On 02/20/2018 05:32 AM, Jesper Dangaard Brouer wrote:
> XDP_REDIRECT calling xdp_do_redirect() can fail for multiple reasons
> (which can be inspected by tracepoints). The current semantics is that
> on failure the driver calling xdp_do_redirect() must handle freeing or
> recycling the page associated with this frame. This can be seen as an
> optimization, as drivers usually have an optimized XDP_DROP code path
> for frame recycling in place already.
>
> The virtio_net driver didn't handle when xdp_do_redirect() failed.
> This caused a memory leak as the page refcnt wasn't decremented on
> failures.
>
> The function __virtnet_xdp_xmit() did handle one type of failure,
> when the xmit queue virtqueue_add_outbuf() is full, which "hides"
> releasing a refcnt on the page. Instead the function __virtnet_xdp_xmit()
> must follow API of xdp_do_redirect(), which on errors leave it up to
> the caller to free the page, of the failed send operation.
>
> Fixes: 186b3c998c50 ("virtio-net: support XDP_REDIRECT")
> Signed-off-by: Jesper Dangaard Brouer <bro...@redhat.com>
> ---
Acked-by: John Fastabend <john.fastab...@gmail.com>
