The following commit has been merged into the locking/core branch of tip:
Commit-ID: a0855d24fc22d49cdc25664fb224caee16998683
Gitweb: https://git.kernel.org/tip/a0855d24fc22d49cdc25664fb224caee16998683
Author: Davidlohr Bueso <dave@xxxxxxxxxxxx>
AuthorDate: Thu, 24 Oct 2019 20:36:34 -07:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 29 Oct 2019 12:22:52 +01:00
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@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: dave@xxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20191025033634.3330-1-dave@xxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/locking/mutex.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 5352ce5..54cc5f9 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);
|