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BUG: KCSAN: data-race in __tty_hangup / tty_hung_up_p

write to 0xffff88801ec21328 of 8 bytes by task 27050 on cpu 1:
 __tty_hangup+0x23a/0x610 drivers/tty/tty_io.c:613
 tty_vhangup+0x13/0x20 drivers/tty/tty_io.c:695
 pty_close+0x298/0x2c0 drivers/tty/pty.c:79
 tty_release+0x255/0xa00 drivers/tty/tty_io.c:1694
 __fput+0x24e/0x4e0 fs/file_table.c:280
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0x8e/0x110 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x17c/0x1b0 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:302
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88801ec21328 of 8 bytes by task 27051 on cpu 0:
 tty_hung_up_p+0x1c/0x40 drivers/tty/tty_io.c:745
 n_tty_write+0x2b3/0xaf0 drivers/tty/n_tty.c:2326
 do_tty_write drivers/tty/tty_io.c:961 [inline]
 file_tty_write+0x3e9/0x630 drivers/tty/tty_io.c:1048
 tty_write+0x24/0x30 drivers/tty/tty_io.c:1055
 call_write_iter include/linux/fs.h:1901 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x6f0/0x7e0 fs/read_write.c:605
 ksys_write+0xce/0x180 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:667
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 27051 Comm: syz-executor.5 Not tainted 5.11.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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