Technology

59201 readers

2829 users here now

This is a most excellent place for technology news and articles.

Our Rules

Follow the lemmy.world rules.
Only tech related content.
Be excellent to each another!
Mod approved content bots can post up to 10 articles per day.
Threads asking for personal tech support may be deleted.
Politics threads may be removed.
No memes allowed as posts, OK to post as comments.
Only approved bots from the list below, to ask if your bot can be added please contact us.
Check for duplicates before posting, duplicates may be removed

Approved Bots

founded 1 year ago

MODERATORS

130

So here's a story of, by far, the weirdest bug I've encountered in my CS career. (threadreaderapp.com)

submitted 5 months ago by RGB@group.lt to c/technology@lemmy.world

23 comments fedilink hide all child comments

Along with @maciejwolczyk we've been training a neural network that learns how to play NetHack, an old roguelike game, that looks like in the screenshot. Recently, something unexpected happened.

you are viewing a single comment's thread
view the rest of the comments

[–] ObsidianNebula@sh.itjust.works 12 points 5 months ago (1 children)

I had an issue where a client reported a crash on login. The exception and stack trace reported were very generic and lent no clues to the cause. I tried debugging but could not reproduce. I eventually figured out that the crash only happened for release (non-debug) builds that were obfuscated. I couldn't find the troublesome code, so I figured out which release introduced the issue, then which commit, then went change by change until I was able to find the cause. It turned out to be a log message in a location that was completely unrelated to login. That exact log message was fine a few lines up. Other code worked fine in that location. For some unknown reason, having that log message in that specific location caused a crash in a completely different area of code.

[–] Arigion@feddit.de 8 points 5 months ago

Usually a sign of multiprocessing/multithreading going wrong, e.g. accessing the same resource without proper locks like opening the same logfile in different processes and trying to write simultaneously. Those errors can be triggered just by reformating the code (or obfuscating in this case), thus changing the runtime behaviour slightly. Hard to find, especially since they're dependent on the speed/workload of the machine running the code.