syzbot


KCSAN: data-race in __stop_tty / pty_write (7)

Status: auto-obsoleted due to no activity on 2022/11/10 14:49
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 124d, last: 124d
similar bugs (6):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __stop_tty / pty_write 1 572d 572d 0/24 auto-closed as invalid on 2021/08/19 13:20
upstream KCSAN: data-race in __stop_tty / pty_write (6) 1 266d 266d 0/24 auto-closed as invalid on 2022/06/22 11:40
upstream KCSAN: data-race in __stop_tty / pty_write (2) 1 490d 490d 0/24 auto-closed as invalid on 2021/11/09 20:04
upstream KCSAN: data-race in __stop_tty / pty_write (4) 1 362d 362d 0/24 auto-closed as invalid on 2022/03/17 12:14
upstream KCSAN: data-race in __stop_tty / pty_write (3) 1 450d 450d 0/24 auto-closed as invalid on 2021/12/20 07:00
upstream KCSAN: data-race in __stop_tty / pty_write (5) 1 319d 319d 0/24 auto-closed as invalid on 2022/04/30 10:57

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

write to 0xffff888121d191bc of 1 bytes by task 2812 on cpu 1:
 __stop_tty+0x3e/0x80 drivers/tty/tty_io.c:760
 n_tty_ioctl_helper+0x2bd/0x340 drivers/tty/tty_ioctl.c:874
 n_tty_ioctl+0xfc/0x1f0 drivers/tty/n_tty.c:2483
 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+0x63/0xcd

read to 0xffff888121d191bc of 1 bytes by task 8 on cpu 0:
 pty_write+0x22/0xa0 drivers/tty/pty.c:115
 tty_put_char+0x7f/0xa0 drivers/tty/tty_io.c:3144
 __process_echoes+0x3b9/0x650 drivers/tty/n_tty.c:717
 flush_echoes drivers/tty/n_tty.c:817 [inline]
 __receive_buf drivers/tty/n_tty.c:1615 [inline]
 n_tty_receive_buf_common+0x844/0xbf0 drivers/tty/n_tty.c:1711
 n_tty_receive_buf2+0x2e/0x40 drivers/tty/n_tty.c:1746
 tty_ldisc_receive_buf+0x5b/0xf0 drivers/tty/tty_buffer.c:457
 tty_port_default_receive_buf+0x54/0x80 drivers/tty/tty_port.c:39
 receive_buf drivers/tty/tty_buffer.c:515 [inline]
 flush_to_ldisc+0x1d9/0x470 drivers/tty/tty_buffer.c:565
 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 arch/x86/entry/entry_64.S:306

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8 Comm: kworker/u4:0 Not tainted 6.0.0-syzkaller-05118-g833477fce7a1-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Workqueue: events_unbound flush_to_ldisc
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci2-upstream-kcsan-gce 2022/10/06 14:38 upstream 833477fce7a1 2c6543ad .config console log report info [disk image] [vmlinux] KCSAN: data-race in __stop_tty / pty_write
* Struck through repros no longer work on HEAD.