KCSAN: data-race in mm_update_next_owner / wb

KCSAN: data-race in mm_update_next_owner / wb_workfn (6)
Status: auto-closed as invalid on 2021/03/04 08:19
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 275d, last: 263d

similar bugs (7):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in mm_update_next_owner / wb_workfn (4)	1	371d	371d	0/22	auto-closed as invalid on 2020/11/16 07:19
upstream	KCSAN: data-race in mm_update_next_owner / wb_workfn (7)	1	219d	219d	0/22	auto-closed as invalid on 2021/04/17 00:26
upstream	KCSAN: data-race in mm_update_next_owner / wb_workfn (3)	2	457d	477d	0/22	auto-closed as invalid on 2020/08/22 21:27
upstream	KCSAN: data-race in mm_update_next_owner / wb_workfn (5)	2	311d	315d	0/22	auto-closed as invalid on 2021/01/15 21:05
upstream	KCSAN: data-race in mm_update_next_owner / wb_workfn (2)	3	567d	657d	0/22	auto-closed as invalid on 2020/06/08 08:14
upstream	KCSAN: data-race in mm_update_next_owner / wb_workfn (8)	4	150d	160d	0/22	auto-closed as invalid on 2021/06/25 06:02
upstream	KCSAN: data-race in mm_update_next_owner / wb_workfn	2	710d	721d	0/22	closed as invalid on 2019/11/19 14:44

Sample crash report:

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

read-write to 0xffff888012ecb02c of 4 bytes by task 12613 on cpu 1:
 wb_workfn+0x6d/0x410 fs/fs-writeback.c:2071
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275
 worker_thread+0x64a/0xaa0 kernel/workqueue.c:2421
 kthread+0x1fd/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff888012ecb02c of 4 bytes by task 15638 on cpu 0:
 mm_update_next_owner+0x1d9/0x4e0 kernel/exit.c:388
 exit_mm+0x327/0x420 kernel/exit.c:500
 do_exit+0x41f/0x1690 kernel/exit.c:812
 do_group_exit+0x16f/0x170 kernel/exit.c:922
 __do_sys_exit_group+0xb/0x10 kernel/exit.c:933
 __se_sys_exit_group+0x5/0x10 kernel/exit.c:931
 __x64_sys_exit_group+0x16/0x20 kernel/exit.c:931
 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: 15638 Comm: syz-executor.5 Not tainted 5.11.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (2):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2021/01/28 08:17	upstream	76c057c84d28	eefc07f2	.config	log	report			info	KCSAN: data-race in mm_update_next_owner / wb_workfn
ci2-upstream-kcsan-gce	2021/01/16 11:32	upstream	1d94330a437a	65a7a854	.config	log	report			info