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Date: Wed, 14 Aug 2024 19:45:54 +0200
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>
Cc: stable@vger.kernel.org, patches@lists.linux.dev,
	Chen Ridong <chenridong@huawei.com>, Tejun Heo <tj@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: Re: [PATCH 6.6 017/568] cgroup/cpuset: Prevent UAF in
 proc_cpuset_show()
Message-ID: <2024081444-outwit-panic-83fa@gregkh>
References: <20240730151639.792277039@linuxfoundation.org>
 <20240730151640.503086745@linuxfoundation.org>
 <xrc6s5oyf3b5hflsffklogluuvd75h2khanrke2laes3en5js2@6kvpkcxs7ufj>
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In-Reply-To: <xrc6s5oyf3b5hflsffklogluuvd75h2khanrke2laes3en5js2@6kvpkcxs7ufj>

On Wed, Aug 14, 2024 at 02:05:59PM +0200, Michal Koutný wrote:
> Hello.
> 
> On Tue, Jul 30, 2024 at 05:42:04PM GMT, Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> > ...
> > Fix this problem by using rcu_read_lock in proc_cpuset_show().
> > As cgroup_root is kfree_rcu after commit d23b5c577715
> > ("cgroup: Make operations on the cgroup root_list RCU safe"),
> > css->cgroup won't be freed during the critical section.
> > To call cgroup_path_ns_locked, css_set_lock is needed, so it is safe to
> > replace task_get_css with task_css.
> 
> This backport requires also the mentioned d23b5c577715 to be
> effective (I noticed that is missing in 6.6.y at the moment).

It is in 6.6.44.

thanks,

greg k-h