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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2019-07-03 11:21:26 +0200
committerIngo Molnar <mingo@kernel.org>2019-07-25 15:39:27 +0200
commit6c11c6e3d5e9e5caf8686cd6a5e4552cfc3ea326 (patch)
tree3c46421fccf883ceb83abb0b2f42a1a0c662a26b /kernel
parent30a35f79faadfeb1b89a7fdb3875f14063519041 (diff)
downloadlinux-6c11c6e3d5e9e5caf8686cd6a5e4552cfc3ea326.tar.bz2
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 <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190703092125.lsdf4gpsh2plhavb@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/locking/mutex.c11
1 files changed, 10 insertions, 1 deletions
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_);