[PATCH v2 -next] net/core/dev: Warn on a too-short GRO frame

[PATCH v2 -next] net/core/dev: Warn on a too-short GRO frame

[Aaron Conole]

From: Aaron Conole <aconole@bytheb.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@bytheb.org>
---
v2:
* Convert from WARN_ON to net_warn_ratelimited

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

diff --git a/net/core/dev.c b/net/core/dev.c
index b9bcbe7..1be269e 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\n",
+					     __func__);
 			napi_reuse_skb(napi, skb);
 			return NULL;
 		}
-- 
2.5.5

Re: [PATCH v2 -next] net/core/dev: Warn on a too-short GRO frame

[Eric Dumazet]

On Fri, 2016-04-01 at 15:58 -0400, Aaron Conole wrote:
> From: Aaron Conole <aconole@bytheb.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@bytheb.org>
> ---


Shouldn't we give a hint of device name ?

(available in napi->dev->name )