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| author | Chuansheng Liu <chuansheng.liu@intel.com> | 2013-12-04 13:58:13 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-12-17 15:35:10 +0100 |
| commit | 91f30a17024ff0d8345e11228af33ee938b13426 (patch) | |
| tree | 283bc22529ed94d7e5f4611609eb935a75032c98 /kernel/locking | |
| parent | bb799d3b980eb803ca2da4a4eefbd9308f8d988a (diff) | |
| download | linux-91f30a17024ff0d8345e11228af33ee938b13426.tar.gz linux-91f30a17024ff0d8345e11228af33ee938b13426.tar.bz2 linux-91f30a17024ff0d8345e11228af33ee938b13426.zip | |
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.c | 7 |
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); } |