syzbot


KCSAN: data-race in __stop_tty / pty_write_room (6)

Status: moderation: reported on 2024/04/22 13:22
Subsystems: serial
[Documentation on labels]
Reported-by: syzbot+9fd3f3b96e850f8c1fea@syzkaller.appspotmail.com
First crash: 35d, last: 5d09h
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __stop_tty / pty_write_room (2) serial 1 453d 453d 0/26 auto-obsoleted due to no activity on 2023/04/12 12:14
upstream KCSAN: data-race in __stop_tty / pty_write_room (5) serial 2 76d 80d 0/26 auto-obsoleted due to no activity on 2024/04/16 09:50
upstream KCSAN: data-race in __stop_tty / pty_write_room (3) serial 3 274d 283d 0/26 auto-obsoleted due to no activity on 2023/10/01 10:28
upstream KCSAN: data-race in __stop_tty / pty_write_room serial 1 738d 738d 0/26 auto-closed as invalid on 2022/06/24 17:06
upstream KCSAN: data-race in __stop_tty / pty_write_room (4) serial 2 124d 125d 0/26 auto-obsoleted due to no activity on 2024/02/28 07:28

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __stop_tty / pty_write_room

write to 0xffff88811633b1bc of 1 bytes by task 3891 on cpu 0:
 __stop_tty+0x42/0x90 drivers/tty/tty_io.c:753
 n_tty_ioctl_helper+0x223/0x240 drivers/tty/tty_ioctl.c:955
 n_tty_ioctl+0xfd/0x200 drivers/tty/n_tty.c:2511
 tty_ioctl+0x886/0xbe0 drivers/tty/tty_io.c:2812
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xd3/0x150 fs/ioctl.c:893
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:893
 x64_sys_call+0x155d/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811633b1bc of 1 bytes by task 28 on cpu 1:
 pty_write_room+0x1c/0x80 drivers/tty/pty.c:131
 tty_write_room+0x3c/0x60 drivers/tty/tty_ioctl.c:69
 __process_echoes+0x36/0x6b0 drivers/tty/n_tty.c:703
 flush_echoes drivers/tty/n_tty.c:807 [inline]
 __receive_buf drivers/tty/n_tty.c:1632 [inline]
 n_tty_receive_buf_common+0x8e6/0xbd0 drivers/tty/n_tty.c:1729
 n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1775
 tty_ldisc_receive_buf+0x63/0x100 drivers/tty/tty_buffer.c:387
 tty_port_default_receive_buf+0x59/0x90 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:445 [inline]
 flush_to_ldisc+0x1ce/0x410 drivers/tty/tty_buffer.c:495
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3312
 worker_thread+0x526/0x730 kernel/workqueue.c:3393
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 28 Comm: kworker/u8:1 Not tainted 6.9.0-syzkaller-10713-g2a8120d7b482 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Workqueue: events_unbound flush_to_ldisc
==================================================================

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/05/22 15:53 upstream 2a8120d7b482 4d098039 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __stop_tty / pty_write_room
2024/05/05 18:18 upstream b9158815de52 610f2a54 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __stop_tty / pty_write_room
2024/04/28 17:58 upstream 2c8159388952 07b455f9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __stop_tty / pty_write_room
2024/04/24 16:22 upstream 9d1ddab261f3 8bdc0f22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __stop_tty / pty_write_room
2024/04/23 05:21 upstream a2c63a3f3d68 36c961ad .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __stop_tty / pty_write_room
2024/04/22 13:21 upstream ed30a4a51bb1 36c961ad .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __stop_tty / pty_write_room
* Struck through repros no longer work on HEAD.