1127586 - Flash plugin hang/crash causing firefox to crash sometime

Status: RESOLVED INCOMPLETE

(Core Graveyard :: Plug-ins, defect)

Description

[Yohann Jardin]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Firefox/38.0
Build ID: 20150129030202

Steps to reproduce:

Go on https://www.youtube.com/


Actual results:

Flash plugin hang and crash. Stopping it sometimes crash firefox, other times it try to load the page again, hang again and so on.


Expected results:

Page should have load.

Mozregression leads me to :
http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=db7c4ffd5a53&tochange=ae5cd7307662

So it is related to :
https://bugzilla.mozilla.org/show_bug.cgi?id=1126450

Tried on another profile, I have no problem.
I desactivated all extensions and plugin I use (except flash), the problem still occur.
What I find weird is that on the profile having the problem, the plugin is marked as "Shockwave Flash is known to be vulnerable and should be updated". But on my second profile, there is no warning.


Tested on windows 7 ultimate, with Shockwave Flash 16.0.0.280
Crash report : https://crash-stats.mozilla.com/report/index/b82c86f9-6ae4-4910-b532-9960d2150129

Comment 1

[Paul Silaghi, QA [:pauly]]

Note that youtube is now using HTML5 instead of Flash.
How did you force Flash to load?

Comment 2

[Yohann Jardin]

I did not do anything special, or so I think.
I just looked in the source code of https://www.youtube.com/ and found:

(function() {
    var delayedEmbed = yt.getConfig('DELAYED_EMBED', []);
    var delayedSwfConfig = {"params":{"allowscriptaccess":"always","bgcolor":"#FFFFFF","allowfullscreen":"false"},"args":{"enablejsapi":1},"min_version":"8.0.0","url":"\/\/s.ytimg.com\/yts\/swf\/masthead_child-vflRMMO6_.swf","html5":false,"attrs":{"height":"1","id":"masthead_child","width":"1"},"url_v9as2":"","url_v8":""};
      delayedSwfConfig.fallbackMessage = function(){};
    delayedEmbed.push({
      'container': "masthead_child_div",
      'swf_config': delayedSwfConfig
    });
    yt.setConfig('DELAYED_EMBED', delayedEmbed);
  })();

delayedSwfConfig contains:
"url":"\/\/s.ytimg.com\/yts\/swf\/masthead_child-vflRMMO6_.swf","html5":false

From another part of the source code, I can see that youtube invite users to use html5 compatible browser when the used browser is not html5 compatible. Seems there is still some Flash on youtube.

---------

https://bugzilla.mozilla.org/show_bug.cgi?id=1126450 references https://bugzilla.mozilla.org/show_bug.cgi?id=1108035. In the last one, dom.ipc.plugins.flash.disable-protected-mode was introduce there.
Whether this value is true or false, Flash hang. However, if I disable protected mode in “%WINDIR%\SysWOW64\Macromed\Flash\mms.cfg”, adding “ProtectedMode=0”, Flash does not hang anymore.

Comment 3

[Benjamin Smedberg]

This sounds very much like bug 1126570.

Did you have a "ProtectedMode=1" setting in your mms.cfg before?

Does flipping "dom.ipc.plugins.sandbox.flash" to false also solve the hang?

Comment 4

[Yohann Jardin]

I had to update flash to participate in a programming challenge and I just re-install v16.0.0.280 and the nightly which build is 20150131030230.
I am able to reproduce this bug.

Did you have a "ProtectedMode=1" setting in your mms.cfg before?
-> I had not. 
mms.cfg was containing the following two lines:
AutoUpdateDisable=1
SilentAutoUpdateEnable=0

Does flipping "dom.ipc.plugins.sandbox.flash" to false also solve the hang?
-> Yes, it does solve the problem.


As I can see with current nightly (20150305072141), I do not face this problem and "dom.ipc.plugins.sandbox.flash" is not in about:config anymore. Trying the devil by adding it manually, putting it at true does not recreate the issue.

If there is anything to verify, let me know. Else, I do not see any point in this thread anymore.

Comment 5

[Benjamin Smedberg]

We backed out the protected-mode and sandbox change, so this bug is probably not useful.