Re: kernel bug in kvm_intel

[Marcelo Tosatti <mtosatti@redhat.com>]

On Tue, Oct 13, 2009 at 08:50:07AM +0200, Avi Kivity wrote:
> On 10/12/2009 08:42 PM, Andrew Theurer wrote:
>> On Sun, 2009-10-11 at 07:19 +0200, Avi Kivity wrote:
>>    
>>> On 10/09/2009 10:04 PM, Andrew Theurer wrote:
>>>      
>>>> This is on latest master branch on kvm.git and qemu-kvm.git, running
>>>> 12 Windows Server2008 VMs, and using oprofile.  I ran again without
>>>> oprofile and did not get the BUG.  I am wondering if anyone else is
>>>> seeing this.
>>>>
>>>> Thanks,
>>>>
>>>> -Andrew
>>>>
>>>>        
>>>>> Oct  9 11:55:13 virtvictory-eth0 kernel: BUG: unable to handle kernel
>>>>> paging request at ffffffff9fe9a2b4
>>>>> Oct  9 11:55:13 virtvictory-eth0 kernel: IP: [<ffffffffa02e1af1>]
>>>>> vmx_vcpu_run+0x26d/0x64f [kvm_intel]
>>>>>          
>>> Can you run this through objdump or gdb to see what source this
>>> corresponds to?
>>>
>>>      
>> Somewhere here I think (?)
>>
>> objdump -d
>>    
>
>
> Look at the address where vmx_vcpu_run starts, add 0x26d, and show the  
> surrounding code.
>
> Thinking about it, it probably _is_ what you showed, due to module page  
> alignment.  But please verify this; I can't reconcile the fault address  
> (ffffffff9fe9a2b) with %rsp at the time of the fault.

There's some scary erratas (such as corrupted RSP pushed on the stack   
on event injected, including NMI which is used by oprofile, right after 
VMExit, AAK56) on the Xeon X55xx spec update.                           

Andrew, you might make sure the firmware/BIOS is uptodate on this
machine before reproducing.