Re: BUG: Guest lockup and 100% CPU load on host

[James Thomason <james@divide.org>]

Jan, 

I spent some time with the same problem over the last two days.  Avi Kivity
suggested adding "clocksource=acpi_pm" to the guest kernel boot line, and
that seems to have resolved the issue. Would you give that a try and let me
know the result?  Also I believe the following bugs might be related:

[ 2351676 ] Guests hang periodically on Ubuntu-8.10
[ 2353811 ] Solaris 10 guest unstable
[ 2494730 ] Guests "stalling" on kvm-82
[ 2138079 ] kvm locks up system
[ 2113643 ] guests AND host still getting stuck under CPU load

Regards, 
James


On 1/15/09 2:10 PM, "Jan C. Bernauer" <jan.bernauer@t-online.de> wrote:

> Hi,
>  
>  while I was trying to get pci passthrough to work without vt-d using
> the 1to1 mapping (it works ;),
> I stumbled upon a solid lock up of the guest.
> (Unpatched source shows the same behaviour)
> 
>  I see a strange look up of the guest OS with the following "features":
>  - guest doesn't respond anymore
>  - triggered by load in the guest.
>  - it seems it is easier to trigger with -smp 2
>  - host shows qemu process with 100% cpu
>  - seems to be cured by  --no-kvm-irqchip
>  - --no-kvm-pit does not help
>  - qmeu console command system_reset works
>  
> Right now, guest OS is linux 2.6.27.1
> Latest KVM from git, host is 2.6.28.
> Older kvms seem to exhibit the same problem.