGE_SIZE / 1024, get_mmu_str(),
+-	       IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "",
++	       pr,
+ 	       IS_ENABLED(CONFIG_SMP) ? " SMP" : "",
+ 	       IS_ENABLED(CONFIG_SMP) ? (" NR_CPUS=" __stringify(NR_CPUS)) : "",
+ 	       debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0276-powerpc-pseries-iommu-Use-a-locallock-instead-local_.patch b/debian/patches-rt/0276-powerpc-pseries-iommu-Use-a-locallock-instead-local_.patch
new file mode 100644
index 000000000..fbd35f4c7
--- /dev/null
+++ b/debian/patches-rt/0276-powerpc-pseries-iommu-Use-a-locallock-instead-local_.patch
@@ -0,0 +1,117 @@
+From afebcd1022d509a6887f066b6601caf561ee1ee5 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 26 Mar 2019 18:31:54 +0100
+Subject: [PATCH 276/323] powerpc/pseries/iommu: Use a locallock instead
+ local_irq_save()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The locallock protects the per-CPU variable tce_page. The function
+attempts to allocate memory while tce_page is protected (by disabling
+interrupts).
+
+Use local_irq_save() instead of local_irq_disable().
+
+Cc: stable-rt@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/powerpc/platforms/pseries/iommu.c | 31 +++++++++++++++++---------
+ 1 file changed, 20 insertions(+), 11 deletions(-)
+
+diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
+index 245f1f8df656..f05555dde8e7 100644
+--- a/arch/powerpc/platforms/pseries/iommu.c
++++ b/arch/powerpc/platforms/pseries/iommu.c
+@@ -24,6 +24,7 @@
+ #include <linux/of.h>
+ #include <linux/iommu.h>
+ #include <linux/rculist.h>
++#include <linux/local_lock.h>
+ #include <asm/io.h>
+ #include <asm/prom.h>
+ #include <asm/rtas.h>
+@@ -190,7 +191,13 @@ static int tce_build_pSeriesLP(unsigned long liobn, long tcenum, long tceshift,
+ 	return ret;
+ }
+ 
+-static DEFINE_PER_CPU(__be64 *, tce_page);
++struct tce_page {
++	__be64 * page;
++	local_lock_t lock;
++};
++static DEFINE_PER_CPU(struct tce_page, tce_page) = {
++	.lock = INIT_LOCAL_LOCK(lock),
++};
+ 
+ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
+ 				     long npages, unsigned long uaddr,
+@@ -212,9 +219,10 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
+ 		                           direction, attrs);
+ 	}
+ 
+-	local_irq_save(flags);	/* to protect tcep and the page behind it */
++	/* to protect tcep and the page behind it */
++	local_lock_irqsave(&tce_page.lock, flags);
+ 
+-	tcep = __this_cpu_read(tce_page);
++	tcep = __this_cpu_read(tce_page.page);
+ 
+ 	/* This is safe to do since interrupts are off when we're called
+ 	 * from iommu_alloc{,_sg}()
+@@ -223,12 +231,12 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
+ 		tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
+ 		/* If allocation fails, fall back to the loop implementation */
+ 		if (!tcep) {
+-			local_irq_restore(flags);
++			local_unlock_irqrestore(&tce_page.lock, flags);
+ 			return tce_build_pSeriesLP(tbl->it_index, tcenum,
+ 					tbl->it_page_shift,
+ 					npages, uaddr, direction, attrs);
+ 		}
+-		__this_cpu_write(tce_page, tcep);
++		__this_cpu_write(tce_page.page, tcep);
+ 	}
+ 
+ 	rpn = __pa(uaddr) >> TCE_SHIFT;
+@@ -258,7 +266,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
+ 		tcenum += limit;
+ 	} while (npages > 0 && !rc);
+ 
+-	local_irq_restore(flags);
++	local_unlock_irqrestore(&tce_page.lock, flags);
+ 
+ 	if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) {
+ 		ret = (int)rc;
+@@ -429,16 +437,17 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
+ 				DMA_BIDIRECTIONAL, 0);
+ 	}
+ 
+-	local_irq_disable();	/* to protect tcep and the page behind it */
+-	tcep = __this_cpu_read(tce_page);
++	/* to protect tcep and the page behind it */
++	local_lock_irq(&tce_page.lock);
++	tcep = __this_cpu_read(tce_page.page);
+ 
+ 	if (!tcep) {
+ 		tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
+ 		if (!tcep) {
+-			local_irq_enable();
++			local_unlock_irq(&tce_page.lock);
+ 			return -ENOMEM;
+ 		}
+-		__this_cpu_write(tce_page, tcep);
++		__this_cpu_write(tce_page.page, tcep);
+ 	}
+ 
+ 	proto_tce = TCE_PCI_READ | TCE_PCI_WRITE;
+@@ -481,7 +490,7 @@ static int tce_setrange_multi_pSeriesLP(unsigned long start_pfn,
+ 
+ 	/* error cleanup: caller will clear whole range */
+ 
+-	local_irq_enable();
++	local_unlock_irq(&tce_page.lock);
+ 	return rc;
+ }
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0277-powerpc-kvm-Disable-in-kernel-MPIC-emulation-for-PRE.patch b/debian/patches-rt/0277-powerpc-kvm-Disable-in-kernel-MPIC-emulation-for-PRE.patch
new file mode 100644
index 000000000..1d465fba1
--- /dev/null
+++ b/debian/patches-rt/0277-powerpc-kvm-Disable-in-kernel-MPIC-emulation-for-PRE.patch
@@ -0,0 +1,45 @@
+From f6ff6354df6d4609ce786969f2fd16afeaf88fba Mon Sep 17 00:00:00 2001
+From: Bogdan Purcareata <bogdan.purcareata@freescale.com>
+Date: Fri, 24 Apr 2015 15:53:13 +0000
+Subject: [PATCH 277/323] powerpc/kvm: Disable in-kernel MPIC emulation for
+ PREEMPT_RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+While converting the openpic emulation code to use a raw_spinlock_t enables
+guests to run on RT, there's still a performance issue. For interrupts sent in
+directed delivery mode with a multiple CPU mask, the emulated openpic will loop
+through all of the VCPUs, and for each VCPUs, it call IRQ_check, which will loop
+through all the pending interrupts for that VCPU. This is done while holding the
+raw_lock, meaning that in all this time the interrupts and preemption are
+disabled on the host Linux. A malicious user app can max both these number and
+cause a DoS.
+
+This temporary fix is sent for two reasons. First is so that users who want to
+use the in-kernel MPIC emulation are aware of the potential latencies, thus
+making sure that the hardware MPIC and their usage scenario does not involve
+interrupts sent in directed delivery mode, and the number of possible pending
+interrupts is kept small. Secondly, this should incentivize the development of a
+proper openpic emulation that would be better suited for RT.
+
+Acked-by: Scott Wood <scottwood@freescale.com>
+Signed-off-by: Bogdan Purcareata <bogdan.purcareata@freescale.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/powerpc/kvm/Kconfig | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
+index 549591d9aaa2..efb5bfe93f70 100644
+--- a/arch/powerpc/kvm/Kconfig
++++ b/arch/powerpc/kvm/Kconfig
+@@ -178,6 +178,7 @@ config KVM_E500MC
+ config KVM_MPIC
+ 	bool "KVM in-kernel MPIC emulation"
+ 	depends on KVM && E500
++	depends on !PREEMPT_RT
+ 	select HAVE_KVM_IRQCHIP
+ 	select HAVE_KVM_IRQFD
+ 	select HAVE_KVM_IRQ_ROUTING
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0278-powerpc-stackprotector-work-around-stack-guard-init-.patch b/debian/patches-rt/0278-powerpc-stackprotector-work-around-stack-guard-init-.patch
new file mode 100644
index 000000000..a46f2fadf
--- /dev/null
+++ b/debian/patches-rt/0278-powerpc-stackprotector-work-around-stack-guard-init-.patch
@@ -0,0 +1,36 @@
+From fdb2b0b4898a26e8910152ed1ab6fa6748d1b839 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 26 Mar 2019 18:31:29 +0100
+Subject: [PATCH 278/323] powerpc/stackprotector: work around stack-guard init
+ from atomic
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+This is invoked from the secondary CPU in atomic context. On x86 we use
+tsc instead. On Power we XOR it against mftb() so lets use stack address
+as the initial value.
+
+Cc: stable-rt@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/powerpc/include/asm/stackprotector.h | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/arch/powerpc/include/asm/stackprotector.h b/arch/powerpc/include/asm/stackprotector.h
+index 1c8460e23583..b1653c160bab 100644
+--- a/arch/powerpc/include/asm/stackprotector.h
++++ b/arch/powerpc/include/asm/stackprotector.h
+@@ -24,7 +24,11 @@ static __always_inline void boot_init_stack_canary(void)
+ 	unsigned long canary;
+ 
+ 	/* Try to get a semi random initial value. */
++#ifdef CONFIG_PREEMPT_RT
++	canary = (unsigned long)&canary;
++#else
+ 	canary = get_random_canary();
++#endif
+ 	canary ^= mftb();
+ 	canary ^= LINUX_VERSION_CODE;
+ 	canary &= CANARY_MASK;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0279-powerpc-Avoid-recursive-header-includes.patch b/debian/patches-rt/0279-powerpc-Avoid-recursive-header-includes.patch
new file mode 100644
index 000000000..64bf1e545
--- /dev/null
+++ b/debian/patches-rt/0279-powerpc-Avoid-recursive-header-includes.patch
@@ -0,0 +1,48 @@
+From 725e44480dc7376b55d990292c119883ddc51288 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 8 Jan 2021 19:48:21 +0100
+Subject: [PATCH 279/323] powerpc: Avoid recursive header includes
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+- The include of bug.h leads to an include of printk.h which gets back
+  to spinlock.h and complains then about missing xchg().
+  Remove bug.h and add bits.h which is needed for BITS_PER_BYTE.
+
+- Avoid the "please don't include this file directly" error from
+  rwlock-rt. Allow an include from/with rtmutex.h.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/powerpc/include/asm/cmpxchg.h               | 2 +-
+ arch/powerpc/include/asm/simple_spinlock_types.h | 2 +-
+ 2 files changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/arch/powerpc/include/asm/cmpxchg.h b/arch/powerpc/include/asm/cmpxchg.h
+index cf091c4c22e5..7371f7e23c35 100644
+--- a/arch/powerpc/include/asm/cmpxchg.h
++++ b/arch/powerpc/include/asm/cmpxchg.h
+@@ -5,7 +5,7 @@
+ #ifdef __KERNEL__
+ #include <linux/compiler.h>
+ #include <asm/synch.h>
+-#include <linux/bug.h>
++#include <linux/bits.h>
+ 
+ #ifdef __BIG_ENDIAN
+ #define BITOFF_CAL(size, off)	((sizeof(u32) - size - off) * BITS_PER_BYTE)
+diff --git a/arch/powerpc/include/asm/simple_spinlock_types.h b/arch/powerpc/include/asm/simple_spinlock_types.h
+index 0f3cdd8faa95..d45561e9e6ba 100644
+--- a/arch/powerpc/include/asm/simple_spinlock_types.h
++++ b/arch/powerpc/include/asm/simple_spinlock_types.h
+@@ -2,7 +2,7 @@
+ #ifndef _ASM_POWERPC_SIMPLE_SPINLOCK_TYPES_H
+ #define _ASM_POWERPC_SIMPLE_SPINLOCK_TYPES_H
+ 
+-#ifndef __LINUX_SPINLOCK_TYPES_H
++#if !defined(__LINUX_SPINLOCK_TYPES_H) && !defined(__LINUX_RT_MUTEX_H)
+ # error "please don't include this file directly"
+ #endif
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0280-POWERPC-Allow-to-enable-RT.patch b/debian/patches-rt/0280-POWERPC-Allow-to-enable-RT.patch
new file mode 100644
index 000000000..955781532
--- /dev/null
+++ b/debian/patches-rt/0280-POWERPC-Allow-to-enable-RT.patch
@@ -0,0 +1,36 @@
+From 934b061dd0089023163d44f7670bc3b0a4ebb7b1 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 11 Oct 2019 13:14:41 +0200
+Subject: [PATCH 280/323] POWERPC: Allow to enable RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Allow to select RT.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ arch/powerpc/Kconfig | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
+index 6d8ce54ad6dd..065ed526be1a 100644
+--- a/arch/powerpc/Kconfig
++++ b/arch/powerpc/Kconfig
+@@ -146,6 +146,7 @@ config PPC
+ 	select ARCH_MIGHT_HAVE_PC_SERIO
+ 	select ARCH_OPTIONAL_KERNEL_RWX		if ARCH_HAS_STRICT_KERNEL_RWX
+ 	select ARCH_SUPPORTS_ATOMIC_RMW
++	select ARCH_SUPPORTS_RT if HAVE_POSIX_CPU_TIMERS_TASK_WORK
+ 	select ARCH_USE_BUILTIN_BSWAP
+ 	select ARCH_USE_CMPXCHG_LOCKREF		if PPC64
+ 	select ARCH_USE_QUEUED_RWLOCKS		if PPC_QUEUED_SPINLOCKS
+@@ -238,6 +239,7 @@ config PPC
+ 	select HAVE_SYSCALL_TRACEPOINTS
+ 	select HAVE_VIRT_CPU_ACCOUNTING
+ 	select HAVE_IRQ_TIME_ACCOUNTING
++	select HAVE_POSIX_CPU_TIMERS_TASK_WORK  if !KVM
+ 	select HAVE_RSEQ
+ 	select IOMMU_HELPER			if PPC64
+ 	select IRQ_DOMAIN
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0281-drivers-block-zram-Replace-bit-spinlocks-with-rtmute.patch b/debian/patches-rt/0281-drivers-block-zram-Replace-bit-spinlocks-with-rtmute.patch
new file mode 100644
index 000000000..4c370a764
--- /dev/null
+++ b/debian/patches-rt/0281-drivers-block-zram-Replace-bit-spinlocks-with-rtmute.patch
@@ -0,0 +1,93 @@
+From b7d25d7dc9f6a1923426c6e235061e825434e4fd Mon Sep 17 00:00:00 2001
+From: Mike Galbraith <umgwanakikbuti@gmail.com>
+Date: Thu, 31 Mar 2016 04:08:28 +0200
+Subject: [PATCH 281/323] drivers/block/zram: Replace bit spinlocks with
+ rtmutex for -rt
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+They're nondeterministic, and lead to ___might_sleep() splats in -rt.
+OTOH, they're a lot less wasteful than an rtmutex per page.
+
+Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/block/zram/zram_drv.c | 36 +++++++++++++++++++++++++++++++++++
+ drivers/block/zram/zram_drv.h |  1 +
+ 2 files changed, 37 insertions(+)
+
+diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
+index 0636df6b67db..1a7523cefbe9 100644
+--- a/drivers/block/zram/zram_drv.c
++++ b/drivers/block/zram/zram_drv.c
+@@ -59,6 +59,40 @@ static void zram_free_page(struct zram *zram, size_t index);
+ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
+ 				u32 index, int offset, struct bio *bio);
+ 
++#ifdef CONFIG_PREEMPT_RT
++static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages)
++{
++	size_t index;
++
++	for (index = 0; index < num_pages; index++)
++		spin_lock_init(&zram->table[index].lock);
++}
++
++static int zram_slot_trylock(struct zram *zram, u32 index)
++{
++	int ret;
++
++	ret = spin_trylock(&zram->table[index].lock);
++	if (ret)
++		__set_bit(ZRAM_LOCK, &zram->table[index].flags);
++	return ret;
++}
++
++static void zram_slot_lock(struct zram *zram, u32 index)
++{
++	spin_lock(&zram->table[index].lock);
++	__set_bit(ZRAM_LOCK, &zram->table[index].flags);
++}
++
++static void zram_slot_unlock(struct zram *zram, u32 index)
++{
++	__clear_bit(ZRAM_LOCK, &zram->table[index].flags);
++	spin_unlock(&zram->table[index].lock);
++}
++
++#else
++
++static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages) { }
+ 
+ static int zram_slot_trylock(struct zram *zram, u32 index)
+ {
+@@ -74,6 +108,7 @@ static void zram_slot_unlock(struct zram *zram, u32 index)
+ {
+ 	bit_spin_unlock(ZRAM_LOCK, &zram->table[index].flags);
+ }
++#endif
+ 
+ static inline bool init_done(struct zram *zram)
+ {
+@@ -1165,6 +1200,7 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize)
+ 
+ 	if (!huge_class_size)
+ 		huge_class_size = zs_huge_class_size(zram->mem_pool);
++	zram_meta_init_table_locks(zram, num_pages);
+ 	return true;
+ }
+ 
+diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
+index f2fd46daa760..7e4dd447e1dd 100644
+--- a/drivers/block/zram/zram_drv.h
++++ b/drivers/block/zram/zram_drv.h
+@@ -63,6 +63,7 @@ struct zram_table_entry {
+ 		unsigned long element;
+ 	};
+ 	unsigned long flags;
++	spinlock_t lock;
+ #ifdef CONFIG_ZRAM_MEMORY_TRACKING
+ 	ktime_t ac_time;
+ #endif
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0282-tpm_tis-fix-stall-after-iowrite-s.patch b/debian/patches-rt/0282-tpm_tis-fix-stall-after-iowrite-s.patch
new file mode 100644
index 000000000..8452ac49c
--- /dev/null
+++ b/debian/patches-rt/0282-tpm_tis-fix-stall-after-iowrite-s.patch
@@ -0,0 +1,84 @@
+From ae8783c450876b505b7c6066ccda3b68e8d08c58 Mon Sep 17 00:00:00 2001
+From: Haris Okanovic <haris.okanovic@ni.com>
+Date: Tue, 15 Aug 2017 15:13:08 -0500
+Subject: [PATCH 282/323] tpm_tis: fix stall after iowrite*()s
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+ioread8() operations to TPM MMIO addresses can stall the cpu when
+immediately following a sequence of iowrite*()'s to the same region.
+
+For example, cyclitest measures ~400us latency spikes when a non-RT
+usermode application communicates with an SPI-based TPM chip (Intel Atom
+E3940 system, PREEMPT_RT kernel). The spikes are caused by a
+stalling ioread8() operation following a sequence of 30+ iowrite8()s to
+the same address. I believe this happens because the write sequence is
+buffered (in cpu or somewhere along the bus), and gets flushed on the
+first LOAD instruction (ioread*()) that follows.
+
+The enclosed change appears to fix this issue: read the TPM chip's
+access register (status code) after every iowrite*() operation to
+amortize the cost of flushing data to chip across multiple instructions.
+
+Signed-off-by: Haris Okanovic <haris.okanovic@ni.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ drivers/char/tpm/tpm_tis.c | 29 +++++++++++++++++++++++++++--
+ 1 file changed, 27 insertions(+), 2 deletions(-)
+
+diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
+index 3e1bb28b7efd..c26ed0ce6b34 100644
+--- a/drivers/char/tpm/tpm_tis.c
++++ b/drivers/char/tpm/tpm_tis.c
+@@ -50,6 +50,31 @@ static inline struct tpm_tis_tcg_phy *to_tpm_tis_tcg_phy(struct tpm_tis_data *da
+ 	return container_of(data, struct tpm_tis_tcg_phy, priv);
+ }
+ 
++#ifdef CONFIG_PREEMPT_RT
++/*
++ * Flushes previous write operations to chip so that a subsequent
++ * ioread*()s won't stall a cpu.
++ */
++static inline void tpm_tis_flush(void __iomem *iobase)
++{
++	ioread8(iobase + TPM_ACCESS(0));
++}
++#else
++#define tpm_tis_flush(iobase) do { } while (0)
++#endif
++
++static inline void tpm_tis_iowrite8(u8 b, void __iomem *iobase, u32 addr)
++{
++	iowrite8(b, iobase + addr);
++	tpm_tis_flush(iobase);
++}
++
++static inline void tpm_tis_iowrite32(u32 b, void __iomem *iobase, u32 addr)
++{
++	iowrite32(b, iobase + addr);
++	tpm_tis_flush(iobase);
++}
++
+ static int interrupts = -1;
+ module_param(interrupts, int, 0444);
+ MODULE_PARM_DESC(interrupts, "Enable interrupts");
+@@ -186,7 +211,7 @@ static int tpm_tcg_write_bytes(struct tpm_tis_data *data, u32 addr, u16 len,
+ 	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
+ 
+ 	while (len--)
+-		iowrite8(*value++, phy->iobase + addr);
++		tpm_tis_iowrite8(*value++, phy->iobase, addr);
+ 
+ 	return 0;
+ }
+@@ -213,7 +238,7 @@ static int tpm_tcg_write32(struct tpm_tis_data *data, u32 addr, u32 value)
+ {
+ 	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
+ 
+-	iowrite32(value, phy->iobase + addr);
++	tpm_tis_iowrite32(value, phy->iobase, addr);
+ 
+ 	return 0;
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0283-signals-Allow-rt-tasks-to-cache-one-sigqueue-struct.patch b/debian/patches-rt/0283-signals-Allow-rt-tasks-to-cache-one-sigqueue-struct.patch
new file mode 100644
index 000000000..a34a3538f
--- /dev/null
+++ b/debian/patches-rt/0283-signals-Allow-rt-tasks-to-cache-one-sigqueue-struct.patch
@@ -0,0 +1,212 @@
+From 1f9d07b4cf227f0cf0800f96c10f9ef143b5d663 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 3 Jul 2009 08:44:56 -0500
+Subject: [PATCH 283/323] signals: Allow rt tasks to cache one sigqueue struct
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+To avoid allocation allow rt tasks to cache one sigqueue struct in
+task struct.
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ include/linux/sched.h  |  1 +
+ include/linux/signal.h |  1 +
+ kernel/exit.c          |  2 +-
+ kernel/fork.c          |  1 +
+ kernel/signal.c        | 69 +++++++++++++++++++++++++++++++++++++++---
+ 5 files changed, 69 insertions(+), 5 deletions(-)
+
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index 665a17e4f69b..a73528e8235d 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -992,6 +992,7 @@ struct task_struct {
+ 	/* Signal handlers: */
+ 	struct signal_struct		*signal;
+ 	struct sighand_struct __rcu		*sighand;
++	struct sigqueue			*sigqueue_cache;
+ 	sigset_t			blocked;
+ 	sigset_t			real_blocked;
+ 	/* Restored if set_restore_sigmask() was used: */
+diff --git a/include/linux/signal.h b/include/linux/signal.h
+index b256f9c65661..ebf6c515a7b2 100644
+--- a/include/linux/signal.h
++++ b/include/linux/signal.h
+@@ -265,6 +265,7 @@ static inline void init_sigpending(struct sigpending *sig)
+ }
+ 
+ extern void flush_sigqueue(struct sigpending *queue);
++extern void flush_task_sigqueue(struct task_struct *tsk);
+ 
+ /* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
+ static inline int valid_signal(unsigned long sig)
+diff --git a/kernel/exit.c b/kernel/exit.c
+index bacdaf980933..b86f388d3e64 100644
+--- a/kernel/exit.c
++++ b/kernel/exit.c
+@@ -199,7 +199,7 @@ static void __exit_signal(struct task_struct *tsk)
+ 	 * Do this under ->siglock, we can race with another thread
+ 	 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
+ 	 */
+-	flush_sigqueue(&tsk->pending);
++	flush_task_sigqueue(tsk);
+ 	tsk->sighand = NULL;
+ 	spin_unlock(&sighand->siglock);
+ 
+diff --git a/kernel/fork.c b/kernel/fork.c
+index 2a11bf5f9e30..dfefb6e7e082 100644
+--- a/kernel/fork.c
++++ b/kernel/fork.c
+@@ -2046,6 +2046,7 @@ static __latent_entropy struct task_struct *copy_process(
+ 	spin_lock_init(&p->alloc_lock);
+ 
+ 	init_sigpending(&p->pending);
++	p->sigqueue_cache = NULL;
+ 
+ 	p->utime = p->stime = p->gtime = 0;
+ #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
+diff --git a/kernel/signal.c b/kernel/signal.c
+index e8819aabe3cd..e1f263cbcf09 100644
+--- a/kernel/signal.c
++++ b/kernel/signal.c
+@@ -20,6 +20,7 @@
+ #include <linux/sched/task.h>
+ #include <linux/sched/task_stack.h>
+ #include <linux/sched/cputime.h>
++#include <linux/sched/rt.h>
+ #include <linux/file.h>
+ #include <linux/fs.h>
+ #include <linux/proc_fs.h>
+@@ -404,13 +405,30 @@ void task_join_group_stop(struct task_struct *task)
+ 	task_set_jobctl_pending(task, mask | JOBCTL_STOP_PENDING);
+ }
+ 
++static inline struct sigqueue *get_task_cache(struct task_struct *t)
++{
++	struct sigqueue *q = t->sigqueue_cache;
++
++	if (cmpxchg(&t->sigqueue_cache, q, NULL) != q)
++		return NULL;
++	return q;
++}
++
++static inline int put_task_cache(struct task_struct *t, struct sigqueue *q)
++{
++	if (cmpxchg(&t->sigqueue_cache, NULL, q) == NULL)
++		return 0;
++	return 1;
++}
++
+ /*
+  * allocate a new signal queue record
+  * - this may be called without locks if and only if t == current, otherwise an
+  *   appropriate lock must be held to stop the target task from exiting
+  */
+ static struct sigqueue *
+-__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
++__sigqueue_do_alloc(int sig, struct task_struct *t, gfp_t flags,
++		    int override_rlimit, int fromslab)
+ {
+ 	struct sigqueue *q = NULL;
+ 	struct user_struct *user;
+@@ -432,7 +450,10 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimi
+ 	rcu_read_unlock();
+ 
+ 	if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
+-		q = kmem_cache_alloc(sigqueue_cachep, flags);
++		if (!fromslab)
++			q = get_task_cache(t);
++		if (!q)
++			q = kmem_cache_alloc(sigqueue_cachep, flags);
+ 	} else {
+ 		print_dropped_signal(sig);
+ 	}
+@@ -449,6 +470,13 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimi
+ 	return q;
+ }
+ 
++static struct sigqueue *
++__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags,
++		 int override_rlimit)
++{
++	return __sigqueue_do_alloc(sig, t, flags, override_rlimit, 0);
++}
++
+ static void __sigqueue_free(struct sigqueue *q)
+ {
+ 	if (q->flags & SIGQUEUE_PREALLOC)
+@@ -458,6 +486,21 @@ static void __sigqueue_free(struct sigqueue *q)
+ 	kmem_cache_free(sigqueue_cachep, q);
+ }
+ 
++static void sigqueue_free_current(struct sigqueue *q)
++{
++	struct user_struct *up;
++
++	if (q->flags & SIGQUEUE_PREALLOC)
++		return;
++
++	up = q->user;
++	if (rt_prio(current->normal_prio) && !put_task_cache(current, q)) {
++		atomic_dec(&up->sigpending);
++		free_uid(up);
++	} else
++		  __sigqueue_free(q);
++}
++
+ void flush_sigqueue(struct sigpending *queue)
+ {
+ 	struct sigqueue *q;
+@@ -470,6 +513,21 @@ void flush_sigqueue(struct sigpending *queue)
+ 	}
+ }
+ 
++/*
++ * Called from __exit_signal. Flush tsk->pending and
++ * tsk->sigqueue_cache
++ */
++void flush_task_sigqueue(struct task_struct *tsk)
++{
++	struct sigqueue *q;
++
++	flush_sigqueue(&tsk->pending);
++
++	q = get_task_cache(tsk);
++	if (q)
++		kmem_cache_free(sigqueue_cachep, q);
++}
++
+ /*
+  * Flush all pending signals for this kthread.
+  */
+@@ -594,7 +652,7 @@ static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *i
+ 			(info->si_code == SI_TIMER) &&
+ 			(info->si_sys_private);
+ 
+-		__sigqueue_free(first);
++		sigqueue_free_current(first);
+ 	} else {
+ 		/*
+ 		 * Ok, it wasn't in the queue.  This must be
+@@ -631,6 +689,8 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *in
+ 	bool resched_timer = false;
+ 	int signr;
+ 
++	WARN_ON_ONCE(tsk != current);
++
+ 	/* We only dequeue private signals from ourselves, we don't let
+ 	 * signalfd steal them
+ 	 */
+@@ -1835,7 +1895,8 @@ EXPORT_SYMBOL(kill_pid);
+  */
+ struct sigqueue *sigqueue_alloc(void)
+ {
+-	struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
++	/* Preallocated sigqueue objects always from the slabcache ! */
++	struct sigqueue *q = __sigqueue_do_alloc(-1, current, GFP_KERNEL, 0, 1);
+ 
+ 	if (q)
+ 		q->flags |= SIGQUEUE_PREALLOC;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0284-signal-Prevent-double-free-of-user-struct.patch b/debian/patches-rt/0284-signal-Prevent-double-free-of-user-struct.patch
new file mode 100644
index 000000000..8a50b4089
--- /dev/null
+++ b/debian/patches-rt/0284-signal-Prevent-double-free-of-user-struct.patch
@@ -0,0 +1,52 @@
+From 9a8853e64ab5f1c44db176464996da3ba86d2a8e Mon Sep 17 00:00:00 2001
+From: Matt Fleming <matt@codeblueprint.co.uk>
+Date: Tue, 7 Apr 2020 10:54:13 +0100
+Subject: [PATCH 284/323] signal: Prevent double-free of user struct
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The way user struct reference counting works changed significantly with,
+
+  fda31c50292a ("signal: avoid double atomic counter increments for user accounting")
+
+Now user structs are only freed once the last pending signal is
+dequeued. Make sigqueue_free_current() follow this new convention to
+avoid freeing the user struct multiple times and triggering this
+warning:
+
+ refcount_t: underflow; use-after-free.
+ WARNING: CPU: 0 PID: 6794 at lib/refcount.c:288 refcount_dec_not_one+0x45/0x50
+ Call Trace:
+  refcount_dec_and_lock_irqsave+0x16/0x60
+  free_uid+0x31/0xa0
+  __dequeue_signal+0x17c/0x190
+  dequeue_signal+0x5a/0x1b0
+  do_sigtimedwait+0x208/0x250
+  __x64_sys_rt_sigtimedwait+0x6f/0xd0
+  do_syscall_64+0x72/0x200
+  entry_SYSCALL_64_after_hwframe+0x49/0xbe
+
+Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
+Reported-by: Daniel Wagner <wagi@monom.org>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/signal.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/kernel/signal.c b/kernel/signal.c
+index e1f263cbcf09..a1eeecb4922d 100644
+--- a/kernel/signal.c
++++ b/kernel/signal.c
+@@ -495,8 +495,8 @@ static void sigqueue_free_current(struct sigqueue *q)
+ 
+ 	up = q->user;
+ 	if (rt_prio(current->normal_prio) && !put_task_cache(current, q)) {
+-		atomic_dec(&up->sigpending);
+-		free_uid(up);
++		if (atomic_dec_and_test(&up->sigpending))
++			free_uid(up);
+ 	} else
+ 		  __sigqueue_free(q);
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0285-genirq-Disable-irqpoll-on-rt.patch b/debian/patches-rt/0285-genirq-Disable-irqpoll-on-rt.patch
new file mode 100644
index 000000000..8033dbbab
--- /dev/null
+++ b/debian/patches-rt/0285-genirq-Disable-irqpoll-on-rt.patch
@@ -0,0 +1,43 @@
+From 4795907a92ad1bf9383b0c748facb436cac71e36 Mon Sep 17 00:00:00 2001
+From: Ingo Molnar <mingo@elte.hu>
+Date: Fri, 3 Jul 2009 08:29:57 -0500
+Subject: [PATCH 285/323] genirq: Disable irqpoll on -rt
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Creates long latencies for no value
+
+Signed-off-by: Ingo Molnar <mingo@elte.hu>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ kernel/irq/spurious.c | 8 ++++++++
+ 1 file changed, 8 insertions(+)
+
+diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c
+index f865e5f4d382..dc7311dd74b1 100644
+--- a/kernel/irq/spurious.c
++++ b/kernel/irq/spurious.c
+@@ -443,6 +443,10 @@ MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
+ 
+ static int __init irqfixup_setup(char *str)
+ {
++#ifdef CONFIG_PREEMPT_RT
++	pr_warn("irqfixup boot option not supported w/ CONFIG_PREEMPT_RT\n");
++	return 1;
++#endif
+ 	irqfixup = 1;
+ 	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
+ 	printk(KERN_WARNING "This may impact system performance.\n");
+@@ -455,6 +459,10 @@ module_param(irqfixup, int, 0644);
+ 
+ static int __init irqpoll_setup(char *str)
+ {
++#ifdef CONFIG_PREEMPT_RT
++	pr_warn("irqpoll boot option not supported w/ CONFIG_PREEMPT_RT\n");
++	return 1;
++#endif
+ 	irqfixup = 2;
+ 	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
+ 				"enabled\n");
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0286-sysfs-Add-sys-kernel-realtime-entry.patch b/debian/patches-rt/0286-sysfs-Add-sys-kernel-realtime-entry.patch
new file mode 100644
index 000000000..e28616641
--- /dev/null
+++ b/debian/patches-rt/0286-sysfs-Add-sys-kernel-realtime-entry.patch
@@ -0,0 +1,54 @@
+From e7909a8ac08579fb76c51cde86c1171c8d1c6c36 Mon Sep 17 00:00:00 2001
+From: Clark Williams <williams@redhat.com>
+Date: Sat, 30 Jul 2011 21:55:53 -0500
+Subject: [PATCH 286/323] sysfs: Add /sys/kernel/realtime entry
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Add a /sys/kernel entry to indicate that the kernel is a
+realtime kernel.
+
+Clark says that he needs this for udev rules, udev needs to evaluate
+if its a PREEMPT_RT kernel a few thousand times and parsing uname
+output is too slow or so.
+
+Are there better solutions? Should it exist and return 0 on !-rt?
+
+Signed-off-by: Clark Williams <williams@redhat.com>
+Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
+---
+ kernel/ksysfs.c | 12 ++++++++++++
+ 1 file changed, 12 insertions(+)
+
+diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
+index e20c19e3ba49..777168d58f02 100644
+--- a/kernel/ksysfs.c
++++ b/kernel/ksysfs.c
+@@ -143,6 +143,15 @@ KERNEL_ATTR_RO(vmcoreinfo);
+ 
+ #endif /* CONFIG_CRASH_CORE */
+ 
++#if defined(CONFIG_PREEMPT_RT)
++static ssize_t realtime_show(struct kobject *kobj,
++			     struct kobj_attribute *attr, char *buf)
++{
++	return sprintf(buf, "%d\n", 1);
++}
++KERNEL_ATTR_RO(realtime);
++#endif
++
+ /* whether file capabilities are enabled */
+ static ssize_t fscaps_show(struct kobject *kobj,
+ 				  struct kobj_attribute *attr, char *buf)
+@@ -233,6 +242,9 @@ static struct attribute * kernel_attrs[] = {
+ #ifndef CONFIG_TINY_RCU
+ 	&rcu_expedited_attr.attr,
+ 	&rcu_normal_attr.attr,
++#endif
++#ifdef CONFIG_PREEMPT_RT
++	&realtime_attr.attr,
+ #endif
+ 	NULL
+ };
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0287-Add-localversion-for-RT-release.patch b/debian/patches-rt/0287-Add-localversion-for-RT-release.patch
new file mode 100644
index 000000000..ee5bf247a
--- /dev/null
+++ b/debian/patches-rt/0287-Add-localversion-for-RT-release.patch
@@ -0,0 +1,22 @@
+From 180a0118d4485cb909de0be0f7ebb61adce763e1 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 8 Jul 2011 20:25:16 +0200
+Subject: [PATCH 287/323] Add localversion for -RT release
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+---
+ localversion-rt | 1 +
+ 1 file changed, 1 insertion(+)
+ create mode 100644 localversion-rt
+
+diff --git a/localversion-rt b/localversion-rt
+new file mode 100644
+index 000000000000..21988f9ad53f
+--- /dev/null
++++ b/localversion-rt
+@@ -0,0 +1 @@
++-rt34
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0288-net-xfrm-Use-sequence-counter-with-associated-spinlo.patch b/debian/patches-rt/0288-net-xfrm-Use-sequence-counter-with-associated-spinlo.patch
new file mode 100644
index 000000000..df8a062a3
--- /dev/null
+++ b/debian/patches-rt/0288-net-xfrm-Use-sequence-counter-with-associated-spinlo.patch
@@ -0,0 +1,43 @@
+From 97138dbb6886695284b96e3680f1533beae6e43a Mon Sep 17 00:00:00 2001
+From: "Ahmed S. Darwish" <a.darwish@linutronix.de>
+Date: Tue, 16 Mar 2021 11:56:30 +0100
+Subject: [PATCH 288/323] net: xfrm: Use sequence counter with associated
+ spinlock
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+A sequence counter write section must be serialized or its internal
+state can get corrupted. A plain seqcount_t does not contain the
+information of which lock must be held to guaranteee write side
+serialization.
+
+For xfrm_state_hash_generation, use seqcount_spinlock_t instead of plain
+seqcount_t.  This allows to associate the spinlock used for write
+serialization with the sequence counter. It thus enables lockdep to
+verify that the write serialization lock is indeed held before entering
+the sequence counter write section.
+
+If lockdep is disabled, this lock association is compiled out and has
+neither storage size nor runtime overhead.
+
+Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
+Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
+---
+ include/net/netns/xfrm.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/include/net/netns/xfrm.h b/include/net/netns/xfrm.h
+index 7b87da22b295..fef22e029c0d 100644
+--- a/include/net/netns/xfrm.h
++++ b/include/net/netns/xfrm.h
+@@ -77,7 +77,7 @@ struct netns_xfrm {
+ 	struct dst_ops		xfrm6_dst_ops;
+ #endif
+ 	spinlock_t		xfrm_state_lock;
+-	seqcount_t		xfrm_state_hash_generation;
++	seqcount_spinlock_t	xfrm_state_hash_generation;
+ 	seqcount_spinlock_t	xfrm_policy_hash_generation;
+ 
+ 	spinlock_t xfrm_policy_lock;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0289-sched-Fix-migration_cpu_stop-requeueing.patch b/debian/patches-rt/0289-sched-Fix-migration_cpu_stop-requeueing.patch
new file mode 100644
index 000000000..54a798b25
--- /dev/null
+++ b/debian/patches-rt/0289-sched-Fix-migration_cpu_stop-requeueing.patch
@@ -0,0 +1,147 @@
+From 013f5d7501b106952e04d54b0803c2d1ae9a4876 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Tue, 8 Jun 2021 00:37:30 -0400
+Subject: [PATCH 289/323] sched: Fix migration_cpu_stop() requeueing
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+commit 8a6edb5257e2a84720fe78cb179eca58ba76126f upstream.
+
+When affine_move_task(p) is called on a running task @p, which is not
+otherwise already changing affinity, we'll first set
+p->migration_pending and then do:
+
+	 stop_one_cpu(cpu_of_rq(rq), migration_cpu_stop, &arg);
+
+This then gets us to migration_cpu_stop() running on the CPU that was
+previously running our victim task @p.
+
+If we find that our task is no longer on that runqueue (this can
+happen because of a concurrent migration due to load-balance etc.),
+then we'll end up at the:
+
+	} else if (dest_cpu < 1 || pending) {
+
+branch. Which we'll take because we set pending earlier. Here we first
+check if the task @p has already satisfied the affinity constraints,
+if so we bail early [A]. Otherwise we'll reissue migration_cpu_stop()
+onto the CPU that is now hosting our task @p:
+
+	stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
+			    &pending->arg, &pending->stop_work);
+
+Except, we've never initialized pending->arg, which will be all 0s.
+
+This then results in running migration_cpu_stop() on the next CPU with
+arg->p == NULL, which gives the by now obvious result of fireworks.
+
+The cure is to change affine_move_task() to always use pending->arg,
+furthermore we can use the exact same pattern as the
+SCA_MIGRATE_ENABLE case, since we'll block on the pending->done
+completion anyway, no point in adding yet another completion in
+stop_one_cpu().
+
+This then gives a clear distinction between the two
+migration_cpu_stop() use cases:
+
+  - sched_exec() / migrate_task_to() : arg->pending == NULL
+  - affine_move_task() : arg->pending != NULL;
+
+And we can have it ignore p->migration_pending when !arg->pending. Any
+stop work from sched_exec() / migrate_task_to() is in addition to stop
+works from affine_move_task(), which will be sufficient to issue the
+completion.
+
+Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()")
+Cc: stable@kernel.org
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
+Link: https://lkml.kernel.org/r/20210224131355.357743989@infradead.org
+Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ kernel/sched/core.c | 39 ++++++++++++++++++++++++++++-----------
+ 1 file changed, 28 insertions(+), 11 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index c847d17e3b04..df9c4c3838c0 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1974,6 +1974,24 @@ static int migration_cpu_stop(void *data)
+ 	rq_lock(rq, &rf);
+ 
+ 	pending = p->migration_pending;
++	if (pending && !arg->pending) {
++		/*
++		 * This happens from sched_exec() and migrate_task_to(),
++		 * neither of them care about pending and just want a task to
++		 * maybe move about.
++		 *
++		 * Even if there is a pending, we can ignore it, since
++		 * affine_move_task() will have it's own stop_work's in flight
++		 * which will manage the completion.
++		 *
++		 * Notably, pending doesn't need to match arg->pending. This can
++		 * happen when tripple concurrent affine_move_task() first sets
++		 * pending, then clears pending and eventually sets another
++		 * pending.
++		 */
++		pending = NULL;
++	}
++
+ 	/*
+ 	 * If task_rq(p) != rq, it cannot be migrated here, because we're
+ 	 * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
+@@ -2246,10 +2264,6 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 			    int dest_cpu, unsigned int flags)
+ {
+ 	struct set_affinity_pending my_pending = { }, *pending = NULL;
+-	struct migration_arg arg = {
+-		.task = p,
+-		.dest_cpu = dest_cpu,
+-	};
+ 	bool complete = false;
+ 
+ 	/* Can the task run on the task's current CPU? If so, we're done */
+@@ -2287,6 +2301,12 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 			/* Install the request */
+ 			refcount_set(&my_pending.refs, 1);
+ 			init_completion(&my_pending.done);
++			my_pending.arg = (struct migration_arg) {
++				.task = p,
++				.dest_cpu = -1,		/* any */
++				.pending = &my_pending,
++			};
++
+ 			p->migration_pending = &my_pending;
+ 		} else {
+ 			pending = p->migration_pending;
+@@ -2317,12 +2337,6 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 		p->migration_flags &= ~MDF_PUSH;
+ 		task_rq_unlock(rq, p, rf);
+ 
+-		pending->arg = (struct migration_arg) {
+-			.task = p,
+-			.dest_cpu = -1,
+-			.pending = pending,
+-		};
+-
+ 		stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
+ 				    &pending->arg, &pending->stop_work);
+ 
+@@ -2335,8 +2349,11 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 		 * is_migration_disabled(p) checks to the stopper, which will
+ 		 * run on the same CPU as said p.
+ 		 */
++		refcount_inc(&pending->refs); /* pending->{arg,stop_work} */
+ 		task_rq_unlock(rq, p, rf);
+-		stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
++
++		stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
++				    &pending->arg, &pending->stop_work);
+ 
+ 	} else {
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0290-sched-Simplify-migration_cpu_stop.patch b/debian/patches-rt/0290-sched-Simplify-migration_cpu_stop.patch
new file mode 100644
index 000000000..4d0841707
--- /dev/null
+++ b/debian/patches-rt/0290-sched-Simplify-migration_cpu_stop.patch
@@ -0,0 +1,142 @@
+From 4f468832c2a5bb5c0bb23b453038ff4fed722061 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Tue, 8 Jun 2021 00:37:31 -0400
+Subject: [PATCH 290/323] sched: Simplify migration_cpu_stop()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+commit c20cf065d4a619d394d23290093b1002e27dff86 upstream.
+
+When affine_move_task() issues a migration_cpu_stop(), the purpose of
+that function is to complete that @pending, not any random other
+p->migration_pending that might have gotten installed since.
+
+This realization much simplifies migration_cpu_stop() and allows
+further necessary steps to fix all this as it provides the guarantee
+that @pending's stopper will complete @pending (and not some random
+other @pending).
+
+Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()")
+Cc: stable@kernel.org
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
+Link: https://lkml.kernel.org/r/20210224131355.430014682@infradead.org
+Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ kernel/sched/core.c | 56 +++++++--------------------------------------
+ 1 file changed, 8 insertions(+), 48 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index df9c4c3838c0..31fa925852e5 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1950,8 +1950,8 @@ static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf,
+  */
+ static int migration_cpu_stop(void *data)
+ {
+-	struct set_affinity_pending *pending;
+ 	struct migration_arg *arg = data;
++	struct set_affinity_pending *pending = arg->pending;
+ 	struct task_struct *p = arg->task;
+ 	int dest_cpu = arg->dest_cpu;
+ 	struct rq *rq = this_rq();
+@@ -1973,25 +1973,6 @@ static int migration_cpu_stop(void *data)
+ 	raw_spin_lock(&p->pi_lock);
+ 	rq_lock(rq, &rf);
+ 
+-	pending = p->migration_pending;
+-	if (pending && !arg->pending) {
+-		/*
+-		 * This happens from sched_exec() and migrate_task_to(),
+-		 * neither of them care about pending and just want a task to
+-		 * maybe move about.
+-		 *
+-		 * Even if there is a pending, we can ignore it, since
+-		 * affine_move_task() will have it's own stop_work's in flight
+-		 * which will manage the completion.
+-		 *
+-		 * Notably, pending doesn't need to match arg->pending. This can
+-		 * happen when tripple concurrent affine_move_task() first sets
+-		 * pending, then clears pending and eventually sets another
+-		 * pending.
+-		 */
+-		pending = NULL;
+-	}
+-
+ 	/*
+ 	 * If task_rq(p) != rq, it cannot be migrated here, because we're
+ 	 * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
+@@ -2002,31 +1983,20 @@ static int migration_cpu_stop(void *data)
+ 			goto out;
+ 
+ 		if (pending) {
+-			p->migration_pending = NULL;
++			if (p->migration_pending == pending)
++				p->migration_pending = NULL;
+ 			complete = true;
+ 		}
+ 
+-		/* migrate_enable() --  we must not race against SCA */
+-		if (dest_cpu < 0) {
+-			/*
+-			 * When this was migrate_enable() but we no longer
+-			 * have a @pending, a concurrent SCA 'fixed' things
+-			 * and we should be valid again. Nothing to do.
+-			 */
+-			if (!pending) {
+-				WARN_ON_ONCE(!cpumask_test_cpu(task_cpu(p), &p->cpus_mask));
+-				goto out;
+-			}
+-
++		if (dest_cpu < 0)
+ 			dest_cpu = cpumask_any_distribute(&p->cpus_mask);
+-		}
+ 
+ 		if (task_on_rq_queued(p))
+ 			rq = __migrate_task(rq, &rf, p, dest_cpu);
+ 		else
+ 			p->wake_cpu = dest_cpu;
+ 
+-	} else if (dest_cpu < 0 || pending) {
++	} else if (pending) {
+ 		/*
+ 		 * This happens when we get migrated between migrate_enable()'s
+ 		 * preempt_enable() and scheduling the stopper task. At that
+@@ -2041,22 +2011,13 @@ static int migration_cpu_stop(void *data)
+ 		 * ->pi_lock, so the allowed mask is stable - if it got
+ 		 * somewhere allowed, we're done.
+ 		 */
+-		if (pending && cpumask_test_cpu(task_cpu(p), p->cpus_ptr)) {
+-			p->migration_pending = NULL;
++		if (cpumask_test_cpu(task_cpu(p), p->cpus_ptr)) {
++			if (p->migration_pending == pending)
++				p->migration_pending = NULL;
+ 			complete = true;
+ 			goto out;
+ 		}
+ 
+-		/*
+-		 * When this was migrate_enable() but we no longer have an
+-		 * @pending, a concurrent SCA 'fixed' things and we should be
+-		 * valid again. Nothing to do.
+-		 */
+-		if (!pending) {
+-			WARN_ON_ONCE(!cpumask_test_cpu(task_cpu(p), &p->cpus_mask));
+-			goto out;
+-		}
+-
+ 		/*
+ 		 * When migrate_enable() hits a rq mis-match we can't reliably
+ 		 * determine is_migration_disabled() and so have to chase after
+@@ -2074,7 +2035,6 @@ static int migration_cpu_stop(void *data)
+ 		complete_all(&pending->done);
+ 
+ 	/* For pending->{arg,stop_work} */
+-	pending = arg->pending;
+ 	if (pending && refcount_dec_and_test(&pending->refs))
+ 		wake_up_var(&pending->refs);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0291-sched-Collate-affine_move_task-stoppers.patch b/debian/patches-rt/0291-sched-Collate-affine_move_task-stoppers.patch
new file mode 100644
index 000000000..b73fb91be
--- /dev/null
+++ b/debian/patches-rt/0291-sched-Collate-affine_move_task-stoppers.patch
@@ -0,0 +1,69 @@
+From e62b758a0149648256ed0fa194d9e107e294d8aa Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Tue, 8 Jun 2021 00:37:32 -0400
+Subject: [PATCH 291/323] sched: Collate affine_move_task() stoppers
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+commit 58b1a45086b5f80f2b2842aa7ed0da51a64a302b upstream.
+
+The SCA_MIGRATE_ENABLE and task_running() cases are almost identical,
+collapse them to avoid further duplication.
+
+Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()")
+Cc: stable@kernel.org
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
+Link: https://lkml.kernel.org/r/20210224131355.500108964@infradead.org
+Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ kernel/sched/core.c | 23 ++++++++---------------
+ 1 file changed, 8 insertions(+), 15 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 31fa925852e5..3130289baf79 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -2291,30 +2291,23 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 		return -EINVAL;
+ 	}
+ 
+-	if (flags & SCA_MIGRATE_ENABLE) {
+-
+-		refcount_inc(&pending->refs); /* pending->{arg,stop_work} */
+-		p->migration_flags &= ~MDF_PUSH;
+-		task_rq_unlock(rq, p, rf);
+-
+-		stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
+-				    &pending->arg, &pending->stop_work);
+-
+-		return 0;
+-	}
+-
+ 	if (task_running(rq, p) || p->state == TASK_WAKING) {
+ 		/*
+-		 * Lessen races (and headaches) by delegating
+-		 * is_migration_disabled(p) checks to the stopper, which will
+-		 * run on the same CPU as said p.
++		 * MIGRATE_ENABLE gets here because 'p == current', but for
++		 * anything else we cannot do is_migration_disabled(), punt
++		 * and have the stopper function handle it all race-free.
+ 		 */
++
+ 		refcount_inc(&pending->refs); /* pending->{arg,stop_work} */
++		if (flags & SCA_MIGRATE_ENABLE)
++			p->migration_flags &= ~MDF_PUSH;
+ 		task_rq_unlock(rq, p, rf);
+ 
+ 		stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
+ 				    &pending->arg, &pending->stop_work);
+ 
++		if (flags & SCA_MIGRATE_ENABLE)
++			return 0;
+ 	} else {
+ 
+ 		if (!is_migration_disabled(p)) {
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0292-sched-Optimize-migration_cpu_stop.patch b/debian/patches-rt/0292-sched-Optimize-migration_cpu_stop.patch
new file mode 100644
index 000000000..87ca79ca8
--- /dev/null
+++ b/debian/patches-rt/0292-sched-Optimize-migration_cpu_stop.patch
@@ -0,0 +1,58 @@
+From b1353ab8df1e6dd3bf9afaef3096749db2a193f1 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Tue, 8 Jun 2021 00:37:33 -0400
+Subject: [PATCH 292/323] sched: Optimize migration_cpu_stop()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+commit 3f1bc119cd7fc987c8ed25ffb717f99403bb308c upstream.
+
+When the purpose of migration_cpu_stop() is to migrate the task to
+'any' valid CPU, don't migrate the task when it's already running on a
+valid CPU.
+
+Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()")
+Cc: stable@kernel.org
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
+Link: https://lkml.kernel.org/r/20210224131355.569238629@infradead.org
+Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ kernel/sched/core.c | 13 ++++++++++++-
+ 1 file changed, 12 insertions(+), 1 deletion(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 3130289baf79..e28fb33afa95 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1988,14 +1988,25 @@ static int migration_cpu_stop(void *data)
+ 			complete = true;
+ 		}
+ 
+-		if (dest_cpu < 0)
++		if (dest_cpu < 0) {
++			if (cpumask_test_cpu(task_cpu(p), &p->cpus_mask))
++				goto out;
++
+ 			dest_cpu = cpumask_any_distribute(&p->cpus_mask);
++		}
+ 
+ 		if (task_on_rq_queued(p))
+ 			rq = __migrate_task(rq, &rf, p, dest_cpu);
+ 		else
+ 			p->wake_cpu = dest_cpu;
+ 
++		/*
++		 * XXX __migrate_task() can fail, at which point we might end
++		 * up running on a dodgy CPU, AFAICT this can only happen
++		 * during CPU hotplug, at which point we'll get pushed out
++		 * anyway, so it's probably not a big deal.
++		 */
++
+ 	} else if (pending) {
+ 		/*
+ 		 * This happens when we get migrated between migrate_enable()'s
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0293-sched-Fix-affine_move_task-self-concurrency.patch b/debian/patches-rt/0293-sched-Fix-affine_move_task-self-concurrency.patch
new file mode 100644
index 000000000..4a906f7cb
--- /dev/null
+++ b/debian/patches-rt/0293-sched-Fix-affine_move_task-self-concurrency.patch
@@ -0,0 +1,96 @@
+From e9faaf024fdd553b55aaed31855385da7e9d505a Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Tue, 8 Jun 2021 00:37:34 -0400
+Subject: [PATCH 293/323] sched: Fix affine_move_task() self-concurrency
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+commit 9e81889c7648d48dd5fe13f41cbc99f3c362484a upstream.
+
+Consider:
+
+   sched_setaffinity(p, X);		sched_setaffinity(p, Y);
+
+Then the first will install p->migration_pending = &my_pending; and
+issue stop_one_cpu_nowait(pending); and the second one will read
+p->migration_pending and _also_ issue: stop_one_cpu_nowait(pending),
+the _SAME_ @pending.
+
+This causes stopper list corruption.
+
+Add set_affinity_pending::stop_pending, to indicate if a stopper is in
+progress.
+
+Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()")
+Cc: stable@kernel.org
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
+Link: https://lkml.kernel.org/r/20210224131355.649146419@infradead.org
+Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ kernel/sched/core.c | 15 ++++++++++++---
+ 1 file changed, 12 insertions(+), 3 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index e28fb33afa95..76fa3daf1f60 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1916,6 +1916,7 @@ struct migration_arg {
+ 
+ struct set_affinity_pending {
+ 	refcount_t		refs;
++	unsigned int		stop_pending;
+ 	struct completion	done;
+ 	struct cpu_stop_work	stop_work;
+ 	struct migration_arg	arg;
+@@ -2034,12 +2035,15 @@ static int migration_cpu_stop(void *data)
+ 		 * determine is_migration_disabled() and so have to chase after
+ 		 * it.
+ 		 */
++		WARN_ON_ONCE(!pending->stop_pending);
+ 		task_rq_unlock(rq, p, &rf);
+ 		stop_one_cpu_nowait(task_cpu(p), migration_cpu_stop,
+ 				    &pending->arg, &pending->stop_work);
+ 		return 0;
+ 	}
+ out:
++	if (pending)
++		pending->stop_pending = false;
+ 	task_rq_unlock(rq, p, &rf);
+ 
+ 	if (complete)
+@@ -2235,7 +2239,7 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 			    int dest_cpu, unsigned int flags)
+ {
+ 	struct set_affinity_pending my_pending = { }, *pending = NULL;
+-	bool complete = false;
++	bool stop_pending, complete = false;
+ 
+ 	/* Can the task run on the task's current CPU? If so, we're done */
+ 	if (cpumask_test_cpu(task_cpu(p), &p->cpus_mask)) {
+@@ -2308,14 +2312,19 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 		 * anything else we cannot do is_migration_disabled(), punt
+ 		 * and have the stopper function handle it all race-free.
+ 		 */
++		stop_pending = pending->stop_pending;
++		if (!stop_pending)
++			pending->stop_pending = true;
+ 
+ 		refcount_inc(&pending->refs); /* pending->{arg,stop_work} */
+ 		if (flags & SCA_MIGRATE_ENABLE)
+ 			p->migration_flags &= ~MDF_PUSH;
+ 		task_rq_unlock(rq, p, rf);
+ 
+-		stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
+-				    &pending->arg, &pending->stop_work);
++		if (!stop_pending) {
++			stop_one_cpu_nowait(cpu_of(rq), migration_cpu_stop,
++					    &pending->arg, &pending->stop_work);
++		}
+ 
+ 		if (flags & SCA_MIGRATE_ENABLE)
+ 			return 0;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0294-sched-Simplify-set_affinity_pending-refcounts.patch b/debian/patches-rt/0294-sched-Simplify-set_affinity_pending-refcounts.patch
new file mode 100644
index 000000000..1230259b8
--- /dev/null
+++ b/debian/patches-rt/0294-sched-Simplify-set_affinity_pending-refcounts.patch
@@ -0,0 +1,129 @@
+From 6681b566fe9ffe9365121a790537ada2e4ef97ba Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <peterz@infradead.org>
+Date: Tue, 8 Jun 2021 00:37:35 -0400
+Subject: [PATCH 294/323] sched: Simplify set_affinity_pending refcounts
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+commit 50caf9c14b1498c90cf808dbba2ca29bd32ccba4 upstream.
+
+Now that we have set_affinity_pending::stop_pending to indicate if a
+stopper is in progress, and we have the guarantee that if that stopper
+exists, it will (eventually) complete our @pending we can simplify the
+refcount scheme by no longer counting the stopper thread.
+
+Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()")
+Cc: stable@kernel.org
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
+Link: https://lkml.kernel.org/r/20210224131355.724130207@infradead.org
+Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ kernel/sched/core.c | 32 ++++++++++++++++++++------------
+ 1 file changed, 20 insertions(+), 12 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 76fa3daf1f60..d3b9d69171a2 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1914,6 +1914,10 @@ struct migration_arg {
+ 	struct set_affinity_pending	*pending;
+ };
+ 
++/*
++ * @refs: number of wait_for_completion()
++ * @stop_pending: is @stop_work in use
++ */
+ struct set_affinity_pending {
+ 	refcount_t		refs;
+ 	unsigned int		stop_pending;
+@@ -2049,10 +2053,6 @@ static int migration_cpu_stop(void *data)
+ 	if (complete)
+ 		complete_all(&pending->done);
+ 
+-	/* For pending->{arg,stop_work} */
+-	if (pending && refcount_dec_and_test(&pending->refs))
+-		wake_up_var(&pending->refs);
+-
+ 	return 0;
+ }
+ 
+@@ -2251,12 +2251,16 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 			push_task = get_task_struct(p);
+ 		}
+ 
++		/*
++		 * If there are pending waiters, but no pending stop_work,
++		 * then complete now.
++		 */
+ 		pending = p->migration_pending;
+-		if (pending) {
+-			refcount_inc(&pending->refs);
++		if (pending && !pending->stop_pending) {
+ 			p->migration_pending = NULL;
+ 			complete = true;
+ 		}
++
+ 		task_rq_unlock(rq, p, rf);
+ 
+ 		if (push_task) {
+@@ -2265,7 +2269,7 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 		}
+ 
+ 		if (complete)
+-			goto do_complete;
++			complete_all(&pending->done);
+ 
+ 		return 0;
+ 	}
+@@ -2316,9 +2320,9 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 		if (!stop_pending)
+ 			pending->stop_pending = true;
+ 
+-		refcount_inc(&pending->refs); /* pending->{arg,stop_work} */
+ 		if (flags & SCA_MIGRATE_ENABLE)
+ 			p->migration_flags &= ~MDF_PUSH;
++
+ 		task_rq_unlock(rq, p, rf);
+ 
+ 		if (!stop_pending) {
+@@ -2334,12 +2338,13 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 			if (task_on_rq_queued(p))
+ 				rq = move_queued_task(rq, rf, p, dest_cpu);
+ 
+-			p->migration_pending = NULL;
+-			complete = true;
++			if (!pending->stop_pending) {
++				p->migration_pending = NULL;
++				complete = true;
++			}
+ 		}
+ 		task_rq_unlock(rq, p, rf);
+ 
+-do_complete:
+ 		if (complete)
+ 			complete_all(&pending->done);
+ 	}
+@@ -2347,7 +2352,7 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 	wait_for_completion(&pending->done);
+ 
+ 	if (refcount_dec_and_test(&pending->refs))
+-		wake_up_var(&pending->refs);
++		wake_up_var(&pending->refs); /* No UaF, just an address */
+ 
+ 	/*
+ 	 * Block the original owner of &pending until all subsequent callers
+@@ -2355,6 +2360,9 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 	 */
+ 	wait_var_event(&my_pending.refs, !refcount_read(&my_pending.refs));
+ 
++	/* ARGH */
++	WARN_ON_ONCE(my_pending.stop_pending);
++
+ 	return 0;
+ }
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0295-sched-Don-t-defer-CPU-pick-to-migration_cpu_stop.patch b/debian/patches-rt/0295-sched-Don-t-defer-CPU-pick-to-migration_cpu_stop.patch
new file mode 100644
index 000000000..e05440c01
--- /dev/null
+++ b/debian/patches-rt/0295-sched-Don-t-defer-CPU-pick-to-migration_cpu_stop.patch
@@ -0,0 +1,100 @@
+From b625852d41e17fb13b4caf7192734866534d9799 Mon Sep 17 00:00:00 2001
+From: Valentin Schneider <valentin.schneider@arm.com>
+Date: Tue, 8 Jun 2021 00:37:36 -0400
+Subject: [PATCH 295/323] sched: Don't defer CPU pick to migration_cpu_stop()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+commit 475ea6c60279e9f2ddf7e4cf2648cd8ae0608361 upstream.
+
+Will reported that the 'XXX __migrate_task() can fail' in migration_cpu_stop()
+can happen, and it *is* sort of a big deal. Looking at it some more, one
+will note there is a glaring hole in the deferred CPU selection:
+
+  (w/ CONFIG_CPUSET=n, so that the affinity mask passed via taskset doesn't
+  get AND'd with cpu_online_mask)
+
+  $ taskset -pc 0-2 $PID
+  # offline CPUs 3-4
+  $ taskset -pc 3-5 $PID
+    `\
+      $PID may stay on 0-2 due to the cpumask_any_distribute() picking an
+      offline CPU and __migrate_task() refusing to do anything due to
+      cpu_is_allowed().
+
+set_cpus_allowed_ptr() goes to some length to pick a dest_cpu that matches
+the right constraints vs affinity and the online/active state of the
+CPUs. Reuse that instead of discarding it in the affine_move_task() case.
+
+Fixes: 6d337eab041d ("sched: Fix migrate_disable() vs set_cpus_allowed_ptr()")
+Reported-by: Will Deacon <will@kernel.org>
+Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Link: https://lkml.kernel.org/r/20210526205751.842360-2-valentin.schneider@arm.com
+Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ kernel/sched/core.c | 20 ++++++++++++--------
+ 1 file changed, 12 insertions(+), 8 deletions(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index d3b9d69171a2..81b342d6629b 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -1958,7 +1958,6 @@ static int migration_cpu_stop(void *data)
+ 	struct migration_arg *arg = data;
+ 	struct set_affinity_pending *pending = arg->pending;
+ 	struct task_struct *p = arg->task;
+-	int dest_cpu = arg->dest_cpu;
+ 	struct rq *rq = this_rq();
+ 	bool complete = false;
+ 	struct rq_flags rf;
+@@ -1991,19 +1990,15 @@ static int migration_cpu_stop(void *data)
+ 			if (p->migration_pending == pending)
+ 				p->migration_pending = NULL;
+ 			complete = true;
+-		}
+ 
+-		if (dest_cpu < 0) {
+ 			if (cpumask_test_cpu(task_cpu(p), &p->cpus_mask))
+ 				goto out;
+-
+-			dest_cpu = cpumask_any_distribute(&p->cpus_mask);
+ 		}
+ 
+ 		if (task_on_rq_queued(p))
+-			rq = __migrate_task(rq, &rf, p, dest_cpu);
++			rq = __migrate_task(rq, &rf, p, arg->dest_cpu);
+ 		else
+-			p->wake_cpu = dest_cpu;
++			p->wake_cpu = arg->dest_cpu;
+ 
+ 		/*
+ 		 * XXX __migrate_task() can fail, at which point we might end
+@@ -2282,7 +2277,7 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 			init_completion(&my_pending.done);
+ 			my_pending.arg = (struct migration_arg) {
+ 				.task = p,
+-				.dest_cpu = -1,		/* any */
++				.dest_cpu = dest_cpu,
+ 				.pending = &my_pending,
+ 			};
+ 
+@@ -2290,6 +2285,15 @@ static int affine_move_task(struct rq *rq, struct task_struct *p, struct rq_flag
+ 		} else {
+ 			pending = p->migration_pending;
+ 			refcount_inc(&pending->refs);
++			/*
++			 * Affinity has changed, but we've already installed a
++			 * pending. migration_cpu_stop() *must* see this, else
++			 * we risk a completion of the pending despite having a
++			 * task on a disallowed CPU.
++			 *
++			 * Serialized by p->pi_lock, so this is safe.
++			 */
++			pending->arg.dest_cpu = dest_cpu;
+ 		}
+ 	}
+ 	pending = p->migration_pending;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0296-printk-Enhance-the-condition-check-of-msleep-in-pr_f.patch b/debian/patches-rt/0296-printk-Enhance-the-condition-check-of-msleep-in-pr_f.patch
new file mode 100644
index 000000000..72589519a
--- /dev/null
+++ b/debian/patches-rt/0296-printk-Enhance-the-condition-check-of-msleep-in-pr_f.patch
@@ -0,0 +1,48 @@
+From 6e1b154dfc59c96068eafef9fafbda28b723d3e6 Mon Sep 17 00:00:00 2001
+From: Chao Qin <chao.qin@intel.com>
+Date: Mon, 19 Jul 2021 10:26:50 +0800
+Subject: [PATCH 296/323] printk: Enhance the condition check of msleep in
+ pr_flush()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+[ Upstream commit 83e9288d9c4295d1195e9d780fcbc42c72ba4a83 ]
+
+There is msleep in pr_flush(). If call WARN() in the early boot
+stage such as in early_initcall, pr_flush() will run into msleep
+when process scheduler is not ready yet. And then the system will
+sleep forever.
+
+Before the system_state is SYSTEM_RUNNING, make sure DO NOT sleep
+in pr_flush().
+
+Fixes: c0b395bd0fe3("printk: add pr_flush()")
+Signed-off-by: Chao Qin <chao.qin@intel.com>
+Signed-off-by: Lili Li <lili.li@intel.com>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Reviewed-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Link: https://lore.kernel.org/lkml/20210719022649.3444072-1-chao.qin@intel.com
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ kernel/printk/printk.c | 4 +++-
+ 1 file changed, 3 insertions(+), 1 deletion(-)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index 14cb111fe9f0..d2205872304d 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -3554,7 +3554,9 @@ bool pr_flush(int timeout_ms, bool reset_on_progress)
+ 	u64 diff;
+ 	u64 seq;
+ 
+-	may_sleep = (preemptible() && !in_softirq());
++	may_sleep = (preemptible() &&
++		     !in_softirq() &&
++		     system_state >= SYSTEM_RUNNING);
+ 
+ 	seq = prb_next_seq(prb);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0297-locking-rwsem-rt-Remove-might_sleep-in-__up_read.patch b/debian/patches-rt/0297-locking-rwsem-rt-Remove-might_sleep-in-__up_read.patch
new file mode 100644
index 000000000..91a9ede63
--- /dev/null
+++ b/debian/patches-rt/0297-locking-rwsem-rt-Remove-might_sleep-in-__up_read.patch
@@ -0,0 +1,31 @@
+From 7131b777e7276a566838fdfb4a0b2ddc44ad2eca Mon Sep 17 00:00:00 2001
+From: Andrew Halaney <ahalaney@redhat.com>
+Date: Tue, 6 Apr 2021 17:19:52 -0500
+Subject: [PATCH 297/323] locking/rwsem-rt: Remove might_sleep() in __up_read()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+There's no chance of sleeping here, the reader is giving up the
+lock and possibly waking up the writer who is waiting on it.
+
+Reported-by: Chunyu Hu <chuhu@redhat.com>
+Signed-off-by: Andrew Halaney <ahalaney@redhat.com>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ kernel/locking/rwsem-rt.c | 1 -
+ 1 file changed, 1 deletion(-)
+
+diff --git a/kernel/locking/rwsem-rt.c b/kernel/locking/rwsem-rt.c
+index 274172d5bb3a..b61edc4dcb73 100644
+--- a/kernel/locking/rwsem-rt.c
++++ b/kernel/locking/rwsem-rt.c
+@@ -198,7 +198,6 @@ void __up_read(struct rw_semaphore *sem)
+ 	if (!atomic_dec_and_test(&sem->readers))
+ 		return;
+ 
+-	might_sleep();
+ 	raw_spin_lock_irq(&m->wait_lock);
+ 	/*
+ 	 * Wake the writer, i.e. the rtmutex owner. It might release the
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0298-mm-zsmalloc-Convert-zsmalloc_handle.lock-to-spinlock.patch b/debian/patches-rt/0298-mm-zsmalloc-Convert-zsmalloc_handle.lock-to-spinlock.patch
new file mode 100644
index 000000000..d26ff0ea0
--- /dev/null
+++ b/debian/patches-rt/0298-mm-zsmalloc-Convert-zsmalloc_handle.lock-to-spinlock.patch
@@ -0,0 +1,82 @@
+From b4a9c84408720dd6da0cdb52fc3e7070aef9c4fe Mon Sep 17 00:00:00 2001
+From: Mike Galbraith <efault@gmx.de>
+Date: Tue, 24 Aug 2021 13:08:14 +0200
+Subject: [PATCH 298/323] mm, zsmalloc: Convert zsmalloc_handle.lock to
+ spinlock_t
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+local_lock_t becoming a synonym of spinlock_t had consequences for the RT
+mods to zsmalloc, which were taking a mutex while holding a local_lock,
+inspiring a lockdep "BUG: Invalid wait context" gripe.
+
+Converting zsmalloc_handle.lock to a spinlock_t restored lockdep silence.
+
+Cc: stable-rt@vger.kernel.org
+Signed-off-by: Mike Galbraith <efault@gmx.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ mm/zsmalloc.c | 12 ++++++------
+ 1 file changed, 6 insertions(+), 6 deletions(-)
+
+diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
+index 7dad2ff3e778..16ce2b05df90 100644
+--- a/mm/zsmalloc.c
++++ b/mm/zsmalloc.c
+@@ -82,7 +82,7 @@
+ 
+ struct zsmalloc_handle {
+ 	unsigned long addr;
+-	struct mutex lock;
++	spinlock_t lock;
+ };
+ 
+ #define ZS_HANDLE_ALLOC_SIZE (sizeof(struct zsmalloc_handle))
+@@ -370,7 +370,7 @@ static unsigned long cache_alloc_handle(struct zs_pool *pool, gfp_t gfp)
+ 	if (p) {
+ 		struct zsmalloc_handle *zh = p;
+ 
+-		mutex_init(&zh->lock);
++		spin_lock_init(&zh->lock);
+ 	}
+ #endif
+ 	return (unsigned long)p;
+@@ -930,7 +930,7 @@ static inline int testpin_tag(unsigned long handle)
+ #ifdef CONFIG_PREEMPT_RT
+ 	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
+ 
+-	return mutex_is_locked(&zh->lock);
++	return spin_is_locked(&zh->lock);
+ #else
+ 	return bit_spin_is_locked(HANDLE_PIN_BIT, (unsigned long *)handle);
+ #endif
+@@ -941,7 +941,7 @@ static inline int trypin_tag(unsigned long handle)
+ #ifdef CONFIG_PREEMPT_RT
+ 	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
+ 
+-	return mutex_trylock(&zh->lock);
++	return spin_trylock(&zh->lock);
+ #else
+ 	return bit_spin_trylock(HANDLE_PIN_BIT, (unsigned long *)handle);
+ #endif
+@@ -952,7 +952,7 @@ static void pin_tag(unsigned long handle) __acquires(bitlock)
+ #ifdef CONFIG_PREEMPT_RT
+ 	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
+ 
+-	return mutex_lock(&zh->lock);
++	return spin_lock(&zh->lock);
+ #else
+ 	bit_spin_lock(HANDLE_PIN_BIT, (unsigned long *)handle);
+ #endif
+@@ -963,7 +963,7 @@ static void unpin_tag(unsigned long handle) __releases(bitlock)
+ #ifdef CONFIG_PREEMPT_RT
+ 	struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
+ 
+-	return mutex_unlock(&zh->lock);
++	return spin_unlock(&zh->lock);
+ #else
+ 	bit_spin_unlock(HANDLE_PIN_BIT, (unsigned long *)handle);
+ #endif
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0299-sched-Fix-get_push_task-vs-migrate_disable.patch b/debian/patches-rt/0299-sched-Fix-get_push_task-vs-migrate_disable.patch
new file mode 100644
index 000000000..f59c122c0
--- /dev/null
+++ b/debian/patches-rt/0299-sched-Fix-get_push_task-vs-migrate_disable.patch
@@ -0,0 +1,46 @@
+From 93c4258bc009109bee258c30fa2a53680c8b1f9a Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Thu, 26 Aug 2021 15:37:38 +0200
+Subject: [PATCH 299/323] sched: Fix get_push_task() vs migrate_disable()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+push_rt_task() attempts to move the currently running task away if the
+next runnable task has migration disabled and therefore is pinned on the
+current CPU.
+
+The current task is retrieved via get_push_task() which only checks for
+nr_cpus_allowed == 1, but does not check whether the task has migration
+disabled and therefore cannot be moved either. The consequence is a
+pointless invocation of the migration thread which correctly observes
+that the task cannot be moved.
+
+Return NULL if the task has migration disabled and cannot be moved to
+another CPU.
+
+Cc: stable-rt@vger.kernel.org
+Fixes: a7c81556ec4d3 ("sched: Fix migrate_disable() vs rt/dl balancing")
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Link: https://lkml.kernel.org/r/20210826133738.yiotqbtdaxzjsnfj@linutronix.de
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ kernel/sched/sched.h | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
+index ad854a670701..bda12827832e 100644
+--- a/kernel/sched/sched.h
++++ b/kernel/sched/sched.h
+@@ -1949,6 +1949,9 @@ static inline struct task_struct *get_push_task(struct rq *rq)
+ 	if (p->nr_cpus_allowed == 1)
+ 		return NULL;
+ 
++	if (p->migration_disabled)
++		return NULL;
++
+ 	rq->push_busy = true;
+ 	return get_task_struct(p);
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0300-sched-Switch-wait_task_inactive-to-HRTIMER_MODE_REL_.patch b/debian/patches-rt/0300-sched-Switch-wait_task_inactive-to-HRTIMER_MODE_REL_.patch
new file mode 100644
index 000000000..720b08fc7
--- /dev/null
+++ b/debian/patches-rt/0300-sched-Switch-wait_task_inactive-to-HRTIMER_MODE_REL_.patch
@@ -0,0 +1,48 @@
+From f29a6f7bb4568b4ac2d5a9226d503db7a2c69bab Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 24 Aug 2021 22:47:37 +0200
+Subject: [PATCH 300/323] sched: Switch wait_task_inactive to
+ HRTIMER_MODE_REL_HARD
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+With PREEMPT_RT enabled all hrtimers callbacks will be invoked in
+softirq mode unless they are explicitly marked as HRTIMER_MODE_HARD.
+During boot kthread_bind() is used for the creation of per-CPU threads
+and then hangs in wait_task_inactive() if the ksoftirqd is not
+yet up and running.
+The hang disappeared since commit
+   26c7295be0c5e ("kthread: Do not preempt current task if it is going to call schedule()")
+
+but enabling function trace on boot reliably leads to the freeze on boot
+behaviour again.
+The timer in wait_task_inactive() can not be directly used by an user
+interface to abuse it and create a mass wake of several tasks at the
+same time which would to long sections with disabled interrupts.
+Therefore it is safe to make the timer HRTIMER_MODE_REL_HARD.
+
+Switch the timer to HRTIMER_MODE_REL_HARD.
+
+Cc: stable-rt@vger.kernel.org
+Link: https://lkml.kernel.org/r/20210826170408.vm7rlj7odslshwch@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ kernel/sched/core.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/kernel/sched/core.c b/kernel/sched/core.c
+index 81b342d6629b..6735872a8508 100644
+--- a/kernel/sched/core.c
++++ b/kernel/sched/core.c
+@@ -2739,7 +2739,7 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state)
+ 			ktime_t to = NSEC_PER_SEC / HZ;
+ 
+ 			set_current_state(TASK_UNINTERRUPTIBLE);
+-			schedule_hrtimeout(&to, HRTIMER_MODE_REL);
++			schedule_hrtimeout(&to, HRTIMER_MODE_REL_HARD);
+ 			continue;
+ 		}
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0301-preempt-Move-preempt_enable_no_resched-to-the-RT-blo.patch b/debian/patches-rt/0301-preempt-Move-preempt_enable_no_resched-to-the-RT-blo.patch
new file mode 100644
index 000000000..41de0ba3d
--- /dev/null
+++ b/debian/patches-rt/0301-preempt-Move-preempt_enable_no_resched-to-the-RT-blo.patch
@@ -0,0 +1,45 @@
+From 8cc1a32ca44ae3484956295c75afcc2234e809ae Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 22 Sep 2021 19:34:40 +0200
+Subject: [PATCH 301/323] preempt: Move preempt_enable_no_resched() to the RT
+ block
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+preempt_enable_no_resched() should point to preempt_enable() on
+PREEMPT_RT so nobody is playing any preempt tricks and enables
+preemption without checking for the need-resched flag.
+
+This was misplaced in v3.14.0-rt1 und remained unnoticed until now.
+
+Point preempt_enable_no_resched() and preempt_enable() on RT.
+
+Cc: stable-rt@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ include/linux/preempt.h | 6 +++---
+ 1 file changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/include/linux/preempt.h b/include/linux/preempt.h
+index af39859f02ee..7b5b2ed55531 100644
+--- a/include/linux/preempt.h
++++ b/include/linux/preempt.h
+@@ -208,12 +208,12 @@ do { \
+ 	preempt_count_dec(); \
+ } while (0)
+ 
+-#ifdef CONFIG_PREEMPT_RT
++#ifndef CONFIG_PREEMPT_RT
+ # define preempt_enable_no_resched() sched_preempt_enable_no_resched()
+-# define preempt_check_resched_rt() preempt_check_resched()
++# define preempt_check_resched_rt() barrier();
+ #else
+ # define preempt_enable_no_resched() preempt_enable()
+-# define preempt_check_resched_rt() barrier();
++# define preempt_check_resched_rt() preempt_check_resched()
+ #endif
+ 
+ #define preemptible()	(preempt_count() == 0 && !irqs_disabled())
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0302-mm-Disable-NUMA_BALANCING_DEFAULT_ENABLED-and-TRANSP.patch b/debian/patches-rt/0302-mm-Disable-NUMA_BALANCING_DEFAULT_ENABLED-and-TRANSP.patch
new file mode 100644
index 000000000..e9b579280
--- /dev/null
+++ b/debian/patches-rt/0302-mm-Disable-NUMA_BALANCING_DEFAULT_ENABLED-and-TRANSP.patch
@@ -0,0 +1,51 @@
+From 4e8d89996a692bd5d4a094e55c0a88044993057f Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 29 Oct 2021 10:07:11 +0200
+Subject: [PATCH 302/323] mm: Disable NUMA_BALANCING_DEFAULT_ENABLED and
+ TRANSPARENT_HUGEPAGE on PREEMPT_RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+TRANSPARENT_HUGEPAGE:
+There are potential non-deterministic delays to an RT thread if a critical
+memory region is not THP-aligned and a non-RT buffer is located in the same
+hugepage-aligned region. It's also possible for an unrelated thread to migrate
+pages belonging to an RT task incurring unexpected page faults due to memory
+defragmentation even if khugepaged is disabled.
+
+Regular HUGEPAGEs are not affected by this can be used.
+
+NUMA_BALANCING:
+There is a non-deterministic delay to mark PTEs PROT_NONE to gather NUMA fault
+samples, increased page faults of regions even if mlocked and non-deterministic
+delays when migrating pages.
+
+[Mel Gorman worded 99% of the commit description].
+
+Link: https://lore.kernel.org/all/20200304091159.GN3818@techsingularity.net/
+Link: https://lore.kernel.org/all/20211026165100.ahz5bkx44lrrw5pt@linutronix.de/
+Cc: stable-rt@vger.kernel.org
+Cc: Mel Gorman <mgorman@techsingularity.net>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Acked-by: Mel Gorman <mgorman@techsingularity.net>
+Link: https://lore.kernel.org/r/20211028143327.hfbxjze7palrpfgp@linutronix.de
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ init/Kconfig | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/init/Kconfig b/init/Kconfig
+index c5f276d782de..a62d2961064b 100644
+--- a/init/Kconfig
++++ b/init/Kconfig
+@@ -878,7 +878,7 @@ config NUMA_BALANCING
+ 	bool "Memory placement aware NUMA scheduler"
+ 	depends on ARCH_SUPPORTS_NUMA_BALANCING
+ 	depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
+-	depends on SMP && NUMA && MIGRATION
++	depends on SMP && NUMA && MIGRATION && !PREEMPT_RT
+ 	help
+ 	  This option adds support for automatic NUMA aware memory/task placement.
+ 	  The mechanism is quite primitive and is based on migrating memory when
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0303-fscache-Use-only-one-fscache_object_cong_wait.patch b/debian/patches-rt/0303-fscache-Use-only-one-fscache_object_cong_wait.patch
new file mode 100644
index 000000000..a2f67e27c
--- /dev/null
+++ b/debian/patches-rt/0303-fscache-Use-only-one-fscache_object_cong_wait.patch
@@ -0,0 +1,129 @@
+From 9ebcbc0c3bbeaa6e13b623ff2d84d3b29e0a1431 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Thu, 28 Oct 2021 17:30:50 +0200
+Subject: [PATCH 303/323] fscache: Use only one fscache_object_cong_wait.
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+In the commit mentioned below, fscache was converted from slow-work to
+workqueue. slow_work_enqueue() and slow_work_sleep_till_thread_needed()
+did not use a per-CPU workqueue. They choose from two global waitqueues
+depending on the SLOW_WORK_VERY_SLOW bit which was not set so it always
+one waitqueue.
+
+I can't find out how it is ensured that a waiter on certain CPU is woken
+up be the other side. My guess is that the timeout in schedule_timeout()
+ensures that it does not wait forever (or a random wake up).
+
+fscache_object_sleep_till_congested() must be invoked from preemptible
+context in order for schedule() to work. In this case this_cpu_ptr()
+should complain with CONFIG_DEBUG_PREEMPT enabled except the thread is
+bound to one CPU.
+
+wake_up() wakes only one waiter and I'm not sure if it is guaranteed
+that only one waiter exists.
+
+Replace the per-CPU waitqueue with one global waitqueue.
+
+Fixes: 8b8edefa2fffb ("fscache: convert object to use workqueue instead of slow-work")
+Reported-by: Gregor Beck <gregor.beck@gmail.com>
+Cc: stable-rt@vger.kernel.org
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ fs/fscache/internal.h |  1 -
+ fs/fscache/main.c     |  6 ------
+ fs/fscache/object.c   | 11 +++++------
+ 3 files changed, 5 insertions(+), 13 deletions(-)
+
+diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
+index 64aa552b296d..7dae569dafb9 100644
+--- a/fs/fscache/internal.h
++++ b/fs/fscache/internal.h
+@@ -95,7 +95,6 @@ extern unsigned fscache_debug;
+ extern struct kobject *fscache_root;
+ extern struct workqueue_struct *fscache_object_wq;
+ extern struct workqueue_struct *fscache_op_wq;
+-DECLARE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
+ 
+ extern unsigned int fscache_hash(unsigned int salt, unsigned int *data, unsigned int n);
+ 
+diff --git a/fs/fscache/main.c b/fs/fscache/main.c
+index 4207f98e405f..85f8cf3a323d 100644
+--- a/fs/fscache/main.c
++++ b/fs/fscache/main.c
+@@ -41,8 +41,6 @@ struct kobject *fscache_root;
+ struct workqueue_struct *fscache_object_wq;
+ struct workqueue_struct *fscache_op_wq;
+ 
+-DEFINE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);
+-
+ /* these values serve as lower bounds, will be adjusted in fscache_init() */
+ static unsigned fscache_object_max_active = 4;
+ static unsigned fscache_op_max_active = 2;
+@@ -138,7 +136,6 @@ unsigned int fscache_hash(unsigned int salt, unsigned int *data, unsigned int n)
+ static int __init fscache_init(void)
+ {
+ 	unsigned int nr_cpus = num_possible_cpus();
+-	unsigned int cpu;
+ 	int ret;
+ 
+ 	fscache_object_max_active =
+@@ -161,9 +158,6 @@ static int __init fscache_init(void)
+ 	if (!fscache_op_wq)
+ 		goto error_op_wq;
+ 
+-	for_each_possible_cpu(cpu)
+-		init_waitqueue_head(&per_cpu(fscache_object_cong_wait, cpu));
+-
+ 	ret = fscache_proc_init();
+ 	if (ret < 0)
+ 		goto error_proc;
+diff --git a/fs/fscache/object.c b/fs/fscache/object.c
+index cb2146e02cd5..55158f30d093 100644
+--- a/fs/fscache/object.c
++++ b/fs/fscache/object.c
+@@ -807,6 +807,8 @@ void fscache_object_destroy(struct fscache_object *object)
+ }
+ EXPORT_SYMBOL(fscache_object_destroy);
+ 
++static DECLARE_WAIT_QUEUE_HEAD(fscache_object_cong_wait);
++
+ /*
+  * enqueue an object for metadata-type processing
+  */
+@@ -815,12 +817,10 @@ void fscache_enqueue_object(struct fscache_object *object)
+ 	_enter("{OBJ%x}", object->debug_id);
+ 
+ 	if (fscache_get_object(object, fscache_obj_get_queue) >= 0) {
+-		wait_queue_head_t *cong_wq =
+-			&get_cpu_var(fscache_object_cong_wait);
+ 
+ 		if (queue_work(fscache_object_wq, &object->work)) {
+ 			if (fscache_object_congested())
+-				wake_up(cong_wq);
++				wake_up(&fscache_object_cong_wait);
+ 		} else
+ 			fscache_put_object(object, fscache_obj_put_queue);
+ 
+@@ -842,16 +842,15 @@ void fscache_enqueue_object(struct fscache_object *object)
+  */
+ bool fscache_object_sleep_till_congested(signed long *timeoutp)
+ {
+-	wait_queue_head_t *cong_wq = this_cpu_ptr(&fscache_object_cong_wait);
+ 	DEFINE_WAIT(wait);
+ 
+ 	if (fscache_object_congested())
+ 		return true;
+ 
+-	add_wait_queue_exclusive(cong_wq, &wait);
++	add_wait_queue_exclusive(&fscache_object_cong_wait, &wait);
+ 	if (!fscache_object_congested())
+ 		*timeoutp = schedule_timeout(*timeoutp);
+-	finish_wait(cong_wq, &wait);
++	finish_wait(&fscache_object_cong_wait, &wait);
+ 
+ 	return fscache_object_congested();
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0304-fscache-Use-only-one-fscache_object_cong_wait.patch b/debian/patches-rt/0304-fscache-Use-only-one-fscache_object_cong_wait.patch
new file mode 100644
index 000000000..ca5c5cbd4
--- /dev/null
+++ b/debian/patches-rt/0304-fscache-Use-only-one-fscache_object_cong_wait.patch
@@ -0,0 +1,31 @@
+From 5fe656c51fcb73a09cf33665bcee0341edaf14c3 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 2 Nov 2021 11:52:05 +0100
+Subject: [PATCH 304/323] fscache: Use only one fscache_object_cong_wait.
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+This is an update of the original patch, removing put_cpu_var() which
+was overseen in the initial patch.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ fs/fscache/object.c | 2 --
+ 1 file changed, 2 deletions(-)
+
+diff --git a/fs/fscache/object.c b/fs/fscache/object.c
+index 55158f30d093..fb9794dce721 100644
+--- a/fs/fscache/object.c
++++ b/fs/fscache/object.c
+@@ -823,8 +823,6 @@ void fscache_enqueue_object(struct fscache_object *object)
+ 				wake_up(&fscache_object_cong_wait);
+ 		} else
+ 			fscache_put_object(object, fscache_obj_put_queue);
+-
+-		put_cpu_var(fscache_object_cong_wait);
+ 	}
+ }
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0305-locking-Drop-might_resched-from-might_sleep_no_state.patch b/debian/patches-rt/0305-locking-Drop-might_resched-from-might_sleep_no_state.patch
new file mode 100644
index 000000000..f424e077f
--- /dev/null
+++ b/debian/patches-rt/0305-locking-Drop-might_resched-from-might_sleep_no_state.patch
@@ -0,0 +1,40 @@
+From 8eddd2dc82853a3df908061f6ddf71bde523917b Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Mon, 6 Sep 2021 18:19:16 +0200
+Subject: [PATCH 305/323] locking: Drop might_resched() from
+ might_sleep_no_state_check()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+might_sleep_no_state_check() serves the same purpose as might_sleep()
+except it is used before sleeping locks are acquired and therefore does
+not check task_struct::state because the state is preserved.
+
+That state is preserved in the locking slow path so we must not schedule
+at the begin of the locking function because the state will be lost and
+not preserved at that time.
+
+Remove might_resched() from might_sleep_no_state_check() to avoid losing the
+state before it is preserved.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ include/linux/kernel.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/include/linux/kernel.h b/include/linux/kernel.h
+index 7b4fdd5b2f7b..4e88ae0b2578 100644
+--- a/include/linux/kernel.h
++++ b/include/linux/kernel.h
+@@ -225,7 +225,7 @@ extern void __cant_migrate(const char *file, int line);
+ 	do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
+ 
+ # define might_sleep_no_state_check() \
+-	do { ___might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
++	do { ___might_sleep(__FILE__, __LINE__, 0); } while (0)
+ 
+ /**
+  * cant_sleep - annotation for functions that cannot sleep
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0306-drm-i915-gt-Queue-and-wait-for-the-irq_work-item.patch b/debian/patches-rt/0306-drm-i915-gt-Queue-and-wait-for-the-irq_work-item.patch
new file mode 100644
index 000000000..c7e1e5838
--- /dev/null
+++ b/debian/patches-rt/0306-drm-i915-gt-Queue-and-wait-for-the-irq_work-item.patch
@@ -0,0 +1,49 @@
+From 45cb435eff7cd17311c87552c32c3a202b09bf51 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Tue, 26 Oct 2021 13:40:53 +0200
+Subject: [PATCH 306/323] drm/i915/gt: Queue and wait for the irq_work item.
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Disabling interrupts and invoking the irq_work function directly breaks
+on PREEMPT_RT.
+PREEMPT_RT does not invoke all irq_work from hardirq context because
+some of the user have spinlock_t locking in the callback function.
+These locks are then turned into a sleeping locks which can not be
+acquired with disabled interrupts.
+
+Using irq_work_queue() has the benefit that the irqwork will be invoked
+in the regular context. In general there is "no" delay between enqueuing
+the callback and its invocation because the interrupt is raised right
+away on architectures which support it (which includes x86).
+
+Use irq_work_queue() + irq_work_sync() instead invoking the callback
+directly.
+
+Reported-by: Clark Williams <williams@redhat.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 5 ++---
+ 1 file changed, 2 insertions(+), 3 deletions(-)
+
+diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
+index 0040b4765a54..3f4f854786f2 100644
+--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
++++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
+@@ -342,10 +342,9 @@ void intel_breadcrumbs_park(struct intel_breadcrumbs *b)
+ 	/* Kick the work once more to drain the signalers */
+ 	irq_work_sync(&b->irq_work);
+ 	while (unlikely(READ_ONCE(b->irq_armed))) {
+-		local_irq_disable();
+-		signal_irq_work(&b->irq_work);
+-		local_irq_enable();
++		irq_work_queue(&b->irq_work);
+ 		cond_resched();
++		irq_work_sync(&b->irq_work);
+ 	}
+ 	GEM_BUG_ON(!list_empty(&b->signalers));
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0307-irq_work-Allow-irq_work_sync-to-sleep-if-irq_work-no.patch b/debian/patches-rt/0307-irq_work-Allow-irq_work_sync-to-sleep-if-irq_work-no.patch
new file mode 100644
index 000000000..2c0ed1db3
--- /dev/null
+++ b/debian/patches-rt/0307-irq_work-Allow-irq_work_sync-to-sleep-if-irq_work-no.patch
@@ -0,0 +1,100 @@
+From cf4bb976aef7af85b7134aa7cffdfa8e058dc5c6 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 24 Nov 2021 17:12:19 +0100
+Subject: [PATCH 307/323] irq_work: Allow irq_work_sync() to sleep if
+ irq_work() no IRQ support.
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+irq_work() triggers instantly an interrupt if supported by the
+architecture. Otherwise the work will be processed on the next timer
+tick. In worst case irq_work_sync() could spin up to a jiffy.
+
+irq_work_sync() is usually used in tear down context which is fully
+preemptible. Based on review irq_work_sync() is invoked from preemptible
+context and there is one waiter at a time. This qualifies it to use
+rcuwait for synchronisation.
+
+Let irq_work_sync() synchronize with rcuwait if the architecture
+processes irqwork via the timer tick.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Link: https://lkml.kernel.org/r/20211006111852.1514359-3-bigeasy@linutronix.de
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ include/linux/irq_work.h | 10 +++++++++-
+ kernel/irq_work.c        | 10 ++++++++++
+ 2 files changed, 19 insertions(+), 1 deletion(-)
+
+diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
+index f941f2d7d71c..3c6d3a96bca0 100644
+--- a/include/linux/irq_work.h
++++ b/include/linux/irq_work.h
+@@ -3,6 +3,7 @@
+ #define _LINUX_IRQ_WORK_H
+ 
+ #include <linux/smp_types.h>
++#include <linux/rcuwait.h>
+ 
+ /*
+  * An entry can be in one of four states:
+@@ -22,6 +23,7 @@ struct irq_work {
+ 		};
+ 	};
+ 	void (*func)(struct irq_work *);
++	struct rcuwait irqwait;
+ };
+ 
+ static inline
+@@ -29,13 +31,19 @@ void init_irq_work(struct irq_work *work, void (*func)(struct irq_work *))
+ {
+ 	atomic_set(&work->flags, 0);
+ 	work->func = func;
++	rcuwait_init(&work->irqwait);
+ }
+ 
+ #define DEFINE_IRQ_WORK(name, _f) struct irq_work name = {	\
+ 		.flags = ATOMIC_INIT(0),			\
+-		.func  = (_f)					\
++		.func  = (_f),					\
++		.irqwait = __RCUWAIT_INITIALIZER(irqwait),	\
+ }
+ 
++static inline bool irq_work_is_busy(struct irq_work *work)
++{
++	return atomic_read(&work->flags) & IRQ_WORK_BUSY;
++}
+ 
+ bool irq_work_queue(struct irq_work *work);
+ bool irq_work_queue_on(struct irq_work *work, int cpu);
+diff --git a/kernel/irq_work.c b/kernel/irq_work.c
+index 8183d30e1bb1..8969aff790e2 100644
+--- a/kernel/irq_work.c
++++ b/kernel/irq_work.c
+@@ -165,6 +165,9 @@ void irq_work_single(void *arg)
+ 	 */
+ 	flags &= ~IRQ_WORK_PENDING;
+ 	(void)atomic_cmpxchg(&work->flags, flags, flags & ~IRQ_WORK_BUSY);
++
++	if (!arch_irq_work_has_interrupt())
++		rcuwait_wake_up(&work->irqwait);
+ }
+ 
+ static void irq_work_run_list(struct llist_head *list)
+@@ -231,6 +234,13 @@ void irq_work_tick_soft(void)
+ void irq_work_sync(struct irq_work *work)
+ {
+ 	lockdep_assert_irqs_enabled();
++	might_sleep();
++
++	if (!arch_irq_work_has_interrupt()) {
++		rcuwait_wait_event(&work->irqwait, !irq_work_is_busy(work),
++				   TASK_UNINTERRUPTIBLE);
++		return;
++	}
+ 
+ 	while (atomic_read(&work->flags) & IRQ_WORK_BUSY)
+ 		cpu_relax();
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0308-irq_work-Handle-some-irq_work-in-a-per-CPU-thread-on.patch b/debian/patches-rt/0308-irq_work-Handle-some-irq_work-in-a-per-CPU-thread-on.patch
new file mode 100644
index 000000000..a6aea41c0
--- /dev/null
+++ b/debian/patches-rt/0308-irq_work-Handle-some-irq_work-in-a-per-CPU-thread-on.patch
@@ -0,0 +1,307 @@
+From 2b803272d74039863a77523d79f79cc938eff7cf Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 24 Nov 2021 17:12:20 +0100
+Subject: [PATCH 308/323] irq_work: Handle some irq_work in a per-CPU thread on
+ PREEMPT_RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The irq_work callback is invoked in hard IRQ context. By default all
+callbacks are scheduled for invocation right away (given supported by
+the architecture) except for the ones marked IRQ_WORK_LAZY which are
+delayed until the next timer-tick.
+
+While looking over the callbacks, some of them may acquire locks
+(spinlock_t, rwlock_t) which are transformed into sleeping locks on
+PREEMPT_RT and must not be acquired in hard IRQ context.
+Changing the locks into locks which could be acquired in this context
+will lead to other problems such as increased latencies if everything
+in the chain has IRQ-off locks. This will not solve all the issues as
+one callback has been noticed which invoked kref_put() and its callback
+invokes kfree() and this can not be invoked in hardirq context.
+
+Some callbacks are required to be invoked in hardirq context even on
+PREEMPT_RT to work properly. This includes for instance the NO_HZ
+callback which needs to be able to observe the idle context.
+
+The callbacks which require to be run in hardirq have already been
+marked. Use this information to split the callbacks onto the two lists
+on PREEMPT_RT:
+- lazy_list
+  Work items which are not marked with IRQ_WORK_HARD_IRQ will be added
+  to this list. Callbacks on this list will be invoked from a per-CPU
+  thread.
+  The handler here may acquire sleeping locks such as spinlock_t and
+  invoke kfree().
+
+- raised_list
+  Work items which are marked with IRQ_WORK_HARD_IRQ will be added to
+  this list. They will be invoked in hardirq context and must not
+  acquire any sleeping locks.
+
+The wake up of the per-CPU thread occurs from irq_work handler/
+hardirq context. The thread runs with lowest RT priority to ensure it
+runs before any SCHED_OTHER tasks do.
+
+[bigeasy: melt tglx's irq_work_tick_soft() which splits irq_work_tick() into a
+	  hard and soft variant. Collected fixes over time from Steven
+	  Rostedt and Mike Galbraith. Move to per-CPU threads instead of
+	  softirq as suggested by PeterZ.]
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Link: https://lkml.kernel.org/r/20211007092646.uhshe3ut2wkrcfzv@linutronix.de
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ include/linux/irq_work.h |  16 +++--
+ kernel/irq_work.c        | 131 ++++++++++++++++++++++++++++-----------
+ kernel/time/timer.c      |   2 -
+ 3 files changed, 106 insertions(+), 43 deletions(-)
+
+diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
+index 3c6d3a96bca0..f551ba9c99d4 100644
+--- a/include/linux/irq_work.h
++++ b/include/linux/irq_work.h
+@@ -40,6 +40,16 @@ void init_irq_work(struct irq_work *work, void (*func)(struct irq_work *))
+ 		.irqwait = __RCUWAIT_INITIALIZER(irqwait),	\
+ }
+ 
++#define __IRQ_WORK_INIT(_func, _flags) (struct irq_work){	\
++	.flags = ATOMIC_INIT(_flags),				\
++	.func = (_func),					\
++	.irqwait = __RCUWAIT_INITIALIZER(irqwait),		\
++}
++
++#define IRQ_WORK_INIT(_func) __IRQ_WORK_INIT(_func, 0)
++#define IRQ_WORK_INIT_LAZY(_func) __IRQ_WORK_INIT(_func, IRQ_WORK_LAZY)
++#define IRQ_WORK_INIT_HARD(_func) __IRQ_WORK_INIT(_func, IRQ_WORK_HARD_IRQ)
++
+ static inline bool irq_work_is_busy(struct irq_work *work)
+ {
+ 	return atomic_read(&work->flags) & IRQ_WORK_BUSY;
+@@ -63,10 +73,4 @@ static inline void irq_work_run(void) { }
+ static inline void irq_work_single(void *arg) { }
+ #endif
+ 
+-#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT)
+-void irq_work_tick_soft(void);
+-#else
+-static inline void irq_work_tick_soft(void) { }
+-#endif
+-
+ #endif /* _LINUX_IRQ_WORK_H */
+diff --git a/kernel/irq_work.c b/kernel/irq_work.c
+index 8969aff790e2..03d09d779ee1 100644
+--- a/kernel/irq_work.c
++++ b/kernel/irq_work.c
+@@ -18,12 +18,37 @@
+ #include <linux/cpu.h>
+ #include <linux/notifier.h>
+ #include <linux/smp.h>
++#include <linux/smpboot.h>
+ #include <linux/interrupt.h>
+ #include <asm/processor.h>
+ 
+ 
+ static DEFINE_PER_CPU(struct llist_head, raised_list);
+ static DEFINE_PER_CPU(struct llist_head, lazy_list);
++static DEFINE_PER_CPU(struct task_struct *, irq_workd);
++
++static void wake_irq_workd(void)
++{
++	struct task_struct *tsk = __this_cpu_read(irq_workd);
++
++	if (!llist_empty(this_cpu_ptr(&lazy_list)) && tsk)
++		wake_up_process(tsk);
++}
++
++#ifdef CONFIG_SMP
++static void irq_work_wake(struct irq_work *entry)
++{
++	wake_irq_workd();
++}
++
++static DEFINE_PER_CPU(struct irq_work, irq_work_wakeup) =
++	IRQ_WORK_INIT_HARD(irq_work_wake);
++#endif
++
++static int irq_workd_should_run(unsigned int cpu)
++{
++	return !llist_empty(this_cpu_ptr(&lazy_list));
++}
+ 
+ /*
+  * Claim the entry so that no one else will poke at it.
+@@ -54,20 +79,28 @@ void __weak arch_irq_work_raise(void)
+ static void __irq_work_queue_local(struct irq_work *work)
+ {
+ 	struct llist_head *list;
+-	bool lazy_work, realtime = IS_ENABLED(CONFIG_PREEMPT_RT);
+-
+-	lazy_work = atomic_read(&work->flags) & IRQ_WORK_LAZY;
+-
+-	/* If the work is "lazy", handle it from next tick if any */
+-	if (lazy_work || (realtime && !(atomic_read(&work->flags) & IRQ_WORK_HARD_IRQ)))
++	bool rt_lazy_work = false;
++	bool lazy_work = false;
++	int work_flags;
++
++	work_flags = atomic_read(&work->flags);
++	if (work_flags & IRQ_WORK_LAZY)
++		lazy_work = true;
++	else if (IS_ENABLED(CONFIG_PREEMPT_RT) &&
++		 !(work_flags & IRQ_WORK_HARD_IRQ))
++		rt_lazy_work = true;
++
++	if (lazy_work || rt_lazy_work)
+ 		list = this_cpu_ptr(&lazy_list);
+ 	else
+ 		list = this_cpu_ptr(&raised_list);
+ 
+-	if (llist_add(&work->llnode, list)) {
+-		if (!lazy_work || tick_nohz_tick_stopped())
+-			arch_irq_work_raise();
+-	}
++	if (!llist_add(&work->llnode, list))
++		return;
++
++	/* If the work is "lazy", handle it from next tick if any */
++	if (!lazy_work || tick_nohz_tick_stopped())
++		arch_irq_work_raise();
+ }
+ 
+ /* Enqueue the irq work @work on the current CPU */
+@@ -110,15 +143,27 @@ bool irq_work_queue_on(struct irq_work *work, int cpu)
+ 		/* Arch remote IPI send/receive backend aren't NMI safe */
+ 		WARN_ON_ONCE(in_nmi());
+ 
+-		if (IS_ENABLED(CONFIG_PREEMPT_RT) && !(atomic_read(&work->flags) & IRQ_WORK_HARD_IRQ)) {
+-			if (llist_add(&work->llnode, &per_cpu(lazy_list, cpu)))
+-				arch_send_call_function_single_ipi(cpu);
+-		} else {
+-			__smp_call_single_queue(cpu, &work->llnode);
++		/*
++		 * On PREEMPT_RT the items which are not marked as
++		 * IRQ_WORK_HARD_IRQ are added to the lazy list and a HARD work
++		 * item is used on the remote CPU to wake the thread.
++		 */
++		if (IS_ENABLED(CONFIG_PREEMPT_RT) &&
++		    !(atomic_read(&work->flags) & IRQ_WORK_HARD_IRQ)) {
++
++			if (!llist_add(&work->llnode, &per_cpu(lazy_list, cpu)))
++				goto out;
++
++			work = &per_cpu(irq_work_wakeup, cpu);
++			if (!irq_work_claim(work))
++				goto out;
+ 		}
++
++		__smp_call_single_queue(cpu, &work->llnode);
+ 	} else {
+ 		__irq_work_queue_local(work);
+ 	}
++out:
+ 	preempt_enable();
+ 
+ 	return true;
+@@ -175,12 +220,13 @@ static void irq_work_run_list(struct llist_head *list)
+ 	struct irq_work *work, *tmp;
+ 	struct llist_node *llnode;
+ 
+-#ifndef CONFIG_PREEMPT_RT
+ 	/*
+-	 * nort: On RT IRQ-work may run in SOFTIRQ context.
++	 * On PREEMPT_RT IRQ-work which is not marked as HARD will be processed
++	 * in a per-CPU thread in preemptible context. Only the items which are
++	 * marked as IRQ_WORK_HARD_IRQ will be processed in hardirq context.
+ 	 */
+-	BUG_ON(!irqs_disabled());
+-#endif
++	BUG_ON(!irqs_disabled() && !IS_ENABLED(CONFIG_PREEMPT_RT));
++
+ 	if (llist_empty(list))
+ 		return;
+ 
+@@ -196,16 +242,10 @@ static void irq_work_run_list(struct llist_head *list)
+ void irq_work_run(void)
+ {
+ 	irq_work_run_list(this_cpu_ptr(&raised_list));
+-	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
+-		/*
+-		 * NOTE: we raise softirq via IPI for safety,
+-		 * and execute in irq_work_tick() to move the
+-		 * overhead from hard to soft irq context.
+-		 */
+-		if (!llist_empty(this_cpu_ptr(&lazy_list)))
+-			raise_softirq(TIMER_SOFTIRQ);
+-	} else
++	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+ 		irq_work_run_list(this_cpu_ptr(&lazy_list));
++	else
++		wake_irq_workd();
+ }
+ EXPORT_SYMBOL_GPL(irq_work_run);
+ 
+@@ -218,15 +258,10 @@ void irq_work_tick(void)
+ 
+ 	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+ 		irq_work_run_list(this_cpu_ptr(&lazy_list));
++	else
++		wake_irq_workd();
+ }
+ 
+-#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT)
+-void irq_work_tick_soft(void)
+-{
+-	irq_work_run_list(this_cpu_ptr(&lazy_list));
+-}
+-#endif
+-
+ /*
+  * Synchronize against the irq_work @entry, ensures the entry is not
+  * currently in use.
+@@ -246,3 +281,29 @@ void irq_work_sync(struct irq_work *work)
+ 		cpu_relax();
+ }
+ EXPORT_SYMBOL_GPL(irq_work_sync);
++
++static void run_irq_workd(unsigned int cpu)
++{
++	irq_work_run_list(this_cpu_ptr(&lazy_list));
++}
++
++static void irq_workd_setup(unsigned int cpu)
++{
++	sched_set_fifo_low(current);
++}
++
++static struct smp_hotplug_thread irqwork_threads = {
++	.store                  = &irq_workd,
++	.setup			= irq_workd_setup,
++	.thread_should_run      = irq_workd_should_run,
++	.thread_fn              = run_irq_workd,
++	.thread_comm            = "irq_work/%u",
++};
++
++static __init int irq_work_init_threads(void)
++{
++	if (IS_ENABLED(CONFIG_PREEMPT_RT))
++		BUG_ON(smpboot_register_percpu_thread(&irqwork_threads));
++	return 0;
++}
++early_initcall(irq_work_init_threads);
+diff --git a/kernel/time/timer.c b/kernel/time/timer.c
+index 1cad0efd635c..a4fdc7cfb723 100644
+--- a/kernel/time/timer.c
++++ b/kernel/time/timer.c
+@@ -1770,8 +1770,6 @@ static __latent_entropy void run_timer_softirq(struct softirq_action *h)
+ {
+ 	struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
+ 
+-	irq_work_tick_soft();
+-
+ 	__run_timers(base);
+ 	if (IS_ENABLED(CONFIG_NO_HZ_COMMON))
+ 		__run_timers(this_cpu_ptr(&timer_bases[BASE_DEF]));
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0309-irq_work-Also-rcuwait-for-IRQ_WORK_HARD_IRQ-on-PREEM.patch b/debian/patches-rt/0309-irq_work-Also-rcuwait-for-IRQ_WORK_HARD_IRQ-on-PREEM.patch
new file mode 100644
index 000000000..ed320f6b7
--- /dev/null
+++ b/debian/patches-rt/0309-irq_work-Also-rcuwait-for-IRQ_WORK_HARD_IRQ-on-PREEM.patch
@@ -0,0 +1,65 @@
+From ca685c962ea2301291d3459ec8717208395b3cf9 Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 24 Nov 2021 17:12:21 +0100
+Subject: [PATCH 309/323] irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on
+ PREEMPT_RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+On PREEMPT_RT most items are processed as LAZY via softirq context.
+Avoid to spin-wait for them because irq_work_sync() could have higher
+priority and not allow the irq-work to be completed.
+
+Wait additionally for !IRQ_WORK_HARD_IRQ irq_work items on PREEMPT_RT.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
+Link: https://lkml.kernel.org/r/20211006111852.1514359-5-bigeasy@linutronix.de
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ include/linux/irq_work.h | 5 +++++
+ kernel/irq_work.c        | 6 ++++--
+ 2 files changed, 9 insertions(+), 2 deletions(-)
+
+diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
+index f551ba9c99d4..2c0059340871 100644
+--- a/include/linux/irq_work.h
++++ b/include/linux/irq_work.h
+@@ -55,6 +55,11 @@ static inline bool irq_work_is_busy(struct irq_work *work)
+ 	return atomic_read(&work->flags) & IRQ_WORK_BUSY;
+ }
+ 
++static inline bool irq_work_is_hard(struct irq_work *work)
++{
++	return atomic_read(&work->flags) & IRQ_WORK_HARD_IRQ;
++}
++
+ bool irq_work_queue(struct irq_work *work);
+ bool irq_work_queue_on(struct irq_work *work, int cpu);
+ 
+diff --git a/kernel/irq_work.c b/kernel/irq_work.c
+index 03d09d779ee1..cbec10c32ead 100644
+--- a/kernel/irq_work.c
++++ b/kernel/irq_work.c
+@@ -211,7 +211,8 @@ void irq_work_single(void *arg)
+ 	flags &= ~IRQ_WORK_PENDING;
+ 	(void)atomic_cmpxchg(&work->flags, flags, flags & ~IRQ_WORK_BUSY);
+ 
+-	if (!arch_irq_work_has_interrupt())
++	if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) ||
++	    !arch_irq_work_has_interrupt())
+ 		rcuwait_wake_up(&work->irqwait);
+ }
+ 
+@@ -271,7 +272,8 @@ void irq_work_sync(struct irq_work *work)
+ 	lockdep_assert_irqs_enabled();
+ 	might_sleep();
+ 
+-	if (!arch_irq_work_has_interrupt()) {
++	if ((IS_ENABLED(CONFIG_PREEMPT_RT) && !irq_work_is_hard(work)) ||
++	    !arch_irq_work_has_interrupt()) {
+ 		rcuwait_wait_event(&work->irqwait, !irq_work_is_busy(work),
+ 				   TASK_UNINTERRUPTIBLE);
+ 		return;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0310-eventfd-Make-signal-recursion-protection-a-task-bit.patch b/debian/patches-rt/0310-eventfd-Make-signal-recursion-protection-a-task-bit.patch
new file mode 100644
index 000000000..719316f76
--- /dev/null
+++ b/debian/patches-rt/0310-eventfd-Make-signal-recursion-protection-a-task-bit.patch
@@ -0,0 +1,150 @@
+From 17c41196e72418f94cf308a8b23fe478612a1610 Mon Sep 17 00:00:00 2001
+From: Thomas Gleixner <tglx@linutronix.de>
+Date: Fri, 17 Dec 2021 11:32:09 +0100
+Subject: [PATCH 310/323] eventfd: Make signal recursion protection a task bit
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Upstream commit b542e383d8c005f06a131e2b40d5889b812f19c6
+
+The recursion protection for eventfd_signal() is based on a per CPU
+variable and relies on the !RT semantics of spin_lock_irqsave() for
+protecting this per CPU variable. On RT kernels spin_lock_irqsave() neither
+disables preemption nor interrupts which allows the spin lock held section
+to be preempted. If the preempting task invokes eventfd_signal() as well,
+then the recursion warning triggers.
+
+Paolo suggested to protect the per CPU variable with a local lock, but
+that's heavyweight and actually not necessary. The goal of this protection
+is to prevent the task stack from overflowing, which can be achieved with a
+per task recursion protection as well.
+
+Replace the per CPU variable with a per task bit similar to other recursion
+protection bits like task_struct::in_page_owner. This works on both !RT and
+RT kernels and removes as a side effect the extra per CPU storage.
+
+No functional change for !RT kernels.
+
+Reported-by: Daniel Bristot de Oliveira <bristot@redhat.com>
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+Tested-by: Daniel Bristot de Oliveira <bristot@redhat.com>
+Acked-by: Jason Wang <jasowang@redhat.com>
+Cc: Al Viro <viro@zeniv.linux.org.uk>
+Link: https://lore.kernel.org/r/87wnp9idso.ffs@tglx
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ fs/aio.c                |  2 +-
+ fs/eventfd.c            | 12 +++++-------
+ include/linux/eventfd.h | 11 +++++------
+ include/linux/sched.h   |  4 ++++
+ 4 files changed, 15 insertions(+), 14 deletions(-)
+
+diff --git a/fs/aio.c b/fs/aio.c
+index c90e045a37bc..e1181dc37be1 100644
+--- a/fs/aio.c
++++ b/fs/aio.c
+@@ -1765,7 +1765,7 @@ static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
+ 		list_del_init(&req->wait.entry);
+ 		list_del(&iocb->ki_list);
+ 		iocb->ki_res.res = mangle_poll(mask);
+-		if (iocb->ki_eventfd && eventfd_signal_count()) {
++		if (iocb->ki_eventfd && eventfd_signal_allowed()) {
+ 			iocb = NULL;
+ 			INIT_WORK(&req->work, aio_poll_put_work);
+ 			schedule_work(&req->work);
+diff --git a/fs/eventfd.c b/fs/eventfd.c
+index 3673eb8de035..ce9ca07d6c00 100644
+--- a/fs/eventfd.c
++++ b/fs/eventfd.c
+@@ -25,8 +25,6 @@
+ #include <linux/idr.h>
+ #include <linux/uio.h>
+ 
+-DEFINE_PER_CPU(int, eventfd_wake_count);
+-
+ static DEFINE_IDA(eventfd_ida);
+ 
+ struct eventfd_ctx {
+@@ -53,21 +51,21 @@ __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, unsigned mask)
+ 	 * Deadlock or stack overflow issues can happen if we recurse here
+ 	 * through waitqueue wakeup handlers. If the caller users potentially
+ 	 * nested waitqueues with custom wakeup handlers, then it should
+-	 * check eventfd_signal_count() before calling this function. If
+-	 * it returns true, the eventfd_signal() call should be deferred to a
++	 * check eventfd_signal_allowed() before calling this function. If
++	 * it returns false, the eventfd_signal() call should be deferred to a
+ 	 * safe context.
+ 	 */
+-	if (WARN_ON_ONCE(this_cpu_read(eventfd_wake_count)))
++	if (WARN_ON_ONCE(current->in_eventfd_signal))
+ 		return 0;
+ 
+ 	spin_lock_irqsave(&ctx->wqh.lock, flags);
+-	this_cpu_inc(eventfd_wake_count);
++	current->in_eventfd_signal = 1;
+ 	if (ULLONG_MAX - ctx->count < n)
+ 		n = ULLONG_MAX - ctx->count;
+ 	ctx->count += n;
+ 	if (waitqueue_active(&ctx->wqh))
+ 		wake_up_locked_poll(&ctx->wqh, EPOLLIN | mask);
+-	this_cpu_dec(eventfd_wake_count);
++	current->in_eventfd_signal = 0;
+ 	spin_unlock_irqrestore(&ctx->wqh.lock, flags);
+ 
+ 	return n;
+diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h
+index c1bd4883e2fa..842d223dfe17 100644
+--- a/include/linux/eventfd.h
++++ b/include/linux/eventfd.h
+@@ -14,6 +14,7 @@
+ #include <linux/err.h>
+ #include <linux/percpu-defs.h>
+ #include <linux/percpu.h>
++#include <linux/sched.h>
+ 
+ /*
+  * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
+@@ -44,11 +45,9 @@ int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *w
+ 				  __u64 *cnt);
+ void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt);
+ 
+-DECLARE_PER_CPU(int, eventfd_wake_count);
+-
+-static inline bool eventfd_signal_count(void)
++static inline bool eventfd_signal_allowed(void)
+ {
+-	return this_cpu_read(eventfd_wake_count);
++	return !current->in_eventfd_signal;
+ }
+ 
+ #else /* CONFIG_EVENTFD */
+@@ -85,9 +84,9 @@ static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
+ 	return -ENOSYS;
+ }
+ 
+-static inline bool eventfd_signal_count(void)
++static inline bool eventfd_signal_allowed(void)
+ {
+-	return false;
++	return true;
+ }
+ 
+ static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt)
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index a73528e8235d..13d4957189bb 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -848,6 +848,10 @@ struct task_struct {
+ 	/* Stalled due to lack of memory */
+ 	unsigned			in_memstall:1;
+ #endif
++#ifdef CONFIG_EVENTFD
++	/* Recursion prevention for eventfd_signal() */
++	unsigned			in_eventfd_signal:1;
++#endif
+ 
+ 	unsigned long			atomic_flags; /* Flags requiring atomic access. */
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0311-stop_machine-Remove-this_cpu_ptr-from-print_stop_inf.patch b/debian/patches-rt/0311-stop_machine-Remove-this_cpu_ptr-from-print_stop_inf.patch
new file mode 100644
index 000000000..653909e6e
--- /dev/null
+++ b/debian/patches-rt/0311-stop_machine-Remove-this_cpu_ptr-from-print_stop_inf.patch
@@ -0,0 +1,38 @@
+From ce2910a453196930e7083aaf13240adcec160afd Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Fri, 17 Dec 2021 11:32:08 +0100
+Subject: [PATCH 311/323] stop_machine: Remove this_cpu_ptr() from
+ print_stop_info().
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+This aligns the patch ("stop_machine: Add function and caller debug
+info) with commit
+  a8b62fd085050 ("stop_machine: Add function and caller debug info")
+
+that was merged upstream and is slightly different.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ kernel/stop_machine.c | 6 +++++-
+ 1 file changed, 5 insertions(+), 1 deletion(-)
+
+diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
+index dbf585cf4b9f..971d8acceaec 100644
+--- a/kernel/stop_machine.c
++++ b/kernel/stop_machine.c
+@@ -51,7 +51,11 @@ static bool stop_machine_initialized = false;
+ 
+ void print_stop_info(const char *log_lvl, struct task_struct *task)
+ {
+-	struct cpu_stopper *stopper = this_cpu_ptr(&cpu_stopper);
++	/*
++	 * If @task is a stopper task, it cannot migrate and task_cpu() is
++	 * stable.
++	 */
++	struct cpu_stopper *stopper = per_cpu_ptr(&cpu_stopper, task_cpu(task));
+ 
+ 	if (task != stopper->thread)
+ 		return;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0312-aio-Fix-incorrect-usage-of-eventfd_signal_allowed.patch b/debian/patches-rt/0312-aio-Fix-incorrect-usage-of-eventfd_signal_allowed.patch
new file mode 100644
index 000000000..978a2de7d
--- /dev/null
+++ b/debian/patches-rt/0312-aio-Fix-incorrect-usage-of-eventfd_signal_allowed.patch
@@ -0,0 +1,38 @@
+From fd840c98e310adf2a03ee242969a9597a909a672 Mon Sep 17 00:00:00 2001
+From: Xie Yongji <xieyongji@bytedance.com>
+Date: Mon, 13 Sep 2021 19:19:28 +0800
+Subject: [PATCH 312/323] aio: Fix incorrect usage of eventfd_signal_allowed()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+commit 4b3749865374899e115aa8c48681709b086fe6d3 upstream.
+
+We should defer eventfd_signal() to the workqueue when
+eventfd_signal_allowed() return false rather than return
+true.
+
+Fixes: b542e383d8c0 ("eventfd: Make signal recursion protection a task bit")
+Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
+Link: https://lore.kernel.org/r/20210913111928.98-1-xieyongji@bytedance.com
+Reviewed-by: Eric Biggers <ebiggers@google.com>
+Signed-off-by: Eric Biggers <ebiggers@google.com>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ fs/aio.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/fs/aio.c b/fs/aio.c
+index e1181dc37be1..e88fd9b58f3f 100644
+--- a/fs/aio.c
++++ b/fs/aio.c
+@@ -1765,7 +1765,7 @@ static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
+ 		list_del_init(&req->wait.entry);
+ 		list_del(&iocb->ki_list);
+ 		iocb->ki_res.res = mangle_poll(mask);
+-		if (iocb->ki_eventfd && eventfd_signal_allowed()) {
++		if (iocb->ki_eventfd && !eventfd_signal_allowed()) {
+ 			iocb = NULL;
+ 			INIT_WORK(&req->work, aio_poll_put_work);
+ 			schedule_work(&req->work);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0313-rt-remove-extra-parameter-from-__trace_stack.patch b/debian/patches-rt/0313-rt-remove-extra-parameter-from-__trace_stack.patch
new file mode 100644
index 000000000..d688d1f6d
--- /dev/null
+++ b/debian/patches-rt/0313-rt-remove-extra-parameter-from-__trace_stack.patch
@@ -0,0 +1,41 @@
+From 38a85604759ae488654bab5c1cd9f23cd0d77ce0 Mon Sep 17 00:00:00 2001
+From: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
+Date: Thu, 12 May 2022 23:25:33 -0300
+Subject: [PATCH 313/323] rt: remove extra parameter from __trace_stack()
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Fix the build error below while keeping the current PREEMPT_RT code:
+
+kernel/trace/trace_events_trigger.c: In function ‘stacktrace_trigger’:
+kernel/trace/trace_events_trigger.c:1227:3: error: too many arguments to function ‘__trace_stack’
+   __trace_stack(file->tr, flags, STACK_SKIP, preempt_count());
+   ^~~~~~~~~~~~~
+In file included from kernel/trace/trace_events_trigger.c:15:
+kernel/trace/trace.h:826:6: note: declared here
+ void __trace_stack(struct trace_array *tr, unsigned int trace_ctx, int skip);
+      ^~~~~~~~~~~~~
+
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ kernel/trace/trace_events_trigger.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
+index 4bc90965abb2..75fef9fcfd0f 100644
+--- a/kernel/trace/trace_events_trigger.c
++++ b/kernel/trace/trace_events_trigger.c
+@@ -1224,7 +1224,7 @@ stacktrace_trigger(struct event_trigger_data *data, void *rec,
+ 
+ 	if (file) {
+ 		local_save_flags(flags);
+-		__trace_stack(file->tr, flags, STACK_SKIP, preempt_count());
++		__trace_stack(file->tr, STACK_SKIP, preempt_count());
+ 	} else
+ 		trace_dump_stack(STACK_SKIP);
+ }
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0314-locking-rtmutex-switch-to-EXPORT_SYMBOL-for-ww_mutex.patch b/debian/patches-rt/0314-locking-rtmutex-switch-to-EXPORT_SYMBOL-for-ww_mutex.patch
new file mode 100644
index 000000000..4cb76be05
--- /dev/null
+++ b/debian/patches-rt/0314-locking-rtmutex-switch-to-EXPORT_SYMBOL-for-ww_mutex.patch
@@ -0,0 +1,43 @@
+From a02b1841d962977869e02fff684931b53c8d4232 Mon Sep 17 00:00:00 2001
+From: Yajun Deng <yajun.deng@linux.dev>
+Date: Wed, 3 Aug 2022 14:24:30 +0800
+Subject: [PATCH 314/323] locking/rtmutex: switch to EXPORT_SYMBOL() for
+ ww_mutex_lock{,_interruptible}()
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+We can use EXPORT_SYMBOL() instead of EXPORT_SYMBOL_GPL() in
+ww_mutex_lock_interruptible() and ww_mutex_lock(). That match
+ww_mutex_unlock() well. And also good for 3rd kernel modules.
+
+Link: https://lore.kernel.org/r/20220803062430.1307312-1-yajun.deng@linux.dev
+Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ kernel/locking/rtmutex.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index 31b374d36d04..b110fc57f733 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -2513,7 +2513,7 @@ ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+ 
+ 	return ret;
+ }
+-EXPORT_SYMBOL_GPL(ww_mutex_lock_interruptible);
++EXPORT_SYMBOL(ww_mutex_lock_interruptible);
+ 
+ int __sched
+ ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+@@ -2533,7 +2533,7 @@ ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+ 
+ 	return ret;
+ }
+-EXPORT_SYMBOL_GPL(ww_mutex_lock);
++EXPORT_SYMBOL(ww_mutex_lock);
+ 
+ void __sched ww_mutex_unlock(struct ww_mutex *lock)
+ {
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0315-ftrace-Fix-improper-usage-of-__trace_stack-function.patch b/debian/patches-rt/0315-ftrace-Fix-improper-usage-of-__trace_stack-function.patch
new file mode 100644
index 000000000..9d6f96753
--- /dev/null
+++ b/debian/patches-rt/0315-ftrace-Fix-improper-usage-of-__trace_stack-function.patch
@@ -0,0 +1,50 @@
+From 54eb98b6f77e491259ac08a1172d36fd6ccf5284 Mon Sep 17 00:00:00 2001
+From: Anand Je Saipureddy <s.anandje1@gmail.com>
+Date: Sat, 23 Jul 2022 12:19:43 +0530
+Subject: [PATCH 315/323] ftrace: Fix improper usage of __trace_stack()
+ function.
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+In kernel/trace/trace_events_trigger.c --> stacktrace_trigger() -->
+__trace_stack() is not defined as per the function definition.
+
+With commit edbaaa13a660
+("tracing: Merge irqflags + preemt counter, add RT bits")
+the irqflags(flags) and preemption counter(preempt_count()) are
+now should be evaluated early by tracing_gen_ctx().
+
+This patch replaces the irqflags and preemption counter
+with tracing_gen_ctx().
+
+Fixes: 5e8446e3820c ("tracing: Dump stacktrace trigger to the corresponding instance")
+Link: https://lore.kernel.org/r/20220723064943.16532-1-s.anandje1@gmail.com
+Signed-off-by: Anand Je Saipureddy <s.anandje1@gmail.com>
+Reviewed-by: Corey Minyard <cminyard@mvista.com>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ kernel/trace/trace_events_trigger.c | 8 +++-----
+ 1 file changed, 3 insertions(+), 5 deletions(-)
+
+diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
+index 75fef9fcfd0f..3c6229f16e81 100644
+--- a/kernel/trace/trace_events_trigger.c
++++ b/kernel/trace/trace_events_trigger.c
+@@ -1220,12 +1220,10 @@ stacktrace_trigger(struct event_trigger_data *data, void *rec,
+ 		   struct ring_buffer_event *event)
+ {
+ 	struct trace_event_file *file = data->private_data;
+-	unsigned long flags;
+ 
+-	if (file) {
+-		local_save_flags(flags);
+-		__trace_stack(file->tr, STACK_SKIP, preempt_count());
+-	} else
++	if (file)
++		__trace_stack(file->tr, tracing_gen_ctx(), STACK_SKIP);
++	else
+ 		trace_dump_stack(STACK_SKIP);
+ }
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0316-rt-arm64-make-_TIF_WORK_MASK-bits-contiguous.patch b/debian/patches-rt/0316-rt-arm64-make-_TIF_WORK_MASK-bits-contiguous.patch
new file mode 100644
index 000000000..38664d0ff
--- /dev/null
+++ b/debian/patches-rt/0316-rt-arm64-make-_TIF_WORK_MASK-bits-contiguous.patch
@@ -0,0 +1,57 @@
+From 599ec4565144185541405febb71e81cf36cad908 Mon Sep 17 00:00:00 2001
+From: Salvatore Bonaccorso <carnil@debian.org>
+Date: Fri, 20 Jan 2023 19:23:03 +0100
+Subject: [PATCH 316/323] rt: arm64: make _TIF_WORK_MASK bits contiguous
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+As same as in commit 870d16757ba8 ("arm64: make _TIF_WORK_MASK bits
+contiguous") in mainline, we need to make the bits of _TIF_WORK_MASK to
+be contiguous in order to use this as an immediate argument to an AND
+instruction in entry.S.
+
+We shuffle these bits down-by-one keeping the existing contiguity after
+inserting TIF_NEED_RESCHED_LAZY in the preempt-rt patch series.
+
+Otherwise, omitting this change will result in a build failure as below:
+
+    arch/arm64/kernel/entry.S: Assembler messages:
+    arch/arm64/kernel/entry.S:763: Error: immediate out of range at operand 3 -- `and x2,x19,#((1<<1)|(1<<0)|(1<<2)|(1<<3)|(1<<4)|(1<<5)|(1<<6)|(1<<13)|(1<<7))'
+
+Reported-by: Vignesh Raghavendra <vigneshr@ti.com>
+Reported-by: Pavel Machek <pavel@denx.de>
+Cc: Mark Rutland <mark.rutland@arm.com>
+Cc: Catalin Marinas <catalin.marinas@arm.com>
+Cc: Will Deacon <will@kernel.org>
+Link: https://lore.kernel.org/lkml/40de655e-26f3-aa7b-f1ec-6877396a9f1e@ti.com/
+Signed-off-by: Salvatore Bonaccorso <carnil@debian.org>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ arch/arm64/include/asm/thread_info.h | 12 ++++++------
+ 1 file changed, 6 insertions(+), 6 deletions(-)
+
+diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
+index 6eb36a2126e8..2afd9ceb66c9 100644
+--- a/arch/arm64/include/asm/thread_info.h
++++ b/arch/arm64/include/asm/thread_info.h
+@@ -70,12 +70,12 @@ void arch_release_task_struct(struct task_struct *tsk);
+ #define TIF_FSCHECK		5	/* Check FS is USER_DS on return */
+ #define TIF_MTE_ASYNC_FAULT	6	/* MTE Asynchronous Tag Check Fault */
+ #define TIF_NOTIFY_SIGNAL	7	/* signal notifications exist */
+-#define TIF_SYSCALL_TRACE	8	/* syscall trace active */
+-#define TIF_SYSCALL_AUDIT	9	/* syscall auditing */
+-#define TIF_SYSCALL_TRACEPOINT	10	/* syscall tracepoint for ftrace */
+-#define TIF_SECCOMP		11	/* syscall secure computing */
+-#define TIF_SYSCALL_EMU		12	/* syscall emulation active */
+-#define TIF_NEED_RESCHED_LAZY	13
++#define TIF_NEED_RESCHED_LAZY	8
++#define TIF_SYSCALL_TRACE	9	/* syscall trace active */
++#define TIF_SYSCALL_AUDIT	10	/* syscall auditing */
++#define TIF_SYSCALL_TRACEPOINT	11	/* syscall tracepoint for ftrace */
++#define TIF_SECCOMP		12	/* syscall secure computing */
++#define TIF_SYSCALL_EMU		13	/* syscall emulation active */
+ #define TIF_MEMDIE		18	/* is terminating due to OOM killer */
+ #define TIF_FREEZE		19
+ #define TIF_RESTORE_SIGMASK	20
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0317-printk-ignore-consoles-without-write-callback.patch b/debian/patches-rt/0317-printk-ignore-consoles-without-write-callback.patch
new file mode 100644
index 000000000..a0942062a
--- /dev/null
+++ b/debian/patches-rt/0317-printk-ignore-consoles-without-write-callback.patch
@@ -0,0 +1,50 @@
+From 7efd125170f344b124a00390d8d7b714beac1698 Mon Sep 17 00:00:00 2001
+From: John Ogness <john.ogness@linutronix.de>
+Date: Fri, 17 Feb 2023 09:53:44 +0106
+Subject: [PATCH 317/323] printk: ignore consoles without write() callback
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The ttynull driver does not provide an implementation for the write()
+callback. This leads to a NULL pointer dereference in the related
+printing kthread, which assumes it can call that callback.
+
+Do not create kthreads for consoles that do not implement the write()
+callback. Also, for pr_flush(), ignore consoles that do not implement
+write() or write_atomic(), since there is no way those consoles can
+flush their output.
+
+Link: https://lore.kernel.org/lkml/1831554214.546921.1676479103702.JavaMail.zimbra@hale.at
+Reported-by: Michael Thalmeier <michael.thalmeier@hale.at>
+Signed-off-by: John Ogness <john.ogness@linutronix.de>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ kernel/printk/printk.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
+index d2205872304d..64747c72fbea 100644
+--- a/kernel/printk/printk.c
++++ b/kernel/printk/printk.c
+@@ -2267,6 +2267,10 @@ static int printk_kthread_func(void *data)
+ /* Must be called within console_lock(). */
+ static void start_printk_kthread(struct console *con)
+ {
++	/* No need to start a printing thread if the console cannot print. */
++	if (!con->write)
++		return;
++
+ 	con->thread = kthread_run(printk_kthread_func, con,
+ 				  "pr/%s%d", con->name, con->index);
+ 	if (IS_ERR(con->thread)) {
+@@ -3566,6 +3570,8 @@ bool pr_flush(int timeout_ms, bool reset_on_progress)
+ 		for_each_console(con) {
+ 			if (!(con->flags & CON_ENABLED))
+ 				continue;
++			if (!con->write && !con->write_atomic)
++				continue;
+ 			printk_seq = atomic64_read(&con->printk_seq);
+ 			if (printk_seq < seq)
+ 				diff += seq - printk_seq;
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0318-kernel-fork-set-wake_q_sleeper.next-NULL-again-in-du.patch b/debian/patches-rt/0318-kernel-fork-set-wake_q_sleeper.next-NULL-again-in-du.patch
new file mode 100644
index 000000000..21e81955f
--- /dev/null
+++ b/debian/patches-rt/0318-kernel-fork-set-wake_q_sleeper.next-NULL-again-in-du.patch
@@ -0,0 +1,61 @@
+From de3bf8893c5067f2c4d7ef3c57144c134e30ad7f Mon Sep 17 00:00:00 2001
+From: Steffen Dirkwinkel <s.dirkwinkel@beckhoff.com>
+Date: Mon, 20 Mar 2023 09:03:47 +0100
+Subject: [PATCH 318/323] kernel: fork: set wake_q_sleeper.next=NULL again in
+ dup_task_struct
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Without this we get system hangs within a couple of days.
+It's also reproducible in minutes with "stress-ng --exec 20".
+
+Example error in dmesg:
+INFO: task stress-ng:163916 blocked for more than 120 seconds.
+      Not tainted 5.10.168-rt83 #2
+"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
+task:stress-ng       state:D stack:    0 pid:163916 ppid: 72833 flags:0x00004000
+Call Trace:
+ __schedule+0x2bd/0x940
+ preempt_schedule_lock+0x23/0x50
+ rt_spin_lock_slowlock_locked+0x117/0x2c0
+ rt_spin_lock_slowlock+0x51/0x80
+ rt_write_lock+0x1e/0x1c0
+ do_exit+0x3ac/0xb20
+ do_group_exit+0x39/0xb0
+ get_signal+0x145/0x960
+ ? wake_up_new_task+0x21f/0x3c0
+ arch_do_signal_or_restart+0xf1/0x830
+ ? __x64_sys_futex+0x146/0x1d0
+ exit_to_user_mode_prepare+0x116/0x1a0
+ syscall_exit_to_user_mode+0x28/0x190
+ entry_SYSCALL_64_after_hwframe+0x61/0xc6
+RIP: 0033:0x7f738d9074a7
+RSP: 002b:00007ffdafda3cb0 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
+RAX: fffffffffffffe00 RBX: 00000000000000ca RCX: 00007f738d9074a7
+RDX: 0000000000028051 RSI: 0000000000000000 RDI: 00007f738be949d0
+RBP: 00007ffdafda3d88 R08: 0000000000000000 R09: 00007f738be94700
+R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000028051
+R13: 00007f738be949d0 R14: 00007ffdafda51e0 R15: 00007f738be94700
+
+Fixes: 1ba44dcf789d ("Merge tag 'v5.10.162' into v5.10-rt")
+Acked-by: Joe Korty <joe.korty@concurrent-rt.com>
+Signed-off-by: Steffen Dirkwinkel <s.dirkwinkel@beckhoff.com>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ kernel/fork.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/kernel/fork.c b/kernel/fork.c
+index dfefb6e7e082..5dc7abedf08f 100644
+--- a/kernel/fork.c
++++ b/kernel/fork.c
+@@ -960,6 +960,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
+ 	tsk->splice_pipe = NULL;
+ 	tsk->task_frag.page = NULL;
+ 	tsk->wake_q.next = NULL;
++	tsk->wake_q_sleeper.next = NULL;
+ 	tsk->pf_io_worker = NULL;
+ 
+ 	account_kernel_stack(tsk, 1);
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0319-Revert-mm-page_alloc-fix-potential-deadlock-on-zonel.patch b/debian/patches-rt/0319-Revert-mm-page_alloc-fix-potential-deadlock-on-zonel.patch
new file mode 100644
index 000000000..1872b2fc8
--- /dev/null
+++ b/debian/patches-rt/0319-Revert-mm-page_alloc-fix-potential-deadlock-on-zonel.patch
@@ -0,0 +1,63 @@
+From 59fc9fa59a8a6eaa1456e7a3035b10152a9e6d94 Mon Sep 17 00:00:00 2001
+From: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
+Date: Thu, 8 Jun 2023 19:47:25 -0300
+Subject: [PATCH 319/323] Revert "mm/page_alloc: fix potential deadlock on
+ zonelist_update_seqseqlock"
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+This reverts commit a992c387b41186ab968fd176ca26b432b05c53ec.
+
+The support for deferred printing was removed in v5.10-rc1-rt1 by commit
+9153e3c5cb0c9 ("printk: remove deferred printing") because:
+
+    Since printing occurs either atomically or from the printing
+    kthread, there is no need for any deferring or tracking possible
+    recursion paths. Remove all printk context tracking.
+
+Also, disabling interrupts in __build_all_zonelists() should produce warnings
+once that code path is hit.
+
+Fixes: a992c387b4118 ("mm/page_alloc: fix potential deadlock on zonelist_update_seq seqlock")
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ mm/page_alloc.c | 16 ----------------
+ 1 file changed, 16 deletions(-)
+
+diff --git a/mm/page_alloc.c b/mm/page_alloc.c
+index c5eb7d6844ae..39d1782b398f 100644
+--- a/mm/page_alloc.c
++++ b/mm/page_alloc.c
+@@ -6043,21 +6043,7 @@ static void __build_all_zonelists(void *data)
+ 	int nid;
+ 	int __maybe_unused cpu;
+ 	pg_data_t *self = data;
+-	unsigned long flags;
+ 
+-	/*
+-	 * Explicitly disable this CPU's interrupts before taking seqlock
+-	 * to prevent any IRQ handler from calling into the page allocator
+-	 * (e.g. GFP_ATOMIC) that could hit zonelist_iter_begin and livelock.
+-	 */
+-	local_irq_save(flags);
+-	/*
+-	 * Explicitly disable this CPU's synchronous printk() before taking
+-	 * seqlock to prevent any printk() from trying to hold port->lock, for
+-	 * tty_insert_flip_string_and_push_buffer() on other CPU might be
+-	 * calling kmalloc(GFP_ATOMIC | __GFP_NOWARN) with port->lock held.
+-	 */
+-	printk_deferred_enter();
+ 	write_seqlock(&zonelist_update_seq);
+ 
+ #ifdef CONFIG_NUMA
+@@ -6092,8 +6078,6 @@ static void __build_all_zonelists(void *data)
+ 	}
+ 
+ 	write_sequnlock(&zonelist_update_seq);
+-	printk_deferred_exit();
+-	local_irq_restore(flags);
+ }
+ 
+ static noinline void __init
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0320-Revert-printk-declare-printk_deferred_-enter-safe-in.patch b/debian/patches-rt/0320-Revert-printk-declare-printk_deferred_-enter-safe-in.patch
new file mode 100644
index 000000000..b52e5aa42
--- /dev/null
+++ b/debian/patches-rt/0320-Revert-printk-declare-printk_deferred_-enter-safe-in.patch
@@ -0,0 +1,53 @@
+From f59d43768ad6d22235cbc9ec14f6307867aefefe Mon Sep 17 00:00:00 2001
+From: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
+Date: Thu, 8 Jun 2023 19:47:25 -0300
+Subject: [PATCH 320/323] Revert "printk: declare
+ printk_deferred_{enter,safe}() in include/linux/printk.h"
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+This reverts commit 32232bcd4e5300e678718d5c29da4dfa07ade01e.
+
+The support for deferred printing was removed in v5.10-rc1-rt1 by commit
+9153e3c5cb0c9 ("printk: remove deferred printing") because:
+
+    Since printing occurs either atomically or from the printing
+    kthread, there is no need for any deferring or tracking possible
+    recursion paths. Remove all printk context tracking.
+
+Fixes: 32232bcd4e530 ("printk: declare printk_deferred_{enter,safe}() in include/linux/printk.h")
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ include/linux/printk.h | 19 -------------------
+ 1 file changed, 19 deletions(-)
+
+diff --git a/include/linux/printk.h b/include/linux/printk.h
+index 83c7734e9802..7e4352467d83 100644
+--- a/include/linux/printk.h
++++ b/include/linux/printk.h
+@@ -609,23 +609,4 @@ static inline void print_hex_dump_debug(const char *prefix_str, int prefix_type,
+ #define print_hex_dump_bytes(prefix_str, prefix_type, buf, len)	\
+ 	print_hex_dump_debug(prefix_str, prefix_type, 16, 1, buf, len, true)
+ 
+-#ifdef CONFIG_PRINTK
+-extern void __printk_safe_enter(void);
+-extern void __printk_safe_exit(void);
+-/*
+- * The printk_deferred_enter/exit macros are available only as a hack for
+- * some code paths that need to defer all printk console printing. Interrupts
+- * must be disabled for the deferred duration.
+- */
+-#define printk_deferred_enter __printk_safe_enter
+-#define printk_deferred_exit __printk_safe_exit
+-#else
+-static inline void printk_deferred_enter(void)
+-{
+-}
+-static inline void printk_deferred_exit(void)
+-{
+-}
+-#endif
+-
+ #endif
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0321-arm64-signal-Use-ARCH_RT_DELAYS_SIGNAL_SEND.patch b/debian/patches-rt/0321-arm64-signal-Use-ARCH_RT_DELAYS_SIGNAL_SEND.patch
new file mode 100644
index 000000000..0c86c88b7
--- /dev/null
+++ b/debian/patches-rt/0321-arm64-signal-Use-ARCH_RT_DELAYS_SIGNAL_SEND.patch
@@ -0,0 +1,89 @@
+From 2074b2bfdbed96348cbb99a1a3920fa7a9e4df46 Mon Sep 17 00:00:00 2001
+From: Wang Yong <wang.yong12@zte.com.cn>
+Date: Tue, 12 Sep 2023 15:14:28 +0800
+Subject: [PATCH 321/323] arm64: signal: Use ARCH_RT_DELAYS_SIGNAL_SEND
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+The ltp test prompts the following bug information under the 5.10 kernel:
+BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:969
+in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 796, name: cat
+Preemption disabled at:
+[<ffffffe40f433980>] do_debug_exception+0x60/0x180
+CPU: 3 PID: 796 Comm: cat Not tainted 5.10.59-rt52-KERNEL_VERSION #38
+Hardware name: linux,dummy-virt (DT)
+Call trace:
+ dump_backtrace+0x0/0x198
+ show_stack+0x20/0x30
+ dump_stack+0xf0/0x13c
+ ___might_sleep+0x140/0x178
+ rt_spin_lock+0x30/0x90
+ force_sig_info_to_task+0x30/0xe0
+ force_sig_fault_to_task+0x54/0x78
+ force_sig_fault+0x1c/0x28
+ arm64_force_sig_fault+0x48/0x78
+ send_user_sigtrap+0x4c/0x80
+ brk_handler+0x3c/0x68
+ do_debug_exception+0xac/0x180
+ el0_dbg+0x34/0x58
+ el0_sync_handler+0x50/0xb8
+ el0_sync+0x180/0x1c0
+
+It has been fixed by
+0c34700de5e7 ("arm64: signal: Use ARCH_RT_DELAYS_SIGNAL_SEND.") in
+higher versions of the kernel. This patch needs to be compatible with 5.10.
+5.10 kernel does not have signal.h file, so adding signal.h file to
+define ARCH_RT_DELAYS_SIGNAL_SEND.
+
+Link: https://lore.kernel.org/r/202309121514283793475@zte.com.cn
+Signed-off-by: Wang Yong <wang.yong12@zte.com.cn>
+Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn>
+Cc: Yang Yang <yang.yang29@zte.com.cn>
+Cc: Xiaokai Ran <ran.xiaokai@zte.com.cn>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ arch/arm64/include/asm/signal.h | 12 ++++++++++++
+ arch/arm64/kernel/signal.c      |  9 +++++++++
+ 2 files changed, 21 insertions(+)
+ create mode 100644 arch/arm64/include/asm/signal.h
+
+diff --git a/arch/arm64/include/asm/signal.h b/arch/arm64/include/asm/signal.h
+new file mode 100644
+index 000000000000..0fb418cf4c17
+--- /dev/null
++++ b/arch/arm64/include/asm/signal.h
+@@ -0,0 +1,12 @@
++/* SPDX-License-Identifier: GPL-2.0 */
++#ifndef __ARM64_ASM_SIGNAL_H
++#define __ARM64_ASM_SIGNAL_H
++
++#include <uapi/asm/signal.h>
++#include <uapi/asm/siginfo.h>
++
++#if defined(CONFIG_PREEMPT_RT)
++#define ARCH_RT_DELAYS_SIGNAL_SEND
++#endif
++
++#endif
+diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
+index 94eed0dc3afc..5b08f55ec85d 100644
+--- a/arch/arm64/kernel/signal.c
++++ b/arch/arm64/kernel/signal.c
+@@ -929,6 +929,15 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
+ 		} else {
+ 			local_daif_restore(DAIF_PROCCTX);
+ 
++#ifdef ARCH_RT_DELAYS_SIGNAL_SEND
++			if (unlikely(current->forced_info.si_signo)) {
++				struct task_struct *t = current;
++
++				force_sig_info(&t->forced_info);
++				t->forced_info.si_signo = 0;
++			}
++#endif
++
+ 			if (thread_flags & _TIF_UPROBE)
+ 				uprobe_notify_resume(regs);
+ 
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0322-rt-mm-page_alloc-backport-missing-bits-from-__build_.patch b/debian/patches-rt/0322-rt-mm-page_alloc-backport-missing-bits-from-__build_.patch
new file mode 100644
index 000000000..8c13d7c63
--- /dev/null
+++ b/debian/patches-rt/0322-rt-mm-page_alloc-backport-missing-bits-from-__build_.patch
@@ -0,0 +1,49 @@
+From dbe86f5017c79c8abb6f42a6f0f1ad8d97dbae46 Mon Sep 17 00:00:00 2001
+From: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
+Date: Wed, 20 Dec 2023 10:20:48 -0300
+Subject: [PATCH 322/323] rt: mm/page_alloc: backport missing bits from
+ __build_all_zonelists() fix
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+A while ago upstream landed commit a2ebb51575828 ("mm/page_alloc: use
+write_seqlock_irqsave() instead write_seqlock() + local_irq_save().")
+to fix a problem that had already been worked on v5.10-rt via commit
+7bdd3bd5143a4 ("Revert "mm/page_alloc: fix potential deadlock on
+zonelist_update_seqseqlock""). Sebastian pointed out it was important
+to backport the missing elements of a2ebb51575828 for code consistency.
+
+Fixes: 7bdd3bd5143a4 ("Revert "mm/page_alloc: fix potential deadlock on zonelist_update_seqseqlock"")
+Cc: stable-rt@vger.kernel.org
+Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ mm/page_alloc.c | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+diff --git a/mm/page_alloc.c b/mm/page_alloc.c
+index 39d1782b398f..cd1e8d0b2269 100644
+--- a/mm/page_alloc.c
++++ b/mm/page_alloc.c
+@@ -6043,8 +6043,9 @@ static void __build_all_zonelists(void *data)
+ 	int nid;
+ 	int __maybe_unused cpu;
+ 	pg_data_t *self = data;
++	unsigned long flags;
+ 
+-	write_seqlock(&zonelist_update_seq);
++	write_seqlock_irqsave(&zonelist_update_seq, flags);
+ 
+ #ifdef CONFIG_NUMA
+ 	memset(node_load, 0, sizeof(node_load));
+@@ -6077,7 +6078,7 @@ static void __build_all_zonelists(void *data)
+ #endif
+ 	}
+ 
+-	write_sequnlock(&zonelist_update_seq);
++	write_sequnlock_irqrestore(&zonelist_update_seq, flags);
+ }
+ 
+ static noinline void __init
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/0323-Linux-5.10.204-rt100-REBASE.patch b/debian/patches-rt/0323-Linux-5.10.204-rt100-REBASE.patch
new file mode 100644
index 000000000..3173940fe
--- /dev/null
+++ b/debian/patches-rt/0323-Linux-5.10.204-rt100-REBASE.patch
@@ -0,0 +1,21 @@
+From 0a50987f60b76f392050410e35609fb4361dcca7 Mon Sep 17 00:00:00 2001
+From: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
+Date: Fri, 22 Dec 2023 17:30:57 -0300
+Subject: [PATCH 323/323] Linux 5.10.204-rt100 REBASE
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
+---
+ localversion-rt | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/localversion-rt b/localversion-rt
+index 21988f9ad53f..79d3e2b9f550 100644
+--- a/localversion-rt
++++ b/localversion-rt
+@@ -1 +1 @@
+--rt34
++-rt100
+-- 
+2.43.0
+
diff --git a/debian/patches-rt/series b/debian/patches-rt/series
new file mode 100644
index 000000000..70c05ce6b
--- /dev/null
+++ b/debian/patches-rt/series
@@ -0,0 +1,323 @@
+0001-z3fold-remove-preempt-disabled-sections-for-RT.patch
+0002-stop_machine-Add-function-and-caller-debug-info.patch
+0003-sched-Fix-balance_callback.patch
+0004-sched-hotplug-Ensure-only-per-cpu-kthreads-run-durin.patch
+0005-sched-core-Wait-for-tasks-being-pushed-away-on-hotpl.patch
+0006-workqueue-Manually-break-affinity-on-hotplug.patch
+0007-sched-hotplug-Consolidate-task-migration-on-CPU-unpl.patch
+0008-sched-Fix-hotplug-vs-CPU-bandwidth-control.patch
+0009-sched-Massage-set_cpus_allowed.patch
+0010-sched-Add-migrate_disable.patch
+0011-sched-Fix-migrate_disable-vs-set_cpus_allowed_ptr.patch
+0012-sched-core-Make-migrate-disable-and-CPU-hotplug-coop.patch
+0013-sched-rt-Use-cpumask_any-_distribute.patch
+0014-sched-rt-Use-the-full-cpumask-for-balancing.patch
+0015-sched-lockdep-Annotate-pi_lock-recursion.patch
+0016-sched-Fix-migrate_disable-vs-rt-dl-balancing.patch
+0017-sched-proc-Print-accurate-cpumask-vs-migrate_disable.patch
+0018-sched-Add-migrate_disable-tracepoints.patch
+0019-sched-Deny-self-issued-__set_cpus_allowed_ptr-when-m.patch
+0020-sched-Comment-affine_move_task.patch
+0021-sched-Unlock-the-rq-in-affine_move_task-error-path.patch
+0022-sched-Fix-migration_cpu_stop-WARN.patch
+0023-sched-core-Add-missing-completion-for-affine_move_ta.patch
+0024-mm-highmem-Un-EXPORT-__kmap_atomic_idx.patch
+0025-highmem-Remove-unused-functions.patch
+0026-fs-Remove-asm-kmap_types.h-includes.patch
+0027-sh-highmem-Remove-all-traces-of-unused-cruft.patch
+0028-asm-generic-Provide-kmap_size.h.patch
+0029-highmem-Provide-generic-variant-of-kmap_atomic.patch
+0030-highmem-Make-DEBUG_HIGHMEM-functional.patch
+0031-x86-mm-highmem-Use-generic-kmap-atomic-implementatio.patch
+0032-arc-mm-highmem-Use-generic-kmap-atomic-implementatio.patch
+0033-ARM-highmem-Switch-to-generic-kmap-atomic.patch
+0034-csky-mm-highmem-Switch-to-generic-kmap-atomic.patch
+0035-microblaze-mm-highmem-Switch-to-generic-kmap-atomic.patch
+0036-mips-mm-highmem-Switch-to-generic-kmap-atomic.patch
+0037-nds32-mm-highmem-Switch-to-generic-kmap-atomic.patch
+0038-powerpc-mm-highmem-Switch-to-generic-kmap-atomic.patch
+0039-sparc-mm-highmem-Switch-to-generic-kmap-atomic.patch
+0040-xtensa-mm-highmem-Switch-to-generic-kmap-atomic.patch
+0041-highmem-Get-rid-of-kmap_types.h.patch
+0042-mm-highmem-Remove-the-old-kmap_atomic-cruft.patch
+0043-io-mapping-Cleanup-atomic-iomap.patch
+0044-Documentation-io-mapping-Remove-outdated-blurb.patch
+0045-highmem-High-implementation-details-and-document-API.patch
+0046-sched-Make-migrate_disable-enable-independent-of-RT.patch
+0047-sched-highmem-Store-local-kmaps-in-task-struct.patch
+0048-mm-highmem-Provide-kmap_local.patch
+0049-io-mapping-Provide-iomap_local-variant.patch
+0050-x86-crashdump-32-Simplify-copy_oldmem_page.patch
+0051-mips-crashdump-Simplify-copy_oldmem_page.patch
+0052-ARM-mm-Replace-kmap_atomic_pfn.patch
+0053-highmem-Remove-kmap_atomic_pfn.patch
+0054-drm-ttm-Replace-kmap_atomic-usage.patch
+0055-drm-vmgfx-Replace-kmap_atomic.patch
+0056-highmem-Remove-kmap_atomic_prot.patch
+0057-drm-qxl-Replace-io_mapping_map_atomic_wc.patch
+0058-drm-nouveau-device-Replace-io_mapping_map_atomic_wc.patch
+0059-drm-i915-Replace-io_mapping_map_atomic_wc.patch
+0060-io-mapping-Remove-io_mapping_map_atomic_wc.patch
+0061-mm-highmem-Take-kmap_high_get-properly-into-account.patch
+0062-highmem-Don-t-disable-preemption-on-RT-in-kmap_atomi.patch
+0063-blk-mq-Don-t-complete-on-a-remote-CPU-in-force-threa.patch
+0064-blk-mq-Always-complete-remote-completions-requests-i.patch
+0065-blk-mq-Use-llist_head-for-blk_cpu_done.patch
+0066-lib-test_lockup-Minimum-fix-to-get-it-compiled-on-PR.patch
+0067-timers-Don-t-block-on-expiry_lock-for-TIMER_IRQSAFE.patch
+0068-kthread-Move-prio-affinite-change-into-the-newly-cre.patch
+0069-genirq-Move-prio-assignment-into-the-newly-created-t.patch
+0070-notifier-Make-atomic_notifiers-use-raw_spinlock.patch
+0071-rcu-Make-RCU_BOOST-default-on-CONFIG_PREEMPT_RT.patch
+0072-rcu-Unconditionally-use-rcuc-threads-on-PREEMPT_RT.patch
+0073-rcu-Enable-rcu_normal_after_boot-unconditionally-for.patch
+0074-doc-Update-RCU-s-requirements-page-about-the-PREEMPT.patch
+0075-doc-Use-CONFIG_PREEMPTION.patch
+0076-tracing-Merge-irqflags-preempt-counter.patch
+0077-tracing-Inline-tracing_gen_ctx_flags.patch
+0078-tracing-Use-in_serving_softirq-to-deduct-softirq-sta.patch
+0079-tracing-Remove-NULL-check-from-current-in-tracing_ge.patch
+0080-printk-inline-log_output-log_store-in-vprintk_store.patch
+0081-printk-remove-logbuf_lock-writer-protection-of-ringb.patch
+0082-printk-limit-second-loop-of-syslog_print_all.patch
+0083-printk-kmsg_dump-remove-unused-fields.patch
+0084-printk-refactor-kmsg_dump_get_buffer.patch
+0085-printk-consolidate-kmsg_dump_get_buffer-syslog_print.patch
+0086-printk-introduce-CONSOLE_LOG_MAX-for-improved-multi-.patch
+0087-printk-use-seqcount_latch-for-clear_seq.patch
+0088-printk-use-atomic64_t-for-devkmsg_user.seq.patch
+0089-printk-add-syslog_lock.patch
+0090-printk-introduce-a-kmsg_dump-iterator.patch
+0091-um-synchronize-kmsg_dumper.patch
+0092-printk-remove-logbuf_lock.patch
+0093-printk-kmsg_dump-remove-_nolock-variants.patch
+0094-printk-kmsg_dump-use-kmsg_dump_rewind.patch
+0095-printk-console-remove-unnecessary-safe-buffer-usage.patch
+0096-printk-track-limit-recursion.patch
+0097-printk-remove-safe-buffers.patch
+0098-printk-convert-syslog_lock-to-spin_lock.patch
+0099-console-add-write_atomic-interface.patch
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