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Date: Sat, 23 Mar 2024 19:36:55 +1100
From: Dave Chinner <david@fromorbit.com>
To: syzbot <syzbot+7766d4a620956dfe7070@syzkaller.appspotmail.com>
Cc: chandan.babu@oracle.com, djwong@kernel.org,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-xfs@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [xfs?] possible deadlock in xfs_icwalk_ag
Message-ID: <Zf6Up3AbYnELO6P2@dread.disaster.area>
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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