syzbot

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BUG: KCSAN: data-race in __stop_tty / do_con_write

write to 0xffff88815b6fddbc of 1 bytes by task 31334 on cpu 0:
 __stop_tty+0x42/0x90 drivers/tty/tty_io.c:753
 n_tty_ioctl_helper+0x21f/0x240 drivers/tty/tty_ioctl.c:955
 n_tty_ioctl+0xfd/0x200 drivers/tty/n_tty.c:2511
 tty_ioctl+0x875/0xbc0 drivers/tty/tty_io.c:2789
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xcf/0x140 fs/ioctl.c:857
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88815b6fddbc of 1 bytes by task 31325 on cpu 1:
 do_con_write+0x1459/0x35d0 drivers/tty/vt/vt.c:2885
 con_write+0x26/0x40 drivers/tty/vt/vt.c:3251
 process_output_block drivers/tty/n_tty.c:574 [inline]
 n_tty_write+0x84a/0xb60 drivers/tty/n_tty.c:2379
 iterate_tty_write drivers/tty/tty_io.c:1021 [inline]
 file_tty_write+0x382/0x680 drivers/tty/tty_io.c:1092
 tty_write+0x28/0x30 drivers/tty/tty_io.c:1113
 call_write_iter include/linux/fs.h:2020 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x48a/0x790 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 31325 Comm: syz-executor.3 Not tainted 6.6.0-syzkaller-14263-gaea6bf908d73 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
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