RE: [Xen-devel] Re: windows bluescreen after restore

["Petersson, Mats" <Mats.Petersson@xxxxxxx>]

> -----Original Message-----
> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Guy Zana
> Sent: 02 May 2007 12:26
> To: Ian Pratt; Amin; xen-devel@xxxxxxxxxxxxxxxxxxx
> Subject: RE: [Xen-devel] Re: windows bluescreen after restore
> 
> IRQL_NOT_LESS_OR_EQUAL happens when a kernel thread with high 
> priority tries to access a virtual address which is paged to 
> the disk (since the paging mechanism in windows runs in a 
> lower priority of the thread). Most of the chances that this 
> is around paging...

Or it's doing a wait or some such at a IRQL (priority level) that is
higher than what the scheduler runs at. In fact, the reason that you
can't page something in at high IRQL has to do with the fact hat the
scheduler is blocked at this level, and the page-in mechanism is a
separate process, which means that it would be necessary to reschedule
in the kernel. Since any "wait" operation will cause rescheduling, those
are also blocked at this level. 

Most likely is that the guest memory mapping or some such got very
confused. 

> 
> If you can reproduce the bug and it happens any time that you 
> do save/restore, I would suggest to try to tun the guest with 
> paging disabled (System Properties -> Advanced -> Performace 
> [Settings] -> Advanced -> Virtual Memory [Change] -> Select 
> "No paging file") and then try to do save&resote.
> 
> STOP 0x8E is KERNEL_MODE_EXCEPTION_NOT_HANDLED and could be a 
> side effect...

Also points to a memory mapping (or other memory corruption) problem in
my experience. 

[I did two years of graphics driver development, and I've managed to get
my fair share of both of these bugchecks]. 

--
Mats
> 
> Thanks,
> Guy.
> 
> > -----Original Message-----
> > From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx 
> > [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of 
> Ian Pratt
> > Sent: Wednesday, May 02, 2007 1:38 AM
> > To: Amin; xen-devel@xxxxxxxxxxxxxxxxxxx
> > Subject: RE: [Xen-devel] Re: windows bluescreen after restore
> > 
> > > information below. Reinstalling windows didn't help. It 
> > happens with 
> > > all 2k3 and xp guests.
> > > IRQL_NOT_LESS_OR_EQUAL
> > > *** STOP: 0x0000000A (0x00000018, 0x00000002, 0x00000000, 
> > 0x80523F59)
> > 
> > Are you doing save/restore cycles on the same machine, or 
> > moving the image between machines?
> > 
> > At what point does the guest crash? Immediately after the 
> > restore, or a few seconds later?
> > 
> > When you have a saved image that crashes on restore, it would 
> > be interesting to try restoring the image again and see if 
> > the guest crashes again (is the error the same?). Repeat 
> > several times. This should give us a clue as to whether the 
> > error is 'baked in' to the saved image, or occurs during restore.
> > 
> > Thanks,
> > Ian
> > 
> >  
> > > Thanks
> > > Amin
> > > 
> > > 
> > > xm info:
> > > release                : 2.6.18-xen
> > > version                : #1 SMP Mon Apr 30 17:10:57 CEST 2007
> > > machine                : x86_64
> > > nr_cpus                : 2
> > > nr_nodes               : 1
> > > sockets_per_node       : 1
> > > cores_per_socket       : 2
> > > threads_per_core       : 1
> > > cpu_mhz                : 2800
> > > hw_caps                :
> > > bfebfbff:20100800:00000000:00000180:0000e43d:00000000:00000001
> > > total_memory           : 4095
> > > free_memory            : 526
> > > xen_major              : 3
> > > xen_minor              : 0
> > > xen_extra              : -unstable
> > > xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p 
> > hvm-3.0-x86_32
> > > hvm-3.0-x86_32p hvm-3.0-x86_64
> > > xen_scheduler          : credit
> > > xen_pagesize           : 4096
> > > platform_params        : virt_start=0xffff800000000000
> > > xen_changeset          : Sat Mar 31 19:02:09 2007 +0100
> > > 14687:8f9ca49175ce
> > > cc_compiler            : gcc version 4.1.1 20070105 (Red 
> > Hat 4.1.1-51)
> > > cc_compile_by          : amin
> > > cc_compile_domain      :
> > > cc_compile_date        : Mon Apr  2 19:33:17 CEST 2007
> > > xend_config_format     : 4
> > > 
> > > 
> > > _______________________________________________
> > > Xen-devel mailing list
> > > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > > http://lists.xensource.com/xen-devel
> > 
> 



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