In my younger days I worked in customer support for a storage company. A customer had one of our products crash (kernel panic) at a sensitive time. We had a cou

In my younger days I worked in customer support for a storage company. A customer had one of our products crash (kernel panic) at a sensitive time. We had a couple of crack engineers I used to hover around to try to pick up gdb tricks so I followed this case with interest—it was a new and unexpected panic. Turns out the crash was caused by the processor taking the wrong branch. Something like this (it wasn’t Intel but you get the picture): test edx, edx jnz $something_that_expects_nonzero_edx Well, edx was 0, but the CPU jumped anyway. So yeah, sometimes ECC isn’t enough. If you’re really paranoid (crypto, milsec) you should execute multiple times and sanity-test.