[moderation] [ext4?] KCSAN: data-race in __writeback_single_inode / iput (6)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4652b8e4f3ff Merge tag '6.7-rc-ksmbd-server-fixes' of git:..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15e6f140e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=561f2d77dae76e1b
dashboard link: https://syzkaller.appspot.com/bug?extid=32f6c22cbfc7a3d98f1e
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [adilger...@dilger.ca bra...@kernel.org linux...@vger.kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org ty...@mit.edu vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6404911ced49/disk-4652b8e4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/811b8c84dc1a/vmlinux-4652b8e4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b68ddd8f7b64/bzImage-4652b8e4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+32f6c2...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __writeback_single_inode / iput

read-write to 0xffff8881005b0438 of 8 bytes by task 22711 on cpu 1:
__writeback_single_inode+0x201/0x860 fs/fs-writeback.c:1661
writeback_sb_inodes+0x514/0xad0 fs/fs-writeback.c:1916
__writeback_inodes_wb+0x9a/0x1a0 fs/fs-writeback.c:1987
wb_writeback+0x264/0x6e0 fs/fs-writeback.c:2094
wb_check_background_flush fs/fs-writeback.c:2164 [inline]
wb_do_writeback fs/fs-writeback.c:2252 [inline]
wb_workfn+0x67f/0x8d0 fs/fs-writeback.c:2279
process_one_work kernel/workqueue.c:2630 [inline]
process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2703
worker_thread+0x525/0x730 kernel/workqueue.c:2784
kthread+0x1d7/0x210 kernel/kthread.c:388
ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

read to 0xffff8881005b0438 of 8 bytes by task 23282 on cpu 0:
iput+0x32/0x5b0 fs/inode.c:1791
blkdev_get_no_open+0xaf/0xe0 block/bdev.c:722
blkdev_get_by_dev+0x64/0x390 block/bdev.c:767
bdev_open_by_dev+0x56/0xd0 block/bdev.c:840
blkdev_open+0xfb/0x200 block/fops.c:600
do_dentry_open+0x635/0xbd0 fs/open.c:948
vfs_open+0x4a/0x50 fs/open.c:1082
do_open fs/namei.c:3622 [inline]
path_openat+0x1819/0x1d70 fs/namei.c:3779
do_filp_open+0xf6/0x200 fs/namei.c:3809
do_sys_openat2+0xab/0x110 fs/open.c:1440
do_sys_open fs/open.c:1455 [inline]
__do_sys_openat fs/open.c:1471 [inline]
__se_sys_openat fs/open.c:1466 [inline]
__x64_sys_openat+0xf3/0x120 fs/open.c:1466
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000020084 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 23282 Comm: udevd Tainted: G W 6.6.0-syzkaller-10396-g4652b8e4f3ff #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.