Re: [PATCH bpf-next v4 2/8] bpf: Enable read/write access to skb metadata through a dynptr

On Fri, 25 Jul 2025 11:43:19 +0200 Jakub Sitnicki wrote:

quoted

Taking about the next step, once skb metadata is preserved past the TC
hook - here my impression from Netdev was that the least suprising thing
to do will be to copy-on-clone or copy-on-write (if we can pull it off).  

Now that Martin has enlightened me [1] how things work today for skb
payload dynptr's, I will first try to follow the same approach, that is:

Make a copy of skb metadata before the BPF program runs, if the program
may write to the metadata.

👍️

On the pskb_expand_head() behavior we should probably ask Daniel?
I suspect it's just to "fail closed". But as you said we can follow
up on that later, not a blocker in practice on Rx.