path: root/kernel
diff options
authorMark Fasheh <>2006-12-22 01:06:15 -0800
committerLinus Torvalds <>2006-12-22 08:55:46 -0800
commitba0084048ab785c2cb1d6cc2cccabe642a5b799a (patch)
tree402f1d6a726413a734ab05415a8f3277d23310e7 /kernel
parent2aea4fb61609ba7ef82f7dc6fca116bda88816e1 (diff)
[PATCH] Conditionally check expected_preempt_count in __resched_legal()
Commit 2d7d253548cffdce80f4e03664686e9ccb1b0ed7 ("fix cond_resched() fix") introduced an 'expected_preempt_count' parameter to __resched_legal() to fix a bug where it was returning a false negative when called from cond_resched_lock() and preemption was enabled. Unfortunately this broke things for when preemption is disabled. preempt_count() will always return zero, thus failing the check against any value of expected_preempt_count not equal to zero. cond_resched_lock() for example, passes an expected_preempt_count value of 1. So fix the fix for the cond_resched() fix by skipping the check of preempt_count() against expected_preempt_count when preemption is disabled. Credit should go to Sunil Mushran for spotting the bug during testing. Signed-off-by: Mark Fasheh <> Acked-by: Ingo Molnar <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'kernel')
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index b81ed8703f70..850bde4b31a2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4619,8 +4619,10 @@ asmlinkage long sys_sched_yield(void)
static inline int __resched_legal(int expected_preempt_count)
if (unlikely(preempt_count() != expected_preempt_count))
return 0;
if (unlikely(system_state != SYSTEM_RUNNING))
return 0;
return 1;