syzbot


KCSAN: data-race in do_con_write / stop_tty (4)

Status: auto-closed as invalid on 2022/09/14 19:26
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 126d, last: 117d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in do_con_write / stop_tty (3) 6 239d 289d 0/24 auto-closed as invalid on 2022/05/16 00:29
upstream KCSAN: data-race in do_con_write / stop_tty 1 499d 499d 0/24 auto-closed as invalid on 2021/08/28 20:41
upstream KCSAN: data-race in do_con_write / stop_tty (2) 7 392d 455d 0/24 auto-closed as invalid on 2021/12/14 11:52

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

write to 0xffff8881373da9bc of 1 bytes by task 23360 on cpu 0:
 __stop_tty drivers/tty/tty_io.c:760 [inline]
 stop_tty+0x54/0xb0 drivers/tty/tty_io.c:784
 n_tty_receive_char_flow_ctrl drivers/tty/n_tty.c:1264 [inline]
 n_tty_receive_char_special drivers/tty/n_tty.c:1273 [inline]
 n_tty_receive_buf_standard+0x6d9/0x3a30 drivers/tty/n_tty.c:1587
 __receive_buf drivers/tty/n_tty.c:1613 [inline]
 n_tty_receive_buf_common+0x72d/0xbf0 drivers/tty/n_tty.c:1711
 n_tty_receive_buf+0x2b/0x40 drivers/tty/n_tty.c:1740
 tiocsti+0x14b/0x1a0 drivers/tty/tty_io.c:2293
 tty_ioctl+0x279/0x970 drivers/tty/tty_io.c:2692
 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 0xffff8881373da9bc of 1 bytes by task 23361 on cpu 1:
 do_con_write+0x1785/0x3590 drivers/tty/vt/vt.c:2931
 con_write+0x25/0x420 drivers/tty/vt/vt.c:3295
 process_output_block drivers/tty/n_tty.c:586 [inline]
 n_tty_write+0x809/0xb10 drivers/tty/n_tty.c:2350
 do_tty_write drivers/tty/tty_io.c:1024 [inline]
 file_tty_write+0x3f9/0x650 drivers/tty/tty_io.c:1095
 tty_write+0x24/0x30 drivers/tty/tty_io.c:1116
 call_write_iter include/linux/fs.h:2192 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x468/0x760 fs/read_write.c:578
 ksys_write+0xe8/0x1a0 fs/read_write.c:631
 __do_sys_write fs/read_write.c:643 [inline]
 __se_sys_write fs/read_write.c:640 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:640
 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

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 23361 Comm: syz-executor.5 Not tainted 5.19.0-syzkaller-13322-gd4252071b97d-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
==================================================================

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/08/10 19:17 upstream d4252071b97d aaa9eaa0 .config log report info KCSAN: data-race in do_con_write / stop_tty
ci2-upstream-kcsan-gce 2022/08/02 09:17 upstream 9de1f9c8ca51 fef302b1 .config log report info KCSAN: data-race in do_con_write / stop_tty
* Struck through repros no longer work on HEAD.