From: Waiman Long <longman@redhat.com>
To: Markus Elfring <Markus.Elfring@web.de>,
Chen Ridong <chenridong@huawei.com>,
cgroups@vger.kernel.org, bpf@vger.kernel.org,
Johannes Weiner <hannes@cmpxchg.org>, Tejun Heo <tj@kernel.org>,
Zefan Li <lizefan.x@bytedance.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] cgroup/cpuset: Prevent UAF in proc_cpuset_show()
Date: Sat, 22 Jun 2024 16:12:57 -0400 [thread overview]
Message-ID: <2c70eff8-c79a-4c99-b8db-491ce25745a0@redhat.com> (raw)
In-Reply-To: <b8792fb5-9efe-4dfc-ab61-6fa55a4b0d51@web.de>
On 6/22/24 16:04, Markus Elfring wrote:
> …
>> +++ b/kernel/cgroup/cpuset.c
> …
>> @@ -5051,10 +5066,12 @@ int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
>> if (!buf)
>> goto out;
>>
>> + mutex_lock(&cpuset_mutex);
>> css = task_get_css(tsk, cpuset_cgrp_id);
>> retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
>> current->nsproxy->cgroup_ns);
>> css_put(css);
>> + mutex_unlock(&cpuset_mutex);
> …
>
> Under which circumstances would you become interested to apply a statement
> like “guard(mutex)(&cpuset_mutex);”?
> https://elixir.bootlin.com/linux/v6.10-rc4/source/include/linux/mutex.h#L196
A mutex guard will be more appropriate if there is an error exit case
that needs to be handled. Otherwise, it is more straight forward and
easier to understand with the simple lock/unlock.
Cheers,
Longman
next prev parent reply other threads:[~2024-06-22 20:13 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-22 11:38 [PATCH -next] cgroup: fix uaf when proc_cpuset_show Chen Ridong
2024-06-22 13:45 ` Markus Elfring
2024-06-24 3:34 ` chenridong
2024-06-22 15:05 ` Waiman Long
2024-06-22 20:04 ` [PATCH] cgroup/cpuset: Prevent UAF in proc_cpuset_show() Markus Elfring
2024-06-22 20:12 ` Waiman Long [this message]
2024-06-23 6:18 ` Markus Elfring
2024-06-23 16:28 ` Waiman Long
2024-06-24 2:59 ` [PATCH -next] cgroup: fix uaf when proc_cpuset_show chenridong
2024-06-24 23:59 ` Waiman Long
2024-06-25 1:46 ` chenridong
2024-06-25 2:40 ` Waiman Long
2024-06-25 3:12 ` chenridong
2024-06-25 10:10 ` Michal Koutný
[not found] ` <920bbfaa-bb76-4aa1-bd07-9a552e3bfdf2@huawei.com>
2024-06-25 14:16 ` Waiman Long
2024-06-25 14:29 ` chenridong
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=2c70eff8-c79a-4c99-b8db-491ce25745a0@redhat.com \
--to=longman@redhat.com \
--cc=Markus.Elfring@web.de \
--cc=bpf@vger.kernel.org \
--cc=cgroups@vger.kernel.org \
--cc=chenridong@huawei.com \
--cc=hannes@cmpxchg.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lizefan.x@bytedance.com \
--cc=tj@kernel.org \
/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