netdev - [PATCH v3 -next] net/core/dev: Warn on a too-short GRO frame

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Message-Id: <1459625203-8637-1-git-send-email-aconole@redhat.com>
Date:	Sat,  2 Apr 2016 15:26:43 -0400
From:	Aaron Conole <aconole@...heb.org>
To:	netdev@...r.kernel.org, Joe Perches <joe@...ches.com>,
	Eric Dumazet <eric.dumazet@...il.com>
Subject: [PATCH v3 -next] net/core/dev: Warn on a too-short GRO frame

From: Aaron Conole <aconole@...heb.org>

When signaling that a GRO frame is ready to be processed, the network stack
correctly checks length and aborts processing when a frame is less than 14
bytes. However, such a condition is really indicative of a broken driver,
and should be loudly signaled, rather than silently dropped as the case is
today.

Convert the condition to use net_warn_ratelimited() to ensure the stack
loudly complains about such broken drivers.

Signed-off-by: Aaron Conole <aconole@...heb.org>
---
v2:
* Switched from WARN_ON to net_warn_ratelimited

v3:
* Amend the string to include device name as a hint

 net/core/dev.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/core/dev.c b/net/core/dev.c
index b9bcbe7..273f10d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4663,6 +4663,8 @@ static struct sk_buff *napi_frags_skb(struct napi_struct *napi)
 	if (unlikely(skb_gro_header_hard(skb, hlen))) {
 		eth = skb_gro_header_slow(skb, hlen, 0);
 		if (unlikely(!eth)) {
+			net_warn_ratelimited("%s: dropping impossible skb from %s\n",
+					     __func__, napi->dev->name);
 			napi_reuse_skb(napi, skb);
 			return NULL;
 		}
-- 
2.5.5