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From:   Jiaqi Yan <jiaqiyan@google.com>
Date:   Fri, 5 May 2023 20:02:13 -0700
Message-ID: <CACw3F53T=bbn6f6db_T_5=udLq-cvChYALhmmpQ1QOkjH-7gpg@mail.gmail.com>
Subject: Re: [syzbot] [mm?] WARNING in shmem_evict_inode
To:     syzbot <syzbot+3d4aa0d3e784b29b1520@syzkaller.appspotmail.com>
Cc:     akpm@linux-foundation.org, hughd@google.com,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        shy828301@gmail.com, syzkaller-bugs@googlegroups.com
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It seems commit 12904d953364 caused the WARNING  when MADV_COLLAPSE on
shmem memory, but right now the root cause is still unclear to me
after some digging. Will keep digging and/or try to repro over the
weekend.

On Fri, May 5, 2023 at 9:51=E2=80=AFAM syzbot
<syzbot+3d4aa0d3e784b29b1520@syzkaller.appspotmail.com> wrote:
>
> syzbot has bisected this issue to:
>
> commit 12904d953364e3bd21789a45137bf90df7cc78ee
> Author: Jiaqi Yan <jiaqiyan@google.com>
> Date:   Wed Mar 29 15:11:21 2023 +0000
>
>     mm/khugepaged: recover from poisoned file-backed memory
>
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=3D14f6703228=
0000
> start commit:   3c4aa4434377 Merge tag 'ceph-for-6.4-rc1' of https://gith=
u..
> git tree:       upstream
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=3D16f6703228=
0000
> console output: https://syzkaller.appspot.com/x/log.txt?x=3D12f6703228000=
0
> kernel config:  https://syzkaller.appspot.com/x/.config?x=3Dc1d541e02d3fa=
ec
> dashboard link: https://syzkaller.appspot.com/bug?extid=3D3d4aa0d3e784b29=
b1520
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=3D14d1973c280=
000
>
> Reported-by: syzbot+3d4aa0d3e784b29b1520@syzkaller.appspotmail.com
> Fixes: 12904d953364 ("mm/khugepaged: recover from poisoned file-backed me=
mory")
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisect=
ion