commit cedce3e730833d26a37826a96e1905b6ef387df9
author Kirill Tkhai <tkhai@yandex.ru> Thu Jul 04 22:48:20 2013 +0400
committer Ingo Molnar <mingo@kernel.org> Fri Jul 12 13:54:03 2013 +0200
tree 10c980e22742f188d40366d2745bfe8c5712f15c
parent 971ee28cbd1ccd87b3164facd9359a534c1d2892

sched/__wake_up_sync_key(): Fix nr_exclusive tasks which lead to WF_SYNC clearing

Only one task can replace the waker.

Signed-off-by: Kirill Tkhai <tkhai@yandex.ru>
CC: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/512421372963700@web25f.yandex.ru
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/core.c

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0d8eb45..f737871 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2660,7 +2660,7 @@
 	if (unlikely(!q))
 		return;
 
-	if (unlikely(!nr_exclusive))
+	if (unlikely(nr_exclusive != 1))
 		wake_flags = 0;
 
 	spin_lock_irqsave(&q->lock, flags);