From: Michal Hocko <mhocko@suse.cz>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
rientjes@google.com, oleg@redhat.com
Subject: Re: [RFC PATCH] oom: Don't count on mm-less current process.
Date: Tue, 23 Dec 2014 14:43:09 +0100 [thread overview]
Message-ID: <20141223134309.GF28549@dhcp22.suse.cz> (raw)
In-Reply-To: <201412232220.IIJ57305.OMOOSVFtFFHQLJ@I-love.SAKURA.ne.jp>
On Tue 23-12-14 22:20:57, Tetsuo Handa wrote:
> Michal Hocko wrote:
> > On Tue 23-12-14 22:00:52, Tetsuo Handa wrote:
[...]
> > > Then, I think deferring SIGKILL might widen race window for abusing TIF_MEMDIE.
> >
> > How would it abuse the flag? The OOM victim has to die and if it needs
> > to allocate then we have to allow it to do so otherwise the whole
> > exercise was pointless. fatal_signal_pending check is not so widespread
> > in the kernel that the task would notice it immediately.
>
> I'm talking about possible delay between TIF_MEMDIE was set on the victim
> and SIGKILL is delivered to the victim.
I can read what you wrote. You are just ignoring my questions it seems
because I haven't got any reason _why it matters_. My point was that the
victim might be looping in the kernel and doing other allocations until
it notices it has fatal_signal_pending and bail out. So the delay
between setting the flag and sending the signal is not that important
AFAICS.
> Why the victim has to die before receiving SIGKILL?
It has to die to resolve the current OOM condition. I haven't written
anything about dying before receiving SIGKILL.
> The victim can access memory reserves until SIGKILL is delivered,
> can't it?
And why does that matter? It would have to do such an allocation anyway
because it wouldn't proceed without it... And the only difference
between having the flag and not having it is that the allocation has
higher chance to succeed with the flag so it will not trigger the OOM
killer again right away. See the point or am I missing something here?
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2014-12-23 13:43 UTC|newest]
Thread overview: 177+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-12 13:54 Tetsuo Handa
2014-12-16 12:47 ` Michal Hocko
2014-12-17 11:54 ` Tetsuo Handa
2014-12-17 13:08 ` Michal Hocko
2014-12-18 12:11 ` Tetsuo Handa
2014-12-18 15:33 ` Michal Hocko
2014-12-19 12:07 ` Tetsuo Handa
2014-12-19 12:49 ` Michal Hocko
2014-12-20 9:13 ` Tetsuo Handa
2014-12-20 11:42 ` Tetsuo Handa
2014-12-22 20:25 ` Michal Hocko
2014-12-23 1:00 ` Tetsuo Handa
2014-12-23 9:51 ` Michal Hocko
2014-12-23 11:46 ` Tetsuo Handa
2014-12-23 11:57 ` Tetsuo Handa
2014-12-23 12:12 ` Tetsuo Handa
2014-12-23 12:27 ` Michal Hocko
2014-12-23 12:24 ` Michal Hocko
2014-12-23 13:00 ` Tetsuo Handa
2014-12-23 13:09 ` Michal Hocko
2014-12-23 13:20 ` Tetsuo Handa
2014-12-23 13:43 ` Michal Hocko [this message]
2014-12-23 14:11 ` Tetsuo Handa
2014-12-23 14:57 ` Michal Hocko
2014-12-19 12:22 ` How to handle TIF_MEMDIE stalls? Tetsuo Handa
2014-12-20 2:03 ` Dave Chinner
2014-12-20 12:41 ` Tetsuo Handa
2014-12-20 22:35 ` Dave Chinner
2014-12-21 8:45 ` Tetsuo Handa
2014-12-21 20:42 ` Dave Chinner
2014-12-22 16:57 ` Michal Hocko
2014-12-22 21:30 ` Dave Chinner
2014-12-23 9:41 ` Johannes Weiner
2014-12-24 1:06 ` Dave Chinner
2014-12-24 2:40 ` Linus Torvalds
2014-12-29 18:19 ` Michal Hocko
2014-12-30 6:42 ` Tetsuo Handa
2014-12-30 11:21 ` Michal Hocko
2014-12-30 13:33 ` Tetsuo Handa
2014-12-31 10:24 ` Tetsuo Handa
2015-02-09 11:44 ` Tetsuo Handa
2015-02-10 13:58 ` Tetsuo Handa
2015-02-10 15:19 ` Johannes Weiner
2015-02-11 2:23 ` Tetsuo Handa
2015-02-11 13:37 ` Tetsuo Handa
2015-02-11 18:50 ` Oleg Nesterov
2015-02-11 18:59 ` Oleg Nesterov
2015-03-14 13:03 ` Tetsuo Handa
2015-02-17 12:23 ` Tetsuo Handa
2015-02-17 12:53 ` Johannes Weiner
2015-02-17 15:38 ` Michal Hocko
2015-02-17 22:54 ` Dave Chinner
2015-02-17 23:32 ` Dave Chinner
2015-02-18 8:25 ` Michal Hocko
2015-02-18 10:48 ` Dave Chinner
2015-02-18 12:16 ` Michal Hocko
2015-02-18 21:31 ` Dave Chinner
2015-02-19 9:40 ` Michal Hocko
2015-02-19 22:03 ` Dave Chinner
2015-02-20 9:27 ` Michal Hocko
2015-02-19 11:01 ` Johannes Weiner
2015-02-19 12:29 ` Michal Hocko
2015-02-19 12:58 ` Michal Hocko
2015-02-19 15:29 ` Tetsuo Handa
2015-02-19 21:53 ` Tetsuo Handa
2015-02-20 9:13 ` Michal Hocko
2015-02-20 13:37 ` Stefan Ring
2015-02-19 13:29 ` Tetsuo Handa
2015-02-20 9:10 ` Michal Hocko
2015-02-20 12:20 ` Tetsuo Handa
2015-02-20 12:38 ` Michal Hocko
2015-02-19 21:43 ` Dave Chinner
2015-02-20 12:48 ` Michal Hocko
2015-02-20 23:09 ` Dave Chinner
2015-02-19 10:24 ` Johannes Weiner
2015-02-19 22:52 ` Dave Chinner
2015-02-20 10:36 ` Tetsuo Handa
2015-02-20 23:15 ` Dave Chinner
2015-02-21 3:20 ` Theodore Ts'o
2015-02-21 9:19 ` Andrew Morton
2015-02-21 13:48 ` Tetsuo Handa
2015-02-21 21:38 ` Dave Chinner
2015-02-22 0:20 ` Johannes Weiner
2015-02-23 10:48 ` Michal Hocko
2015-02-23 11:23 ` Tetsuo Handa
2015-02-23 21:33 ` David Rientjes
2015-02-22 14:48 ` __GFP_NOFAIL and oom_killer_disabled? Tetsuo Handa
2015-02-23 10:21 ` Michal Hocko
2015-02-23 13:03 ` Tetsuo Handa
2015-02-24 18:14 ` Michal Hocko
2015-02-25 11:22 ` Tetsuo Handa
2015-02-25 16:02 ` Michal Hocko
2015-02-25 21:48 ` Tetsuo Handa
2015-02-25 21:51 ` Andrew Morton
2015-02-21 12:00 ` How to handle TIF_MEMDIE stalls? Tetsuo Handa
2015-02-23 10:26 ` Michal Hocko
2015-02-21 11:12 ` Tetsuo Handa
2015-02-21 21:48 ` Dave Chinner
2015-02-21 23:52 ` Johannes Weiner
2015-02-23 0:45 ` Dave Chinner
2015-02-23 1:29 ` Andrew Morton
2015-02-23 7:32 ` Dave Chinner
2015-02-27 18:24 ` Vlastimil Babka
2015-02-28 0:03 ` Dave Chinner
2015-02-28 15:17 ` Theodore Ts'o
2015-03-02 9:39 ` Vlastimil Babka
2015-03-02 22:31 ` Dave Chinner
2015-03-03 9:13 ` Vlastimil Babka
2015-03-04 1:33 ` Dave Chinner
2015-03-04 8:50 ` Vlastimil Babka
2015-03-04 11:03 ` Dave Chinner
2015-03-07 0:20 ` Johannes Weiner
2015-03-07 3:43 ` Dave Chinner
2015-03-07 15:08 ` Johannes Weiner
2015-03-02 20:22 ` Johannes Weiner
2015-03-02 23:12 ` Dave Chinner
2015-03-03 2:50 ` Johannes Weiner
2015-03-04 6:52 ` Dave Chinner
2015-03-04 15:04 ` Johannes Weiner
2015-03-04 17:38 ` Theodore Ts'o
2015-03-04 23:17 ` Dave Chinner
2015-02-28 16:29 ` Johannes Weiner
2015-02-28 16:41 ` Theodore Ts'o
2015-02-28 22:15 ` Johannes Weiner
2015-03-01 11:17 ` Tetsuo Handa
2015-03-06 11:53 ` Tetsuo Handa
2015-03-01 13:43 ` Theodore Ts'o
2015-03-01 16:15 ` Johannes Weiner
2015-03-01 19:36 ` Theodore Ts'o
2015-03-01 20:44 ` Johannes Weiner
2015-03-01 20:17 ` Johannes Weiner
2015-03-01 21:48 ` Dave Chinner
2015-03-02 0:17 ` Dave Chinner
2015-03-02 12:46 ` Brian Foster
2015-02-28 18:36 ` Vlastimil Babka
2015-03-02 15:18 ` Michal Hocko
2015-03-02 16:05 ` Johannes Weiner
2015-03-02 17:10 ` Michal Hocko
2015-03-02 17:27 ` Johannes Weiner
2015-03-02 16:39 ` Theodore Ts'o
2015-03-02 16:58 ` Michal Hocko
2015-03-04 12:52 ` Dave Chinner
2015-02-17 14:59 ` Michal Hocko
2015-02-17 14:50 ` Michal Hocko
2015-02-17 14:37 ` Michal Hocko
2015-02-17 14:44 ` Michal Hocko
2015-02-16 11:23 ` Tetsuo Handa
2015-02-16 15:42 ` Johannes Weiner
2015-02-17 11:57 ` Tetsuo Handa
2015-02-17 13:16 ` Johannes Weiner
2015-02-17 16:50 ` Michal Hocko
2015-02-17 23:25 ` Dave Chinner
2015-02-18 8:48 ` Michal Hocko
2015-02-18 11:23 ` Tetsuo Handa
2015-02-18 12:29 ` Michal Hocko
2015-02-18 14:06 ` Tetsuo Handa
2015-02-18 14:25 ` Michal Hocko
2015-02-19 10:48 ` Tetsuo Handa
2015-02-20 8:26 ` Michal Hocko
2015-02-23 22:08 ` David Rientjes
2015-02-24 11:20 ` Tetsuo Handa
2015-02-24 15:20 ` Theodore Ts'o
2015-02-24 21:02 ` Dave Chinner
2015-02-25 14:31 ` Tetsuo Handa
2015-02-27 7:39 ` Dave Chinner
2015-02-27 12:42 ` Tetsuo Handa
2015-02-27 13:12 ` Dave Chinner
2015-03-04 12:41 ` Tetsuo Handa
2015-03-04 13:25 ` Dave Chinner
2015-03-04 14:11 ` Tetsuo Handa
2015-03-05 1:36 ` Dave Chinner
2015-02-17 16:33 ` Michal Hocko
2014-12-29 17:40 ` [PATCH] mm: get rid of radix tree gfp mask for pagecache_get_page (was: Re: How to handle TIF_MEMDIE stalls?) Michal Hocko
2014-12-29 18:45 ` Linus Torvalds
2014-12-29 19:33 ` Michal Hocko
2014-12-30 13:42 ` Michal Hocko
2014-12-30 21:45 ` Linus Torvalds
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