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Date: Wed, 21 Feb 2024 11:48:09 +0100
From: Michal Hocko <mhocko@suse.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: "GONG, Ruiqi" <gongruiqi1@huawei.com>, linux-kernel@vger.kernel.org,
	stable@vger.kernel.org, Johannes Weiner <hannes@cmpxchg.org>,
	Roman Gushchin <roman.gushchin@linux.dev>,
	Shakeel Butt <shakeelb@google.com>,
	Muchun Song <muchun.song@linux.dev>, cgroups@vger.kernel.org,
	linux-mm@kvack.org, Wang Weiyang <wangweiyang2@huawei.com>,
	Xiu Jianfeng <xiujianfeng@huawei.com>
Subject: Re: [PATCH stable] memcg: add refcnt for pcpu stock to avoid UAF
 problem in drain_all_stock()
Message-ID: <ZdXU6QAujPI27ita@tiehlicka>
References: <20240221081801.69764-1-gongruiqi1@huawei.com>
 <2024022119-bogged-action-c877@gregkh>
 <ZdW4xR-Ke227pxjG@tiehlicka>
 <2024022134-tackiness-earmuff-59ef@gregkh>
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In-Reply-To: <2024022134-tackiness-earmuff-59ef@gregkh>

On Wed 21-02-24 11:33:55, Greg KH wrote:
> On Wed, Feb 21, 2024 at 09:48:05AM +0100, Michal Hocko wrote:
> > On Wed 21-02-24 09:40:29, Greg KH wrote:
> > > On Wed, Feb 21, 2024 at 04:18:01PM +0800, GONG, Ruiqi wrote:
> > > > commit 1a3e1f40962c445b997151a542314f3c6097f8c3 upstream.
> > > > 
> > > > There was a kernel panic happened on an in-house environment running
> > > > 3.10, and the same problem was reproduced on 4.19:
> > > 
> > > Now queued up, thanks!
> > 
> > Give it some more time Greg, http://lkml.kernel.org/r/ZdW2gMajIw_cUN2-@tiehlicka
> 
> Oops, now dropped, thanks!

Race conditions. The thing got resolved in the mean time. The patch is a
partial backport, and I am OK with that. Now with my questions resolved
this is good to know but a note about this being a partial backport in
the changelog would be nice.

-- 
Michal Hocko
SUSE Labs