diff options
Diffstat (limited to 'debian/patches-rt/0154-rtmutex-annotate-sleeping-lock-context.patch')
| -rw-r--r-- | debian/patches-rt/0154-rtmutex-annotate-sleeping-lock-context.patch | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/debian/patches-rt/0154-rtmutex-annotate-sleeping-lock-context.patch b/debian/patches-rt/0154-rtmutex-annotate-sleeping-lock-context.patch new file mode 100644 index 000000000..916d8d802 --- /dev/null +++ b/debian/patches-rt/0154-rtmutex-annotate-sleeping-lock-context.patch @@ -0,0 +1,308 @@ +From ac520c8f628b0eeff2af71b77289199262510960 Mon Sep 17 00:00:00 2001 +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Thu, 21 Sep 2017 14:25:13 +0200 +Subject: [PATCH 154/347] rtmutex: annotate sleeping lock context +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +The RCU code complains on schedule() within a rcu_readlock() section. +The valid scenario on -RT is if a sleeping is held. In order to suppress +the warning the mirgrate_disable counter was used to identify the +invocation of schedule() due to lock contention. + +Grygorii Strashko report that during CPU hotplug we might see the +warning via + rt_spin_lock() -> migrate_disable() -> pin_current_cpu() -> __read_rt_lock() + +because the counter is not yet set. +It is also possible to trigger the warning from cpu_chill() +(seen on a kblockd_mod_delayed_work_on() caller). + +To address this RCU warning I annotate the sleeping lock context. The +counter is incremented before migrate_disable() so the warning Grygorii +should not trigger anymore. Additionally I use that counter in +cpu_chill() to avoid the RCU warning from there. + +Reported-by: Grygorii Strashko <grygorii.strashko@ti.com> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + include/linux/preempt.h | 9 ++++++++ + include/linux/sched.h | 26 ++++++++++++++++++++++ + kernel/locking/rtmutex.c | 12 ++++++++-- + kernel/locking/rwlock-rt.c | 18 +++++++++++---- + kernel/rcu/tree_plugin.h | 6 ++++- + kernel/sched/core.c | 45 ++++++++++++++++++++++++++++++++++++++ + 6 files changed, 109 insertions(+), 7 deletions(-) + +diff --git a/include/linux/preempt.h b/include/linux/preempt.h +index 27c3176d88d2..9eafc34898b4 100644 +--- a/include/linux/preempt.h ++++ b/include/linux/preempt.h +@@ -211,6 +211,15 @@ extern void migrate_enable(void); + + int __migrate_disabled(struct task_struct *p); + ++#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE) ++ ++extern void migrate_disable(void); ++extern void migrate_enable(void); ++static inline int __migrate_disabled(struct task_struct *p) ++{ ++ return 0; ++} ++ + #else + #define migrate_disable() barrier() + #define migrate_enable() barrier() +diff --git a/include/linux/sched.h b/include/linux/sched.h +index 5374ade34b87..4f8fcba23c1d 100644 +--- a/include/linux/sched.h ++++ b/include/linux/sched.h +@@ -673,6 +673,15 @@ struct task_struct { + # ifdef CONFIG_SCHED_DEBUG + int migrate_disable_atomic; + # endif ++ ++#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE) ++ int migrate_disable; ++# ifdef CONFIG_SCHED_DEBUG ++ int migrate_disable_atomic; ++# endif ++#endif ++#ifdef CONFIG_PREEMPT_RT_FULL ++ int sleeping_lock; + #endif + + #ifdef CONFIG_PREEMPT_RCU +@@ -1810,6 +1819,23 @@ static __always_inline bool need_resched(void) + return unlikely(tif_need_resched()); + } + ++#ifdef CONFIG_PREEMPT_RT_FULL ++static inline void sleeping_lock_inc(void) ++{ ++ current->sleeping_lock++; ++} ++ ++static inline void sleeping_lock_dec(void) ++{ ++ current->sleeping_lock--; ++} ++ ++#else ++ ++static inline void sleeping_lock_inc(void) { } ++static inline void sleeping_lock_dec(void) { } ++#endif ++ + /* + * Wrappers for p->thread_info->cpu access. No-op on UP. + */ +diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c +index 11bcae2184c4..ded2296f848a 100644 +--- a/kernel/locking/rtmutex.c ++++ b/kernel/locking/rtmutex.c +@@ -1141,6 +1141,7 @@ void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock) + + void __lockfunc rt_spin_lock(spinlock_t *lock) + { ++ sleeping_lock_inc(); + migrate_disable(); + spin_acquire(&lock->dep_map, 0, 0, _RET_IP_); + rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock); +@@ -1155,6 +1156,7 @@ void __lockfunc __rt_spin_lock(struct rt_mutex *lock) + #ifdef CONFIG_DEBUG_LOCK_ALLOC + void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass) + { ++ sleeping_lock_inc(); + migrate_disable(); + spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_); + rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock); +@@ -1168,6 +1170,7 @@ void __lockfunc rt_spin_unlock(spinlock_t *lock) + spin_release(&lock->dep_map, 1, _RET_IP_); + rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock); + migrate_enable(); ++ sleeping_lock_dec(); + } + EXPORT_SYMBOL(rt_spin_unlock); + +@@ -1193,12 +1196,15 @@ int __lockfunc rt_spin_trylock(spinlock_t *lock) + { + int ret; + ++ sleeping_lock_inc(); + migrate_disable(); + ret = __rt_mutex_trylock(&lock->lock); +- if (ret) ++ if (ret) { + spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); +- else ++ } else { + migrate_enable(); ++ sleeping_lock_dec(); ++ } + return ret; + } + EXPORT_SYMBOL(rt_spin_trylock); +@@ -1210,6 +1216,7 @@ int __lockfunc rt_spin_trylock_bh(spinlock_t *lock) + local_bh_disable(); + ret = __rt_mutex_trylock(&lock->lock); + if (ret) { ++ sleeping_lock_inc(); + migrate_disable(); + spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); + } else +@@ -1225,6 +1232,7 @@ int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags) + *flags = 0; + ret = __rt_mutex_trylock(&lock->lock); + if (ret) { ++ sleeping_lock_inc(); + migrate_disable(); + spin_acquire(&lock->dep_map, 0, 1, _RET_IP_); + } +diff --git a/kernel/locking/rwlock-rt.c b/kernel/locking/rwlock-rt.c +index 8f90afe111ce..c3b91205161c 100644 +--- a/kernel/locking/rwlock-rt.c ++++ b/kernel/locking/rwlock-rt.c +@@ -305,12 +305,15 @@ int __lockfunc rt_read_trylock(rwlock_t *rwlock) + { + int ret; + ++ sleeping_lock_inc(); + migrate_disable(); + ret = do_read_rt_trylock(rwlock); +- if (ret) ++ if (ret) { + rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_); +- else ++ } else { + migrate_enable(); ++ sleeping_lock_dec(); ++ } + return ret; + } + EXPORT_SYMBOL(rt_read_trylock); +@@ -319,18 +322,22 @@ int __lockfunc rt_write_trylock(rwlock_t *rwlock) + { + int ret; + ++ sleeping_lock_inc(); + migrate_disable(); + ret = do_write_rt_trylock(rwlock); +- if (ret) ++ if (ret) { + rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_); +- else ++ } else { + migrate_enable(); ++ sleeping_lock_dec(); ++ } + return ret; + } + EXPORT_SYMBOL(rt_write_trylock); + + void __lockfunc rt_read_lock(rwlock_t *rwlock) + { ++ sleeping_lock_inc(); + migrate_disable(); + rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_); + do_read_rt_lock(rwlock); +@@ -339,6 +346,7 @@ EXPORT_SYMBOL(rt_read_lock); + + void __lockfunc rt_write_lock(rwlock_t *rwlock) + { ++ sleeping_lock_inc(); + migrate_disable(); + rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_); + do_write_rt_lock(rwlock); +@@ -350,6 +358,7 @@ void __lockfunc rt_read_unlock(rwlock_t *rwlock) + rwlock_release(&rwlock->dep_map, 1, _RET_IP_); + do_read_rt_unlock(rwlock); + migrate_enable(); ++ sleeping_lock_dec(); + } + EXPORT_SYMBOL(rt_read_unlock); + +@@ -358,6 +367,7 @@ void __lockfunc rt_write_unlock(rwlock_t *rwlock) + rwlock_release(&rwlock->dep_map, 1, _RET_IP_); + do_write_rt_unlock(rwlock); + migrate_enable(); ++ sleeping_lock_dec(); + } + EXPORT_SYMBOL(rt_write_unlock); + +diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h +index 5f6de49dc78e..35f3552b7463 100644 +--- a/kernel/rcu/tree_plugin.h ++++ b/kernel/rcu/tree_plugin.h +@@ -337,9 +337,13 @@ static void rcu_preempt_note_context_switch(bool preempt) + struct task_struct *t = current; + struct rcu_data *rdp; + struct rcu_node *rnp; ++ int sleeping_l = 0; + + lockdep_assert_irqs_disabled(); +- WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0); ++#if defined(CONFIG_PREEMPT_RT_FULL) ++ sleeping_l = t->sleeping_lock; ++#endif ++ WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0 && !sleeping_l); + if (t->rcu_read_lock_nesting > 0 && + !t->rcu_read_unlock_special.b.blocked) { + +diff --git a/kernel/sched/core.c b/kernel/sched/core.c +index 9494e2007118..555dea10764e 100644 +--- a/kernel/sched/core.c ++++ b/kernel/sched/core.c +@@ -7348,4 +7348,49 @@ void migrate_enable(void) + preempt_enable(); + } + EXPORT_SYMBOL(migrate_enable); ++ ++#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT_BASE) ++void migrate_disable(void) ++{ ++ struct task_struct *p = current; ++ ++ if (in_atomic() || irqs_disabled()) { ++#ifdef CONFIG_SCHED_DEBUG ++ p->migrate_disable_atomic++; ++#endif ++ return; ++ } ++#ifdef CONFIG_SCHED_DEBUG ++ if (unlikely(p->migrate_disable_atomic)) { ++ tracing_off(); ++ WARN_ON_ONCE(1); ++ } ++#endif ++ ++ p->migrate_disable++; ++} ++EXPORT_SYMBOL(migrate_disable); ++ ++void migrate_enable(void) ++{ ++ struct task_struct *p = current; ++ ++ if (in_atomic() || irqs_disabled()) { ++#ifdef CONFIG_SCHED_DEBUG ++ p->migrate_disable_atomic--; ++#endif ++ return; ++ } ++ ++#ifdef CONFIG_SCHED_DEBUG ++ if (unlikely(p->migrate_disable_atomic)) { ++ tracing_off(); ++ WARN_ON_ONCE(1); ++ } ++#endif ++ ++ WARN_ON_ONCE(p->migrate_disable <= 0); ++ p->migrate_disable--; ++} ++EXPORT_SYMBOL(migrate_enable); + #endif +-- +2.36.1 + |