syzbot


KCSAN: data-race in __stop_tty / n_tty_receive_char (3)

Status: auto-closed as invalid on 2022/08/13 02:09
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 150d, last: 150d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __stop_tty / n_tty_receive_char (4) 2 61d 66d 0/24 auto-obsoleted due to no activity on 2022/11/10 02:34
upstream KCSAN: data-race in __stop_tty / n_tty_receive_char (2) 2 240d 248d 0/24 auto-closed as invalid on 2022/05/15 01:17
upstream KCSAN: data-race in __stop_tty / n_tty_receive_char 1 435d 435d 0/24 auto-closed as invalid on 2021/11/01 13:40

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

write to 0xffff88814684a1bc of 1 bytes by task 32485 on cpu 1:
 __stop_tty+0x3e/0x80 drivers/tty/tty_io.c:760
 n_tty_ioctl_helper+0x2bd/0x340 drivers/tty/tty_ioctl.c:870
 n_tty_ioctl+0xfc/0x1f0 drivers/tty/n_tty.c:2430
 tty_ioctl+0x71e/0x970 drivers/tty/tty_io.c:2787
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

read to 0xffff88814684a1bc of 1 bytes by task 4608 on cpu 0:
 n_tty_receive_char+0x3b/0x6a0 drivers/tty/n_tty.c:1386
 n_tty_receive_buf_standard drivers/tty/n_tty.c:1545 [inline]
 __receive_buf drivers/tty/n_tty.c:1562 [inline]
 n_tty_receive_buf_common+0xef3/0x4c40 drivers/tty/n_tty.c:1658
 n_tty_receive_buf2+0x2e/0x40 drivers/tty/n_tty.c:1693
 tty_ldisc_receive_buf+0x5b/0xf0 drivers/tty/tty_buffer.c:452
 tty_port_default_receive_buf+0x54/0x80 drivers/tty/tty_port.c:39
 receive_buf drivers/tty/tty_buffer.c:472 [inline]
 flush_to_ldisc+0x1ca/0x2f0 drivers/tty/tty_buffer.c:522
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4608 Comm: kworker/u4:2 Not tainted 5.19.0-rc5-syzkaller-00200-ga471da3100ef-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
Workqueue: events_unbound flush_to_ldisc
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/07/09 02:08 upstream a471da3100ef b5765a15 .config log report info KCSAN: data-race in __stop_tty / n_tty_receive_char
* Struck through repros no longer work on HEAD.