syzbot

==================================================================
BUG: KCSAN: data-race in do_con_write / stop_tty

write to 0xffff888114379dbc of 1 bytes by task 11134 on cpu 0:
 __stop_tty drivers/tty/tty_io.c:753 [inline]
 stop_tty+0x58/0xc0 drivers/tty/tty_io.c:777
 n_tty_receive_char_flow_ctrl+0x87/0x1a0 drivers/tty/n_tty.c:1254
 n_tty_receive_char_special drivers/tty/n_tty.c:1359 [inline]
 n_tty_receive_buf_standard+0x4e1/0x2e30 drivers/tty/n_tty.c:1604
 __receive_buf drivers/tty/n_tty.c:1640 [inline]
 n_tty_receive_buf_common+0x83a/0xbe0 drivers/tty/n_tty.c:1739
 n_tty_receive_buf+0x30/0x40 drivers/tty/n_tty.c:1779
 tiocsti+0x166/0x1d0 drivers/tty/tty_io.c:2299
 tty_ioctl+0x415/0xbe0 drivers/tty/tty_io.c:2717
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xd3/0x150 fs/ioctl.c:893
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:893
 x64_sys_call+0x15cc/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888114379dbc of 1 bytes by task 11135 on cpu 1:
 do_con_write+0x1a29/0x25f0 drivers/tty/vt/vt.c:3072
 con_write+0x26/0x40 drivers/tty/vt/vt.c:3434
 process_output_block drivers/tty/n_tty.c:574 [inline]
 n_tty_write+0x849/0xb90 drivers/tty/n_tty.c:2389
 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
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x78f/0x900 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
 x64_sys_call+0x27dd/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 11135 Comm: syz.2.2209 Not tainted 6.11.0-rc4-syzkaller-00236-g60f0560f53e3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
==================================================================