Re: [RFC PATCH] net: add dataref destructor to sk_buff

From: Gregory Haskins
Date: Tue Nov 17 2009 - 07:33:58 EST


Herbert Xu wrote:
> On Mon, Nov 16, 2009 at 09:22:57AM -0500, Gregory Haskins wrote:
>> But really, this is somewhat orthogonal to the original problem, so let
>> me see if we can bring it back on topic. Michael stated that this patch
>> in question may be problematic because there are places in the stack
>> that can get_page() without also maintaining a reference to the shinfo
>> object. Evgeniy seems to say the opposite. I am not sure who is right,
>> or if I misunderstood one or both of them. Any thoughts?
>
> There are loads of places where this can happen. Start with
> pskb_expand_head.

Indeed, I see your point. Looks like we can potentially solve that with
an extra level of indirection. E.g. skb->shinfo->owner, with a
ref-count+callback. Thoughts?

Kind Regards,
-Greg


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