--- if_an.c.orig	2007-09-12 15:08:26.000000000 +0800
+++ if_an.c	2007-10-30 09:34:45.000000000 +0800
@@ -1151,6 +1151,10 @@
 
 	sc = xsc;
 	AN_LOCK(sc);
+	if (sc->an_gone) {
+		AN_UNLOCK(sc);
+		return;
+	}
 	ifp = sc->an_ifp;
 
 	sc->an_status.an_type = AN_RID_STATUS;