When calling console.profile/profileEnd between long running JS, or back to back, or even with a small delay, it seems that `console.profile()` hits possibly at the same time as `console.profileEnd()`, which results in starting the profile AFTER the time range, meaning profileEnd will never be found, so the console profile recording will go on indefinitely. Can easily recreate this or use the sourcemaps[0] benchmark which will do it. This scenarios work in chrome's profiler. Scenarios where this will fail: 0: console.profile(); console.profileEnd(); 1: console.profile() <long running js> console.profileEnd() 2: console.profile() <long running js or nothing at all> setTimeout(() => console.profileEnd(), 0); [0] https://github.com/mozilla/source-map/blob/master/bench/bench.html

On my machine ( 2013 MBAir, 10.10, latest dev edition w/e10s ), 5ms seems to be the minimum eg console.profile(); setTimeout(() => console.profileEnd(), 5); Anything less ( run from scratchpad ) and I need to re-run the second line to end the profile. I wish console.profile returned a handle that had ( once the profile was up and running ) an end() method.

Triaging. Filter on ADRENOCORTICOTROPIC (yes).

Duping to bug 1240249, as this is the same undelying issue.