Commit 2d467090 authored Nov 09, 2010 by Peter Zijlstra Committed by Ingo Molnar Nov 10, 2010

sched: Fix runnable condition for stoptask



Heiko reported that the TASK_RUNNING check is not sufficient for
CONFIG_PREEMPT=y since we can get preempted with !TASK_RUNNING.

He suggested adding a ->se.on_rq test to the existing TASK_RUNNING
one, however TASK_RUNNING will always have ->se.on_rq, so we might as
well reduce that to a single test.

[ stop tasks should never get preempted, but its good to handle
  this case correctly should this ever happen ]

Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent aae6d3dd

kernel/sched_stoptask.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -26,7 +26,7 @@ static struct task_struct pick_next_task_stop(struct rq rq)
	{		{
	struct task_struct *stop = rq->stop;		struct task_struct *stop = rq->stop;

	if (stop && stop->state == TASK_RUNNING)		if (stop && stop->se.on_rq)
	return stop;		return stop;

	return NULL;		return NULL;