According to comment #28, this appears to be a bug with virtualbox and not the kernel. I am changing the bug properties accordingly.
** Changed in: linux (Ubuntu) Status: Confirmed => Invalid -- -11 & later kernels won't boot with acpi, -10 works, Lucid https://bugs.launchpad.net/bugs/510571 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs