Re: [PATCHv4 bpf-next 0/2] xdp: add dev map multicast support

Hangbin Liu
2020-06-16T09:47:56Z

On Tue, Jun 16, 2020 at 11:09:22AM +0200, Jesper Dangaard Brouer wrote:
> > > BTW, when using pktgen, I got an panic because the skb don't have enough
> > > header room. The code path looks like
> > >
> > > do_xdp_generic()
> > > - netif_receive_generic_xdp()
> > > - skb_headroom(skb) < XDP_PACKET_HEADROOM
> > > - pskb_expand_head()
> > > - BUG_ON(skb_shared(skb))
> > >
> > > So I added a draft patch for pktgen, not sure if it has any influence.
> >
> > Hmm, as Jesper said pktgen was really not intended to be used this way,
> > so I guess that's why. I guess I'll let him comment on whether he thinks
> > it's worth fixing; or you could send this as a proper patch and see if
> > anyone complains about it ;)
>
> Don't use pktgen in this way with veth. If anything pktgen should
> detect that you use pktgen in virtual interfaces and reject/disallow
> that you do this.

OK, got it.

Thanks
Hangbin