udp: properly flush normal packet at GRO time

If an UDP packet enters the GRO engine but is not eligible for aggregation and is not targeting an UDP tunnel, udp_gro_receive() will not set the flush bit, and packet could delayed till the next napi flush. Fix the issue ensuring non GROed packets traverse skb_gro_flush_final(). Reported-and-tested-by: Matthias Treydte <[email protected]> Fixes: 18f25dc ("udp: skip L4 aggregation for UDP tunnel packets") Signed-off-by: Paolo Abeni <[email protected]> Signed-off-by: David S. Miller <[email protected]>
niw · Jul 2, 2021 · b43c890 · b43c890
1 parent b225802
commit b43c890
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
@@ -525,8 +525,10 @@ struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
 
 		if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
 		    (sk && udp_sk(sk)->gro_enabled) || NAPI_GRO_CB(skb)->is_flist)
-			pp = call_gro_receive(udp_gro_receive_segment, head, skb);
-		return pp;
+			return call_gro_receive(udp_gro_receive_segment, head, skb);
+
+		/* no GRO, be sure flush the current packet */
+		goto out;
 	}
 
 	if (NAPI_GRO_CB(skb)->encap_mark ||