KCSAN: data-race in exit_signals / kthread

KCSAN: data-race in exit_signals / kthread_unpark (3)
Status: auto-closed as invalid on 2021/07/05 17:15
Reported-by: syzbot+3cf231e9e732c716afe4@syzkaller.appspotmail.com
First crash: 386d, last: 57d

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in exit_signals / kthread_unpark				3	631d	634d	0/22	closed as invalid on 2019/11/19 13:44
upstream	KCSAN: data-race in exit_signals / kthread_unpark (2)				19	415d	614d	0/22	closed as invalid on 2020/06/18 14:24

Sample crash report:

==================================================================
BUG: KCSAN: data-race in exit_signals / kthread_unpark

write to 0xffff88812702906c of 4 bytes by task 8594 on cpu 0:
 exit_signals+0xe1/0x4a0 kernel/signal.c:2927
 do_exit+0x194/0x1560 kernel/exit.c:782
 kthread+0x1d8/0x1f0 kernel/kthread.c:315
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff88812702906c of 4 bytes by task 1767 on cpu 1:
 to_kthread kernel/kthread.c:83 [inline]
 kthread_unpark+0x1f/0x150 kernel/kthread.c:557
 kthread_stop+0xa6/0x250 kernel/kthread.c:640
 loop_unprepare_queue drivers/block/loop.c:927 [inline]
 __loop_clr_fd+0x4cb/0x640 drivers/block/loop.c:1258
 lo_release+0xfc/0x120 drivers/block/loop.c:1924
 __blkdev_put+0x408/0x460 fs/block_dev.c:1583
 blkdev_put+0x23e/0x2c0 fs/block_dev.c:1636
 kill_block_super+0x7b/0x90 fs/super.c:1398
 deactivate_locked_super+0x65/0xd0 fs/super.c:335
 deactivate_super+0x85/0x90 fs/super.c:366
 cleanup_mnt+0x267/0x2d0 fs/namespace.c:1136
 __cleanup_mnt+0x15/0x20 fs/namespace.c:1143
 task_work_run+0xae/0x130 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x156/0x190 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:301
 do_syscall_64+0x56/0x90 arch/x86/entry/common.c:57
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00388040 -> 0x00388044

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1767 Comm: syz-executor.5 Not tainted 5.13.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (48):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Title
ci2-upstream-kcsan-gce	2021/05/31 17:14	upstream	c2131f7e73c9	032639db	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/05/07 22:37	upstream	1ad77a05cfae	bc5434be	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/04/21 05:29	upstream	1fe5501ba1ab	c0ced557	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/04/16 20:36	upstream	2f7b98d1e55c	7e2b734b	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/03/30 05:43	upstream	1e43c377a79f	6a81331a	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/03/28 23:08	upstream	36a14638f7c0	a8529b82	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/03/27 08:12	upstream	0f4498cef9f5	a8529b82	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/03/26 13:09	upstream	db24726bfefa	a8529b82	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/03/22 03:52	upstream	5ee96fa9dd78	bea32f74	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/03/17 06:09	upstream	1df27313f50a	fdb2bb2c	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/03/16 07:12	upstream	1a4431a5db2b	fdb2bb2c	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/03/16 01:49	upstream	1e28eed17697	fdb2bb2c	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/03/14 16:27	upstream	88fe49249c99	4a003785	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/02/21 16:37	upstream	e767b3530acb	3e5ed8b4	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/02/21 03:23	upstream	f40ddce88593	3e5ed8b4	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/02/20 09:26	upstream	f40ddce88593	f689d40a	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/02/11 19:21	upstream	291009f656e8	a5f86b15	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/02/11 10:39	upstream	291009f656e8	a52ee10a	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/01/27 02:44	upstream	13391c60da33	55a7d4df	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/01/24 10:43	upstream	e1ae4b0be158	52e37319	.config	log	report	info	KCSAN: data-race in exit_signals / kthread_unpark
ci2-upstream-kcsan-gce	2021/01/05 11:55	upstream	36bbbd0e234d	a0234d98	.config	log	report	info
ci2-upstream-kcsan-gce	2021/01/02 18:40	upstream	eda809aef534	79264ae3	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/20 22:35	upstream	6a447b0e3151	04201c06	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/19 01:40	upstream	3644e2d2dda7	04201c06	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/30 17:13	upstream	b65054597872	76831598	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/24 01:31	upstream	418baf2c28f3	878fb17a	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/23 14:13	upstream	418baf2c28f3	0d27f508	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/23 06:02	upstream	68d3fa235fd8	0d27f508	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/16 14:48	upstream	09162bc32c88	1bf9a662	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/14 03:11	upstream	9e6a39eae450	1bf9a662	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/09 20:06	upstream	f8394f232b1e	cba33199	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/04 19:17	upstream	4ef8451b3326	cba33199	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/26 21:21	upstream	3650b228f83a	a7aac492	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/20 18:11	upstream	270315b8235e	ff4a3345	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/18 09:27	upstream	9d9af1007bc0	fea47c01	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/15 23:01	upstream	726eb70e0d34	6e262c73	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/14 09:47	upstream	6ad4bf6ea160	fc7735a2	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/09 03:25	upstream	3d006ee42dde	92390980	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/01 22:35	upstream	fcadab740480	9602ddf4	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/10 06:11	upstream	34d4ddd359db	ac7ca78e	.config	log	report
ci2-upstream-kcsan-gce	2020/08/31 07:36	upstream	dcc5c6f013d8	d5a3ae1f	.config	log	report
ci2-upstream-kcsan-gce	2020/08/19 10:01	upstream	18445bf405cb	e1c29030	.config	log	report
ci2-upstream-kcsan-gce	2020/08/15 14:24	upstream	c9c9735c46f5	5ce13532	.config	log	report
ci2-upstream-kcsan-gce	2020/08/15 01:05	upstream	a1d21081a60d	5ce13532	.config	log	report
ci2-upstream-kcsan-gce	2020/08/07 15:05	upstream	86cfccb66937	28ac5c9e	.config	log	report
ci2-upstream-kcsan-gce	2020/07/27 19:42	upstream	92ed30191993	cb93dc6a	.config	log	report
ci2-upstream-kcsan-gce	2020/07/19 01:54	upstream	6cf7ccba29dc	9c812472	.config	log	report
ci2-upstream-kcsan-gce	2020/07/06 20:55	upstream	5c82ec00dd00	ef278c73	.config	log	report