KCSAN: data-race in iput / move_expired_inodes

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 68d3fa23 Merge tag 'efi-urgent-for-v5.10-rc3' of git://git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13fd1705500000
kernel config: https://syzkaller.appspot.com/x/.config?x=89a86a84f1254241
dashboard link: https://syzkaller.appspot.com/bug?extid=f498927a394c8b4c3914
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f49892...@syzkaller.appspotmail.com

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

read-write to 0xffff88810d79fb18 of 8 bytes by task 324 on cpu 0:
move_expired_inodes+0x1bf/0x490 fs/fs-writeback.c:1257
queue_io+0xe1/0x2b0 fs/fs-writeback.c:1304
wb_writeback+0x255/0x660 fs/fs-writeback.c:1892
wb_do_writeback+0x101/0x5d0 fs/fs-writeback.c:2039
wb_workfn+0xb8/0x410 fs/fs-writeback.c:2080
process_one_work+0x3e1/0x950 kernel/workqueue.c:2272
worker_thread+0x635/0xb90 kernel/workqueue.c:2418
kthread+0x1fa/0x220 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff88810d79fb18 of 8 bytes by task 8459 on cpu 1:
iput+0x2e/0x510 fs/inode.c:1670
dentry_unlink_inode+0x1f3/0x210 fs/dcache.c:374
d_delete+0x70/0xa0 fs/dcache.c:2470
vfs_unlink+0x38f/0x3b0 fs/namei.c:3847
do_unlinkat+0x28a/0x4d0 fs/namei.c:3897
__do_sys_unlink fs/namei.c:3943 [inline]
__se_sys_unlink fs/namei.c:3941 [inline]
__x64_sys_unlink+0x2c/0x30 fs/namei.c:3941
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8459 Comm: syz-executor.2 Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

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