locking/mutex: Fix debug_mutexes

debug_mutex_unlock() would bail when !debug_locks and forgets to actually unlock. Reported-by: "Michael L. Semon" <[email protected]> Reported-by: "Kirill A. Shutemov" <[email protected]> Reported-by: Valdis Kletnieks <[email protected]> Fixes: 6f008e7 ("locking/mutex: Fix debug checks") Tested-by: Dave Jones <[email protected]> Cc: Jason Low <[email protected]> Signed-off-by: Peter Zijlstra <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
djekels-zz · Apr 11, 2014 · a227960 · a227960
1 parent 467cbd2
commit a227960
Showing 1 changed file with 9 additions and 10 deletions.
diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
@@ -71,18 +71,17 @@ void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
 
 void debug_mutex_unlock(struct mutex *lock)
 {
-	if (unlikely(!debug_locks))
-		return;
+	if (likely(debug_locks)) {
+		DEBUG_LOCKS_WARN_ON(lock->magic != lock);
 
-	DEBUG_LOCKS_WARN_ON(lock->magic != lock);
+		if (!lock->owner)
+			DEBUG_LOCKS_WARN_ON(!lock->owner);
+		else
+			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);
+		DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
+		mutex_clear_owner(lock);
+	}
 
 	/*
 	 * __mutex_slowpath_needs_to_unlock() is explicitly 0 for debug