syzbot


KCSAN: data-race in do_con_write / stop_tty (2)

Status: auto-closed as invalid on 2021/12/14 11:52
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 445d, last: 382d
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 (4) 2 108d 116d 0/24 auto-closed as invalid on 2022/09/14 19:26
upstream KCSAN: data-race in do_con_write / stop_tty (3) 6 229d 279d 0/24 auto-closed as invalid on 2022/05/16 00:29
upstream KCSAN: data-race in do_con_write / stop_tty 1 489d 489d 0/24 auto-closed as invalid on 2021/08/28 20:41

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

write to 0xffff88813a6225bc of 1 bytes by task 5502 on cpu 1:
 __stop_tty drivers/tty/tty_io.c:768 [inline]
 stop_tty+0x54/0xb0 drivers/tty/tty_io.c:794
 n_tty_receive_char_special drivers/tty/n_tty.c:1274 [inline]
 n_tty_receive_buf_standard drivers/tty/n_tty.c:1558 [inline]
 __receive_buf drivers/tty/n_tty.c:1577 [inline]
 n_tty_receive_buf_common+0x110d/0x4e70 drivers/tty/n_tty.c:1674
 n_tty_receive_buf+0x2b/0x40 drivers/tty/n_tty.c:1703
 tiocsti drivers/tty/tty_io.c:2310 [inline]
 tty_ioctl+0x969/0x1130 drivers/tty/tty_io.c:2719
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:860
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813a6225bc of 1 bytes by task 5497 on cpu 0:
 do_con_write+0x2055/0x5f40 drivers/tty/vt/vt.c:2931
 con_write+0x20/0x40 drivers/tty/vt/vt.c:3295
 process_output_block drivers/tty/n_tty.c:592 [inline]
 n_tty_write+0x77b/0xaf0 drivers/tty/n_tty.c:2288
 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:2162 [inline]
 do_iter_readv_writev+0x2de/0x380 fs/read_write.c:725
 do_iter_write+0x192/0x5c0 fs/read_write.c:851
 vfs_writev fs/read_write.c:924 [inline]
 do_writev+0x250/0x4d0 fs/read_write.c:967
 __do_sys_writev fs/read_write.c:1040 [inline]
 __se_sys_writev fs/read_write.c:1037 [inline]
 __x64_sys_writev+0x41/0x50 fs/read_write.c:1037
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 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: 5497 Comm: syz-executor.4 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (7):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/11/09 11:47 upstream e851dfae4371 8ab17e57 .config log report info KCSAN: data-race in do_con_write / stop_tty
ci2-upstream-kcsan-gce 2021/11/08 21:10 upstream e851dfae4371 d29682f1 .config log report info KCSAN: data-race in do_con_write / stop_tty
ci2-upstream-kcsan-gce 2021/10/31 14:45 upstream 180eca540ae0 098b5d53 .config log report info KCSAN: data-race in do_con_write / stop_tty
ci2-upstream-kcsan-gce 2021/09/29 11:08 upstream a4e6f95a891a e08fe937 .config log report info KCSAN: data-race in do_con_write / stop_tty
ci2-upstream-kcsan-gce 2021/09/12 13:56 upstream 78e709522d2c 3ce60af8 .config log report info KCSAN: data-race in do_con_write / stop_tty
ci2-upstream-kcsan-gce 2021/09/09 22:29 upstream a3fa7a101dcf e2776ee4 .config log report info KCSAN: data-race in do_con_write / stop_tty
ci2-upstream-kcsan-gce 2021/09/07 00:20 upstream 4b93c544e90e 6ca60148 .config log report info KCSAN: data-race in do_con_write / stop_tty
* Struck through repros no longer work on HEAD.