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SubjectRe: [PATCH] khungtaskd: Kick stuck processes
On Thu 08-02-18 19:07:53, Chris Wilson wrote:
> After spotting a stuck process, and having decided not to panic, give
> the task a kick to see if that helps it to recover (e.g. to paper over a
> missed wake up).

huh, this is just no-no. watchdog is there to report problems not
interfere. You cannot never know whether the sleeper is prepared for
spurious wakeups. Do not paper over bugs...

> References: https://bugs.freedesktop.org/show_bug.cgi?id=104009
> References: https://bugs.freedesktop.org/show_bug.cgi?id=104682
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> ---
> kernel/hung_task.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/kernel/hung_task.c b/kernel/hung_task.c
> index 751593ed7c0b..b32acb6bcc63 100644
> --- a/kernel/hung_task.c
> +++ b/kernel/hung_task.c
> @@ -132,6 +132,8 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
> trigger_all_cpu_backtrace();
> panic("hung_task: blocked tasks");
> }
> +
> + wake_up_process(t);
> }
>
> /*
> --
> 2.16.1

--
Michal Hocko
SUSE Labs

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