660460 - FF freezes when Save window is open; Unresponsive script error resource://gre/modules/NetworkPrioritizer.jsm:175

Status: RESOLVED DUPLICATE of bug 476541

(Firefox :: General, defect)

Description

[bigk316]

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_7; en-us) AppleWebKit/533.21.1 (KHTML, like Gecko) Version/5.0.5 Safari/533.21.1
Build Identifier: Firefox Beta 5.0

If I have the Save window open, I get the following
"Warning: Unresponsive script
A script on this page...
Script: resource://gre/modules/NetworkPrioritizer.jsm:175"
I cannot do anything to Stop Script or Continue Buttons, as this window is behind the Save As window, & I cannot save using the forefront window until I stop the Unresponsive Script.
I have to Force Quit Firefox every time. 
I have experienced this proble with every version of Firefox.

Reproducible: Always

Steps to Reproduce:
1.Leave a Save As window for awhile;
2.
3.

Actual Results:  
The Unresponsive Script window appears behind the Save As window, so I cannot Save As until I close the Unresponsive Script window, which I cannot do until I close the Save window, which is not allowed until I close the Unresponsive Script window.

Expected Results:  
I should be able to Save As or close the Save As window, or close the Unresponsive Script window; however I cannot do either & I have to Force Quit Firefox.

I have only tried this on Mac OSX 10.6.5
This has been an issue for every version of Firefox I have downloaded.

Comment 1

[Daniel Veditz [:dveditz]]

Not a security problem that needs to be hidden, this is just a bad state you can get into and not something an attacker can force.

There's an existing bug about dueling modal dialogs leading to this stuck state, but this particular instance of it may not be a duplicate. It seems odd for the NetworkPrioritizer module to be doing so much work that it triggers the slow script dialog. Is it always that script? Does this happen in safe-mode (which temporarily disables you add-ons)? If it doesn't, what addons do you have? You can get the list by entering about:support in the address bar.

Details on how to start in safe-mode:
http://support.mozilla.com/en-US/kb/Safe+Mode

Comment 2

[Wayne Mery (:wsmwk)]

bigk, can you please reply to daniel's comment 1?   thanks.
(dveditz refers to is bug 476541)

Comment 3

[bigk316]

Sorry for the late reply. Firefox freezes whether in Safe Mode or not; this happens whenever I leave a Save As window open for a while; I don't know if it happens with other open windows.
The problem seems to be with NetworkPrioririzer.

Comment 4

[Osmose [:osmose, :mkelly]]

Attachment: Screenshot of issue

I can reproduce this bug on Firefox 12.0a1 (2011-12-30) in OS X 10.6.8. Seems to be an issue with any modal dialog.

Bug 476541 seems to have a lot of people reporting this issue as well, although the bug itself seems to focus on dialogs brought up by alert(). The new alert dialog causes a different type of freeze: in the case of modal dialogs, the save window still functions, but doesn't close when pressing the save or cancel buttons. With an alert() dialog, the entire browser becomes unresponsive (Mac beachball, and the OS recognizes a freeze and allows a Force Quit).