syzbot

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BUG: KCSAN: data-race in __se_sys_ioctl / __tty_hangup

write to 0xffff888100c1c928 of 8 bytes by task 10820 on cpu 1:
 __tty_hangup+0x247/0x650 drivers/tty/tty_io.c:630
 tty_vhangup drivers/tty/tty_io.c:711 [inline]
 tty_ioctl+0x532/0x1150 drivers/tty/tty_io.c:2745
 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+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888100c1c928 of 8 bytes by task 10825 on cpu 0:
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xa5/0x140 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+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffffffff8308fa28 -> 0xffffffff8308f928

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10825 Comm: syz-executor.4 Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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