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authorChuansheng Liu <chuansheng.liu@intel.com>2013-12-04 09:58:13 +0400
committerIngo Molnar <mingo@kernel.org>2013-12-17 18:35:10 +0400
commit91f30a17024ff0d8345e11228af33ee938b13426 (patch)
tree283bc22529ed94d7e5f4611609eb935a75032c98 /kernel/locking
parentbb799d3b980eb803ca2da4a4eefbd9308f8d988a (diff)
downloadlinux-91f30a17024ff0d8345e11228af33ee938b13426.tar.xz
mutexes: Give more informative mutex warning in the !lock->owner case
When mutex debugging is enabled and an imbalanced mutex_unlock() is called, we get the following, slightly confusing warning: [ 364.208284] DEBUG_LOCKS_WARN_ON(lock->owner != current) But in that case the warning is due to an imbalanced mutex_unlock() call, and the lock->owner is NULL - so the message is misleading. So improve the message by testing for this case specifically: DEBUG_LOCKS_WARN_ON(!lock->owner) Signed-off-by: Liu, Chuansheng <chuansheng.liu@intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1386136693.3650.48.camel@cliu38-desktop-build [ Improved the changelog, changed the patch to use !lock->owner consistently. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/mutex-debug.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
index 7e3443fe1f48..faf6f5b53e77 100644
--- a/kernel/locking/mutex-debug.c
+++ b/kernel/locking/mutex-debug.c
@@ -75,7 +75,12 @@ void debug_mutex_unlock(struct mutex *lock)
return;
DEBUG_LOCKS_WARN_ON(lock->magic != lock);
- DEBUG_LOCKS_WARN_ON(lock->owner != current);
+
+ if (!lock->owner)
+ DEBUG_LOCKS_WARN_ON(!lock->owner);
+ else
+ DEBUG_LOCKS_WARN_ON(lock->owner != current);
+
DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
mutex_clear_owner(lock);
}