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War story: the hardest bug I ever debugged

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462 points jakevoytko | 1 comments | 24 Mar 25 14:37 UTC | HN request time: 0.001s | source
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BobbyTables2 ◴[27 Mar 25 03:27 UTC] No.43490119[source]▶
Interesting writeup, but 2 days to debug “the hardest bug ever”, while accurate, seems a bit overdone.

Though abs() returning negative numbers is hilarious.. “You had one job…”

To me, the hardest bugs are nearly irreproducible “Heisenbugs” that vanish when instrumentation is added.

I’m not just talking about concurrency issues either…

The kind of bug where a reproduction attempt takes a week, not parallelizable due to HW constraints, and logging instrumentation makes it go away or fail differently.

2 days is cute though.

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1. rowanG077 ◴[27 Mar 25 11:37 UTC] No.43492539[source]▶
I don't think taking how long something took to debug in number of days is at all interesting. Trivial bugs can take weeks to debug for a noob. Insanely hard bugs takes hours to debug for genius devs, maybe even without any reproducer, just by thinking about it.