User-Agent: Mozilla/5.0 (X11; Linux i686; rv:2.0b9pre) Gecko/20110108 Firefox/4.0b9pre Build Identifier: using arguments.callee.caller from a JSM can trigger an xpcom leak nsStringStats => mAllocCount: 58343 => mReallocCount: 2921 => mFreeCount: 51739 -- LEAKED 6604 !!! => mAdoptCount: 1873 => mAdoptFreeCount: 1871 -- LEAKED 2 !!! Reproducible: Always Steps to Reproduce: 1. install the attached .xpi on a debug build of firefox 2. close firefox 3. look at stdout --enable-application=browser --enable-debug --enable-jemalloc --enable-optimize=-O2 Built from https://hg.mozilla.org/mozilla-central/rev/df3c1150dd7a

Here's what's in the XPI. modules/debuger.js, in its entirety: > var EXPORTED_SYMBOLS = [ 'get_debug' ]; > > function MAIN_debug () { > arguments.callee.caller; > } > function get_debug() { > return function local_debug() { > dump(arguments.callee.caller); > MAIN_debug(); > dump('leaking'); > } > } A script in chrome/overlay.xul does this: > function crash() { > var debuger = Components.utils.import("resource://earthangel/debuger.js"); > var debug = debuger.get_debug('foo'); > debug('test'); > } > crash(); (Clever confirmed for me that despite its name, this function doesn't crash; it just leaks.) Apart from the usual boilerplate, that's it.

jorendorff, should this block (hard, soft, or 2.x)?

(In reply to comment #4) > jorendorff, should this block (hard, soft, or 2.x)? Let's ask this question officially!

njn/jorendorff - drivers need more info to understand blocking here. How frequently would the leak be encountered, how painful, is it a regression?

Andreas, Blake, should this block?

I know nothing about this bug. Comment 3 was just me being nice. :) Sorry.

I don't know anything about this code and jorendorff told me he doesn't either, so Andreas or Blake will need to decide.

Is this a regression?

Andreas says this is liveable if it's not a regression, but we don't know yet. Who can determine that and re-nom if so?

I can do that tonight if nobody beats me to it.

This is a bit odd, overlaying browser.xul is essential to the leak. I've reduced this to a testcase, looking for a known good build now.

This is a regression from 3.6. Continuing to bisect.

with my past testing, i couldnt get it to leak multiple times, so it wont snowball out of control and use up all ram

Comment 15 is bogus, this is not a regression from 3.6. The behavior of the test suite changed such that the test does not leak before http://hg.mozilla.org/mozilla-central/rev/13153bb68e1b, but the extension version leaks on 3.6.

Build identifier: Mozilla/5.0 (X11; Linux i686; rv:25.0) Gecko/20130711 Firefox/25.0 WFM on the above build (latest Nightly) with the steps from bug description. Please reopen if it occurs again.