Comment 47 for bug 1011792

I would be very surprised if there was anything Ubuntu specific in the autogroup area. The whole kernel source is mainly what is upstream. There are a few additional drivers, but really only a couple and I don't think they get used here. One thing might be noteworthy, if 3.5.6-1-arch translates into based on upstream stable 3.5.6, this is one stable version ahead of what is in Quantal (we currently stopped at 3.5.5 in order to settle for release, after that we will pick up .6 and .7 which is in the pipe). One option then might be a fix that came with 3.5.6 (which has a possibility to be in the upstream stable pipe for 3.2).

On some experiment I did, I tried to get a better feeling about the relation between VCPUs and the problem. Given it being a race, results probably need to be looked at carefully. But it seemed that with 2 and 4 VCPUs, there seemed no isses. With 8 the problem was seen.

If the guess about 3.5.6 possibly fixing this would be true, this could be verified by installing mainline kernels into the instance. With the install base being 12.04 (Precise) this should be as simple as installing the packages and rebooting. The mainline kernels can be found at:

http://kernel.ubuntu.com/~kernel-ppa/mainline/

Those package are build from the unmodified upstream sources with just the ubuntu config applied (The -quantal for example means the config was taken from Quantal). So v3.5.5-quantal would show the problem and v3.5.6-qunatal should be ok.