KCSAN: data-race in mm_update_next_owner / wb_workfn (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 85a2c56c Merge tag 'pm-5.10-rc6' of git://git.kernel.org/p..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12e8addd500000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9b19d1bde60f8d
dashboard link: https://syzkaller.appspot.com/bug?extid=f3959732ea167115302e
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+f39597...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in mm_update_next_owner / wb_workfn

read-write to 0xffff888100c0c024 of 4 bytes by task 8 on cpu 0:
wb_workfn+0x243/0x410 fs/fs-writeback.c:2099
process_one_work+0x3e1/0x950 kernel/workqueue.c:2272
worker_thread+0x635/0xb90 kernel/workqueue.c:2418
kthread+0x1fd/0x220 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff888100c0c024 of 4 bytes by task 17666 on cpu 1:
mm_update_next_owner+0x1d9/0x4e0 kernel/exit.c:387
exit_mm+0x2ff/0x370 kernel/exit.c:485
do_exit+0x3c8/0x1630 kernel/exit.c:796
do_group_exit+0x16f/0x170 kernel/exit.c:906
__do_sys_exit_group+0xb/0x10 kernel/exit.c:917
__se_sys_exit_group+0x5/0x10 kernel/exit.c:915
__x64_sys_exit_group+0x16/0x20 kernel/exit.c:915
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: 17666 Comm: syz-executor.0 Not tainted 5.10.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[syzbot]

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