diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 8cd2782a31e4..0033fa7cd792 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -662,6 +662,7 @@ static void igmp6_group_added(struct ifmcaddr6 *mc)
 	    IPV6_ADDR_SCOPE_LINKLOCAL)
 		return;
 
+	memset(&buf, 0, MAX_ADDR_LEN);
 	spin_lock_bh(&mc->mca_lock);
 	if (!(mc->mca_flags&MAF_LOADED)) {
 		mc->mca_flags |= MAF_LOADED;
@@ -698,6 +699,7 @@ static void igmp6_group_dropped(struct ifmcaddr6 *mc)
 	    IPV6_ADDR_SCOPE_LINKLOCAL)
 		return;
 
+	memset(&buf, 0, MAX_ADDR_LEN);
 	spin_lock_bh(&mc->mca_lock);
 	if (mc->mca_flags&MAF_LOADED) {
 		mc->mca_flags &= ~MAF_LOADED;