[lkml]   [2022]   [Jan]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    Patch in this message
    Subject[PATCH 5.16 0201/1039] igc: AF_XDP zero-copy metadata adjust breaks SKBs on XDP_PASS
    From: Jesper Dangaard Brouer <>

    [ Upstream commit 4fa8fcd3440101dbacf4fae91de69877ef751977 ]

    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 <>
    Tested-by: Nechama Kraus <>
    Acked-by: Maciej Fijalkowski <>
    Signed-off-by: Tony Nguyen <>
    Signed-off-by: Sasha Levin <>
    drivers/net/ethernet/intel/igc/igc_main.c | 4 +++-
    1 file changed, 3 insertions(+), 1 deletion(-)

    diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
    index d28a80a009537..d83e665b3a4f2 100644
    --- a/drivers/net/ethernet/intel/igc/igc_main.c
    +++ b/drivers/net/ethernet/intel/igc/igc_main.c
    @@ -2448,8 +2448,10 @@ static struct sk_buff *igc_construct_skb_zc(struct igc_ring *ring,

    skb_reserve(skb, xdp->data_meta - xdp->data_hard_start);
    memcpy(__skb_put(skb, totalsize), xdp->data_meta, totalsize);
    - if (metasize)
    + if (metasize) {
    skb_metadata_set(skb, metasize);
    + __skb_pull(skb, metasize);
    + }

    return skb;

     \ /
      Last update: 2022-01-24 23:11    [W:2.160 / U:0.300 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site