--- channels/sig_pri.c.2011-02-23	2011-02-23 10:11:03.000000000 -0700
+++ channels/sig_pri.c	2011-02-23 10:20:13.000000000 -0700
@@ -870,6 +870,9 @@
 	else
 		return NULL;
 
+	if (!c)
+		return NULL;
+
 	if (!p->owner)
 		p->owner = c;
 	p->isidlecall = 0;