I had the same problem with a macbook on an up-to-date edgy system, but I haven't had any kernel panic since I appended "noapic acpi=force irqpoll" to the kernel cmdline.
-- Kernel panic - not syncing: IO-APIC + timer doesn't work! https://launchpad.net/bugs/52553 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
