--- a/kernel/pf_ring.c
+++ b/kernel/pf_ring.c
@@ -3902,7 +3902,7 @@ static int hash_pkt_cluster(ring_cluster
       break;
     }
     /* else, fall through, because it's like 2-tuple for non-TCP packets */
-
+    fallthrough;
   case cluster_per_flow_2_tuple:
   case cluster_per_inner_flow_2_tuple:
     flags |= mask_2_tuple;