syzbot


KCSAN: data-race in __stop_tty / do_con_write (9)

Status: moderation: reported on 2024/02/27 21:06
Subsystems: serial
[Documentation on labels]
Reported-by: syzbot+d50b91c25f8ad1b6edc4@syzkaller.appspotmail.com
First crash: 53d, last: 32d
Similar bugs (8)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __stop_tty / do_con_write (2) serial 1 898d 898d 0/26 auto-closed as invalid on 2021/12/10 00:27
upstream KCSAN: data-race in __stop_tty / do_con_write (3) serial 2 752d 754d 0/26 auto-closed as invalid on 2022/05/05 09:26
upstream KCSAN: data-race in __stop_tty / do_con_write serial 3 970d 1009d 0/26 auto-closed as invalid on 2021/09/28 23:33
upstream KCSAN: data-race in __stop_tty / do_con_write (8) serial 5 168d 133d 0/26 auto-obsoleted due to no activity on 2023/12/24 00:05
upstream KCSAN: data-race in __stop_tty / do_con_write (5) serial 1 524d 524d 0/26 auto-obsoleted due to no activity on 2022/12/19 02:12
upstream KCSAN: data-race in __stop_tty / do_con_write (7) serial 7 310d 324d 0/26 auto-obsoleted due to no activity on 2023/07/20 09:58
upstream KCSAN: data-race in __stop_tty / do_con_write (6) kernel 1 438d 438d 0/26 auto-obsoleted due to no activity on 2023/04/04 15:34
upstream KCSAN: data-race in __stop_tty / do_con_write (4) serial 1 575d 575d 0/26 auto-obsoleted due to no activity on 2022/10/28 19:26

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

write to 0xffff8881572495bc of 1 bytes by task 24496 on cpu 1:
 __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:904 [inline]
 __se_sys_ioctl+0xd3/0x150 fs/ioctl.c:890
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:890
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

read to 0xffff8881572495bc of 1 bytes by task 24493 on cpu 0:
 do_con_write+0x179/0x3640 drivers/tty/vt/vt.c:2885
 con_write+0x26/0x40 drivers/tty/vt/vt.c:3251
 process_output_block drivers/tty/n_tty.c:574 [inline]
 n_tty_write+0x849/0xb90 drivers/tty/n_tty.c:2379
 iterate_tty_write drivers/tty/tty_io.c:1021 [inline]
 file_tty_write+0x386/0x690 drivers/tty/tty_io.c:1096
 tty_write+0x28/0x30 drivers/tty/tty_io.c:1117
 call_write_iter include/linux/fs.h:2108 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x771/0x8e0 fs/read_write.c:590
 ksys_write+0xeb/0x1b0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:652
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 24493 Comm: syz-executor.0 Not tainted 6.8.0-syzkaller-11608-gd95fcdf4961d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/19 21:58 upstream d95fcdf4961d e104824c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __stop_tty / do_con_write
2024/02/27 21:06 upstream 45ec2f5f6ed3 d367cbe5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __stop_tty / do_con_write
* Struck through repros no longer work on HEAD.