This is happening while running code coverage tests on talos, being investigated in bug 1414593. Bisect attributes it to a JS change in Activity Stream. https://treeherder.mozilla.org/#/jobs?repo=try&author=edilee@gmail.com&fromchange=0534a2c0d4502267f81357322891c18aee8a694a&filter-searchStr=ccov%20g5&tochange=62b0395210633288d697f6a69eb9e07f954a2bf5&selectedJob=143633100

Link to stack trace https://treeherder.mozilla.org/logviewer.html#?job_id=143633100&repo=try&lineNumber=18263

<jandem> andreio: it's an assertion failure, could be a shutdown leak <jandem> andreio: similar to bug 1411322 <firebot> bugzil.la/1411322 — FIXED, apehrson⊙mozilla.com — Assertion failure: pages_.empty(), at /builds/worker/workspace/build/src/js/src/jit/ProcessExecutabl <jandem> it's the same assert

Jan, can you take this?

(In reply to Jason Orendorff [:jorendorff] from comment #3) > Jan, can you take this? See comment 2. I don't think this is a bug in the JS engine but (similar to bug 1411322) a leak elsewhere that trigers the "we freed all executable pages" assert.

The leak is being tracked in bug 1414593. I wasn't sure about the info in the stack trace but it sounds like this bug is invalid then?