From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: Dom0 crash with apache bench (ab)
Date: Mon, 14 Sep 2015 11:11:08 -0400
Message-ID: <20150914144957.GC19667@x230>
References: <CAEDV+gJ1MyAPbfX-rp6eNKacecQfn9LNpSGC7BuSYFep+0iG2w@mail.gmail.com>
	<20150728145022.GE26623@x230.dumpdata.com>
	<1438095319.11600.165.camel@citrix.com>
	<CAEDV+gL_e9Ak0_nzaH+k6LQn2+EAOHHoviQ8zKj-xFnC84SwJQ@mail.gmail.com>
	<alpine.DEB.2.02.1507311122240.11337@kaball.uk.xensource.com>
	<55BB4DBA.2040909@citrix.com>
	<CAEDV+g+tVz_WA9TLjAN+J-qKn1KaebbFihub+Sn0Q3AZZ4YT3A@mail.gmail.com>
	<20150914124008.GA17195@cbox>
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To: Christoffer Dall <cdall@cs.columbia.edu>
Cc: Wei Liu <wei.liu2@citrix.com>, Ian Campbell <ian.campbell@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, xen-devel@lists.xen.org, Christoffer Dall <christofferdall@gmail.com>, David Vrabel <david.vrabel@citrix.com>
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On Mon, Sep 14, 2015 at 02:40:08PM +0200, Christoffer Dall wrote:
> On Fri, Jul 31, 2015 at 03:17:56PM +0200, Christoffer Dall wrote:
> > On Fri, Jul 31, 2015 at 12:28 PM, David Vrabel <david.vrabel@citrix.com>
> > wrote:
> > 
> > > On 31/07/15 11:24, Stefano Stabellini wrote:
> > > > This is a Linux Dom0 crash on x86 (Dell PowerEdge R320, Xeon E5-2450),
> > > > CC'ing relevant people. As you can see from the links below the crash
> > > > is:
> > > >
> > > > [ 253.619326] Call Trace:
> > > > [ 253.619330] <IRQ>
> > > > [ 253.619332] [<ffffffff815d7c25>] ? skb_copy_ubufs+0xa5/0x230
> > > > [ 253.619347] [<ffffffff815e8525>] __netif_receive_skb_core+0x6f5/0x940
> > > > [ 253.619353] [<ffffffff815e8788>] __netif_receive_skb+0x18/0x60
> > > > [ 253.619360] [<ffffffff815e87f8>] netif_receive_skb_internal+0x28/0x90
> > > > [ 253.619366] [<ffffffff815e91f5>] napi_gro_frags+0x125/0x1a0
> > > > [ 253.619378] [<ffffffffa01b1173>] mlx4_en_process_rx_cq+0x753/0xb50
> > > [mlx4_en]
> > > > [ 253.619387] [<ffffffffa01b1657>] mlx4_en_poll_rx_cq+0x97/0x160
> > > [mlx4_en]
> > >
> > > What makes you think this is Xen specific?  I suggest raising this the
> > > the mlx4 maintainers.
> > >
> > >
> > Linux native and KVM guests (same hw, same kernel version+config) run just
> > fine under the same workload.
> > 
> Ping?
> 
> >From the fact that bare-metal and KVM works fine with this hardware I
> still think it's reasonable to assume that it's a Xen issue and not a
> mlx4 issue.
> 
> Is this completely flawed?

I have a feeling it is an mlx4 issue but you don't easily reproduce it
under baremetal. Is there any way you could boot baremetal with
'iommu=soft swiotlb=force' to see if you can reproduce it under those
conditions?

thanks!
> 
> Thanks,
> -Christoffer
> 
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