syzbot


KCSAN: data-race in n_tty_close / pty_close (2)

Status: auto-closed as invalid on 2022/06/27 03:27
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 197d, last: 197d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in n_tty_close / pty_close 1 805d 805d 0/24 auto-closed as invalid on 2020/10/27 12:08

Sample crash report:
==================================================================
BUG: KCSAN: data-race in n_tty_close / pty_close

write to 0xffff88813b4529d9 of 1 bytes by task 26990 on cpu 0:
 pty_close+0x120/0x280 drivers/tty/pty.c:61
 tty_release+0x255/0x9d0 drivers/tty/tty_io.c:1758
 __fput+0x292/0x510 fs/file_table.c:317
 ____fput+0x11/0x20 fs/file_table.c:350
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x124/0x130 kernel/entry/common.c:169
 exit_to_user_mode_prepare kernel/entry/common.c:201 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x6a/0x90 kernel/entry/common.c:294
 do_syscall_64+0x37/0x70 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813b4529d9 of 1 bytes by task 26999 on cpu 1:
 n_tty_packet_mode_flush drivers/tty/n_tty.c:342 [inline]
 n_tty_close+0x54/0x120 drivers/tty/n_tty.c:1792
 tty_ldisc_close drivers/tty/tty_ldisc.c:456 [inline]
 tty_ldisc_kill drivers/tty/tty_ldisc.c:608 [inline]
 tty_ldisc_hangup+0x35d/0x470 drivers/tty/tty_ldisc.c:724
 __tty_hangup+0x438/0x5b0 drivers/tty/tty_io.c:637
 tty_vhangup drivers/tty/tty_io.c:707 [inline]
 tty_ioctl+0x49f/0x970 drivers/tty/tty_io.c:2718
 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+0x44/0xae

value changed: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 26999 Comm: syz-executor.2 Not tainted 5.18.0-rc7-syzkaller-00185-g978df3e15846-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/05/23 03:20 upstream 978df3e15846 7268fa62 .config log report info KCSAN: data-race in n_tty_close / pty_close
* Struck through repros no longer work on HEAD.