syzbot

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BUG: KCSAN: data-race in isig / pty_close

write to 0xffff88812107f9d9 of 1 bytes by task 11185 on cpu 1:
 pty_close+0x120/0x280 drivers/tty/pty.c:61
 tty_release+0x255/0xa00 drivers/tty/tty_io.c:1758
 __fput+0x295/0x520 fs/file_table.c:317
 ____fput+0x11/0x20 fs/file_table.c:350
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x160/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88812107f9d9 of 1 bytes by task 11195 on cpu 0:
 n_tty_packet_mode_flush drivers/tty/n_tty.c:342 [inline]
 isig+0x1b5/0x280 drivers/tty/n_tty.c:1123
 n_tty_receive_signal_char drivers/tty/n_tty.c:1213 [inline]
 n_tty_receive_char_special drivers/tty/n_tty.c:1241 [inline]
 n_tty_receive_buf_standard drivers/tty/n_tty.c:1530 [inline]
 __receive_buf drivers/tty/n_tty.c:1549 [inline]
 n_tty_receive_buf_common+0x12c5/0x4e70 drivers/tty/n_tty.c:1645
 n_tty_receive_buf+0x2b/0x40 drivers/tty/n_tty.c:1674
 tiocsti drivers/tty/tty_io.c:2293 [inline]
 tty_ioctl+0x978/0x1130 drivers/tty/tty_io.c:2692
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:860
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11195 Comm: syz-executor.2 Not tainted 5.17.0-rc6-syzkaller-00054-gfb184c4af9b9-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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