Index: sys/netinet/igmp.c
===================================================================
RCS file: /cvsroot/src/sys/netinet/igmp.c,v
retrieving revision 1.55
diff -p -u -r1.55 igmp.c
--- sys/netinet/igmp.c	29 May 2014 23:02:48 -0000	1.55
+++ sys/netinet/igmp.c	22 Aug 2014 16:50:12 -0000
@@ -469,6 +469,8 @@ igmp_input(struct mbuf *m, ...)
 int
 igmp_joingroup(struct in_multi *inm)
 {
+
+	KASSERT(mutex_owned(softnet_lock));
 	KASSERT(in_multi_lock_held());
 	inm->inm_state = IGMP_IDLE_MEMBER;
 
@@ -494,6 +496,8 @@ igmp_joingroup(struct in_multi *inm)
 void
 igmp_leavegroup(struct in_multi *inm)
 {
+
+	KASSERT(mutex_owned(softnet_lock));
 	KASSERT(in_multi_lock_held());
 
 	switch (inm->inm_state) {
Index: sys/netinet/ip_output.c
===================================================================
RCS file: /cvsroot/src/sys/netinet/ip_output.c,v
retrieving revision 1.230
diff -p -u -r1.230 ip_output.c
--- sys/netinet/ip_output.c	6 Jun 2014 00:11:19 -0000	1.230
+++ sys/netinet/ip_output.c	22 Aug 2014 16:50:12 -0000
@@ -1645,8 +1645,11 @@ ip_freemoptions(struct ip_moptions *imo)
 	int i;
 
 	if (imo != NULL) {
-		for (i = 0; i < imo->imo_num_memberships; ++i)
+		for (i = 0; i < imo->imo_num_memberships; ++i) {
+			mutex_enter(softnet_lock);
 			in_delmulti(imo->imo_membership[i]);
+			mutex_exit(softnet_lock);
+		}
 		kmem_free(imo, sizeof(*imo));
 	}
 }