linux-kernel - [RFC] 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: <1505409289-57031-1-git-send-email-yang.s@alibaba-inc.com>
Date:   Fri, 15 Sep 2017 01:14:46 +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
Cc:     "Yang Shi" <yang.s@...baba-inc.com>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>
Subject: [RFC] 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, /proc/slabinfo can print an extra column for reclaimable
flag and 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.

Yang Shi (3):
      mm: slab: output reclaimable flag in /proc/slabinfo
      tools: slabinfo: add "-U" option to show unreclaimable slabs only
      mm: oom: show unreclaimable slab info when kernel panic

 mm/oom_kill.c       | 13 +++++++++++--
 mm/slab.c           |  1 +
 mm/slab.h           |  7 +++++++
 mm/slab_common.c    | 27 +++++++++++++++++++++++++++
 mm/slub.c           |  1 +
 tools/vm/slabinfo.c | 11 ++++++++++-
 6 files changed, 57 insertions(+), 3 deletions(-)