heisenbug

See also: Heisenbug

English

WOTD – 19 February 2012

Alternative forms

Heisenbug

Etymology

(ca. 1983) Blend of Heisenberg +‎ bug. Named for the Heisenberg uncertainty principle, which states very roughly that any attempt to measure the position of a subatomic particle will disrupt its movement, making it harder to predict.

Pronunciation

IPA^(key): /ˈhaɪzənˌbʌɡ/
Audio (UK): (file)

Noun

heisenbug (plural heisenbugs)

(computing) A software bug which fails to manifest itself or manifests differently during debugging.
- 1987 January 4, Don Lindsay, “More Heisen-debugs”, in RISKS Digest, volume 4, number 36:
  I recently encountered a particularly infuriating Heisenbug. A large program, when given a large input, was just mysteriously dying. Of course, I ran it under the debugger. The mystery deepened: the program returned quietly to the debugger.
- 1994 January 20, Heinz Wrobel, “'Heisenbugs'”, in comp.programming‎^[1] (Usenet), message-ID <heinz.0i4s@hwg.muc.de>:
  Except for pointer messups in C on my side, the Heisenbugs I've come across were hardly ever caused by _me_.
- 2014 December 8, Vince Weaver, “Re: Linux 3.18 released”, in linux-kernel mailing list‎^[2], message-ID <alpine.DEB.2.10.1412081331580.28373@pianoman.cluster.toy>:
  There are multiple perf related issues like this that are hard to track down. They are borderline heisenbugs that are possibly race conditions, so bisecting doesn't work and even things like enablibg^[sic] ftrace will make the issue go away (or crash ftrace itself).