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sched: Fix the PREEMPT_ACTIVE check in __trace_sched_switch_state()

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task_preempt_count() has nothing to do with the actual preempt counter,
thread_info->saved_preempt_count is only valid right after switch_to().

__trace_sched_switch_state() can use preempt_count(), prev is still the
current task when trace_sched_switch() is called.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
[ Added BUG_ON(). ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20141007195108.GB28002@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Oleg Nesterov 2014-10-07 21:51:08 +02:00 committed by Ingo Molnar
parent 9de05d4871
commit 8f9fbf092c
1 changed files with 6 additions and 3 deletions
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9
include/trace/events/sched.h
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@ -97,16 +97,19 @@ static inline long __trace_sched_switch_state(struct task_struct *p)
long state = p->state;
#ifdef CONFIG_PREEMPT
#ifdef CONFIG_SCHED_DEBUG
BUG_ON(p != current);
#endif /* CONFIG_SCHED_DEBUG */
/*
* For all intents and purposes a preempted task is a running task.
*/
if (task_preempt_count(p) & PREEMPT_ACTIVE)
if (preempt_count() & PREEMPT_ACTIVE)
state = TASK_RUNNING | TASK_STATE_MAX;
#endif
#endif /* CONFIG_PREEMPT */
return state;
}
#endif
#endif /* CREATE_TRACE_POINTS */
/*
* Tracepoint for task switches, performed by the scheduler: