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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200616094741.GU102436@dhcp-12-153.nay.redhat.com>
Date:   Tue, 16 Jun 2020 17:47:41 +0800
From:   Hangbin Liu <liuhangbin@...il.com>
To:     Jesper Dangaard Brouer <brouer@...hat.com>
Cc:     Toke Høiland-Jørgensen <toke@...hat.com>,
        bpf@...r.kernel.org, netdev@...r.kernel.org,
        Jiri Benc <jbenc@...hat.com>,
        Eelco Chaudron <echaudro@...hat.com>, ast@...nel.org,
        Daniel Borkmann <daniel@...earbox.net>,
        Lorenzo Bianconi <lorenzo.bianconi@...hat.com>
Subject: Re: [PATCHv4 bpf-next 0/2] xdp: add dev map multicast support

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