linux-kernel - [PATCH 0/2] mm, oom: do not grant oom victims full memory reserves access

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20170727090357.3205-1-mhocko@kernel.org>
Date:   Thu, 27 Jul 2017 11:03:55 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     David Rientjes <rientjes@...gle.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Roman Gushchin <guro@...com>,
        Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
        <linux-mm@...ck.org>, LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 0/2] mm, oom: do not grant oom victims full memory reserves access

Hi,
this is a part of a larger series I posted back in Oct last year [1]. I
have dropped patch 3 because it was incorrect and patch 4 is not
applicable without it.

The primary reason to apply patch 1 is to remove a risk of the complete
memory depletion by oom victims. While this is a theoretical risk right
now there is a demand for memcg aware oom killer which might kill all
processes inside a memcg which can be a lot of tasks. That would make
the risk quite real.

This issue is addressed by limiting access to memory reserves. We no
longer use TIF_MEMDIE to grant the access and use tsk_is_oom_victim
instead. See Patch 1 for more details. Patch 2 is a trivial follow up
cleanup.

I would still like to get rid of TIF_MEMDIE completely but I do not have
time to do it now and it is not a pressing issue.

[1] http://lkml.kernel.org/r/20161004090009.7974-1-mhocko@kernel.org