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Re: [Xen-users] Xen system hang or freeze

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Subject: Re: [Xen-users] Xen system hang or freeze
From: Martin Fernau <m.fernau@xxxxxxxxxx>
Date: Mon, 6 Apr 2009 09:44:57 +0200
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With "stock xen kernel" you mean the original Kernel from 
"http://www.xen.org/download/"; ? I currently use the xen-kernel 2.6.18-r12 
from my distro. So I could give it a try...

How dit you get notice of these kernel oops and/or soft IRQ lockups? I'm not 
able to discover _any_ abnormal events on my system as all logfiles are clean. 
There must be a way to debug this...

The only USB device I currently have attached to my dom0 is a Smart-UPS 
System. I don't know if this really could kill the whole machine as the 
communication between dom0 and this ups should be very very low.

We must find a way to discover these lockups. Are there any debug-log 
functionality we could enable in xen to start to discover this problem?

I'm afraid that these lockups could become a ko criteria for xen in the future 
for professional servers...

Am Sonntag, 5. April 2009 22:33:36 schrieb thomas morgan:
> Over the last year, I've experienced a couple of sources of lockups.
> The first was resolved by going to the stock xen kernel
> compiled from source (had been using the Debian etch kernel; found
> commentary online describing the same symptoms on Ubuntu, Redhat, and
> CentOS though, each with their distro-specific kernel).
> This one tended to result in kernel oops messages--soft IRQ lockups as
> I recall. Lockup would start with a domU and within a few minutes
> would kill the dom0 too. The fastest way to trigger this one was to
> create and shutdown domU's, although I don't recall that being the
> only way.
> The second, with the stock kernel, was an errant USB hub attached to a
> xen host. Removing the hub resolved the issue. These were complete,
> sudden lockups of the dom0 and all domUs -- basically everything.
> Higher traffic over the USB port would trigger this lockup.
> So, for those who haven't tried the stock xen kernel, and are able to
> try it (based on driver support, etc.), it might help.
> --t

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