ld = tty_ldisc_ref(tty);
switch (arg) {
case TCIFLUSH:
- if (ld->flush_buffer)
+ if (ld && ld->flush_buffer)
ld->flush_buffer(tty);
break;
case TCIOFLUSH:
- if (ld->flush_buffer)
+ if (ld && ld->flush_buffer)
ld->flush_buffer(tty);
/* fall through */
case TCOFLUSH: