> -----Original Message----- > From: Anthony Wright [mailto:anth...@overnetdata.com] > Sent: 06 September 2016 14:37 > To: Paul Durrant <paul.durr...@citrix.com>; Xen-devel <xen- > de...@lists.xen.org> > Subject: Re: Bug in hash changes to netback in 4.7.2 kernel > > On 06/09/2016 13:57, Paul Durrant wrote: > >> -----Original Message----- > >> From: Anthony Wright [mailto:anth...@overnetdata.com] > >> Sent: 06 September 2016 13:23 > >> To: Xen-devel <xen-devel@lists.xen.org> > >> Cc: Paul Durrant <paul.durr...@citrix.com> > >> Subject: Bug in hash changes to netback in 4.7.2 kernel > >> > >> When I run Xen (4.7.0) nested in VirtualBox (5.0.24_Ubuntu r108355) > >> with a > >> linux-4.7.2 Dom0 kernel, none of my DomU's (linux-3.17.3) have > >> network connectivity because they reject all packets with the error > 'Invalid extra type: > >> 4'. When I run exactly the same setup on bare metal, I don't get the > >> error messages. > >> > >> From poking around in the code this seems to be because the 4.7.2 > >> kernel wrongly decides that the DomU's will understand > >> EXTRA_TYPE_HASH, and so attach it to the network packet. Since the > >> DomU's don't understand the extra info their netfront driver rejects the > whole packet. > > The code in xenvif_select_queue() deliberately clears the skb->sw_hash > field (which gates adding the new extra type) if the hash algorithm selected > by the frontend is 'none', which should be the default. So, unless you have a > frontend that is implementing the control ring protocol, but failing to > recognize the new extra type I'm not how you're seeing the problem... > unless somehow a packet which hash is getting into netback's start_xmit > without first having gone through select_queue? > I very much doubt that the frontend is implementing the control ring > protocol, the DomUs are running stock linux-3.17.3. I build the system from > source, so happy to re-compile with debug code.
Well, if you could have a look to see whether the skbs have sw_hash set when they get into net_rx_action() that would be something, and also check whether xenvif_select_queue() is being properly called. I'll take a look and see if I can repro this myself when I get some time. Paul _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
