--- sys/net/if_stf.c.orig	2017-02-15 13:04:46.104907000 +0700
+++ sys/net/if_stf.c	2017-06-17 18:17:19.395830000 +0700
@@ -360,6 +360,7 @@ stf_encapcheck(const struct mbuf *m, int
 static int
 stf_getsrcifa6(struct ifnet *ifp, struct in6_addr *addr, struct in6_addr *mask)
 {
+	struct rm_priotracker in_ifa_tracker;
 	struct ifaddr *ia;
 	struct in_ifaddr *ia4;
 	struct in6_ifaddr *ia6;
@@ -375,9 +376,11 @@ stf_getsrcifa6(struct ifnet *ifp, struct
 			continue;
 
 		bcopy(GET_V4(&sin6->sin6_addr), &in, sizeof(in));
+		IN_IFADDR_RLOCK(&in_ifa_tracker);
 		LIST_FOREACH(ia4, INADDR_HASH(in.s_addr), ia_hash)
 			if (ia4->ia_addr.sin_addr.s_addr == in.s_addr)
 				break;
+		IN_IFADDR_RUNLOCK(&in_ifa_tracker);
 		if (ia4 == NULL)
 			continue;