Adding debian version 6.1.76-1.debian/6.1.76-1

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

1 files changed, 116 insertions, 0 deletions

diff --git a/debian/patches-rt/0014-tick-Fix-timer-storm-since-introduction-of-timersd.patch b/debian/patches-rt/0014-tick-Fix-timer-storm-since-introduction-of-timersd.patch
new file mode 100644
index 000000000..11eeed939
--- /dev/null
+++ b/debian/patches-rt/0014-tick-Fix-timer-storm-since-introduction-of-timersd.patch
@@ -0,0 +1,116 @@
+From ae3e63c4320c0c2d3865ba8ecff64a6d03948ce7 Mon Sep 17 00:00:00 2001
+From: Frederic Weisbecker <frederic@kernel.org>
+Date: Tue, 5 Apr 2022 03:07:52 +0200
+Subject: [PATCH 14/62] tick: Fix timer storm since introduction of timersd
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.1/older/patches-6.1.69-rt21.tar.xz
+
+If timers are pending while the tick is reprogrammed on nohz_mode, the
+next expiry is not armed to fire now, it is delayed one jiffy forward
+instead so as not to raise an inextinguishable timer storm with such
+scenario:
+
+1) IRQ triggers and queue a timer
+2) ksoftirqd() is woken up
+3) IRQ tail: timer is reprogrammed to fire now
+4) IRQ exit
+5) TIMER interrupt
+6) goto 3)
+
+...all that until we finally reach ksoftirqd.
+
+Unfortunately we are checking the wrong softirq vector bitmask since
+timersd kthread has split from ksoftirqd. Timers now have their own
+vector state field that must be checked separately. As a result, the
+old timer storm is back. This shows up early on boot with extremely long
+initcalls:
+
+	[  333.004807] initcall dquot_init+0x0/0x111 returned 0 after 323822879 usecs
+
+and the cause is uncovered with the right trace events showing just
+10 microseconds between ticks (~100 000 Hz):
+
+|swapper/-1 1dn.h111 60818582us : hrtimer_expire_entry: hrtimer=00000000e0ef0f6b function=tick_sched_timer now=60415486608
+|swapper/-1 1dn.h111 60818592us : hrtimer_expire_entry: hrtimer=00000000e0ef0f6b function=tick_sched_timer now=60415496082
+|swapper/-1 1dn.h111 60818601us : hrtimer_expire_entry: hrtimer=00000000e0ef0f6b function=tick_sched_timer now=60415505550
+
+Fix this by checking the right timer vector state from the nohz code.
+
+Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
+Cc: Mel Gorman <mgorman@suse.de>
+Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Cc: Thomas Gleixner <tglx@linutronix.de>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Link: https://lkml.kernel.org/r/20220405010752.1347437-2-frederic@kernel.org
+---
+ include/linux/interrupt.h | 12 ++++++++++++
+ kernel/softirq.c          |  7 +------
+ kernel/time/tick-sched.c  |  2 +-
+ 3 files changed, 14 insertions(+), 7 deletions(-)
+
+diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
+index f459b0f27c94..a5091ac97fc6 100644
+--- a/include/linux/interrupt.h
++++ b/include/linux/interrupt.h
+@@ -611,9 +611,16 @@ extern void raise_softirq(unsigned int nr);
+ 
+ #ifdef CONFIG_PREEMPT_RT
+ DECLARE_PER_CPU(struct task_struct *, timersd);
++DECLARE_PER_CPU(unsigned long, pending_timer_softirq);
++
+ extern void raise_timer_softirq(void);
+ extern void raise_hrtimer_softirq(void);
+ 
++static inline unsigned int local_pending_timers(void)
++{
++        return __this_cpu_read(pending_timer_softirq);
++}
++
+ #else
+ static inline void raise_timer_softirq(void)
+ {
+@@ -624,6 +631,11 @@ static inline void raise_hrtimer_softirq(void)
+ {
+ 	raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+ }
++
++static inline unsigned int local_pending_timers(void)
++{
++        return local_softirq_pending();
++}
+ #endif
+ 
+ DECLARE_PER_CPU(struct task_struct *, ksoftirqd);
+diff --git a/kernel/softirq.c b/kernel/softirq.c
+index 1892af494cdd..ab1fe34326ba 100644
+--- a/kernel/softirq.c
++++ b/kernel/softirq.c
+@@ -639,12 +639,7 @@ static inline void tick_irq_exit(void)
+ 
+ #ifdef CONFIG_PREEMPT_RT
+ DEFINE_PER_CPU(struct task_struct *, timersd);
+-static DEFINE_PER_CPU(unsigned long, pending_timer_softirq);
+-
+-static unsigned int local_pending_timers(void)
+-{
+-        return __this_cpu_read(pending_timer_softirq);
+-}
++DEFINE_PER_CPU(unsigned long, pending_timer_softirq);
+ 
+ static void wake_timersd(void)
+ {
+diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
+index 798e1841d286..b52e1861b913 100644
+--- a/kernel/time/tick-sched.c
++++ b/kernel/time/tick-sched.c
+@@ -800,7 +800,7 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now)
+ 
+ static inline bool local_timer_softirq_pending(void)
+ {
+-	return local_softirq_pending() & BIT(TIMER_SOFTIRQ);
++	return local_pending_timers() & BIT(TIMER_SOFTIRQ);
+ }
+ 
+ static ktime_t tick_nohz_next_event(struct tick_sched *ts, int cpu)
+-- 
+2.43.0
+