Comment 8 for bug 793486

From the comments, it sounds like this is a regression in the kernel between versions 2.6.39.4 to 3.0.0-0300rc1. A git bisection search can be utilized to narrow in on where the regression occurred. Please see https://wiki.ubuntu.com/Kernel/KernelBisection

Reassigning to the kernel team for further follow up, since they'll need to ensure the faulty patch is backed out or replaced.