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References: <20210526235257.2769473-1-nao.horiguchi@gmail.com>
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From:   Muchun Song <songmuchun@bytedance.com>
Date:   Thu, 27 May 2021 10:43:44 +0800
Message-ID: <CAMZfGtXgZ1R9BSE5=sgxKwHLUdo1zCmr4QBHhncpUxJVpzfi-Q@mail.gmail.com>
Subject: Re: [External] [PATCH v1] hugetlb: pass head page to remove_hugetlb_page()
To:     Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc:     Linux Memory Management List <linux-mm@kvack.org>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Michal Hocko <mhocko@suse.com>,
        Oscar Salvador <osalvador@suse.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        David Hildenbrand <david@redhat.com>,
        Naoya Horiguchi <naoya.horiguchi@nec.com>,
        LKML <linux-kernel@vger.kernel.org>
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On Thu, May 27, 2021 at 7:53 AM Naoya Horiguchi <nao.horiguchi@gmail.com> wrote:
>
> From: Naoya Horiguchi <naoya.horiguchi@nec.com>
>
> When memory_failure() or soft_offline_page() is called on a tail page of
> some hugetlb page, "BUG: unable to handle page fault" error can be
> triggered.
>
> remove_hugetlb_page() dereferences page->lru, so it's assumed that the
> page points to a head page, but one of the caller,
> dissolve_free_huge_page(), provides remove_hugetlb_page() with 'page'
> which could be a tail page.  So pass 'head' to it, instead.
>
> Fixes: 6eb4e88a6d27 ("hugetlb: create remove_hugetlb_page() to separate functionality")
> Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>

Thanks Naoya!

Reviewed-by: Muchun Song <songmuchun@bytedance.com>