Commit a63b03e2 authored by Chris Wilson's avatar Chris Wilson Committed by Ingo Molnar

mutex: Always clear owner field upon mutex_unlock()

Currently if DEBUG_MUTEXES is enabled, the mutex->owner field is only
cleared iff debug_locks is active. This exposes a race to other users of
the field where the mutex->owner may be still set to a stale value,
potentially upsetting mutex_spin_on_owner() among others.

References: default avatarChris Wilson <>
Signed-off-by: default avatarPeter Zijlstra (Intel) <>
Acked-by: default avatarDavidlohr Bueso <>
Cc: Daniel Vetter <>
Cc: Linus Torvalds <>
Link: default avatarIngo Molnar <>
parent 11c8f01b
......@@ -80,13 +80,13 @@ void debug_mutex_unlock(struct mutex *lock)
DEBUG_LOCKS_WARN_ON(lock->owner != current);
DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->;
* __mutex_slowpath_needs_to_unlock() is explicitly 0 for debug
* mutexes so that we can do it here after we've verified state.
atomic_set(&lock->count, 1);
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