680475 - Firefox 6.0final crash [@ gfxMixedFontFamily::ReplaceFontEntry]

Status: RESOLVED DUPLICATE of bug 665360

(Core :: Graphics, defect)

Description

[Zack Weinberg (:zwol)]

A friend of mine sees an intermittent but reproducible crash in Firefox 6.0 (final release) on a web-based game he's developing.  Here are some crash reports:

http://crash-stats.mozilla.com/report/index/bp-7dcd9e4a-85f6-48f8-ad82-194a52110818
http://crash-stats.mozilla.com/report/index/bp-6f57c6e3-2f77-4662-b114-151b62110818
http://crash-stats.mozilla.com/report/index/bp-91ec33a2-0ef2-408e-b843-6f9802110818
http://crash-stats.mozilla.com/report/index/bp-736d9a83-88c1-4469-a2ea-90ae92110817
http://crash-stats.mozilla.com/report/index/bp-d8c664a3-71ed-48ab-a592-e59592110817

It looks to be all the same signature:

0 gfxMixedFontFamily::ReplaceFontEntry
1 nsUserFontSet::ReplaceFontEntry
2 gfxUserFontSet::OnLoadComplete
3 nsFontFaceLoader::OnStreamComplete

The game does make use of @font-face.  There is a certain resemblance to bug 650639, however that should have been fixed for 6.0final as I understand it, and unless I misunderstood my informant, there is no dynamic manipulation of @font-face rules involved.

(will correct product and component shortly.)

Comment 1

[Zack Weinberg (:zwol)]

Socorro finds 269 crashes with this signature in the past two days:

https://crash-stats.mozilla.com/report/list?product=Firefox&query_search=signature&query_type=contains&query=ReplaceFontEntry&reason_type=contains&date=08%2F19%2F2011%2010%3A04%3A09&range_value=2&range_unit=days&hang_type=any&process_type=any&do_query=1&signature=gfxMixedFontFamily%3A%3AReplaceFontEntry%28gfxFontEntry%2A%2C%20gfxFontEntry%2A%29

Comment 2

[Zack Weinberg (:zwol)]

More detail (>-quoted text is my informant, unquoted text is me):

> Well, I am using jquery to modify the contents of existing DIVs, and
> populating them with stuff that is then rendered using the downloaded
> font-face. Dunno if that's considered weird, but it's something that I
> would wager most sites using downloadable fonts aren't doing.

"Weird" would be if you were using JavaScript to *add or remove @font-face rules* as the game was played.  Bug 650639 appears to have involved that kind of trickery.

What you are doing should not cause the browser to have to reload the style sheet and/or the font itself.

> This occurs upon loading the page, and then continues as the game is
> played- however, the crashes only ever occur upon initially opening
> the page, never later.

This makes sense: the crash happens inside routines that are called when the font finishes downloading.  You don't manipulate the style sheet, so the font is downloaded once when the page is first loaded, and that's the only opportunity to trigger the crash.

> Another thing worth noting is that this is so far only occurring when
> I am running the game from file: rather than http:. However I haven't
> made enough tests of the latter to determine for certain that it won't
> crash, since my desktop version has already moved beyond the demo
> version and so that's where I work from.

Other people seem to be seeing the same crash on unrelated websites, so I'm not going to say for sure that it's impossible over http: -- however, file: and http: behave very differently in terms of what happens when, this could be a problem with that.

-----

I have also been given permission to link to the game: http://www.darkunknown.org/darkunknown/darkunknown.html  Note however the stuff above about file: vs http:, don't close this bug just because you can't reproduce it on the live site.

Comment 3

[Jonathan Kew [:jfkthame]]

This looks like bug 665360 to me. Any reason not to mark it as a dupe?

Comment 4

[Zack Weinberg (:zwol)]

Would you mind cc:ing me on that bug so I can see whether it sounds like the same thing?

Comment 5

[Zack Weinberg (:zwol)]

Yeah, I agree, same problem.