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From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Tejun Heo <tj@kernel.org>, Roman Gushchin <guro@fb.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Vladimir Davydov <vdavydov.dev@gmail.com>,
	David Rientjes <rientjes@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-mm <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm,page_alloc: PF_WQ_WORKER threads must sleep at should_reclaim_retry().
Date: Tue, 31 Jul 2018 07:09:28 +0200	[thread overview]
Message-ID: <20180731050928.GA4557@dhcp22.suse.cz> (raw)
In-Reply-To: <6f433d59-4a56-b698-e119-682bb8bf6713@i-love.sakura.ne.jp>

On Tue 31-07-18 06:01:48, Tetsuo Handa wrote:
> On 2018/07/31 4:10, Michal Hocko wrote:
> > Since should_reclaim_retry() should be a natural reschedule point,
> > let's do the short sleep for PF_WQ_WORKER threads unconditionally in
> > order to guarantee that other pending work items are started. This will
> > workaround this problem and it is less fragile than hunting down when
> > the sleep is missed. E.g. we used to have a sleeping point in the oom
> > path but this has been removed recently because it caused other issues.
> > Having a single sleeping point is more robust.
> 
> linux.git has not removed the sleeping point in the OOM path yet. Since removing the
> sleeping point in the OOM path can mitigate CVE-2016-10723, please do so immediately.

is this an {Acked,Reviewed,Tested}-by?

I will send the patch to Andrew if the patch is ok. 

> (And that change will conflict with Roman's cgroup aware OOM killer patchset. But it
> should be easy to rebase.)

That is still a WIP so I would lose sleep over it.
-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2018-07-31  5:09 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-26 11:06 Tetsuo Handa
2018-07-26 11:39 ` Michal Hocko
2018-07-27 15:47   ` Tetsuo Handa
2018-07-30  9:32     ` Michal Hocko
2018-07-30 14:34       ` Tetsuo Handa
2018-07-30 14:46         ` Michal Hocko
2018-07-30 14:54           ` Tejun Heo
2018-07-30 15:25             ` Tetsuo Handa
2018-07-30 15:44               ` Tejun Heo
2018-07-30 18:51                 ` Michal Hocko
2018-07-30 19:10                   ` Michal Hocko
2018-07-30 21:01                     ` Tetsuo Handa
2018-07-31  5:09                       ` Michal Hocko [this message]
2018-07-31 10:47                         ` Tetsuo Handa
2018-07-31 11:15                           ` Michal Hocko
2018-07-31 11:30                             ` Tetsuo Handa
2018-07-31 11:55                               ` Michal Hocko
2018-08-02 22:05                         ` Tetsuo Handa
2018-08-03  6:16                           ` Michal Hocko
2018-08-21 21:07                             ` Tetsuo Handa
2018-08-22  7:32                               ` Michal Hocko
2018-08-23 20:06                               ` David Rientjes
2018-08-23 21:00                                 ` Tetsuo Handa
2018-08-23 22:45                                   ` David Rientjes
2018-08-24  0:31                                     ` Tetsuo Handa
2018-09-05 13:20                                       ` Tetsuo Handa
2018-09-05 13:40                                         ` Michal Hocko
2018-09-05 13:53                                           ` Tetsuo Handa
2018-09-05 14:04                                             ` Michal Hocko
2018-09-06  1:00                                               ` Tetsuo Handa
2018-09-06  5:57                                                 ` Michal Hocko
2018-09-06  6:22                                                   ` Tetsuo Handa
2018-09-06  7:03                                                   ` Tetsuo Handa
2018-07-30 19:14                   ` Tejun Heo
2018-08-27 13:51 Michal Hocko

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