From: Michal Hocko <mhocko@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: linux-mm@kvack.org,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
David Rientjes <rientjes@google.com>,
Vladimir Davydov <vdavydov@parallels.com>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 5/6] mm, oom: kill all tasks sharing the mm
Date: Tue, 31 May 2016 09:43:18 +0200 [thread overview]
Message-ID: <20160531074318.GD26128@dhcp22.suse.cz> (raw)
In-Reply-To: <20160530181816.GA25480@redhat.com>
On Mon 30-05-16 20:18:16, Oleg Nesterov wrote:
> On 05/30, Michal Hocko wrote:
> >
> > @@ -852,8 +852,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
> > continue;
> > if (same_thread_group(p, victim))
> > continue;
> > - if (unlikely(p->flags & PF_KTHREAD) || is_global_init(p) ||
> > - p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) {
> > + if (unlikely(p->flags & PF_KTHREAD) || is_global_init(p)) {
> > /*
> > * We cannot use oom_reaper for the mm shared by this
> > * process because it wouldn't get killed and so the
> > @@ -862,6 +861,11 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
> > can_oom_reap = false;
> > continue;
> > }
> > + if (p->signal->oom_score_adj == OOM_ADJUST_MIN)
> > + pr_warn("%s pid=%d shares mm with oom disabled %s pid=%d. Seems like misconfiguration, killing anyway!"
> > + " Report at linux-mm@kvack.org\n",
> > + victim->comm, task_pid_nr(victim),
> > + p->comm, task_pid_nr(p));
>
> Oh, yes, I personally do agree ;)
>
> perhaps the is_global_init() == T case needs a warning too? the previous changes
> take care about vfork() from /sbin/init, so the only reason we can see it true
> is that /sbin/init shares the memory with a memory hog... Nevermind, forget.
I have another two patches waiting for this to settle and one of them
adds a warning to that path.
> This is a bit off-topic, but perhaps we can also change the PF_KTHREAD check later.
> Of course we should not try to kill this kthread, but can_oom_reap can be true in
> this case. A kernel thread which does use_mm() should handle the errors correctly
> if (say) get_user() fails because we unmap the memory.
I was worried that the kernel thread would see a zero page so this could
lead to a data corruption.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2016-05-31 7:43 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-30 13:05 [PATCH 0/6 -v2] Handle oom bypass more gracefully Michal Hocko
2016-05-30 13:05 ` [PATCH 1/6] proc, oom: drop bogus task_lock and mm check Michal Hocko
2016-05-30 13:49 ` Vladimir Davydov
2016-05-30 17:43 ` Oleg Nesterov
2016-05-31 7:32 ` Michal Hocko
2016-05-31 22:53 ` Oleg Nesterov
2016-06-01 6:53 ` Michal Hocko
2016-06-01 10:41 ` Tetsuo Handa
2016-06-01 10:48 ` Michal Hocko
2016-05-30 13:05 ` [PATCH 2/6] proc, oom_adj: extract oom_score_adj setting into a helper Michal Hocko
2016-05-30 13:05 ` [PATCH 3/6] mm, oom_adj: make sure processes sharing mm have same view of oom_score_adj Michal Hocko
2016-05-31 7:41 ` Michal Hocko
2016-05-30 13:05 ` [PATCH 4/6] mm, oom: skip vforked tasks from being selected Michal Hocko
2016-05-30 19:28 ` Oleg Nesterov
2016-05-31 7:42 ` Michal Hocko
2016-05-31 21:43 ` Oleg Nesterov
2016-06-01 7:09 ` Michal Hocko
2016-06-01 14:12 ` Tetsuo Handa
2016-06-01 14:25 ` Michal Hocko
2016-06-02 10:45 ` Tetsuo Handa
2016-06-02 11:20 ` Michal Hocko
2016-06-02 11:31 ` Tetsuo Handa
2016-06-02 12:55 ` Michal Hocko
2016-05-30 13:05 ` [PATCH 5/6] mm, oom: kill all tasks sharing the mm Michal Hocko
2016-05-30 18:18 ` Oleg Nesterov
2016-05-31 7:43 ` Michal Hocko [this message]
2016-05-31 21:48 ` Oleg Nesterov
2016-05-30 13:05 ` [PATCH 6/6] mm, oom: fortify task_will_free_mem Michal Hocko
2016-05-30 17:35 ` Oleg Nesterov
2016-05-31 7:46 ` Michal Hocko
2016-05-31 22:29 ` Oleg Nesterov
2016-06-01 7:03 ` Michal Hocko
2016-05-31 15:03 ` Tetsuo Handa
2016-05-31 15:10 ` Michal Hocko
2016-05-31 15:29 ` Tetsuo Handa
2016-06-01 7:25 ` Michal Hocko
2016-06-01 12:04 ` Tetsuo Handa
2016-06-01 12:43 ` Michal Hocko
2016-06-02 14:03 ` [PATCH 7/6] mm, oom: task_will_free_mem should skip oom_reaped tasks Michal Hocko
2016-06-02 15:24 ` Tetsuo Handa
2016-06-02 15:50 ` Michal Hocko
-- strict thread matches above, loose matches on Subject: below --
2016-05-26 12:40 [PATCH 0/5] Handle oom bypass more gracefully Michal Hocko
2016-05-26 12:40 ` [PATCH 5/6] mm, oom: kill all tasks sharing the mm Michal Hocko
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