net: use DEBUG_NET_WARN_ON_ONCE() in dev_loopback_xmit()

One check in dev_loopback_xmit() has not caught issues
in the past.

Keep it for CONFIG_DEBUG_NET=y builds only.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/dev.c b/net/core/dev.c
index 511cf5d..39cb905 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3925,7 +3925,7 @@ int dev_loopback_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
        skb->pkt_type = PACKET_LOOPBACK;
        if (skb->ip_summed == CHECKSUM_NONE)
                skb->ip_summed = CHECKSUM_UNNECESSARY;
-       WARN_ON(!skb_dst(skb));
+       DEBUG_NET_WARN_ON_ONCE(!skb_dst(skb));
        skb_dst_force(skb);
        netif_rx(skb);
        return 0;