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: 285d, last: 22m

Sample crash report:

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

write to 0xffffc90000e09000 of 8 bytes by task 21 on cpu 0:
 put_tty_queue drivers/tty/n_tty.c:320 [inline]
 n_tty_receive_char_fast drivers/tty/n_tty.c:1451 [inline]
 n_tty_receive_buf_fast drivers/tty/n_tty.c:1609 [inline]
 __receive_buf drivers/tty/n_tty.c:1644 [inline]
 n_tty_receive_buf_common+0x14a8/0x1e70 drivers/tty/n_tty.c:1742
 n_tty_receive_buf2+0x2e/0x40 drivers/tty/n_tty.c:1777
 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+0x1b5/0x2b0 drivers/tty/tty_buffer.c:533
 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffffc90000e09000 of 8 bytes by task 31634 on cpu 1:
 eraser drivers/tty/n_tty.c:845 [inline]
 n_tty_receive_char_special+0x16bf/0x3a70 drivers/tty/n_tty.c:1316
 n_tty_receive_buf_fast drivers/tty/n_tty.c:1610 [inline]
 __receive_buf drivers/tty/n_tty.c:1644 [inline]
 n_tty_receive_buf_common+0xe48/0x1e70 drivers/tty/n_tty.c:1742
 n_tty_receive_buf+0x2b/0x40 drivers/tty/n_tty.c:1771
 tiocsti drivers/tty/tty_io.c:2196 [inline]
 tty_ioctl+0x8e3/0xfd0 drivers/tty/tty_io.c:2572
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl fs/ioctl.c:753 [inline]
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl+0xc9/0x130 fs/ioctl.c:760
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:760
 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: 1 PID: 31634 Comm: syz-executor.0 Not tainted 5.8.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (394):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Maintainers
ci2-upstream-kcsan-gce	2020/08/05 21:51	upstream	fffe3ae0	0487ea6f	.config	log	report	gregkh@linuxfoundation.org, jirislaby@kernel.org, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/08/05 11:26	upstream	c0842fbc	b7129355	.config	log	report	gregkh@linuxfoundation.org, jirislaby@kernel.org, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/08/04 21:49	upstream	c0842fbc	02034dac	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/08/04 15:32	upstream	c0842fbc	80a06902	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/08/04 00:43	upstream	e4cbce4d	96dd3623	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/08/03 12:40	upstream	bcf87687	96dd3623	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/08/03 00:04	upstream	142c3326	96dd3623	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/08/02 16:59	upstream	ac3a0c84	96dd3623	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/08/01 18:36	upstream	d52daa86	8df85ed9	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/08/01 04:14	upstream	7dc6fd0f	8df85ed9	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/31 11:37	upstream	d8b9faec	8df85ed9	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/30 22:10	upstream	e2c46b57	8df85ed9	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/30 11:16	upstream	83bdc727	b0947553	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/30 08:54	upstream	83bdc727	233283a1	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/29 19:05	upstream	6ba1b005	233283a1	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/29 08:06	upstream	6ba1b005	19a8de55	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/28 19:37	upstream	6ba1b005	cb93dc6a	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/27 08:05	upstream	92ed3019	cb93dc6a	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/26 21:09	upstream	1ada9010	51265195	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/26 10:52	upstream	04300d66	51265195	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/26 02:17	upstream	04300d66	1f7cc1ca	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/25 11:51	upstream	23ee3e4e	1f7cc1ca	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/24 23:08	upstream	68845a55	0a13649c	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/24 10:45	upstream	f37e99ac	554af388	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/23 22:47	upstream	f37e99ac	70c104a1	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/23 16:07	upstream	d15be546	70c104a1	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/23 02:41	upstream	d15be546	340ea530	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/22 19:15	upstream	8c26c87b	128cd85f	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/22 14:14	upstream	4fa640dc	128cd85f	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/22 01:57	upstream	4fa640dc	21f1765e	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/21 14:28	upstream	4fa640dc	e562dd8a	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/21 05:16	upstream	4fa640dc	d88894e6	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/21 00:54	upstream	4fa640dc	8caeeeb7	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/20 09:42	upstream	5714ee50	8caeeeb7	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/19 10:13	upstream	f932d58a	9c812472	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/18 22:20	upstream	6cf7ccba	9c812472	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/18 06:01	upstream	6a70f89c	9c812472	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/17 01:10	upstream	07a56bb8	54b3c45e	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/16 14:03	upstream	f8456690	b090c643	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/16 00:49	upstream	994e99a9	ada108d0	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/15 00:05	upstream	e9919e11	ada108d0	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/14 22:33	upstream	e9919e11	6f458026	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/14 12:14	upstream	0dc589da	6f458026	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2020/07/14 02:30	upstream	0dc589da	ce4c95b3	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2019/12/12 17:49	https://github.com/google/ktsan.git kcsan	ef798c30	08003f64	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2019/12/12 07:06	https://github.com/google/ktsan.git kcsan	ef798c30	d973f528	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org
ci2-upstream-kcsan-gce	2019/10/25 06:55	https://github.com/google/ktsan.git kcsan	05f22368	d01bb02a	.config	log	report	gregkh@linuxfoundation.org, jslaby@suse.com, linux-kernel@vger.kernel.org