Re: [syzbot] [mm?] WARNING in shmem_evict_inode

[Jiaqi Yan]

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 AM syzbot
<syzbot+3d4aa0d3e784b29b1520@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> syzbot has bisected this issue to:
>
> commit 12904d953364e3bd21789a45137bf90df7cc78ee
> Author: Jiaqi Yan <jiaqiyan@xxxxxxxxxx>
> 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=14f67032280000
> start commit:   3c4aa4434377 Merge tag 'ceph-for-6.4-rc1' of https://githu..
> git tree:       upstream
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=16f67032280000
> console output: https://syzkaller.appspot.com/x/log.txt?x=12f67032280000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c1d541e02d3faec
> dashboard link: https://syzkaller.appspot.com/bug?extid=3d4aa0d3e784b29b1520
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14d1973c280000
>
> Reported-by: syzbot+3d4aa0d3e784b29b1520@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: 12904d953364 ("mm/khugepaged: recover from poisoned file-backed memory")
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection