Comment 7 for bug 192294

it seems that i can't reproduce this problem on the hardy then kernel.

it is possible it only happens on the Xen kernel from http://xen.org/download/

It might be a few days before i can test further as we need to do some benchmarks on Xen and KVM in a working state.

I can't test more later.

This bug (bug #199533) still exists and might or might not be related. Again, more testing is needed.

https://bugs.launchpad.net/ubuntu/+source/xen-3.2/+bug/199533