OOM kernel panic on bootup in debian/ubuntu guests

Hi,

I'm not sure if this is the correct venue for this question; feel free to redirect.

When I start debian or ubuntu guests on a debian host running KVM 0.12.5, my guests kernel-panic immediately after bootup -- the OOM killer kills every process on the system and then dies itself.

This problem only occurs if I enable the virtio-balloon driver -- without it, the guests run just fine. Also, this does not happen on CentOS guests, which also run fine and which balloon up/down happily.

The problem occurs just after the system gives me a getty -- if I have the guest consoled, I'll see a login prompt but never get a chance to use it.

I've tried compiling a vanilla kernel on an ubuntu guest, but the problem persisted. I'm not sure where to go from here, so any tips on debugging the problem are appreciated.

--Igor