KCSAN: data-race in kcompactd / mm_update_next_owner (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b6505459 Linux 5.10-rc6
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1550151d500000
kernel config: https://syzkaller.appspot.com/x/.config?x=c949fed53798f819
dashboard link: https://syzkaller.appspot.com/bug?extid=c011c9a099437b856992
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linu...@kvack.org]

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+c011c9...@syzkaller.appspotmail.com

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

read-write to 0xffff8881017cb064 of 4 bytes by task 1655 on cpu 1:
freezer_do_not_count include/linux/freezer.h:109 [inline]
freezable_schedule_timeout include/linux/freezer.h:191 [inline]
kcompactd+0x366/0xde0 mm/compaction.c:2818
kthread+0x1fd/0x220 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff8881017cb064 of 4 bytes by task 13305 on cpu 0:
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: 0 PID: 13305 Comm: syz-executor.4 Not tainted 5.10.0-rc6-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.