syzbot

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BUG: KCSAN: data-race in __stop_tty / do_con_write

write to 0xffff8881382a25bc of 1 bytes by task 11950 on cpu 0:
 __stop_tty+0x3e/0x80 drivers/tty/tty_io.c:760
 n_tty_ioctl_helper+0x310/0x450 drivers/tty/tty_ioctl.c:872
 n_tty_ioctl+0xfc/0x1f0 drivers/tty/n_tty.c:2381
 tty_ioctl+0xaf7/0x1130 drivers/tty/tty_io.c:2787
 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/0x50 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881382a25bc of 1 bytes by task 11942 on cpu 1:
 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:581 [inline]
 n_tty_write+0x77b/0xaf0 drivers/tty/n_tty.c:2248
 do_tty_write drivers/tty/tty_io.c:1024 [inline]
 file_tty_write+0x409/0x660 drivers/tty/tty_io.c:1095
 tty_write+0x24/0x30 drivers/tty/tty_io.c:1116
 call_write_iter include/linux/fs.h:2079 [inline]
 new_sync_write fs/read_write.c:504 [inline]
 vfs_write+0x755/0x8b0 fs/read_write.c:591
 ksys_write+0xd9/0x190 fs/read_write.c:644
 __do_sys_write fs/read_write.c:656 [inline]
 __se_sys_write fs/read_write.c:653 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:653
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x50 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 11942 Comm: syz-executor.0 Not tainted 5.17.0-syzkaller-13410-g74164d284b29-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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