Commit-ID:  a227960fe0cafcc229a8d6bb8b454a3a0b33719d
Gitweb:     http://git.kernel.org/tip/a227960fe0cafcc229a8d6bb8b454a3a0b33719d
Author:     Peter Zijlstra <pet...@infradead.org>
AuthorDate: Thu, 10 Apr 2014 16:15:59 +0200
Committer:  Ingo Molnar <mi...@kernel.org>
CommitDate: Fri, 11 Apr 2014 10:40:35 +0200

locking/mutex: Fix debug_mutexes

debug_mutex_unlock() would bail when !debug_locks and forgets to
actually unlock.

Reported-by: "Michael L. Semon" <mlsemo...@gmail.com>
Reported-by: "Kirill A. Shutemov" <kir...@shutemov.name>
Reported-by: Valdis Kletnieks <valdis.kletni...@vt.edu>
Fixes: 6f008e72cd11 ("locking/mutex: Fix debug checks")
Tested-by: Dave Jones <da...@redhat.com>
Cc: Jason Low <jason.l...@hp.com>
Signed-off-by: Peter Zijlstra <pet...@infradead.org>
Link: 
http://lkml.kernel.org/r/20140410141559.ge13...@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
 kernel/locking/mutex-debug.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
index e1191c9..5cf6731 100644
--- 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
--
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