syzbot

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BUG: KCSAN: data-race in __tty_hangup / tty_hung_up_p

write to 0xffff88813c2e9e28 of 8 bytes by task 7814 on cpu 0:
 __tty_hangup+0x1e2/0x510 drivers/tty/tty_io.c:622
 tty_vhangup drivers/tty/tty_io.c:701 [inline]
 tty_ioctl+0x604/0xbc0 drivers/tty/tty_io.c:2717
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xc9/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88813c2e9e28 of 8 bytes by task 7819 on cpu 1:
 tty_hung_up_p+0x20/0x40 drivers/tty/tty_io.c:746
 n_tty_write+0x2dc/0xa80 drivers/tty/n_tty.c:2343
 do_tty_write drivers/tty/tty_io.c:1018 [inline]
 file_tty_write+0x3a0/0x600 drivers/tty/tty_io.c:1089
 tty_write+0x28/0x30 drivers/tty/tty_io.c:1110
 do_iter_write+0x4ae/0x770 fs/read_write.c:860
 vfs_writev+0x1a2/0x310 fs/read_write.c:933
 do_writev+0xf8/0x220 fs/read_write.c:976
 __do_sys_writev fs/read_write.c:1049 [inline]
 __se_sys_writev fs/read_write.c:1046 [inline]
 __x64_sys_writev+0x45/0x50 fs/read_write.c:1046
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0xffffffff84e92a30 -> 0xffffffff84e928c0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7819 Comm: syz-executor.3 Not tainted 6.4.0-rc5-syzkaller-00017-ga27648c74210 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
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