Commit-ID: 6c11c6e3d5e9e5caf8686cd6a5e4552cfc3ea326 Gitweb: https://git.kernel.org/tip/6c11c6e3d5e9e5caf8686cd6a5e4552cfc3ea326 Author: Sebastian Andrzej Siewior <bige...@linutronix.de> AuthorDate: Wed, 3 Jul 2019 11:21:26 +0200 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Thu, 25 Jul 2019 15:39:27 +0200
locking/mutex: Test for initialized mutex An uninitialized/ zeroed mutex will go unnoticed because there is no check for it. There is a magic check in the unlock's slowpath path which might go unnoticed if the unlock happens in the fastpath. Add a ->magic check early in the mutex_lock() and mutex_trylock() path. Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Acked-by: Will Deacon <w...@kernel.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Link: https://lkml.kernel.org/r/20190703092125.lsdf4gpsh2plh...@linutronix.de Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/locking/mutex.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index edd1c082dbf5..5e069734363c 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -908,6 +908,10 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, might_sleep(); +#ifdef CONFIG_DEBUG_MUTEXES + DEBUG_LOCKS_WARN_ON(lock->magic != lock); +#endif + ww = container_of(lock, struct ww_mutex, base); if (use_ww_ctx && ww_ctx) { if (unlikely(ww_ctx == READ_ONCE(ww->ctx))) @@ -1379,8 +1383,13 @@ __ww_mutex_lock_interruptible_slowpath(struct ww_mutex *lock, */ int __sched mutex_trylock(struct mutex *lock) { - bool locked = __mutex_trylock(lock); + bool locked; + +#ifdef CONFIG_DEBUG_MUTEXES + DEBUG_LOCKS_WARN_ON(lock->magic != lock); +#endif + locked = __mutex_trylock(lock); if (locked) mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
