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From: Oleg Nesterov <oleg@redhat.com>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Roland McGrath <roland@hack.frob.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	amanieu@gmail.com, pmoore@redhat.com,
	Ingo Molnar <mingo@kernel.org>,
	vdavydov@parallels.com, qiaowei.ren@intel.com, dave@stgolabs.net,
	palmer@dabbelt.com, LKML <linux-kernel@vger.kernel.org>,
	syzkaller <syzkaller@googlegroups.com>,
	Kostya Serebryany <kcc@google.com>,
	Alexander Potapenko <glider@google.com>,
	Sasha Levin <sasha.levin@oracle.com>
Subject: Re: WARNING in task_participate_group_stop
Date: Mon, 2 Nov 2015 17:36:54 +0100	[thread overview]
Message-ID: <20151102163654.GA18804@redhat.com> (raw)
In-Reply-To: <20151102151333.GA17152@redhat.com>

On 11/02, Oleg Nesterov wrote:
>
> On 11/02, Dmitry Vyukov wrote:
> >
> > But I wasn't able
> > to figure out what's the root cause (why task does not have
> > JOBCTL_STOP_PENDING) and maybe the same WARNING can be triggered
> > without root and/or with other than init process. So still posting it
> > here.
>
> Yes I think you are right. SIGSTOP can race with SIGKILL which (unlike SIGCONT)
> doesn't clear JOBCTL_STOP_DEQUEUED/PENDING/etc.

I was wrong... I forgot that complete_signal(SIGKILL) sets SIGNAL_GROUP_EXIT.
Unless SIGNAL_UNKILLABLE is set, and this is what makes init "special".

So it seems that everything is clear. Except I can't understand why your
test-case doesn't work for me ;) It should.

Oleg.


  parent reply	other threads:[~2015-11-02 15:40 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-02 13:25 WARNING in task_participate_group_stop Dmitry Vyukov
2015-11-02 15:13 ` Oleg Nesterov
2015-11-02 14:21   ` Dmitry Vyukov
2015-11-02 15:33     ` Oleg Nesterov
2015-11-02 16:36   ` Oleg Nesterov [this message]
2015-11-02 18:06     ` Oleg Nesterov
2015-11-04 19:18       ` [PATCH 0/1] (Was: WARNING in task_participate_group_stop) Oleg Nesterov
2015-11-04 19:19         ` [PATCH 1/1] signal: kill the obsolete SIGNAL_UNKILLABLE check in complete_signal() Oleg Nesterov
2015-11-05  1:21           ` Andrew Morton
2015-11-05 16:08             ` Oleg Nesterov
2015-11-05 18:02               ` Oleg Nesterov
  -- strict thread matches above, loose matches on Subject: below --
2017-10-30 19:12 WARNING in task_participate_group_stop syzbot
2017-10-30 19:20 ` Dmitry Vyukov
2017-10-31 16:34   ` Oleg Nesterov
2017-11-01  5:55     ` Dmitry Vyukov
2017-11-02 17:01       ` Oleg Nesterov
2017-11-06 11:02         ` Dmitry Vyukov
2017-11-06 11:25           ` Jamie Iles
2017-11-06 11:56             ` Dmitry Vyukov
2017-11-06 12:26               ` Jamie Iles
2017-11-06 14:31             ` Oleg Nesterov
2017-11-07 17:31               ` Dmitry Vyukov

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