sched: Fix cond_resched_lock() in !CONFIG_PREEMPT
The might_sleep() test inside cond_resched_lock() assumes the
spinlock is held and then preemption is disabled. This is true
with CONFIG_PREEMPT but the preempt_count() doesn't change
otherwise.
Check by starting from the appropriate preempt offset depending
on the config.
Reported-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1248458723-12146-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index cbbfca6..c472414 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2293,8 +2293,14 @@
extern int __cond_resched_lock(spinlock_t *lock);
+#ifdef CONFIG_PREEMPT
+#define PREEMPT_LOCK_OFFSET PREEMPT_OFFSET
+#else
+#define PREEMPT_LOCK_OFFSET 0
+#endif
+
#define cond_resched_lock(lock) ({ \
- __might_sleep(__FILE__, __LINE__, PREEMPT_OFFSET); \
+ __might_sleep(__FILE__, __LINE__, PREEMPT_LOCK_OFFSET); \
__cond_resched_lock(lock); \
})