From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934961AbeBML4q (ORCPT ); Tue, 13 Feb 2018 06:56:46 -0500 Received: from mx2.suse.de ([195.135.220.15]:35712 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934861AbeBML4p (ORCPT ); Tue, 13 Feb 2018 06:56:45 -0500 Date: Tue, 13 Feb 2018 12:56:42 +0100 From: Michal Hocko To: Chris Wilson Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Tetsuo Handa , Andrew Morton Subject: Re: [PATCH] khungtaskd: Kick stuck processes Message-ID: <20180213115642.GR3443@dhcp22.suse.cz> References: <20180208190753.17690-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180208190753.17690-1-chris@chris-wilson.co.uk> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > Cc: Ingo Molnar > Cc: Tetsuo Handa > Cc: Andrew Morton > --- > 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