Re: [Xen-devel] I cannot get any message from domU by console / pv_ops domU kernel crashes with xen_create_contiguous_region failed

[Michael D Labriola <mlabriol@xxxxxxxx>]

Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> wrote on 12/22/2009 
03:37:09 PM:

> On Tue, Dec 22, 2009 at 03:07:21PM -0500, Konrad Rzeszutek Wilk wrote:
> > > A also can't seem to pass devices through (unless I'm doing it 
wrong). 
> > > When trying to pass my soundcard do the domU, it appears to be 
> > > appropriately hidden from dom0 via xen-pciback.hide kernel param 
> > > (/var/log/messages says 'pciback 0000:00:1b.0: seizing device') 
> but when I 
> > > try to start my domU with iommu=soft and pci=["00:1b.0"] I get 
adozen or 
> > 
> > You are doing it right.
> > 
> > > so "BUG: scheduling while atomic" messages w/ call traces.  My domU 
> > > eventually starts up ok, but lspci returns with no output.
> > 
> > Hmm, I wonder if this patch is in your tree:
> > 
> > commit 1aa61698354ca0582b07eb865e0432a13b459f11
> > Author: Ian Campbell <ian.campbell@xxxxxxxxxx>
> > Date:   Thu Dec 17 14:08:25 2009 +0000
> > 
> >     xen: fix hang on suspend.
> > 
> > and causing this (or maybe the pciback driver is the culprit and
> > the above patch exposes a bug?).
> 
> Bummer. Can't blame Ian for it :-(
> 
> I updated dom0 with that patch and I am not seeing the failure you 
described.

Yes, I have that commit too.


> 
> > 
> > Try reverting that patch and seeing what happens. I the meantime let
> > me compile a new Dom0 with the above mentioned commit and see if I get
> > the failure too.
> 
> Instead of that recommendation try enabling debug options. You can do 
this
> the manual way:
> 
> diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
> index cc3b51b..ae1648a 100644
> --- a/drivers/pci/xen-pcifront.c
> +++ b/drivers/pci/xen-pcifront.c
> @@ -30,7 +30,7 @@
>  #define INVALID_GRANT_REF (0)
>  #define INVALID_EVTCHN    (-1)
> 
> -
> +#define DEBUG 1
>  struct pci_bus_entry {
>     struct list_head list;
>     struct pci_bus *bus;
> diff --git a/drivers/xen/blkback/blkback.c 
b/drivers/xen/blkback/blkback.c
> index 815c0c6..a871a2c 100644
> --- a/drivers/xen/blkback/blkback.c
> +++ b/drivers/xen/blkback/blkback.c
> @@ -64,7 +64,7 @@ MODULE_PARM_DESC(reqs, "Number of blkback requests
> to allocate");
> 
>  /* Run-time switchable: /sys/module/blkback/parameters/ */
>  static unsigned int log_stats = 0;
> -static unsigned int debug_lvl = 0;
> +static unsigned int debug_lvl = 1;
>  module_param(log_stats, int, 0644);
>  module_param(debug_lvl, int, 0644);
> 
> 
> Or fiddle with the debug_lvl in /sys/ namespace. 
> 
> That might shed some light on what is happening. Also do provide the
> output of Dom0, DomU and the lspci -vvv in Dom0 please.
> 

Recompiled with debug turned on as shown.  Attached /var/log/messages from 
dom0 and domU, lscpi output, and my kernel .config.

Any chance it's PREEMPT related?

-Mike

Attachment: messages.domU
Description: Binary data

Attachment: config
Description: Binary data

Attachment: lspci.dom0
Description: Binary data

Attachment: messages.dom0
Description: Binary data

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