[PATCH] cond_resched(): fix bogus might_sleep() warning
The BKS might be reacquired before we have dropped PREEMPT_ACTIVE, which
could trigger a second could trigger a second cond_resched() call. Bug
found by Hirofumi Ogawa.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/sched.c b/kernel/sched.c
index 5f2182d..4107db0 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -3877,6 +3877,13 @@
static inline void __cond_resched(void)
{
+ /*
+ * The BKS might be reacquired before we have dropped
+ * PREEMPT_ACTIVE, which could trigger a second
+ * cond_resched() call.
+ */
+ if (unlikely(preempt_count()))
+ return;
do {
add_preempt_count(PREEMPT_ACTIVE);
schedule();
