KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char

KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
Status: moderation: reported on 2019/12/12 22:35
Reported-by: syzbot+6636788b7ec318c30f07@syzkaller.appspotmail.com
First crash: 546d, last: 10h56m

Sample crash report:

==================================================================
BUG: KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special

write to 0xffffc9000f13d018 of 8 bytes by task 6592 on cpu 0:
 echo_char_raw drivers/tty/n_tty.c:840 [inline]
 eraser drivers/tty/n_tty.c:1075 [inline]
 n_tty_receive_char_special+0x1797/0x3ac0 drivers/tty/n_tty.c:1312
 n_tty_receive_buf_fast drivers/tty/n_tty.c:1606 [inline]
 __receive_buf drivers/tty/n_tty.c:1640 [inline]
 n_tty_receive_buf_common+0xe0c/0x1e20 drivers/tty/n_tty.c:1739
 n_tty_receive_buf+0x2b/0x40 drivers/tty/n_tty.c:1768
 tiocsti drivers/tty/tty_io.c:2316 [inline]
 tty_ioctl+0x96f/0x1130 drivers/tty/tty_io.c:2717
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffffc9000f13d018 of 8 bytes by task 22 on cpu 1:
 add_echo_byte drivers/tty/n_tty.c:839 [inline]
 echo_char drivers/tty/n_tty.c:945 [inline]
 n_tty_receive_char_fast drivers/tty/n_tty.c:1444 [inline]
 n_tty_receive_buf_fast drivers/tty/n_tty.c:1605 [inline]
 __receive_buf drivers/tty/n_tty.c:1640 [inline]
 n_tty_receive_buf_common+0x1337/0x1e20 drivers/tty/n_tty.c:1739
 n_tty_receive_buf2+0x2e/0x40 drivers/tty/n_tty.c:1774
 tty_ldisc_receive_buf+0x61/0xf0 drivers/tty/tty_buffer.c:461
 tty_port_default_receive_buf+0x54/0x80 drivers/tty/tty_port.c:38
 receive_buf drivers/tty/tty_buffer.c:481 [inline]
 flush_to_ldisc+0x1c5/0x2c0 drivers/tty/tty_buffer.c:533
 process_one_work+0x3e9/0x8f0 kernel/workqueue.c:2275
 worker_thread+0x636/0xae0 kernel/workqueue.c:2421
 kthread+0x1d0/0x1f0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 22 Comm: kworker/u4:1 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound flush_to_ldisc
==================================================================

Crashes (912):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Title
ci2-upstream-kcsan-gce	2021/04/22 22:48	upstream	90c911ad	33c28d03	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/22 11:34	upstream	16fc44d6	33c28d03	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/21 20:06	upstream	16fc44d6	2bc8999a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/21 18:05	upstream	16fc44d6	95777977	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/21 07:55	upstream	1fe5501b	95777977	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/21 00:11	upstream	1fe5501b	c0ced557	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/20 07:25	upstream	7af08140	c0ced557	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/19 22:26	upstream	7af08140	4285c989	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/19 19:21	upstream	bf05bf16	4285c989	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/19 07:20	upstream	bf05bf16	50f523d7	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/18 23:10	upstream	bf05bf16	7e2b734b	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/18 09:25	upstream	c98ff1d0	7e2b734b	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/17 20:09	upstream	194cf482	7e2b734b	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/17 06:54	upstream	9cdbf646	7e2b734b	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/16 17:50	upstream	2f7b98d1	7e2b734b	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/16 12:18	upstream	7e25f40e	7e2b734b	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/15 16:36	upstream	7f75285c	c59079a6	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/14 22:50	upstream	7f75285c	fcdb12ba	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/14 11:11	upstream	50987bec	3134b37f	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/13 19:32	upstream	89698bec	a184b83e	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/12 22:47	upstream	89698bec	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/12 09:39	upstream	d434405a	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/11 19:52	upstream	7d900724	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/11 03:56	upstream	52e44129	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/10 14:31	upstream	d4961772	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/10 01:40	upstream	4e04e751	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/09 11:58	upstream	17e7124a	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/08 21:56	upstream	3fb4f979	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/08 08:56	upstream	454859c5	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/07 19:19	upstream	3a229812	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/06 21:37	upstream	2d743660	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/05 18:50	upstream	0a50438c	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/04 22:30	upstream	e49d033b	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/04 03:40	upstream	2023a53b	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/03 13:26	upstream	d93a0d43	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/02 23:32	upstream	0a84c2e4	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/02 07:34	upstream	1678e493	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/04/01 18:42	upstream	ffd9fb54	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/03/31 19:11	upstream	d19cc4bf	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/03/31 06:41	upstream	5e46d1b7	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/03/30 16:49	upstream	2bb25b3a	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/03/29 10:34	upstream	a5e13c6d	a8529b82	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/03/28 20:12	upstream	36a14638	a8529b82	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/03/27 01:21	upstream	0f4498ce	a8529b82	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/03/26 11:32	upstream	db24726b	a8529b82	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/03/26 11:22	upstream	db24726b	a8529b82	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/03/25 22:25	upstream	00232240	6a383ecf	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/03/25 09:00	upstream	e1381380	6a383ecf	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/03/24 20:40	upstream	4ee998b0	607e3baf	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/03/24 14:35	upstream	7acac4b3	607e3baf	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/03/23 18:23	upstream	7acac4b3	e613994b	.config	log	report	info	KCSAN: data-race in n_tty_receive_buf_common / n_tty_receive_char_special
ci2-upstream-kcsan-gce	2021/01/17 10:15	upstream	0da0a8a0	813be542	.config	log	report	info
ci2-upstream-kcsan-gce	2019/12/12 17:49	https://github.com/google/ktsan.git kcsan	ef798c30	08003f64	.config	log	report
ci2-upstream-kcsan-gce	2019/12/12 07:06	https://github.com/google/ktsan.git kcsan	ef798c30	d973f528	.config	log	report
ci2-upstream-kcsan-gce	2019/10/25 06:55	https://github.com/google/ktsan.git kcsan	05f22368	d01bb02a	.config	log	report