From: Andrew Morton <akpm@linux-foundation.org>
To: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: gorcunov@openvz.org, mhocko@suse.com, aryabinin@virtuozzo.com,
hannes@cmpxchg.org, penguin-kernel@I-love.SAKURA.ne.jp,
shakeelb@google.com, jbacik@fb.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: Fix int overflow in callers of do_shrink_slab()
Date: Fri, 28 Sep 2018 14:15:09 -0700 [thread overview]
Message-ID: <20180928141509.fd8f8ac8c0ea61f0cb79d494@linux-foundation.org> (raw)
In-Reply-To: <153813407177.17544.14888305435570723973.stgit@localhost.localdomain>
On Fri, 28 Sep 2018 14:28:32 +0300 Kirill Tkhai <ktkhai@virtuozzo.com> wrote:
> do_shrink_slab() returns unsigned long value, and
> the placing into int variable cuts high bytes off.
> Then we compare ret and 0xfffffffe (since SHRINK_EMPTY
> is converted to ret type).
>
> Thus, big number of objects returned by do_shrink_slab()
> may be interpreted as SHRINK_EMPTY, if low bytes of
> their value are equal to 0xfffffffe. Fix that
> by declaration ret as unsigned long in these functions.
Sigh. How many times has this happened.
> Reported-by: Cyrill Gorcunov <gorcunov@openvz.org>
What did he report? Was it code inspection? Did the kernel explode?
etcetera. I'm thinking that the fix should be backported but to
determine that, we need to understand the end-user runtime effects, as
always. Please.
next prev parent reply other threads:[~2018-09-28 21:15 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-28 11:28 Kirill Tkhai
2018-09-28 11:34 ` Cyrill Gorcunov
2018-09-28 11:35 ` Josef Bacik
2018-09-28 21:15 ` Andrew Morton [this message]
2018-09-28 21:21 ` Cyrill Gorcunov
2018-09-28 23:58 ` Kirill Tkhai
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180928141509.fd8f8ac8c0ea61f0cb79d494@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=aryabinin@virtuozzo.com \
--cc=gorcunov@openvz.org \
--cc=hannes@cmpxchg.org \
--cc=jbacik@fb.com \
--cc=ktkhai@virtuozzo.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=penguin-kernel@I-love.SAKURA.ne.jp \
--cc=shakeelb@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox