> The task-local transmit recursion counter covers synchronous
> dev_queue_xmit() recursion, but does not follow a duplicated skb through
> asynchronous receive paths. Carry a bounded duplication depth with the skb
> and preserve it across skb and XDP conversions.
>
> Store the depth in the sk_buff headers group. __copy_skb_header() copies
> that group with a single memcpy(), so skb_clone() preserves the depth.
> Propagate it explicitly when veth converts an skb to an XDP buffer and
> when XDP buffers or frames are converted back to skbs in the core and
> virtio paths. Preserve it through zero-copy XDP frame conversion as well.
>
> Clear the depth when GRO reuses an skb and when AF_XDP or libeth
> reinitializes a recycled XDP buffer, so a fresh packet does not inherit
> stale recursion state.
>
> Keep the existing recursion limit and reject MIRRED flow offload where
> the software depth cannot be enforced.
>
> Fixes: 502061f81d3e ("netfilter: nf_tables: add packet duplication to the
> netdev family")
> Cc: [email protected]
> Reported-by: Vega <[email protected]>
> Assisted-by: LLM
> Co-developed-by: Luxing Yin <[email protected]>
> Signed-off-by: Luxing Yin <[email protected]>
> Signed-off-by: Zihan Xi <[email protected]>
Sashiko has reviewed this patch and found no issues. It looks great!
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Sashiko AI review ยท
https://sashiko.dev/#/patchset/[email protected]?part=2
