Index: sys/net/if_gre.c
===================================================================
--- sys/net/if_gre.c	(revision 360684)
+++ sys/net/if_gre.c	(working copy)
@@ -107,6 +107,9 @@ static void	gre_clone_destroy(struct ifnet *);
 VNET_DEFINE_STATIC(struct if_clone *, gre_cloner);
 #define	V_gre_cloner	VNET(gre_cloner)
 
+#ifdef VIMAGE
+static void	gre_reassign(struct ifnet *, struct vnet *, char *);
+#endif
 static void	gre_qflush(struct ifnet *);
 static int	gre_transmit(struct ifnet *, struct mbuf *);
 static int	gre_ioctl(struct ifnet *, u_long, caddr_t);
@@ -183,6 +186,9 @@ gre_clone_create(struct if_clone *ifc, int unit, c
 	GRE2IFP(sc)->if_ioctl = gre_ioctl;
 	GRE2IFP(sc)->if_transmit = gre_transmit;
 	GRE2IFP(sc)->if_qflush = gre_qflush;
+#ifdef VIMAGE
+	GRE2IFP(sc)->if_reassign = gre_reassign;
+#endif
 	GRE2IFP(sc)->if_capabilities |= IFCAP_LINKSTATE;
 	GRE2IFP(sc)->if_capenable |= IFCAP_LINKSTATE;
 	if_attach(GRE2IFP(sc));
@@ -190,7 +196,22 @@ gre_clone_create(struct if_clone *ifc, int unit, c
 	return (0);
 }
 
+#ifdef VIMAGE
 static void
+gre_reassign(struct ifnet *ifp, struct vnet *new_vnet, char *unused __unused)
+{
+	struct gre_softc *sc;
+
+	sx_xlock(&gre_ioctl_sx);
+	sc = ifp->if_softc;
+	if (sc != NULL) {
+		gre_delete_tunnel(sc);
+	}
+	sx_xunlock(&gre_ioctl_sx);
+}
+#endif /* VIMAGE */
+
+static void
 gre_clone_destroy(struct ifnet *ifp)
 {
 	struct gre_softc *sc;