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References: <20210401030141.37061-1-songmuchun@bytedance.com>
In-Reply-To: <20210401030141.37061-1-songmuchun@bytedance.com>
From:   Shakeel Butt <shakeelb@google.com>
Date:   Wed, 31 Mar 2021 20:04:48 -0700
Message-ID: <CALvZod6pg1N4FLEAtjD5=nfBr9vA-3G-BBezbW=PhuOY+d__1g@mail.gmail.com>
Subject: Re: [PATCH] mm: memcontrol: fix forget to obtain the ref to objcg in split_page_memcg
To:     Muchun Song <songmuchun@bytedance.com>
Cc:     Roman Gushchin <guro@fb.com>, Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>,
        Xiongchun duan <duanxiongchun@bytedance.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>
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On Wed, Mar 31, 2021 at 8:02 PM Muchun Song <songmuchun@bytedance.com> wrote:
>
> Christian Borntraeger reported a warning about "percpu ref
> (obj_cgroup_release) <= 0 (-1) after switching to atomic".
> Because we forgot to obtain the reference to the objcg and
> wrongly obtain the reference of memcg.
>
> Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>

Looks good to me.

Reviewed-by: Shakeel Butt <shakeelb@google.com>