linux-kernel - [PATCH 0/2 v4] oom: capture unreclaimable slab info in oom message when kernel panic

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: <1505947132-4363-1-git-send-email-yang.s@alibaba-inc.com>
Date:   Thu, 21 Sep 2017 06:38:50 +0800
From:   "Yang Shi" <yang.s@...baba-inc.com>
To:     cl@...ux.com, penberg@...nel.org, rientjes@...gle.com,
        iamjoonsoo.kim@....com, akpm@...ux-foundation.org,
        mhocko@...nel.org
Cc:     "Yang Shi" <yang.s@...baba-inc.com>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH 0/2 v4] oom: capture unreclaimable slab info in oom message when kernel panic

Recently we ran into a oom issue, kernel panic due to no killable process.
The dmesg shows huge unreclaimable slabs used almost 100% memory, but kdump doesn't capture vmcore due to some reason.

So, it may sound better to capture unreclaimable slab info in oom message when kernel panic to aid trouble shooting and cover the corner case.
Since kernel already panic, so capturing more information sounds worthy and doesn't bother normal oom killer.

With the patchset, tools/vm/slabinfo has a new option, "-U", to show unreclaimable slab only.

And, oom will print all non zero (num_objs * size != 0) unreclaimable slabs in oom killer message.

For details, please see the commit log for each commit.

Changelog v3 —> v4:
* Solved the comments from David
* Added David’s Acked-by in patch 1

Changelog v2 —> v3:
* Show used size and total size of each kmem cache per David’s comment

Changelog v1 —> v2:
* Removed the original patch 1 (“mm: slab: output reclaimable flag in /proc/slabinfo”) since Christoph suggested it might break the compatibility and /proc/slabinfo is legacy
* Added Christoph’s Acked-by
* Removed acquiring slab_mutex per Tetsuo’s comment

Yang Shi (2):
      tools: slabinfo: add "-U" option to show unreclaimable slabs only
      mm: oom: show unreclaimable slab info when kernel panic

 mm/oom_kill.c       |  3 +++
 mm/slab.h           |  8 ++++++++
 mm/slab_common.c    | 26 ++++++++++++++++++++++++++
 tools/vm/slabinfo.c | 11 ++++++++++-
 4 files changed, 47 insertions(+), 1 deletion(-)