A few years ago I designed a way to detect bit-flips in Firefox crash reports and last year we deployed an actual memory tester that runs on user machines after the browser crashes. Today I was looking at the data that comes out of these tests and now I'm 100% positive that the heuristic is sound and a lot of the crashes we see are from users with bad memory or similarly flaky hardware. Here's a few numbers to give you an idea of how large the problem is. 🧵 1/5
There’s a jump instruction by an address read from RAM, a bit flip occurred so a condition “if friend greet else kill” worked as “if friend rape else kill”. Absolutely anything can happen, that wasn’t determined by program design flaws and errors. A digital computer is a deterministic system (sometimes there are intentional non-deterministic elements like analog-based RNGs), this is non-deterministic random changes of the state.
In concrete terms - things break without reason. A perfect program with no bugs, if such exists, will do random wrong things if bit flips occur. Clear enough?
I always love it when folks who don’t actually know what they’re talking about, comment like they do…
It’s not just the browser. This example is the browser, but it’s your entire system stability that is affected by random bit flips.
Removed by mod
There’s a jump instruction by an address read from RAM, a bit flip occurred so a condition “if friend greet else kill” worked as “if friend rape else kill”. Absolutely anything can happen, that wasn’t determined by program design flaws and errors. A digital computer is a deterministic system (sometimes there are intentional non-deterministic elements like analog-based RNGs), this is non-deterministic random changes of the state.
In concrete terms - things break without reason. A perfect program with no bugs, if such exists, will do random wrong things if bit flips occur. Clear enough?