On 26/11/2021 16.25, Maciej Fijalkowski wrote:

On Mon, Nov 15, 2021 at 09:36:25PM +0100, Jesper Dangaard Brouer wrote:

quoted

Driver already implicitly supports XDP metadata access in AF_XDP
zero-copy mode, as xsk_buff_pool's xp_alloc() naturally set xdp_buff
data_meta equal data.

This works fine for XDP and AF_XDP, but if a BPF-prog adjust via
bpf_xdp_adjust_meta() and choose to call XDP_PASS, then igc function
igc_construct_skb_zc() will construct an invalid SKB packet. The
function correctly include the xdp->data_meta area in the memcpy, but
forgot to pull header to take metasize into account.

Fixes: fc9df2a0b520 ("igc: Enable RX via AF_XDP zero-copy")
Signed-off-by: Jesper Dangaard Brouer<redacted>

Acked-by: Maciej Fijalkowski<maciej.fijalkowski@intel.com>

Great catch. Will take a look at other ZC enabled Intel drivers if they
are affected as well.

Thanks a lot for taking this task!!! :-)
--Jesper