Bug Stories

Automated CI was not quite as big back then as it is now; we had some in-house CI-ish facilities, one of which was buildbot: a small Python script that continuously built all of our projects one after another, reporting successes/failures in a simple UI.

One day I was puzzled to discover that buildbot hung trying to build a tiny Java applet. Just a handful of .java files. But it had been stuck for more than four hours at that point.

I ssh’d into buildbot and looked at what exactly the hung process was doing. It was not javac. It was jarsigner.

Then it dawned on me. jarsigner needed some crypto-safe randomness, it was trying to get it by default from /dev/random, not from /dev/urandom, and the machine ran out of entropy!

I ticketed a change, but as an interim measure, I went to the server room, switched the console to buildbot’s server, and moved the mouse vigorously for some seconds. It proceeded.

My personal list of stories of this kind includes:

- Car allergic to vanilla ice cream: https://www.cs.cmu.edu/~wkw/humour/carproblems.txt

- Can't log in when standing up: https://www.reddit.com/r/talesfromtechsupport/comments/3v52p...

- OpenOffice won't print on Tuesdays: https://bugs.launchpad.net/ubuntu/+source/cupsys/+bug/255161...

- Wi-Fi only works when it's raining: https://predr.ag/blog/wifi-only-works-when-its-raining/

It’s been a bit since I’ve added stories. I’ll need to add some more with this renewed interest.

Let me know if have a good story!

Looks like a cleaner version of The Daily WTF: https://thedailywtf.com