syzbot


KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios

Status: moderation: reported on 2023/12/08 00:02
Subsystems: serial
[Documentation on labels]
Reported-by: syzbot+fbbe380cd0f9624f998b@syzkaller.appspotmail.com
First crash: 974d, last: 1d17h

Sample crash report:
==================================================================
BUG: KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios

write to 0xffff8881034f3908 of 44 bytes by task 9538 on cpu 1:
 tty_set_termios+0xc0/0x8c0 drivers/tty/tty_ioctl.c:335
 set_termios+0x490/0x4d0 drivers/tty/tty_ioctl.c:512
 tty_mode_ioctl+0x379/0x5c0 drivers/tty/tty_ioctl.c:-1
 n_tty_ioctl_helper+0x91/0x210 drivers/tty/tty_ioctl.c:982
 n_tty_ioctl+0x101/0x200 drivers/tty/n_tty.c:2509
 tty_ioctl+0x83f/0xb80 drivers/tty/tty_io.c:2801
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
 x64_sys_call+0x1816/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881034f3921 of 1 bytes by task 3634 on cpu 0:
 n_tty_is_char_flow_ctrl drivers/tty/n_tty.c:1204 [inline]
 n_tty_receive_char_flow_ctrl+0x23/0x1a0 drivers/tty/n_tty.c:1225
 n_tty_lookahead_flow_ctrl+0xed/0x130 drivers/tty/n_tty.c:1500
 tty_port_default_lookahead_buf+0x91/0xc0 drivers/tty/tty_port.c:59
 lookahead_bufs drivers/tty/tty_buffer.c:428 [inline]
 flush_to_ldisc+0x288/0x340 drivers/tty/tty_buffer.c:498
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3346
 worker_thread+0x582/0x770 kernel/workqueue.c:3427
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x122/0x1b0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x11 -> 0xe7

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3634 Comm: kworker/u8:8 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: events_unbound flush_to_ldisc
==================================================================

Crashes (629):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/12 10:24 upstream 67029a49db6c ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/10/10 13:29 upstream 5472d60c129f ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/10/04 11:31 upstream cbf33b8e0b36 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/10/03 16:13 upstream e406d57be7bd 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/27 21:23 upstream fec734e8d564 001c9061 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/27 07:37 upstream 083fc6d7fa0d 001c9061 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/26 04:34 upstream 4ff71af020ae 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/23 15:34 upstream cec1e6e5d1ab 0ac7291c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/22 00:32 upstream 2d5bd41a4505 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/21 13:47 upstream f975f08c2e89 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/20 19:08 upstream 3b08f56fbbb9 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/20 01:54 upstream cd89d487374c 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/19 05:02 upstream cbf658dd0941 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/17 20:54 upstream d4b779985a6c e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/17 17:42 upstream 5aca7966d2a7 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/16 08:08 upstream 46a51f4f5eda e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/14 22:35 upstream 79e8447ec662 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/14 11:55 upstream f83a4f2a4d8c e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/11 11:13 upstream 7aac71907bde fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/08 02:52 upstream 6ab41fca2e80 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/05 22:38 upstream c8ed9b5c02a5 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/04 20:38 upstream 08b06c30a445 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/02 08:26 upstream b320789d6883 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/09/01 03:56 upstream 5c3b3264e585 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/08/30 22:22 upstream 11e7861d680c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/08/30 01:16 upstream fb679c832b64 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/08/28 16:54 upstream 07d9df80082b e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/08/18 21:51 upstream c17b750b3ad9 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/08/17 21:32 upstream 99bade344cfa 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/08/16 22:53 upstream 90d970cade8e 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/08/12 01:23 upstream 8f5ae30d69d7 c06e8995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/08/09 20:51 upstream 561c80369df0 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/08/02 04:50 upstream 0905809b38bd 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/08/01 19:12 upstream f2d282e1dfb3 40127d41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/08/01 06:45 upstream f2d282e1dfb3 0c075d67 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/07/29 14:52 upstream ae388edd4a8f c4a95487 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/07/27 04:59 upstream 302f88ff3584 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/07/25 11:26 upstream 94ce1ac2c9b4 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/07/24 21:05 upstream 25fae0b93d1d 65d60d73 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/07/23 12:29 upstream 89be9a83ccf1 e1dd4f22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/07/19 18:06 upstream 4871b7cb27f4 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/07/13 05:16 upstream 3f31a806a62e 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/07/13 05:16 upstream 3f31a806a62e 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/07/09 21:04 upstream 733923397fd9 f4e5e155 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/07/08 11:34 upstream d7b8f8e20813 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/07/04 04:18 upstream 17bbde2e1716 76ad128c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/07/02 14:34 upstream 66701750d556 bc80e4f0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/07/01 11:03 upstream 66701750d556 6e83b42d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2025/06/30 23:14 upstream d0b3b7b22dfa 6e83b42d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2023/12/07 12:32 upstream bee0e7762ad2 0a02ce36 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
2023/12/03 06:38 upstream 1b8af6552cb7 f819d6f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char_flow_ctrl / tty_set_termios
* Struck through repros no longer work on HEAD.