r0 = syz_open_dev$tty20(0xc, 0x4, 0x1)
ioctl$TIOCSETD(r0, 0x5423, &(0x7f0000000180)=0x1b)
ioctl$BTRFS_IOC_GET_SUBVOL_ROOTREF(r0, 0xd000943d, 0x0)