diff --git a/sys/netinet6/ip6_flow.c b/sys/netinet6/ip6_flow.c
index 6c56d3b08ca8..e69c873b81fe 100644
--- a/sys/netinet6/ip6_flow.c
+++ b/sys/netinet6/ip6_flow.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: ip6_flow.c,v 1.22 2014/04/01 13:11:44 pooka Exp $	*/
+/*	$NetBSD: ip6_flow.c,v 1.23 2014/05/20 20:23:56 bouyer Exp $	*/
 
 /*-
  * Copyright (c) 2007 The NetBSD Foundation, Inc.
@@ -38,7 +38,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ip6_flow.c,v 1.22 2014/04/01 13:11:44 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ip6_flow.c,v 1.23 2014/05/20 20:23:56 bouyer Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -308,13 +308,14 @@ ip6flow_fastforward(struct mbuf **mp)
 
 	ip6f->ip6f_uses++;
 
+	KERNEL_LOCK(1, NULL);
 	/* Send on its way - straight to the interface output routine. */
 	if ((error = (*rt->rt_ifp->if_output)(rt->rt_ifp, m, dst, rt)) != 0) {
 		ip6f->ip6f_dropped++;
 	} else {
 		ip6f->ip6f_forwarded++;
 	}
-
+	KERNEL_UNLOCK_ONE(NULL);
 	return 1;
 }
 
diff --git a/sys/netinet6/nd6.c b/sys/netinet6/nd6.c
index 745bec0acd65..e41c3cf86680 100644
--- a/sys/netinet6/nd6.c
+++ b/sys/netinet6/nd6.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: nd6.c,v 1.149 2014/05/17 20:44:24 rmind Exp $	*/
+/*	$NetBSD: nd6.c,v 1.150 2014/05/20 20:23:56 bouyer Exp $	*/
 /*	$KAME: nd6.c,v 1.279 2002/06/08 11:16:51 itojun Exp $	*/
 
 /*
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nd6.c,v 1.149 2014/05/17 20:44:24 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nd6.c,v 1.150 2014/05/20 20:23:56 bouyer Exp $");
 
 #include "opt_ipsec.h"
 
@@ -2257,9 +2257,13 @@ nd6_output(struct ifnet *ifp, struct ifnet *origifp, struct mbuf *m0,
 		goto bad;
 	}
 
+	KERNEL_LOCK(1, NULL);
 	if ((ifp->if_flags & IFF_LOOPBACK) != 0)
-		return (*ifp->if_output)(origifp, m, sin6tocsa(dst), rt);
-	return (*ifp->if_output)(ifp, m, sin6tocsa(dst), rt);
+		error = (*ifp->if_output)(origifp, m, sin6tocsa(dst), rt);
+	else
+		error = (*ifp->if_output)(ifp, m, sin6tocsa(dst), rt);
+	KERNEL_UNLOCK_ONE(NULL);
+	return error;
 
   bad:
 	if (m != NULL)