--- sys/net/if.c	(revision 340543)
+++ sys/net/if.c	(working copy)
@@ -1032,6 +1032,8 @@ if_detach_internal(struct ifnet *ifp, int vmove, s
 		if (iter == ifp) {
 			TAILQ_REMOVE(&V_ifnet, ifp, if_link);
 			found = 1;
+			if (!vmove)
+				ifp->if_flags |= IFF_DYING;
 			break;
 		}
 	IFNET_WUNLOCK();
--- sys/net/rtsock.c	(revision 340543)
+++ sys/net/rtsock.c	(working copy)
@@ -1555,7 +1555,7 @@ sysctl_dumpentry(struct radix_node *rn, void *vw)
 	info.rti_info[RTAX_NETMASK] = rtsock_fix_netmask(rt_key(rt),
 	    rt_mask(rt), &ss);
 	info.rti_info[RTAX_GENMASK] = 0;
-	if (rt->rt_ifp) {
+	if (rt->rt_ifp && !(rt->rt_ifp->if_flags & IFF_DYING)) {
 		info.rti_info[RTAX_IFP] = rt->rt_ifp->if_addr->ifa_addr;
 		info.rti_info[RTAX_IFA] = rt->rt_ifa->ifa_addr;
 		if (rt->rt_ifp->if_flags & IFF_POINTOPOINT)
@@ -1913,8 +1913,10 @@ sysctl_rtsock(SYSCTL_HANDLER_ARGS)
 			rnh = rt_tables_get_rnh(fib, i);
 			if (rnh != NULL) {
 				RIB_RLOCK(rnh); 
+				IFNET_RLOCK_NOSLEEP();
 			    	error = rnh->rnh_walktree(&rnh->head,
 				    sysctl_dumpentry, &w);
+				IFNET_RUNLOCK_NOSLEEP();
 				RIB_RUNLOCK(rnh);
 			} else if (af != 0)
 				error = EAFNOSUPPORT;