[Xen-devel] Bug in hash changes to netback in 4.7.2 kernel

[Anthony Wright <anthony@xxxxxxxxxxxxxxx>]

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.

I'm guessing that the nesting is confusing the new hash code.

I also wonder if the DomU's should simply ignore extra info that they don't 
understand rather than rejecting the packet.

Cheers,

Anthony

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