Re: [libvirt] [PATCH RFC] Add domainSave/Restore to libxl driver

[Jim Fehlig <jfehlig novell com>]

Jim Fehlig wrote:
> Markus Groß wrote:
>   
>> This patch adds save/restore functionality to the libxl driver.
>>
>> It is a v2 of this patch:
>> https://www.redhat.com/archives/libvir-list/2011-April/msg00338.html
>>
>> v2:
>> * header is now padded and has a version field
>> * the correct restore function from libxl is used
>> * only create the restore event once in libxlVmStart
>>   
>>     
>
> Hi Markus,
>
> Finally found time to try your patch.  Thanks for the patience :-).
>
>   
>> However I ran into a reproducible segfault.
>> Assume you saved a vm with:
>> # virsh save domU foo.img
>>   
>>     
>
> I think the problem actually lies in the save function.  The domain does
> not appear to be cleaned up properly.  From xl's perspective after virsh
> save domU foo.img
>
> xen33: # xl list
> Name                                        ID   Mem VCPUs      State  
> Time(s)
> Domain-0                                  0    2023     8            
> r-----     330.0
> (null)                                         11     1         
> 2             --pssd      27.1
>
> The orphaned domain disappears after libvirtd restart.

I manged to track down this problem, patch posted to xen-devel

http://lists.xensource.com/archives/html/xen-devel/2011-05/msg01314.html


>   
>> If you restore the save image,
>> destroy the vm and restore it again, a segfault occurs:
>> # virsh restore foo.img
>> # virsh destroy domU
>> # virsh restore foo.img
>> # segfault
>>     

But I still see the segfault, in addition to domain not booting and
consuming 100% cpu on first restore :-(.  I'll look at these issues next.

Regards,
Jim