From 76458faeb285b1536abc3e75ea318564543269c3 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 8 Jun 2022 09:04:32 -0700
Subject: [PATCH] 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>
---
 net/core/dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 511cf5d3aade6..39cb9055da37e 100644
--- 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;