On Sun, Nov 08, 2015 at 05:02:52PM -0500, Peter Hurley wrote:

+void tty_ldisc_closing(struct tty_struct *tty)
+{
+	struct tty_ldisc *ld = tty_ldisc_ref(tty);
+
+	if (ld->ops->closing)
+		ld->ops->closing(tty);
+	if (ld)
+		tty_ldisc_deref(ld);
+}

That looks strange.  Do you need to check ld _before_ dereferencing?

Johannes