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From:   Yang Shi <shy828301@gmail.com>
Date:   Fri, 3 Mar 2023 10:55:09 -0800
Message-ID: <CAHbLzkp1HdbSJsef2qvVt5txWHE36vj3h3=L=G74eXxjj6cmyA@mail.gmail.com>
Subject: Re: [PATCH v4 0/3] mm/khugepaged: fix khugepaged+shmem races
To:     Peter Xu <peterx@redhat.com>
Cc:     David Stevens <stevensd@chromium.org>, linux-mm@kvack.org,
        Matthew Wilcox <willy@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Kirill A . Shutemov" <kirill@shutemov.name>,
        David Hildenbrand <david@redhat.com>,
        Hugh Dickins <hughd@google.com>, linux-kernel@vger.kernel.org,
        "Zach O'Keefe" <zokeefe@google.com>
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On Fri, Mar 3, 2023 at 7:35=E2=80=AFAM Peter Xu <peterx@redhat.com> wrote:
>
> On Fri, Feb 17, 2023 at 05:54:36PM +0900, David Stevens wrote:
> > From: David Stevens <stevensd@chromium.org>
> >
> > Fix two races in khugepaged+shmem that cause issues with userfaultfd an=
d
> > lseek, respectively.
> >
> > v3 -> v4:
> >  - Base changes on mm-everything (fba720cb4dc0)
> >  - Add patch to refactor error handling control flow in collapse_file
> >  - Rebase userfaultfd patch with no significant logic changes
> >  - Different approach for fixing lseek race
>
> I just noticed this one hasn't landed unstable, so I guess I just posted =
a
> trivial cleanup that can conflict with this so it won't apply cleanly..
>
> https://lore.kernel.org/r/20230303151218.311015-1-peterx@redhat.com
>
> The resolution will be fairly straightforward though, and I'm happy to
> rebase that one to this since this targets a real bug so should have high=
er
> priority.
>
> I guess it's possible Andrew thought the series has unsettled comment so
> Andrew could just have ignored that whole set in the mark ups.  A repost
> could possibly clarify that.

IIUC this series should need to be rebased on top of your clean up patch?

>
> Again, it'll always great to get another eye on this slightly involved
> series. Matthew / Yang were already on the list, also copying Zach for hi=
s
> recent works on khugepaged just in case he spots anything wrong.

I had a quick look at it before, I didn't recall I spotted anything
wrong about khugepaged, but I'm not familiar with userfaultfd.

>
> Thanks,
>
> --
> Peter Xu
>