KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_special

Status: auto-closed as invalid on 2021/04/20 18:26
Subsystems: serial
[Documentation on labels]
Reported-by: syzbot+fdab22f6fdfe878fbb0a@syzkaller.appspotmail.com
First crash: 2244d, last: 1976d
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_special (2) serial 6 36 1862d 1935d 0/29 auto-closed as invalid on 2021/08/12 15:55

Sample crash report:
==================================================================
BUG: KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_special

write to 0xffffc90002bc1018 of 8 bytes by task 10361 on cpu 0:
 echo_char drivers/tty/n_tty.c:840 [inline]
 eraser drivers/tty/n_tty.c:1039 [inline]
 n_tty_receive_char_special+0x142e/0x3ac0 drivers/tty/n_tty.c:1312
 n_tty_receive_buf_standard drivers/tty/n_tty.c:1580 [inline]
 __receive_buf drivers/tty/n_tty.c:1642 [inline]
 n_tty_receive_buf_common+0x191c/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+0x91a/0x10c0 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+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffffc90002bc1018 of 8 bytes by task 300 on cpu 1:
 echo_char_raw drivers/tty/n_tty.c:840 [inline]
 finish_erasing drivers/tty/n_tty.c:957 [inline]
 n_tty_receive_char_inline+0x224/0x680 drivers/tty/n_tty.c:1412
 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
 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+0x3e1/0x950 kernel/workqueue.c:2275
 worker_thread+0x616/0xa70 kernel/workqueue.c:2421
 kthread+0x20b/0x230 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: 300 Comm: kworker/u4:2 Not tainted 5.12.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound flush_to_ldisc
==================================================================

Crashes (65):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/03/16 18:26 upstream 1df27313f50a fdb2bb2c .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_special
2021/03/07 14:33 upstream a38fd8748464 c599ed12 .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_special
2021/02/06 16:12 upstream 1e0d27fce010 0655e081 .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_inline / n_tty_receive_char_special
2021/01/14 17:08 upstream 65f0d2414b70 468dbb55 .config console log report info ci2-upstream-kcsan-gce
2021/01/14 02:09 upstream 65f0d2414b70 269d24e8 .config console log report info ci2-upstream-kcsan-gce
2021/01/13 22:17 upstream 65f0d2414b70 a945f0a3 .config console log report info ci2-upstream-kcsan-gce
2021/01/13 11:40 upstream e609571b5ffa a945f0a3 .config console log report info ci2-upstream-kcsan-gce
2021/01/06 15:19 upstream 9f1abbe97c08 fff20c29 .config console log report info ci2-upstream-kcsan-gce
2020/12/26 04:04 upstream 5814bc2d4cc2 821e0b09 .config console log report info ci2-upstream-kcsan-gce
2020/12/13 20:53 upstream ec6f5e0e5ca0 8f160dd5 .config console log report info ci2-upstream-kcsan-gce
2020/12/12 21:39 upstream 7b1b868e1d91 bca53db9 .config console log report info ci2-upstream-kcsan-gce
2020/12/12 02:40 upstream 7f376f1917d7 bca53db9 .config console log report info ci2-upstream-kcsan-gce
2020/12/11 11:38 upstream 33dc9614dc20 ba24ffcd .config console log report info ci2-upstream-kcsan-gce
2020/12/11 00:13 upstream 9fca90cf2892 f900b48c .config console log report info ci2-upstream-kcsan-gce
2020/12/10 10:41 upstream a2f5ea9e314b c090b4da .config console log report info ci2-upstream-kcsan-gce
2020/12/09 10:09 upstream a68a0262abda 99917735 .config console log report info ci2-upstream-kcsan-gce
2020/12/08 00:06 upstream cd796ed33450 51a9082e .config console log report info ci2-upstream-kcsan-gce
2020/12/07 10:50 upstream 0477e9288185 f80ce148 .config console log report info ci2-upstream-kcsan-gce
2020/12/06 21:35 upstream 8100a58044f8 c521566d .config console log report info ci2-upstream-kcsan-gce
2020/12/06 10:07 upstream 7059c2c00a21 f12ba0c5 .config console log report info ci2-upstream-kcsan-gce
2020/11/28 14:48 upstream c84e1efae022 3c7136c0 .config console log report info ci2-upstream-kcsan-gce
2020/11/24 07:12 upstream d5beb3140f91 1ab681a4 .config console log report info ci2-upstream-kcsan-gce
2020/11/23 04:27 upstream 68d3fa235fd8 0d27f508 .config console log report info ci2-upstream-kcsan-gce
2020/11/20 18:09 upstream 4d02da974ea8 68068804 .config console log report info ci2-upstream-kcsan-gce
2020/11/19 20:19 upstream 131ad0b6f529 0767f13f .config console log report info ci2-upstream-kcsan-gce
2020/11/17 21:59 upstream 111e91a6df50 09323409 .config console log report info ci2-upstream-kcsan-gce
2020/11/02 03:58 upstream 31f020064f9d 8bc4594f .config console log report info ci2-upstream-kcsan-gce
2020/11/02 03:39 upstream 31f020064f9d 8bc4594f .config console log report info ci2-upstream-kcsan-gce
2020/10/28 04:50 upstream ed8780e3f2ec 96e03c1c .config console log report info ci2-upstream-kcsan-gce
2020/10/25 17:00 upstream d76913908102 a1839e81 .config console log report info ci2-upstream-kcsan-gce
2020/10/25 16:59 upstream d76913908102 a1839e81 .config console log report info ci2-upstream-kcsan-gce
2020/10/23 08:26 upstream 96485e446260 4e740c00 .config console log report info ci2-upstream-kcsan-gce
2020/10/18 08:58 upstream 9d9af1007bc0 fea47c01 .config console log report info ci2-upstream-kcsan-gce
2020/09/28 09:41 upstream a1b8638ba132 6bfdbe89 .config console log report info ci2-upstream-kcsan-gce
2020/09/26 05:03 upstream 7c7ec3226f5f 4a006f63 .config console log report info ci2-upstream-kcsan-gce
2020/09/12 19:04 upstream 729e3d091984 21d289c2 .config console log report ci2-upstream-kcsan-gce
2020/09/08 18:14 upstream f4d51dffc6c0 abf9ba4f .config console log report ci2-upstream-kcsan-gce
2020/09/07 08:08 upstream a8205e310011 abf9ba4f .config console log report ci2-upstream-kcsan-gce
2020/08/28 22:55 upstream 15bc20c6af4c d5a3ae1f .config console log report ci2-upstream-kcsan-gce
2020/08/21 10:38 upstream da2968ff879b 1d75fe45 .config console log report ci2-upstream-kcsan-gce
2020/08/19 18:14 upstream 18445bf405cb db787902 .config console log report ci2-upstream-kcsan-gce
2020/08/18 09:12 upstream 06a4ec1d9dc6 5ce13532 .config console log report ci2-upstream-kcsan-gce
2020/08/10 16:06 upstream fc80c51fd4b2 7adc7b65 .config console log report ci2-upstream-kcsan-gce
2020/08/10 01:46 upstream 9420f1ce0186 70301872 .config console log report ci2-upstream-kcsan-gce
2020/08/05 13:01 upstream c0842fbc1b18 b7129355 .config console log report ci2-upstream-kcsan-gce
2020/08/05 13:01 upstream c0842fbc1b18 b7129355 .config console log report ci2-upstream-kcsan-gce
2020/08/04 15:51 upstream c0842fbc1b18 80a06902 .config console log report ci2-upstream-kcsan-gce
2020/07/31 06:26 upstream e2c46b5762c6 8df85ed9 .config console log report ci2-upstream-kcsan-gce
2020/07/30 05:24 upstream 6ba1b005ffc3 233283a1 .config console log report ci2-upstream-kcsan-gce
2020/07/30 05:23 upstream 6ba1b005ffc3 233283a1 .config console log report ci2-upstream-kcsan-gce
2020/07/30 05:23 upstream 6ba1b005ffc3 233283a1 .config console log report ci2-upstream-kcsan-gce
2020/07/29 07:21 upstream 6ba1b005ffc3 19a8de55 .config console log report ci2-upstream-kcsan-gce
2020/07/28 21:58 upstream 6ba1b005ffc3 cb93dc6a .config console log report ci2-upstream-kcsan-gce
2020/07/27 08:30 upstream 92ed30191993 cb93dc6a .config console log report ci2-upstream-kcsan-gce
2020/07/26 12:03 upstream 04300d66f0a0 51265195 .config console log report ci2-upstream-kcsan-gce
2020/07/24 20:32 upstream f37e99aca03f 554af388 .config console log report ci2-upstream-kcsan-gce
2020/07/20 17:14 upstream 5714ee50bb43 8caeeeb7 .config console log report ci2-upstream-kcsan-gce
2020/07/20 17:04 upstream 5714ee50bb43 8caeeeb7 .config console log report ci2-upstream-kcsan-gce
2020/07/20 17:03 upstream 5714ee50bb43 8caeeeb7 .config console log report ci2-upstream-kcsan-gce
2020/07/20 16:55 upstream 5714ee50bb43 8caeeeb7 .config console log report ci2-upstream-kcsan-gce
2020/07/07 18:26 upstream bfe91da29bfa 42723355 .config console log report ci2-upstream-kcsan-gce
2020/07/06 11:03 upstream dcb7fd82c75e ac5a135b .config console log report ci2-upstream-kcsan-gce
2020/07/06 11:01 upstream dcb7fd82c75e ac5a135b .config console log report ci2-upstream-kcsan-gce
2020/07/04 14:31 upstream 35e884f89df4 4f739670 .config console log report ci2-upstream-kcsan-gce
2020/06/21 16:32 upstream 64677779e896 4f2acff9 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.