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authorDavidlohr Bueso <dave@stgolabs.net>2019-10-24 20:36:34 -0700
committerIngo Molnar <mingo@kernel.org>2019-10-29 12:22:52 +0100
commita0855d24fc22d49cdc25664fb224caee16998683 (patch)
treedd119b46e9fc2214fc272b2b878799614b728257 /kernel/locking
parent751459043cc87c3f0098034b15ca5252d12539ab (diff)
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>
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/mutex.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 5352ce50a97e..54cc5f9286e9 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -733,6 +733,9 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne
*/
void __sched mutex_unlock(struct mutex *lock)
{
+#ifdef CONFIG_DEBUG_MUTEXES
+ WARN_ON(in_interrupt());
+#endif
#ifndef CONFIG_DEBUG_LOCK_ALLOC
if (__mutex_unlock_fast(lock))
return;
@@ -1413,6 +1416,7 @@ int __sched mutex_trylock(struct mutex *lock)
#ifdef CONFIG_DEBUG_MUTEXES
DEBUG_LOCKS_WARN_ON(lock->magic != lock);
+ WARN_ON(in_interrupt());
#endif
locked = __mutex_trylock(lock);