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locking/mutex: Complain upon mutex API misuse in IRQ contexts 

Add warning checks if mutex_trylock() or mutex_unlock() are used in
IRQ contexts, under CONFIG_DEBUG_MUTEXES=y.

While the mutex rules and semantics are explicitly documented, this allows
to expose any abusers and robustifies the whole thing.

While trylock and unlock are non-blocking, calling from IRQ context
is still forbidden (lock must be within the same context as unlock).

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Link: https://lkml.kernel.org/r/20191025033634.3330-1-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Davidlohr Bueso 2019-10-24 20:36:34 -07:00 committed by Ingo Molnar
parent 751459043c
commit a0855d24fc
1 changed files with 4 additions and 0 deletions
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4
kernel/locking/mutex.c
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@ -733,6 +733,9 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne
*/ */
void __sched mutex_unlock(struct mutex *lock) void __sched mutex_unlock(struct mutex *lock)
{ {
#ifdef CONFIG_DEBUG_MUTEXES
WARN_ON(in_interrupt());
#endif
#ifndef CONFIG_DEBUG_LOCK_ALLOC #ifndef CONFIG_DEBUG_LOCK_ALLOC
if (__mutex_unlock_fast(lock)) if (__mutex_unlock_fast(lock))
return; return;
@ -1413,6 +1416,7 @@ int __sched mutex_trylock(struct mutex *lock)
#ifdef CONFIG_DEBUG_MUTEXES #ifdef CONFIG_DEBUG_MUTEXES
DEBUG_LOCKS_WARN_ON(lock->magic != lock); DEBUG_LOCKS_WARN_ON(lock->magic != lock);
WARN_ON(in_interrupt());
#endif #endif
locked = __mutex_trylock(lock); locked = __mutex_trylock(lock);