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Date:   Tue, 17 Jan 2023 14:55:32 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Jann Horn <jannh@google.com>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        "Zach O'Keefe" <zokeefe@google.com>, linux-kernel@vger.kernel.org,
        David Hildenbrand <david@redhat.com>,
        Yang Shi <shy828301@gmail.com>, linux-mm@kvack.org
Subject: Re: [PATCH] mm/khugepaged: Fix ->anon_vma race
Message-Id: <20230117145532.94132510f8bc538d5465fd43@linux-foundation.org>
In-Reply-To: <CAG48ez36Nio9GzU_m168AEJMXxtcNtdgq6YpAhLq-aKNQA_9fg@mail.gmail.com>
References: <20230111133351.807024-1-jannh@google.com>
        <CAG48ez36Nio9GzU_m168AEJMXxtcNtdgq6YpAhLq-aKNQA_9fg@mail.gmail.com>
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On Tue, 17 Jan 2023 20:12:49 +0100 Jann Horn <jannh@google.com> wrote:

> On Wed, Jan 11, 2023 at 2:33 PM Jann Horn <jannh@google.com> wrote:
> > If an ->anon_vma is attached to the VMA, collapse_and_free_pmd() requires
> > it to be locked. retract_page_tables() bails out if an ->anon_vma is
> > attached, but does this check before holding the mmap lock (as the comment
> > above the check explains).
> 
> @akpm please replace the commit message with the following, and maybe
> also add a "Link:" entry pointing to
> https://lore.kernel.org/linux-mm/CAG48ez3434wZBKFFbdx4M9j6eUwSUVPd4dxhzW_k_POneSDF+A@mail.gmail.com/
> for the reproducer.

Done, thanks.