Re: [syzbot] [nilfs2?] INFO: task hung in nilfs_segctor_thread

From: Dmitry Vyukov
Date: Wed Feb 15 2023 - 03:53:11 EST


On Wed, 15 Feb 2023 at 07:02, Yu Zhao <yuzhao@xxxxxxxxxx> wrote:
> > On Tue, 14 Feb 2023 00:14:42 -0800
> > > syzbot has found a reproducer for the following issue on:
> > >
> > > HEAD commit: f6feea56f66d Merge tag 'mm-hotfixes-stable-2023-02-13-13-5..
> > > git tree: upstream
> > > console+strace: https://syzkaller.appspot.com/x/log.txt?x=165ee62b480000
> > > kernel config: https://syzkaller.appspot.com/x/.config?x=42ba4da8e1e6af9f
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=f0c4082ce5ebebdac63b
> > > compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
> > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14ba7207480000
> > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15fd30d0c80000
> > >
> > > Downloadable assets:
> > > disk image: https://storage.googleapis.com/syzbot-assets/1ae0143f08d5/disk-f6feea56.raw.xz
> > > vmlinux: https://storage.googleapis.com/syzbot-assets/18b8a23fa0cb/vmlinux-f6feea56.xz
> > > kernel image: https://storage.googleapis.com/syzbot-assets/d915f4c5c8c0/bzImage-f6feea56.xz
> > > mounted in repro: https://storage.googleapis.com/syzbot-assets/1acd3b288433/mount_0.gz
> > >
>
> > > folio_mark_accessed+0x51c/0xf00 mm/swap.c:515
> >
> > Syzbot was launched without MGLRU enabled [1].
> > Dmitry could you turn it on by default?
>
> Thanks for the heads up!
>
> (I should have followed up with Dmitry earlier... doing it now.)

Here is configs change (speak up if you don't agree with something):
https://github.com/google/syzkaller/pull/3683/commits/e3c95b410e328b52fef013a8071e47c6c278b1ed