Sometimes the bug isn't in your code, it's in the CPU
First off, I would say that is some pretty awesome work by this guy to chase this down.  Including his work with the manufacturer to help them reliably recreate the issue.<p>Second, I would say that over the course of my 10 year career in managing developers, I've heard many, many times that the bug was in the kernel, or in the hardware, or in the complier, or in the other lower level thing the developer had no control over.  This has been the correct diagnosis exactly once.  If I had to guess, I would say about 5%.