diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 091cee551cd9..a5ec9a0cbb80 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -2390,17 +2390,17 @@ static int ip6_mc_leave_src(struct sock *sk, struct ipv6_mc_socklist *iml,
 {
 	int err;
 
-	/* callers have the socket lock and rtnl lock
-	 * so no other readers or writers of iml or its sflist
-	 */
+	write_lock_bh(&iml->sflock);
 	if (!iml->sflist) {
 		/* any-source empty exclude case */
-		return ip6_mc_del_src(idev, &iml->addr, iml->sfmode, 0, NULL, 0);
+		err = ip6_mc_del_src(idev, &iml->addr, iml->sfmode, 0, NULL, 0);
+	} else {
+		err = ip6_mc_del_src(idev, &iml->addr, iml->sfmode,
+				iml->sflist->sl_count, iml->sflist->sl_addr, 0);
+		sock_kfree_s(sk, iml->sflist, IP6_SFLSIZE(iml->sflist->sl_max));
+		iml->sflist = NULL;
 	}
-	err = ip6_mc_del_src(idev, &iml->addr, iml->sfmode,
-		iml->sflist->sl_count, iml->sflist->sl_addr, 0);
-	sock_kfree_s(sk, iml->sflist, IP6_SFLSIZE(iml->sflist->sl_max));
-	iml->sflist = NULL;
+	write_unlock_bh(&iml->sflock);
 	return err;
 }