Re: [syzbot] [xfs?] possible deadlock in xfs_icwalk_ag

Dave Chinner
2024-03-23T08:37:00Z

On Sat, Mar 23, 2024 at 01:09:28AM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: fe46a7dd189e Merge tag 'sound-6.9-rc1' of git://git.kernel..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=11525d81180000
> kernel config: https://syzkaller.appspot.com/x/.config?x=fe78468a74fdc3b7
> dashboard link: https://syzkaller.appspot.com/bug?extid=7766d4a620956dfe7070
> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/0f7abe4afac7/disk-fe46a7dd.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/82598d09246c/vmlinux-fe46a7dd.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/efa23788c875/bzImage-fe46a7dd.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+7766d4a620956dfe7070@syzkaller.appspotmail.com
>
> ======================================================
> WARNING: possible circular locking dependency detected
> 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Not tainted
> ------------------------------------------------------
> kswapd0/89 is trying to acquire lock:
> ffff88814af18118 (&xfs_dir_ilock_class){++++}-{3:3}, at: xfs_reclaim_inode fs/xfs/xfs_icache.c:945 [inline]
> ffff88814af18118 (&xfs_dir_ilock_class){++++}-{3:3}, at: xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1631 [inline]
> ffff88814af18118 (&xfs_dir_ilock_class){++++}-{3:3}, at: xfs_icwalk_ag+0x1216/0x1aa0 fs/xfs/xfs_icache.c:1713
>
> but task is already holding lock:
> ffffffff8e21f720 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6774 [inline]
> ffffffff8e21f720 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb3f/0x36e0 mm/vmscan.c:7146
>
> which lock already depends on the new lock.

#syz dup: possible deadlock in xfs_qm_dqget_cache_insert

--
Dave Chinner
david@fromorbit.com