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authorIngo Molnar <mingo@elte.hu>2005-07-07 17:57:04 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-07-07 18:23:47 -0700
commit5bbcfd9000887c0da7d57cc7b3ac869fc0dd5aa9 (patch)
tree7047a60dc99e5484560b40027c81f92a4e291b29 /kernel/sched.c
parenta4014d8f61a6a136d22422cf8aa978e6495dbad9 (diff)
downloadlwn-5bbcfd9000887c0da7d57cc7b3ac869fc0dd5aa9.tar.gz
lwn-5bbcfd9000887c0da7d57cc7b3ac869fc0dd5aa9.zip
[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>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 5f2182d42241..4107db0dc091 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -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();