When you collect lots of coredumps you'll get a long tail of bizarre, one-off crashes. Some of these are subtle memory corruption bugs that cause random crashes

When you collect lots of coredumps you'll get a long tail of bizarre, one-off crashes. Some of these are subtle memory corruption bugs that cause random crashes, but others are caused by bitflips-- either faulty DRAM or cosmic rays. Usually you throw your hands up and only look at crashes that happen multiple times because they're more likely to be reproducible. The unique factor here is that rr provides _reproducible_ crash recordings, so when it fails to reproduce a crash, you've found some nondeterminism-- either a bug in rr where it didn't replay syscalls correctly or nail down thread behavior accurately, or a hardware issue like this.