mutex-debug: check mutex magic before owner

Currently, the mutex debug code checks the lock->owner before lock->magic, so
a corrupt mutex will most likely result in failing the owner check, rather
than the magic check.

This change to debug_mutex_unlock does the magic check first, so
we have a better idea of what breaks.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/mutex-debug.c b/kernel/mutex-debug.c
index 3aaa06c..1d94160 100644 (file)
--- a/kernel/mutex-debug.c
+++ b/kernel/mutex-debug.c
@@ -79,8 +79,8 @@ void debug_mutex_unlock(struct mutex *lock)
        if (unlikely(!debug_locks))
                return;
 
-       DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
        DEBUG_LOCKS_WARN_ON(lock->magic != lock);
+       DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
        DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
        DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
 }