From MozillaZine Knowledge Base

This article describes the Mozilla crash reporting system used in Firefox 3, SeaMonkey 2 and Thunderbird 3.

Firefox 3, Thunderbird 3 and SeaMonkey 2 have a new, open source crash reporting system. The new reporting system incorporates the Breakpad crash reporting tool developed by Google engineers and the Socorro web server for processing crash report data, using a new user interface called the Mozilla Crash Reporter, also known as "Breakpad". This replaces Quality Feedback Agent (aka "Talkback") of previous Mozilla applications.

Mozilla Crash Reporter

Crash Reporter is a core part of Firefox 3, Thunderbird 3, and SeaMonkey 2 program installation. Unlike the "Talkback" global extension, it cannot be deselected during custom Windows install [1]. The crash reporter tool, "crashreporter.exe" on Windows, "crashreporter.app" on Mac OS and "crashreporter" on Linux, is located in the program's installation directory.

When your Mozilla application crashes, it saves a binary "dump" file and you will see a notification, similar to the one shown here. This Crash Reporter allows you to submit a crash data report to a web server. The Socorro-based web server at crash-stats.mozilla.com is used to search and view crash report data.

Mozilla Crash Reporter is enabled by default and there is no user interface to disable it. Advanced users who prefer the standard application error notifications (e.g., the Windows error dialog "<application> has encountered a problem and needs to close" and Event Viewer record) can disable the Mozilla Crash Reporter by setting the environment variable MOZ_CRASHREPORTER_DISABLE to 1. [2]. You can also disable the Mozilla Crash Reporter by opening the "application.ini" file in the installation directory, finding the entry [Crash Reporter] Enabled=1 and changing the 1 to 0 (you will need to repeat the edit if an application update replaces the file).

Why didn't Breakpad capture my crash?

In some installations with a problematic plug-in or an old operating system library, a Mozilla application may crash but no "dump" file is captured, so the crash reporter is unable to report the crash. See fixes or workarounds listed at Related bug reports that may enable it to capture the dump file in the future.

Location of crash reports

Crash reports are stored in the the following locations, using Firefox as an example:

• Windows 2000/XP: C:\Documents and Settings\<username>\Application Data\Mozilla\Firefox\Crash Reports\
• Windows Vista: C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Crash Reports\
• Mac OS: /Users/<username>/Library/Application Support/Firefox/Crash Reports/
• Linux: /home/<username>/.mozilla/firefox/Crash Reports/

Note: On Windows and Linux, these locations are hidden by default so you will need to show hidden files and folders.

The "Crash Reports" directory has two folders: "pending" and "submitted", respectively for crash reports that haven't been submitted to the server yet and for reports that have already been sent.

Viewing crash reports

You can use about:crashes to view submitted crash reports:

• In Firefox or SeaMonkey, type about:crashes in the Location Bar (address bar) to open the "Submitted Crash Reports" page.
• In Thunderbird, use one of these methods:
  • In the Code: line of the Error Console, type openDialog("about:crashes"); and, to the immediate right, click Evaluate.
  • In "Tools -> Options -> General -> Location", type about:crashes and click OK. Then do Go, Mail Start Page
  • Install the ViewAbout Extension

In about:crashes, click on a Report ID to view the crash data.

You can alternately use the data that stored on your computer when a crash report is submitted, to locate and view the report. This can be useful if your Mozilla application will not open or crashes at startup and you cannot access the Submitted Crash Reports list.

Each submitted crash report is identified as a text file, located in the "Crash Reports" folder within the "submitted" subfolder (see Location of crash reports, above). Files are named bp-GUID where GUID is a unique identifier and functions as the report's ID. You can open the text file for a given crash report to view its contents.

For example, a file "bp-3c2a9b80-a143-11dd-8241-001cc4e2bf68.txt" created 10-28-2008 may contain the following text:

Crash ID: bp-3c2a9b80-a143-11dd-8241-001cc4e2bf68
You can view details of this crash at 
http://crash-stats.mozilla.com/report/index/3c2a9b80-a143-11dd-8241-001cc4e2bf68?date=2008-10-23-20

Text files for submitted crash reports (at time of writing) may now include only the Crash ID, without a URL. For example, a file "bp-031b02bb-26b6-4168-ac0e-2de492090531.txt" created 5-31-2009 may contain only the following text:

Crash ID: bp-031b02bb-26b6-4168-ac0e-2de492090531

Append the GUID portion of the Crash ID to the Breakpad report URL (currently http://crash-stats.mozilla.com/report/index/) and go to that URL to view the crash report (e.g., http://crash-stats.mozilla.com/report/index/031b02bb-26b6-4168-ac0e-2de492090531).

Referencing crash reports in Bugzilla

Comments in Bugzilla should reference crash reports using the Crash ID, bp-GUID, including the "bp-" prefix before the GUID; for example, bp-031b02bb-26b6-4168-ac0e-2de492090531 (see above). Crash reports referenced in this way are linked by Bugzilla to the correct report at http://crash-stats.mozilla.com/

See also

• Breakpad.reportURL

External links

• Mozilla Crash Reporter (Firefox Support)
• Breakpad - MozillaWiki
• Crash reporting - MDC
• How to get a stacktrace for a bug report - MDC
• Breakpad development and server operation
• Crash Report Helper - Extension for analyzing Mozilla crash reports
• How mozilla finds crash bugs

Related bug reports

• Bug 216827 – implement an open-sourced crash reporting tool to replace talkback.
• Bug 379396 – Enable Breakpad Support In Thunderbird
• Bug 382124 – Crash Reporter (= Breakpad) doesn't write minidumps on Windows 2000 (old DbgHelp.dll / MiniDumpWriteDump())
  Windows 2000. Fix: from Breakpad issue 76 download dbghelp.dll, put it in directory of application .exe file (e.g., C:\Program Files\Mozilla Firefox\).
• Bug 383125 – Use breakpad for SeaMonkey trunk
• Bug 411490 – about:crashes
• Bug 422308 – Breakpad does not catch crash when flash plugin is active
  Windows. Fix: upgrade to Flash 10.
• Bug 503645 – Flash 10 prevents Breakpad from catching crashes
  Linux. Workaround: disable Flash plugin.