From: Markus Elfring <Markus.Elfring@web.de>
To: "Chen Ridong" <chenridong@huawei.com>,
cgroups@vger.kernel.org, "Aditya Kali" <adityakali@google.com>,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Michal Koutný" <mkoutny@suse.com>,
"Serge Hallyn" <sergeh@kernel.org>, "Tejun Heo" <tj@kernel.org>,
"Waiman Long" <longman@redhat.com>,
"Zefan Li" <lizefan.x@bytedance.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH V4] cgroup/cpuset: Prevent UAF in proc_cpuset_show()
Date: Sun, 30 Jun 2024 11:20:58 +0200 [thread overview]
Message-ID: <e5a78840-b623-485c-b467-828a5a0b7d37@web.de> (raw)
In-Reply-To: <20240628013604.573498-1-chenridong@huawei.com>
…
> +++ b/kernel/cgroup/cpuset.c
…
> @@ -5051,10 +5052,14 @@ int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
> if (!buf)
> goto out;
>
> - css = task_get_css(tsk, cpuset_cgrp_id);
> - retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
> - current->nsproxy->cgroup_ns);
> - css_put(css);
> + rcu_read_lock();
> + spin_lock_irq(&css_set_lock);
> + css = task_css(tsk, cpuset_cgrp_id);
> + retval = cgroup_path_ns_locked(css->cgroup, buf, PATH_MAX,
> + current->nsproxy->cgroup_ns);
> + spin_unlock_irq(&css_set_lock);
> + rcu_read_unlock();
…
Under which circumstances would you become interested to apply statements
like the following?
* guard(rcu)();
https://elixir.bootlin.com/linux/v6.10-rc5/source/include/linux/rcupdate.h#L1093
* guard(spinlock_irq)(&css_set_lock);
https://elixir.bootlin.com/linux/v6.10-rc5/source/include/linux/spinlock.h#L567
Regards,
Markus
next prev parent reply other threads:[~2024-06-30 9:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-28 1:36 Chen Ridong
2024-06-28 17:11 ` Tejun Heo
2024-06-30 9:20 ` Markus Elfring [this message]
2024-06-30 17:03 ` Tejun Heo
2024-06-30 18:00 ` [V4] " Markus Elfring
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