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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>
This commit is contained in:
Frederic Weisbecker 2009-07-24 20:05:23 +02:00 committed by Ingo Molnar
parent a004cd4218
commit 716a42348c
1 changed files with 7 additions and 1 deletions
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8
include/linux/sched.h
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@ -2293,8 +2293,14 @@ extern int _cond_resched(void);
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); \
})