This is a working page to track all activities and analysis related to hang issues in the Firefox Desktop.

Background

We are currently investigating the follow types of hangs.
- There are plugin hangs which we catch and receive a plugin and browser side crash report.
- There are browser hangs which we really have no visibility into.
  - There are real hangs where the browser becomes unresponsive.
  - There are hangs resulting from intermittent freezing.

Browser Hangs

We have little visibility around issues when the browser hangs but we have several activities in the works to investigate this further.

bug 429592 - Catch browser hangs.
- STATUS: Patch checked in but backed out due to orange tests.
- Dependent bug 694345 in Socorro for adding signature to use these reports. Sheila tracking to get this done ASAP.
Release Management is working on a project to investigate winqual reports that are generated when the user kills the browser.
- STATUS: The crash team has access to the WinQual data and will start looking at the reports.
We are following up on a number of anecdotal instances of hang issues with Firefox. Marcia in QA is helping out and we are putting together some instructions we can circulate that will help us catch hang information in certain cases.

There are a number of bugs that relate to hang issues that we are investigating.

bug 690632 - Bret hang issue - Flash plugin hangs and we aren't killing it.
- STATUS: Bret installed the latest version of Flash. The plugin is getting killed. Working with QA to investigate but seems like standard Flash hang.
bug 691533 - Pandora won't play
- STATUS: Erica's bug. Still needs further investigation.
bug 687710 - Restoring session causes hang from nsSHEntry parent loop.

bug 686025 - Startup crash/hang reported by Blizzard.
- STATUS: Fixed in FF8
- Dependent bug 691509 - Also fixed in FF8
bug 687610 - [10.6] QuickTime hangs FF while trying to play a sound from the plugin process. We have some STR and a dev involved to help resolve the issue.
- STATUS: Fixed in FF9.
bug 692260 - Increase in network.http.max-connections appears to cause hang, requires browser restart.
- STATUS: Fixed in FF8.

There are a number of things we are doing to track plugin hangs.

We have a number of reports that breakdown hangs with Flash for various versions
Data point for Sep 28th, 2011 - 14% of all crash issues were hangs in the plugin process.
85% of our hangs happen in the Flash process - Flash hangs in versions 4.0 and higher
- Keep in mind that not everybody updates to the most recent version of Flash so some of our problems are happening in older versions but have since been fixed.
The crashkill team is putting together an updated list of current Flash related hangs and will work to get some traction on them.

bug 651192 - Implement new AsyncDrawing model for plugins. This involves removing support for windowed plugins since they cause hangs. Hangs don't happen with windowless plugins and we'd like everything to be windowless for other reasons as well. We can't really remove windowed plugins until we have an alternative and this bug represents part #1 of that.
- STATUS: Talking to Josh, we made some progress on this but not much. Work will probably resume in another month or so.