From: Waiman Long <longman@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: "Jens Axboe" <axboe@kernel.dk>,
"Josef Bacik" <josef@toxicpanda.com>,
"Zefan Li" <lizefan.x@bytedance.com>,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
cgroups@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
"Michal Koutný" <mkoutny@suse.com>,
"Dennis Zhou (Facebook)" <dennisszhou@gmail.com>,
"Yi Zhang" <yi.zhang@redhat.com>
Subject: Re: [PATCH-block v2 1/3] bdi, blk-cgroup: Fix potential UAF of blkcg
Date: Mon, 12 Dec 2022 17:16:38 -0500 [thread overview]
Message-ID: <b60f19c9-1e40-d621-dae5-f42bf99d6e90@redhat.com> (raw)
In-Reply-To: <Y5enmzQM7BIiEv9n@slm.duckdns.org>
On 12/12/22 17:13, Tejun Heo wrote:
> On Sun, Dec 11, 2022 at 05:20:56PM -0500, Waiman Long wrote:
>> static void blkcg_destroy_blkgs(struct blkcg *blkcg)
>> {
>> + /*
>> + * blkcg_destroy_blkgs() shouldn't be called with all the blkcg
>> + * references gone.
>> + */
>> + if (WARN_ON_ONCE(!css_tryget(&blkcg->css)))
>> + return;
> Wouldn't it make more sense to use percpu_ref_is_zero()? It's not like the
> obtained extra reference does anything, right?
Yes, that makes sense. Will incorporate the change in the next version.
Thanks,
Longman
next prev parent reply other threads:[~2022-12-12 22:16 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-11 22:20 [PATCH-block v2 0/3] blk-cgroup: Fix potential UAF & miscellaneous cleanup Waiman Long
2022-12-11 22:20 ` [PATCH-block v2 1/3] bdi, blk-cgroup: Fix potential UAF of blkcg Waiman Long
2022-12-12 22:13 ` Tejun Heo
2022-12-12 22:16 ` Waiman Long [this message]
2022-12-11 22:20 ` [PATCH-block v2 2/3] blk-cgroup: Don't flush a blkg if destroyed Waiman Long
2022-12-12 12:59 ` Michal Koutný
2022-12-12 14:58 ` Waiman Long
2022-12-12 22:16 ` Tejun Heo
2022-12-13 0:21 ` Waiman Long
2022-12-11 22:20 ` [PATCH-block v2 3/3] blk-cgroup: Flush stats at blkgs destruction path Waiman Long
2022-12-12 22:24 ` Tejun Heo
2022-12-13 0:19 ` Waiman Long
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=b60f19c9-1e40-d621-dae5-f42bf99d6e90@redhat.com \
--to=longman@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=axboe@kernel.dk \
--cc=cgroups@vger.kernel.org \
--cc=dennisszhou@gmail.com \
--cc=hannes@cmpxchg.org \
--cc=josef@toxicpanda.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lizefan.x@bytedance.com \
--cc=mkoutny@suse.com \
--cc=tj@kernel.org \
--cc=yi.zhang@redhat.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