KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char

KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
Status: moderation: reported on 2020/12/06 12:03
Reported-by: syzbot+ae21a27816f424fd3dda@syzkaller.appspotmail.com
First crash: 304d, last: 1d12h

Sample crash report:

==================================================================
BUG: KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline

write to 0xffffc9000e7b5000 of 8 bytes by task 10675 on cpu 0:
 put_tty_queue drivers/tty/n_tty.c:315 [inline]
 n_tty_receive_char_inline+0x66c/0x680 drivers/tty/n_tty.c:1422
 n_tty_receive_buf_standard drivers/tty/n_tty.c:1579 [inline]
 __receive_buf drivers/tty/n_tty.c:1642 [inline]
 n_tty_receive_buf_common+0x1893/0x1e20 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 0xffffc9000e7b5000 of 8 bytes by task 13779 on cpu 1:
 n_tty_receive_char_inline+0x26d/0x680 drivers/tty/n_tty.c:1414
 n_tty_receive_buf_standard drivers/tty/n_tty.c:1579 [inline]
 __receive_buf drivers/tty/n_tty.c:1642 [inline]
 n_tty_receive_buf_common+0x1893/0x1e20 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
 paste_selection+0x250/0x340 drivers/tty/vt/selection.c:408
 tioclinux+0xe5/0x450 drivers/tty/vt/vt.c:3163
 vt_ioctl+0x26e/0x1ed0 drivers/tty/vt/vt_ioctl.c:723
 tty_ioctl+0xa30/0x1130 drivers/tty/tty_io.c:2801
 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 13779 Comm: syz-executor.5 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (34):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Title
ci2-upstream-kcsan-gce	2021/04/19 19:45	upstream	bf05bf16	4285c989	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/04/19 13:59	upstream	bf05bf16	50f523d7	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/04/17 13:17	upstream	9cdbf646	7e2b734b	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/04/15 03:29	upstream	7f75285c	fcdb12ba	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/04/12 12:26	upstream	d434405a	6a81331a	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/03/25 10:10	upstream	e1381380	6a383ecf	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/03/20 03:53	upstream	8b12a62a	3d01c4de	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/03/14 21:15	upstream	75013c6c	cc1cff8f	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/03/10 15:04	upstream	05a59d79	26967e35	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/03/03 21:26	upstream	f69d02e3	06ed56cd	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/02/22 00:23	upstream	55f62bc8	a659b3f1	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/02/05 20:26	upstream	dd86e7fa	23a562df	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/01/28 00:46	upstream	76c057c8	a57db36f	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/01/21 11:52	upstream	75439bc4	d4f4eca5	.config	log	report	info	KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_inline
ci2-upstream-kcsan-gce	2021/01/10 04:48	upstream	2ff90100	2c1f2513	.config	log	report	info
ci2-upstream-kcsan-gce	2020/12/10 11:38	upstream	a2f5ea9e	2a55c22b	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/29 17:19	upstream	aae5ab85	a0092f9d	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/08 01:40	upstream	4429f14a	cba33199	.config	log	report	info
ci2-upstream-kcsan-gce	2020/11/07 14:56	upstream	659caaf6	cba33199	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/27 01:25	upstream	41ba50b0	8b3eaf58	.config	log	report	info
ci2-upstream-kcsan-gce	2020/10/02 09:06	upstream	fcadab74	9602ddf4	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/23 12:07	upstream	805c6d3c	287cd75a	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/16 20:28	upstream	5925fa68	77507d02	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/15 14:52	upstream	fc4f28bb	9e681632	.config	log	report	info
ci2-upstream-kcsan-gce	2020/09/12 09:18	upstream	e8878ab8	79fb24e2	.config	log	report
ci2-upstream-kcsan-gce	2020/09/06 11:16	upstream	dd9fb9bb	abf9ba4f	.config	log	report
ci2-upstream-kcsan-gce	2020/09/05 01:47	upstream	c70672d8	abf9ba4f	.config	log	report
ci2-upstream-kcsan-gce	2020/08/15 01:38	upstream	c9c9735c	5ce13532	.config	log	report
ci2-upstream-kcsan-gce	2020/07/21 14:59	upstream	4fa640dc	e562dd8a	.config	log	report
ci2-upstream-kcsan-gce	2020/07/07 20:25	upstream	bfe91da2	08fc4ef1	.config	log	report
ci2-upstream-kcsan-gce	2020/06/29 14:35	upstream	9ebcfadb	df01f6fc	.config	log	report
ci2-upstream-kcsan-gce	2020/06/29 11:11	upstream	9ebcfadb	3ff434cc	.config	log	report
ci2-upstream-kcsan-gce	2020/06/23 18:14	upstream	3e08a952	6930bbef	.config	log	report
ci2-upstream-kcsan-gce	2020/06/20 11:12	upstream	672f9255	c655ec77	.config	log	report