syzbot


KCSAN: data-race in __stop_tty / do_con_write

Status: auto-closed as invalid on 2021/09/28 23:33
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 507d, last: 468d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __stop_tty / do_con_write (2) 1 396d 396d 0/24 auto-closed as invalid on 2021/12/10 00:27
upstream KCSAN: data-race in __stop_tty / do_con_write (3) 2 250d 252d 0/24 auto-closed as invalid on 2022/05/05 09:26
upstream KCSAN: data-race in __stop_tty / do_con_write (4) 1 73d 73d 0/24 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 0xffff8881360739bc of 1 bytes by task 30977 on cpu 1:
 __stop_tty+0x3e/0x80 drivers/tty/tty_io.c:768
 n_tty_ioctl_helper+0x333/0x4c0 drivers/tty/tty_ioctl.c:876
 n_tty_ioctl+0x102/0x200 drivers/tty/n_tty.c:2421
 tty_ioctl+0xa8f/0x1120 drivers/tty/tty_io.c:2814
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881360739bc of 1 bytes by task 30973 on cpu 0:
 do_con_write+0x1fc5/0x5d90 drivers/tty/vt/vt.c:2891
 con_write+0x20/0x40 drivers/tty/vt/vt.c:3255
 n_tty_write+0x39b/0xaf0 drivers/tty/n_tty.c:2311
 do_tty_write drivers/tty/tty_io.c:1038 [inline]
 file_tty_write+0x409/0x660 drivers/tty/tty_io.c:1110
 tty_write+0x24/0x30 drivers/tty/tty_io.c:1131
 call_write_iter include/linux/fs.h:2114 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x69d/0x770 fs/read_write.c:605
 ksys_write+0xce/0x180 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:667
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 30973 Comm: syz-executor.0 Not tainted 5.14.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/08/24 23:27 upstream 6e764bcd1cf7 b599f2fc .config log report info KCSAN: data-race in __stop_tty / do_con_write
ci2-upstream-kcsan-gce 2021/07/25 09:33 upstream 7ffca2bb9d8b 4d1b57d4 .config log report info KCSAN: data-race in __stop_tty / do_con_write
ci2-upstream-kcsan-gce 2021/07/16 21:41 upstream d936eb238744 f115ae98 .config log report info KCSAN: data-race in __stop_tty / do_con_write
* Struck through repros no longer work on HEAD.