KCSAN: data-race in get_signal / ptrace_check

KCSAN: data-race in get_signal / ptrace_check_attach (2)
Status: moderation: reported on 2020/09/21 10:02
Reported-by: syzbot+670667eef68c9ab0c5fc@syzkaller.appspotmail.com
First crash: 324d, last: 2h02m

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in get_signal / ptrace_check_attach				23	329d	524d	0/22	closed as invalid on 2020/06/18 14:24

Sample crash report:

==================================================================
BUG: KCSAN: data-race in get_signal / ptrace_check_attach

write to 0xffff888136454518 of 8 bytes by task 8390 on cpu 0:
 ptrace_signal kernel/signal.c:2526 [inline]
 get_signal+0xbd7/0x1610 kernel/signal.c:2706
 arch_do_signal_or_restart+0x2a/0x220 arch/x86/kernel/signal.c:789
 handle_signal_work kernel/entry/common.c:147 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x109/0x190 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

read to 0xffff888136454518 of 8 bytes by task 8410 on cpu 1:
 ptrace_freeze_traced kernel/ptrace.c:179 [inline]
 ptrace_check_attach+0x144/0x250 kernel/ptrace.c:248
 __do_sys_ptrace kernel/ptrace.c:1291 [inline]
 __se_sys_ptrace+0xd8/0x1b0 kernel/ptrace.c:1261
 __x64_sys_ptrace+0x51/0x60 kernel/ptrace.c:1261
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8410 Comm: syz-executor.1 Tainted: G        W         5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (168):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Title
ci2-upstream-kcsan-gce	2021/05/09 18:22	upstream	b7415964	bc5434be	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/05/08 00:45	upstream	1ad77a05	bc5434be	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/05/07 04:41	upstream	e4866123	06585184	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/05/06 18:09	upstream	8404c9fb	06585184	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/05/05 06:25	upstream	d665ea6e	06c27ff5	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/05/04 00:37	upstream	6f8ee8d3	ad61f371	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/05/02 11:53	upstream	17ae69ab	77e2b668	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/05/01 03:05	upstream	65c61de9	77e2b668	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/30 01:18	upstream	8ca5297e	77e2b668	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/29 10:57	upstream	d72cd4ad	77e2b668	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/29 00:42	upstream	68a32ba1	77e2b668	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/28 06:15	upstream	e359bce3	77e2b668	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/28 03:29	upstream	e359bce3	805b5003	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/27 19:09	upstream	4a0225c3	805b5003	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/26 11:07	upstream	9f4ad9e4	805b5003	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/26 02:47	upstream	d2d09fbe	2a82f1b3	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/25 19:05	upstream	d2d09fbe	36c88236	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/24 02:16	upstream	8db5efb8	17f0b706	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/23 15:11	upstream	18a3c5f7	17f0b706	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/23 08:56	upstream	90c911ad	590921a5	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/22 13:08	upstream	16fc44d6	33c28d03	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/22 08:29	upstream	16fc44d6	2bc8999a	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/20 11:18	upstream	7af08140	c0ced557	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/20 01:13	upstream	7af08140	4285c989	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/19 04:04	upstream	bf05bf16	7e2b734b	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/18 11:41	upstream	c98ff1d0	7e2b734b	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/16 23:13	upstream	2f7b98d1	7e2b734b	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/16 12:51	upstream	7e25f40e	7e2b734b	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/15 21:00	upstream	7f75285c	c59079a6	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/14 22:55	upstream	7f75285c	fcdb12ba	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/13 22:18	upstream	eebe426d	a184b83e	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/10 11:52	upstream	4e04e751	6a81331a	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/07 13:49	upstream	2d743660	6a81331a	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/06 01:21	upstream	0a50438c	6a81331a	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/05 07:22	upstream	e49d033b	6a81331a	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/03 00:06	upstream	0a84c2e4	6a81331a	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/04/02 15:51	upstream	1678e493	6a81331a	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/03/30 17:59	upstream	2bb25b3a	6a81331a	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/03/30 01:58	upstream	1e43c377	6a81331a	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/03/29 16:43	upstream	a5e13c6d	a8529b82	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/03/28 10:08	upstream	0f4498ce	a8529b82	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/03/26 21:09	upstream	db24726b	a8529b82	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/03/25 04:59	upstream	4ee998b0	607e3baf	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/03/23 02:09	upstream	0d02ec6b	8092f30d	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/03/18 16:10	upstream	6417f031	7216542e	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/03/18 03:53	upstream	6417f031	fdb2bb2c	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/03/16 12:35	upstream	1a4431a5	fdb2bb2c	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/03/14 05:39	upstream	88fe4924	4a003785	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/03/10 22:40	upstream	05a59d79	764067f3	.config	log	report	info	KCSAN: data-race in get_signal / ptrace_check_attach
ci2-upstream-kcsan-gce	2021/01/14 05:24	upstream	65f0d241	269d24e8	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/20 20:44	upstream	bdcf11de	9564d2e9	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/20 05:49	upstream	325d0eab	53ce8104	.config	log	report	info
ci2-upstream-kcsan-gce	2020/06/19 04:15	upstream	5e857ce6	bc258b50	.config	log	report