From mboxrd@z Thu Jan  1 00:00:00 1970
From: Anthony Wright <anthony@overnetdata.com>
Subject: Re: PV DomU running linux 3.17.3 causing xen-netback
 fatal error in Dom0
Date: Tue, 2 Dec 2014 15:40:30 +0000 (GMT)
Message-ID: <22601913.16.1417534830002.JavaMail.root@zimbra.overnetdata.com>
References: <547CB0AF.6010901@citrix.com>
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To: David Vrabel <david.vrabel@citrix.com>
Cc: xen-devel@lists.xensource.com, Wei Liu <wei.liu2@citrix.com>, Ian Campbell <ian.campbell@citrix.com>
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----- Original Message -----
> On 01/12/14 14:22, David Vrabel wrote:
> > On 28/11/14 15:19, Anthony Wright wrote:
> > The guest's frontend driver isn't putting valid requests onto the
> > ring
> > (it crosses a page boundary) so this is a frontend bug.
> 
> This VIF protocol is weird. The first slot contains a txreq with a
> size
> for the total length of the packet, subsequent slots have sizes for
> that
> fragment only.
> 
> netback then has to calculate how long the first slot is, by
> subtracting
> all the size from the following slots.
> 
> So something has gone wrong but it's not obvious what it is. Any
> chance
> you can dump the ring state when it happens?
Really sorry, but how do I dump the ring state? I can a root shell on both the Dom0 & DomU, but I don't know the command to use to dump the ring state.

Anthony.