Re: BUG_ON in mmu.c:436

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Ryan Harper wrote:
> * Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org> [2007-09-24 02:57]:
>   
>> Ryan Harper wrote:
>>     
>>> I've run into a nasty bug while trying to install a Linux guest using
>>> VMware Server inside a kvm guest (full dmesg attached and recreate
>>> instructions below bug).
>>>
>>>  
>>>       
>> Can you reproduce this with AUDIT turned on (top of mmu.c)? AUDIT is 
>> very slow, so it's recommended to reduce guest memory as much as possible.
>>     
>
> Working on it -- running for the better part of today with 256MB and I'm
> still booting up the guest.  I'll let you know how things go tomorrow.
> Any thoughts on how to speed audit runs up other than lower guest
> memory?
>   

Hmm.  Reduce the number of shadow page tables (KVM_NUM_MMU_PAGES).  You
can also turn a few passes off in the main audit function, but that of
course reduces its effectiveness.

btw, the error may occur before the guest fails, so keep an eye on
dmesg.  Once it hits things will slow down even more due to a flood of
printks.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.


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