KCSAN: data-race in io_wqe_worker / mm_update_next

KCSAN: data-race in io_wqe_worker / mm_update_next_owner (2)
Status: auto-closed as invalid on 2020/11/23 20:14
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 419d, last: 405d

similar bugs (3):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in io_wqe_worker / mm_update_next_owner (4)	1	313d	313d	0/22	auto-closed as invalid on 2021/02/23 15:55
upstream	KCSAN: data-race in io_wqe_worker / mm_update_next_owner	1	597d	597d	0/22	auto-closed as invalid on 2020/06/18 13:53
upstream	KCSAN: data-race in io_wqe_worker / mm_update_next_owner (3)	2	350d	356d	0/22	auto-closed as invalid on 2021/01/17 04:50

Sample crash report:

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

read-write to 0xffff88812b736024 of 4 bytes by task 7498 on cpu 0:
 io_worker_exit fs/io-wq.c:226 [inline]
 io_wqe_worker+0x55f/0x810 fs/io-wq.c:617
 kthread+0x1ff/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff88812b736024 of 4 bytes by task 7501 on cpu 1:
 mm_update_next_owner+0x1e9/0x4c0 kernel/exit.c:387
 exit_mm+0x2b5/0x320 kernel/exit.c:482
 do_exit+0x40e/0x1670 kernel/exit.c:793
 do_group_exit+0x16f/0x170 kernel/exit.c:903
 __do_sys_exit_group+0xb/0x10 kernel/exit.c:914
 __se_sys_exit_group+0x5/0x10 kernel/exit.c:912
 __x64_sys_exit_group+0x16/0x20 kernel/exit.c:912
 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: 7501 Comm: syz-executor.2 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (3):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info
ci2-upstream-kcsan-gce	2020/10/19 20:08	upstream	7cf726a59435	ff4a3345	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/17 10:50	upstream	54a4c789ca80	6e262c73	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/05 10:08	upstream	549738f15da0	5ef9c291	.config	log	report	info