netdev - sk_buff handling in packet handler

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Date:	Sat, 16 May 2009 12:31:28 -0400
From:	Claude Robitaille <clauder@...edian.com>
To:	netdev@...r.kernel.org
Subject: sk_buff handling in packet handler

Hi all,

My question is a development question so I hope this is the correct list 
to post it. If not just tell me and I will find another list...

I am developing a packet handler that I register via dev_add_pack. All 
is fine except that after a while the kernel crashes. I suspect my 
handler not doing something correct...

The handler is registered with the ETH_P_ALL list, listening on a 
specific interface.

After many attempt at reducing the scope of what my handler is doing I 
now simply do a return in my handler. When I send lots of frames to 
interface that I am listening to after a while I start getting kernel 
messages about low memory and eventually even get exception dumps.

I suspect that the handler needs to do something with the sk_buff but I 
am not sure what. I printed the content of the sk_buff and found that 
the skb_buff is not cloned (looking on the web I had found that the 
sk_buff should have been cloned) and that he number of users is 1.

Should I simply do a dev_kfree_skb? What are the rules governing the use 
of the sk_buff in a packet handler? Should I clone the sk_buff?

Also, a related question, the packet handler is expected to return an 
int. What should be returned?

Thanks

Claude

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