Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong fatal_signal_pending() check in oom_kill_process()

From	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Newsgroups	linux.kernel
Subject	Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong fatal_signal_pending() check in oom_kill_process()
Date	2015-10-02 16:40 +0200
Message-ID	<qf9F7-690-7@gated-at.bofh.it> (permalink)
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Oleg Nesterov wrote:
> Tetsuo, sorry, I don't understand your question...
> 
> > because it is possible that T starts the coredump, T sends SIGKILL to P,
> > P calls out_of_memory() on GFP_FS allocation,
> 
> yes, and since fatal_signal_pending() == T we do not even check
> task_will_free_mem().
> 
> > P misses to set SIGKILL on T?
> >
> > Since T sends SIGKILL to all clone(CLONE_VM) tasks upon coredump, P needs
> > to do
> >
> > [...snip...]
> 
> > after mark_oom_victim(current) in case T is not in the same thread group?
> 
> I do not see how this depends on "not in the same thread group". This
> fatal_signal_pending() doesn't look right in any case.

You already answered my question. ;-)
You confirmed this is a possible silent hang up path (I mean, hang up
without OOM killer messages).

> > If yes, what happens if some task failed to receive SIGKILL due to
> > p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN condition?
> 
> Oh. This is another issue. I already tried to suggest to remove this
> check. But this needs more discussion, hopefully we can do this later.

OK.
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[PATCH -mm v2 1/3] mm/oom_kill: remove the wrong  fatal_signal_pending() check in oom_kill_process() Oleg Nesterov <oleg@redhat.com> - 2015-09-30 20:30 +0200
  Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong fatal_signal_pending()check in oom_kill_process() Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2015-10-01 13:00 +0200
  Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong  fatal_signal_pending() check in oom_kill_process() Michal Hocko <mhocko@kernel.org> - 2015-10-01 14:50 +0200
    Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong  fatal_signal_pending() check in oom_kill_process() Oleg Nesterov <oleg@redhat.com> - 2015-10-01 17:10 +0200
      Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong  fatal_signal_pending() check in oom_kill_process() Michal Hocko <mhocko@kernel.org> - 2015-10-01 17:30 +0200
        Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong  fatal_signal_pending() check in oom_kill_process() Oleg Nesterov <oleg@redhat.com> - 2015-10-01 17:50 +0200
          Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong  fatal_signal_pending() check in oom_kill_process() Michal Hocko <mhocko@kernel.org> - 2015-10-01 18:20 +0200
            Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong  fatal_signal_pending() check in oom_kill_process() Oleg Nesterov <oleg@redhat.com> - 2015-10-01 20:00 +0200
              Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong fatal_signal_pending() check in oom_kill_process() Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2015-10-02 13:40 +0200
                Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong  fatal_signal_pending() check in oom_kill_process() Michal Hocko <mhocko@kernel.org> - 2015-10-02 14:20 +0200
                Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong fatal_signal_pending() check in oom_kill_process() Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2015-10-02 14:40 +0200
                Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong  fatal_signal_pending() check in oom_kill_process() Michal Hocko <mhocko@kernel.org> - 2015-10-02 15:40 +0200
                Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong fatal_signal_pending() check in oom_kill_process() Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2015-10-02 16:10 +0200
                Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong  fatal_signal_pending() check in oom_kill_process() Oleg Nesterov <oleg@redhat.com> - 2015-10-02 16:20 +0200
                Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong  fatal_signal_pending() check in oom_kill_process() Oleg Nesterov <oleg@redhat.com> - 2015-10-02 16:10 +0200
                Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong  fatal_signal_pending() check in oom_kill_process() Michal Hocko <mhocko@kernel.org> - 2015-10-02 16:30 +0200
                Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong  fatal_signal_pending() check in oom_kill_process() Oleg Nesterov <oleg@redhat.com> - 2015-10-02 16:00 +0200
                Re: [PATCH -mm v2 1/3] mm/oom_kill: remove the wrong fatal_signal_pending() check in oom_kill_process() Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2015-10-02 16:40 +0200

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