Re: [PATCH RFC net-next] net: Assert napi_gro_cb size against skb->cb[]

[Florian Westphal <fw@strlen.de>]

Florian Fainelli <f.fainelli@gmail.com> wrote:
> On 64-bits hosts, napi_gro_cb is 48 bytes, which is exactly the size of
> skb->cb[], while on 32-bits hosts it is 36 bytes, but if it were to
> grow, we would not be catching a size inflation as we should.
> ---
>  net/core/dev.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 4870c3556a5a..20bc82604b75 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -4115,6 +4115,8 @@ static void skb_gro_reset_offset(struct sk_buff *skb)
>  	const struct skb_shared_info *pinfo = skb_shinfo(skb);
>  	const skb_frag_t *frag0 = &pinfo->frags[0];
>  
> +	BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct napi_gro_cb));

commit c3c7c254b2e8cd99b0adf288c2a1bddacd7ba255
already added a check for this.