bugLinterna Mágica - Bugs: bug #37303, Facebook photo viewer freezes...


bug #37303: Facebook photo viewer freezes chromium due to Linterna Magica

Submitter:  None
Submitted:  Sun 09 Sep 2012 06:47:08 AM UTC
Category:  None Severity:  2 - Minor
Item Group:  None Status:  Fixed
Privacy:  Public Assigned to:  valkov
Open/Closed:  Closed Release:  0.0.12
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Sat 29 Dec 2012 06:57:51 AM UTC, comment #12: 

I'm considering this bug report obsolete then. I'm closing it. Thanks.

Ivaylo Valkov <valkov>
Group administrator
Fri 28 Dec 2012 05:46:00 PM UTC, comment #11: 

Hi, this used to happen to only chrome/chromium and doubt that facebook was the culprit because if you have many tabs open the browser froze right the way and need to use the power button to kill it whether facebook was loaded or not. If FB was loaded the scrolling was slow.

As a result I have disabled LM on these browsers for a while. About a week ago I tried again with the latest LM build and did some random testing. After a week I can confirm that everything works now without issue with 30+ tabs open and the FB slow scrolling problem is gone too. Think that might have been a problem with Chrome all along and many updates have fixed it. Don't know about Chromium because my version is very outdated and have decided to remove it.

Tue 25 Dec 2012 10:44:57 AM UTC, comment #10: 


Any news on this issue?

It seems Facebook stopped working with Linterna Mágica (trunk), so I'll be trying to make it work again. Any information that could lead to resolving this issue would be appreciated. Thanks.

Ivaylo Valkov <valkov>
Group administrator
Fri 26 Oct 2012 10:28:25 AM UTC, comment #9: 

Thanks for reporting and testing.

It might be that Facebook does browser user-agent sniffing and serves different content according to that. It is not uncommon.

Once there was bloating only in Firefox for some website. The reason was it served large JavaScript only for Firefox. I am guessing that when the browser bloats it is because of a large script that Linterna Mágica is trying to parse.

Ivaylo Valkov <valkov>
Group administrator
Fri 26 Oct 2012 10:22:55 AM UTC, comment #8: 

This is rather weird. After some more testings and observations this appears to happen only in Ubuntu (gnome shell or Unity) But in Fedora (gnome shell) LM seems to work well on Chrome and Chromium with 30+ tabs open including several instances of facebook and cpu usage is still low. So LM is not the culprit apparantly.

Fri 12 Oct 2012 05:39:58 AM UTC, comment #7: 

Hi, after experimenting a little I find that Chrome/Chromium only freezes up when many tabs are loaded with LM activated. If it is just one tab with facebook then it just scroll very slowly and the exclusion workaround would eliminate that. But system still hangs with 100% cpu usage and maxed out memory if multiple tabs are loaded and FB is not one of them (but if LM is deactivated then I can load multiple tabs with no problem) So it seems that FB per se is not the only culprit.

It may be that since Chrome/chromium doesn't have an option to load tabs on demand like Firefox or Midori so  LM is simultaneously trying to read them at once. It could also be that something has changed in Chrome/Chromium recently. This didn't happen before.

Wed 10 Oct 2012 06:53:12 PM UTC, comment #6: 

The power button? Ouch! I never imagined JavaScript inside a browser could do that. Sorry.

Ivaylo Valkov <valkov>
Group administrator
Wed 10 Oct 2012 06:50:49 PM UTC, comment #5: 

Hi, I will make some investigations and get back to you in a few days. However, not sure if I can provide the debug log because as it is now, the whole system (not just the browser) freezes up when FB load with LM enabled and the only way to get out is to kill it with the power button.

Thanks for the quick reply.

Wed 10 Oct 2012 06:17:02 PM UTC, comment #4: 


Thanks for supplying more information for this bug, although you are not the original submitter.

Could you submit the debug messages from the Linterna Mágica svn trunk build when the debug option [1] is enabled? Thanks.

When Linterna Mágica is enabled after an FB page had loaded it actually does not run on that page. That is why the issue does not occur. Userscripts are loaded on page load.

There is a temporary work-around that will block Linterna Mágica on such problematic pages. Assuming the @excluce rule/tag is supported by the userscripts implementation. The original Greasemonkey extension supports this. [2] The syntax is the same [2][3] as for the @include rule.

The work-around consist in adding an @exclude rule for every problematic page in the installed userscript file.  Probably the userscripts extension has a option to do this directly from the browser:

For example:

@exclude http://.*facebook.com
@exclude https://.*facebook.com

should block FB support.

So, is it there publicly available FB page on which the issue could be observed?

Please report separate issues in new bug reports. Link to other bug reports, if there is relevant information there. Thanks.

[1] http://download.savannah.gnu.org/releases/linterna-magica/latest_docs/linterna_magica.html#Configuration
[2] http://wiki.greasespot.net/Include_and_exclude_rules
[3] http://download.savannah.gnu.org/releases/linterna-magica/latest_docs/linterna_magica.html#Stop-execution-on-every-site

Ivaylo Valkov <valkov>
Group administrator
Wed 10 Oct 2012 04:43:39 PM UTC, comment #3: 

I am not OP but maybe I can supply some information. If LM is activated and then start Facebook,the page will take forever to load with a little white circle spinning if you attempt to scroll. Since a few days ago it has gotten worse in that the system will hang because cpu will be at 100% and memory will run out if several tabs are open (say 10). But if LM is disabled then everything is fine. I have tried other user scripts with tampermonkey without issue, therefore TM is not the culprit.

On the other hand, if one goes to FB before activating LM then everything is fine.

That only happens with chrome/chromium but not the other browsers you mentioned.

It happens mostly with FB but to a lesser degree with some other sites too. For example, http://www.thestar.com/ (which is a newspaper)


Mon 24 Sep 2012 07:01:15 PM UTC, comment #2: 


Can you provide some of the information I've requested to further investigate the bug? I will be forced to close it if you are unable to provide the requested information in the recent future. Thanks.

Ivaylo Valkov <valkov>
Group administrator
Sun 09 Sep 2012 07:26:37 AM UTC, comment #1: 


First of all Chromium is not officially supported because it has licensing issues [1] and at least for part of the code it is not clear is it free software. This issue have a lower priority especially while I am working on the interface changes in task #12203. In other words - don't set your hopes too high.

Can you bereproduce this issue with Firefox (Abrowser, IceCat, Iceweasel), Epiphany or Midori?

I don't use Facebook. Point me to a direct link that is accessible without account and login. I am not planning to make an account just for testing.

There was an issue (bug #36622) a while ago about freezing and it is supposed to be fixed. I see you've set the release to 0.0.12. Is that correct? Release 0.0.12-1 is missing in the tracker, because I forgot to add it. It is pretty much the same thing as 0.0.12.

The exception is on purpose. The code around it is intended to inject Linterna Mágica in the page as a regular JavaScript code where it runs. It is a work-around for Firefox and the limitations the Greasemonkey (and probably Scriptish) extension has in the sandboxed environment. The main reason for the injection is that in the sandboxed environment there is no access to the video plugin JavaScript API or it is hard. When the code is injected in the page, execution in the sandbox scope must stop. The exception method is the only one that guarantees that there is no JavaScript syntax error. The Greasemonkey extension runs the userscript code in a function, but if the code simply exits that function with return statement, the syntax will be invalid in Epiphany, for example, where there is no function in that scope. Userscripts implementations for other browsers just run the script in the page. So there is nothing to worry about this exact exception.

If you can wait for the bloating process to finish while Linterna Mágica's debug mode is on and provide the output it could help. Have in mind that it could take a lot of time. There were times when similar bloating in Firefox took around 20 minutes to finish.

P.S. I've added the e-mail you provided in the CC (the "Mail Notification Carbon-Copy List" section) filed of the bug report. The tracker will send copies of comments for this bug to that e-mail. If that is not desirable, please notify me to remove it. You will not be able to do so yourself, because of your anonymous status.

[1] http://libreplanet.org/wiki/List_of_software_that_does_not_respect_the_Free_System_Distribution_Guidelines#chromium-browser

Ivaylo Valkov <valkov>
Group administrator
Sun 09 Sep 2012 06:47:08 AM UTC, original submission:  

Version 0.0.12-1
Browser: Chromium 18.0.1025.168 (Developer Build 134367 Linux) Ubuntu 12.04
Url: Facebook.com (upon clicking a photo in the feed and entering theater viewer mode)

Facebook has been freezing up for me for the past few weeks, and I think Linterna Magica is the culprit. Whenever I click a photo thumbnail in my feed and the Facebook pop-up "Theater" photo viewer pops up, that browser tab freezes. Upon further inspection of the Javascript console, it looks like Linterna-Magica is doing things right when my browser freezes. The log says:

"Uncaught Linterna Magica left the greasemonkey scope! Script was injected in page"

...right when the freeze begins.

Let me know (cossrooper at gmail dawt com) if you need any other logs... I'm not sure what else to provide.



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file #26510:  ChromiumLinterna.png added by None (38KiB - image/png - Screenshot of the error in the Chromium JS console)


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    Follow 6 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2012-12-29 valkov StatusNone Fixed
        Open/ClosedOpen Closed
    2012-09-09 valkov Severity3 - Normal 2 - Minor
        Assigned toNone valkov
        Carbon-Copy- Added -email is unavailable-
    2012-09-09 None Attached File- Added ChromiumLinterna.png, #26510

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