794464 - Firefox occasionally goes into partial-freeze mode, disabling keyboard and buttons

Status: RESOLVED INCOMPLETE

(Firefox :: General, defect)

Description

[WBT]

This is a bug that I have been observing for many months now, and still haven't gotten it down to a specific test case with precisely known and reproducible starting conditions.  It appears to happen randomly but generally only after Firefox has been open for a while - making it hard to reproduce.  

I will describe the symptoms here in the event that anybody else can help diagnose or suggest possible causes, and add information to this bug as it becomes available.

In the partial-freeze mode, Firefox works as normal with the following exceptions:
(A) Text Entry: Keystrokes are rarely passed through to the field where the cursor is.  A small fraction, perhaps around one in ten, make it into the web form field, address bar, search bar, or add-on interface window, and the rest are ignored.  To type, one must either press each key a large number of times, often winding up with several keystrokes that never registered but more than one that did in quick succession at the end.  Alternatively (and this is my preferred strategy, in writing this bug report for example), one could type into Notepad or a word processor (which works perfectly fine), copy that text, and paste it in.

(B) Keyboard copy operations (CTRL+C) generally do not work.  

(C) Certain buttons do not work - for example, New Tab.  The workaround to this is to click on a link in an external program, or middle-click on a webpage link, which opens fine in a new tab as usual, and then paste the desired address in the address bar or navigate using a shortcut button (like Home)/bookmark/recent history item.

(D) Dialog interface buttons don't work.  
Examples: D1: Save or Replace Session or even Cancel in the Session Manager add-on interface window, while the X in that window works. Menu items to bring that interface window up work fine.
D2: The Software Update window still comes up but the interface buttons buttons (Ask Later or Update Firefox) do nothing; X closes the window.  (The release notes link also does nothing).
D3: Bringing up the Options menu, the OK/Cancel buttons there work.  

Mouse-based browsing works fine.  The browsing works pretty well, including embedded videos (e. g. from YouTube).  This mode is pretty stable and it can continue like this for days, not having a partial crash followed a few minutes later by an all-out crash.  

Because it happens so rarely / is hard to reproduce, and because I consider certain add-ons to be core functionality, I have not tried to reproduce this in Safe Mode.  

The workaround is to open Task Manager, kill the Firefox process, and restart Firefox. 

Please do not close this quickly WORKSFORME (like Bug 659212, which may be a duplicate) or INCOMPLETE simply because the bug is hard to reproduce.  I have observed it many, many times over a long period, and have spent many hours trying to nail down the particular causes. If you know what might be causing this, or have some ideas of things to test next time it happens, please note them in the comments.  Thank you.

Comment 1

[Ioana (away)]

WBT, can you reproduce this issue with a clean profile or in safe mode?
http://support.mozilla.com/kb/Basic+Troubleshooting#w_8-make-a-new-profile
http://support.mozilla.com/kb/Safe+Mode

This issue might be provoked by an add-on you have installed in your Firefox.

Comment 2

[WBT]

(Quoting comment #0)
> Because it happens so rarely / is hard to reproduce, and because I consider
> certain add-ons to be core functionality, I have not tried to reproduce this
> in Safe Mode.  
> ...
> Please do not close this quickly WORKSFORME (like Bug 659212, which may be a
> duplicate) or INCOMPLETE simply because the bug is hard to reproduce.  I
> have observed it many, many times over a long period, and have spent many
> hours trying to nail down the particular causes. If you know what might be
> causing this, or have some ideas of things to test next time it happens,
> please note them in the comments.  Thank you.

Unfortunately, I can't be running in safe mode or with a clean profile all the time.  It's very intermittent and unpredictable as to when it starts happening.  The bug is filed here in case there are other things I can test after observing it, or if other people notice the same thing and can comment on what they've found.

Comment 3

[Ioana (away)]

@WBT: That makes sense, but it was worth a try :) Can you at least add the add-ons you have in a comment here? There might be one we already know provokes issues such as this.

Comment 4

[WBT]

Sure.  I have the following extensions installed (but observed this many times before the starred ones were installed, as they went on recently):
Abine 0.748
AdblockPlus 2.1.2 (enables pages to load in a reasonable time over slower connections)
Bargain Book Mole 0.5
BlockSite 0.7.1.1
ChatZilla 0.9.89
*HeaderTool 0.5.4 and
*ModifyHeaders 0.7.1.1 and
*Cookies Manager+ 1.5.1.1  (helps with quickly testing certain APIs)
Cydral Image Search Engine 1.0.4
Dictionary (EN/DE) 0.0.4
FEBE 7.0.3.5
Firebug 1.10.4
Google Shortcuts 2.1.8.1
HTTPS-Everywhere 3.0.1
Is It Compatible? 0.5.3
Media Converter 1.0.3
New Tab Homepage 0.4.3
Paste to Tab and Go 0.7
*Redirect Cleaner 2.1.0
ReloadEvery 13.0.0
Session Manager 0.7.9.1
Status-4-Evar 2012.07.08.17
Symantec Intrusion Prevention 11.1.1.5 - 1
TabFind 1.2
TabGroups Manager 2011.11.28.1
Tile Tabs 7.2
TinEye Reverse Image Search 1.1
Zotero 3.0.8
Zotero Word for Windows Integration 3.1.8

These version numbers may not correspond exactly to an observed occurrence, as I've been lucky and haven't seen this in several days (actually, it's just had full-out crashes that bring up the Crash Reporter instead, so it may be that Firefox hasn't been up long enough to observe this bug).  
I also have several add-ons that have been disabled because of incompatibility (without warning, on software update, as described in https://groups.google.com/forum/?fromgroups=#!topic/mozilla.dev.apps.thunderbird/rjy-yA7XevE). 

For themes I have only the default theme.

For plugins I have:
2007 Microsoft Office system 12.0.4518.1014
AlternaTIFF 2.0.1.1
Google Earth Plugin 6.1.0.5001
Google Talk Plugin 3.9.1.9832
Google Talk Plugin Video Accelerator 0.1.44.23
Google Update 1.3.21.123
IBM 821 Conference Plugin 8.2.10.911
iTunes Application Detector 1.0.1.1.
Java Deployment Toolkit 7.0.70.11 10.7.2.11
Java(TM) Platform SE 7 U7 10.7.2.11
Microsoft Office 2010 14.0.4761.1000
Microsoft Office 2010 14.0.4730.1010
PDF-XChange Viewer 2.5.193.0
Photo Gallery 16.4.3503.728
QuickTime Plug-in 7.7.1 7.7.1.0
Shockwave Flash 11.4.402.265
Shockwave for Director 11.5.7.609
Silverlight Plug-In 5.1.10411.0
Winamp Application Detector 5.5.8.2975
Yahoo Application State Plugin 1.0.0.7

Same disclaimer as above about version numbers.  Also, to anybody hoping to use this detailed information about my system state in an exploit, the versions are subject to change.

Comment 5

[WBT]

(Quoting comment #2)
>I've been lucky and haven't seen this in several days

Oops, spoke too soon.  It was getting to be about that time to see it again; I'm observing it now.  This comment is typed in Notepad and copied into the bug window (via mouse right-click Paste, not CTRL+V).  It is just as described above.

Any suggestions for further tests?

Comment 6

[WBT]

Would it be useful to keep a log here with further observations, to help gauge frequency?  I've been observing this again in the last few hours; will restart FF now to clear.

Comment 7

[Wayne Mery (:wsmwk)]

You need to narrow down the cause. 
How many tabs are open when you see this?

Comment 8

[WBT]

I agree that I as one user cannot by myself narrow down the cause enough to point to a patch.  I thought bug reporting and fixing was a collaborative activity and that if others still brave enough to report bugs went to make a report and searched for duplicates, they might be willing to comment on / support one that's open (whereas comments on closed bugs pointing out that they still happen might be predicted to be ignored).  
I keep a lot of tabs open (as an answer to your question) - usually a 3-digit number across a handful of windows - and lately have been getting error messages about Shockwave Flash not responding, even when I don't think I'm using that (and even when not touching the browser), though I think that's a separate issue primarily with flash.

Comment 9

[Phoenix]

You can install Profiler Add-On, capture problem trace and post it here for further investigation

Comment 10

[Phoenix]

Is this still present in latest Firefox version?

Comment 11

[WBT]

As I see certain add-ons as core functionality, and they are disabled in the latest Firefox, I am not testing in the latest Firefox.

Comment 12

[Phoenix]

Thank you for the reply, please reopen if you'll see this again on latest version