Messages in this thread Patch in this message | | | Date | Thu, 3 Dec 2015 13:36:50 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH] sched: remove false-positive warning from wake_up_process() |
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On Mon, Nov 30, 2015 at 08:34:20PM -0500, Sasha Levin wrote: > Futex can have a spurious wake up before we actually wake it up on our own, > which will trigger this warning if the task is still stopped.
I've edited the changelog like so, please let me know if that is fine with you.
Thanks.
--- Subject: sched: Remove false-positive warning from wake_up_process() From: Sasha Levin <sasha.levin@oracle.com> Date: Mon, 30 Nov 2015 20:34:20 -0500
Because wakeups can (fundamentally) be late, a task might not be in the expected state. Therefore testing against a task's state is racy, and can yield false positives.
Fixes: 9067ac85d533 ("wake_up_process() should be never used to wakeup a TASK_STOPPED/TRACED task") Cc: oleg@redhat.com Cc: torvalds@linux-foundation.org Cc: mingo@redhat.com Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: http://lkml.kernel.org/r/1448933660-23082-1-git-send-email-sasha.levin@oracle.com --- kernel/sched/core.c | 1 - 1 file changed, 1 deletion(-)
--- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2160,7 +2160,6 @@ static void try_to_wake_up_local(struct */ int wake_up_process(struct task_struct *p) { - WARN_ON(task_is_stopped_or_traced(p)); return try_to_wake_up(p, TASK_NORMAL, 0); } EXPORT_SYMBOL(wake_up_process);
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