syzbot

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BUG: KCSAN: data-race in __tty_hangup / tty_hung_up_p

write to 0xffff888105dbea28 of 8 bytes by task 8722 on cpu 0:
 __tty_hangup+0x247/0x680 drivers/tty/tty_io.c:630
 tty_vhangup drivers/tty/tty_io.c:712 [inline]
 tty_ioctl+0x532/0x1120 drivers/tty/tty_io.c:2746
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888105dbea28 of 8 bytes by task 8716 on cpu 1:
 tty_hung_up_p+0x1c/0x40 drivers/tty/tty_io.c:762
 n_tty_write+0x2b3/0xaf0 drivers/tty/n_tty.c:2348
 do_tty_write drivers/tty/tty_io.c:1043 [inline]
 file_tty_write+0x409/0x660 drivers/tty/tty_io.c:1133
 tty_write+0x24/0x30 drivers/tty/tty_io.c:1140
 call_write_iter include/linux/fs.h:2114 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x69d/0x770 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+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8716 Comm: agetty Not tainted 5.13.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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