On Sat, 31 Mar 2018 02:22:35 +0800 kbuild test robot [off-list ref] wrote:

reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__

[...]

   417	
   418	static bool __virtnet_xdp_xmit(struct virtnet_info *vi,
   419				       struct xdp_buff *xdp)
   420	{

[...]

   445	
   446		/* Make room for virtqueue hdr (also change xdpf->headroom?) */
   447		xdpf->data -= vi->hdr_len;
   448		/* Zero header and leave csum up to XDP layers */
   449		hdr = xdpf->data;
   450		memset(hdr, 0, vi->hdr_len);
 > 451		hdr->hdr.hdr_len = xdpf->len; /* Q: is this needed? */ 

I'll just remove this line, as Jason previously told me that it is not
strictly necessary (so lets avoid playing with endianness here).

   452		xdpf->len   += vi->hdr_len;
   453	

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer