From: Ingo Molnar <mingo@elte.hu>
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>
---
kernel/sched.c | 7 +++++++
1 files changed, 7 insertions(+)
diff -puN kernel/sched.c~cond_resched-fix-bogus-might_sleep-warning kernel/sched.c
--- 25/kernel/sched.c~cond_resched-fix-bogus-might_sleep-warning Wed Jul 6 13:46:38 2005
+++ 25-akpm/kernel/sched.c Wed Jul 6 13:46:38 2005
@@ -3877,6 +3877,13 @@ asmlinkage long sys_sched_yield(void)
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();
_