Index: sys/x86/xen/xen_intr.c
===================================================================
--- sys/x86/xen/xen_intr.c
+++ sys/x86/xen/xen_intr.c
@@ -299,8 +299,9 @@
 
 		vector = first_evtchn_irq + isrc_idx;
 		isrc = (struct xenisrc *)intr_lookup_source(vector);
-		if (isrc != NULL
-		 && isrc->xi_type == EVTCHN_TYPE_UNBOUND) {
+		if (__predict_true(isrc != NULL) &&
+		    __predict_true(isrc->xi_intsrc.is_pic == &xen_intr_pic) &&
+		    isrc->xi_type == EVTCHN_TYPE_UNBOUND) {
 			KASSERT(isrc->xi_intsrc.is_handlers == 0,
 			    ("Free evtchn still has handlers"));
 			isrc->xi_type = type;
@@ -352,7 +353,12 @@
 	isrc->xi_intsrc.is_pic = &xen_intr_pic;
 	isrc->xi_vector = vector;
 	isrc->xi_type = type;
-	intr_register_source(&isrc->xi_intsrc);
+	if (__predict_false(intr_register_source(&isrc->xi_intsrc) != 0)) {
+		free(isrc, M_XENINTR);
+		printf("%s(): WARNING failed to register IRQ %u\n", __func__,
+		    vector);
+		return (NULL);
+	}
 
 	return (isrc);
 }