From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <Ian.Campbell@citrix.com>
Subject: Re: [Xen-devel] compound skb frag pages appearing in start_xmit
Date: Tue, 20 Nov 2012 11:36:53 +0000
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Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	Konrad Rzeszutek Wilk <konrad@kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"Marcos E. Matsunaga" <Marcos.Matsunaga@oracle.com>,
	xen-devel <xen-devel@lists.xen.org>,
	Sander Eikelenboom <linux@eikelenboom.it>,
	"ANNIE LI" <annie.li@oracle.com>,
	Eric Dumazet <edumazet@google.com>
To: Stefan Bader <stefan.bader@canonical.com>
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On Tue, 2012-11-20 at 09:21 +0000, Ian Campbell wrote:
> On Tue, 2012-11-20 at 08:30 +0000, Stefan Bader wrote:
> > >> When I tried to rebase my persistent grant netfront/netback patch on 
> > >> latest kernel, netperf/netserver test never succeeded. I did some test 
> > >> to find out that v3.6-rc7 works fine, but v3.7-rc1, v3.7-rc2 and 
> > >> v3.7-rc4 does not succeed in netperf/netserver test. So I keep my 
> > >> persistent grant patch only based on v3.4-rc3 now.
> > > 
> > >> Konrad thought about commit 6a8ed462f16b8455eec5ae00eb6014159a6721f0 in 
> > >> v3.7-rc1, and suggested me to test your debug patch in netfront. This 
> > >> BUG_ON happens soon after running the netperf/netserver test case.
> > > 
> > >> Thanks
> > >> Annie
> > > 
> > > Is there any progression with this bug (rc6 is out the door, so the
> > release of 3.7-final seems to be eminent and this bug completely
> > cripples any networking with guests) ?
> > > 
> > 
> > +1 on that. I was testing yesterday with a PVM domU running 3.7-rc5 on Xen 4.2
> > (but also reported from EC2 running Xen 3.4.3) c with one VCPU. I actually can
> > trigger it by just ssh'ing into the domU (from another machine) and then run
> > "find /". Output starts to stutter and then stops completely. When this happens
> > a new connection still can be made and as long as only shorter output is
> > generated the ssh connection is ok. From a dump taken it looks like user-space
> > is waiting in some select call (without any warnon I rather won't see the tx path).
> 
> Annie, are you still looking into this or shall I?

I'll assume that silence == No. Will post a patch shortly.

Ian.