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Date:   Wed, 9 Mar 2022 13:30:10 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc:     linux-mm@kvack.org, Mike Kravetz <mike.kravetz@oracle.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        Yang Shi <shy828301@gmail.com>,
        Naoya Horiguchi <naoya.horiguchi@nec.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] mm/hwpoison: set PageHWPoison after taking page lock
 in memory_failure_hugetlb()
Message-Id: <20220309133010.0f04c2ac4939edbdb35723bb@linux-foundation.org>
In-Reply-To: <20220309091449.2753904-1-naoya.horiguchi@linux.dev>
References: <20220309091449.2753904-1-naoya.horiguchi@linux.dev>
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On Wed,  9 Mar 2022 18:14:49 +0900 Naoya Horiguchi <naoya.horiguchi@linux.dev> wrote:

> There is a race condition between memory_failure_hugetlb() and hugetlb
> free/demotion, which causes setting PageHWPoison flag on the wrong page
> (which was a hugetlb when memory_failrue() was called, but was removed
> or demoted when memory_failure_hugetlb() is called).  This results in
> killing wrong processes.  So set PageHWPoison flag with holding page lock,

What are the runtime effects of this?  Do we think a -stable backport
is needed?

Are we missing a reported-by here?  I'm too lazy to hunt down who it was.