Contributors Crash Course

As a contributor or a fix it yourself type of person, reading these crash reports can be an adventure. These are the details of what each argument can mean with a lot of technical detail.

Warning: This article contains technical details!


Have you ever submitted a crash report? No? Well, we’ll tell you what you need to know!
First take a look at Crash Stats. All of this data is part of the telemetry data that users submit when they use Firefox.

Note: If you would like to turn this on you can go to and choose from which statistics to opt into automatically.
new fx menu -->Options/Preferences ---> AdvancedData Choice

Review of the basics

Please go through each of these first to make sure the crash is actually related to Firefox.

When users submit the crash report, this is where you come to the rescue!

Note: To check if the reports were successfully sent, verify the “bp” is in the front of the report.

Examples and Challenge

Questions to get you started

What to recognize in some examples:
Example reports from common crashes include Flash, hardware acceleration, out of memory crashes, plugin crashes, and add-on crashes.

Example 1
Try these steps:

  1. Open the report and notice the version number. Is it the latest version?
  2. Check these first:
  • Match the System Details given in the crash report and in the question.
  • Check to see if a bug has been filed.
  • View the Source by clicking the link to the right of the Crashing Threads table. Do you see anything that pops out there?
  • Firefox version - make sure they are not stuck on an old begat channel.
  • What was running right before it crashed? What modules?

Challenge questions

  1. What module is listed when Firefox crashed?
  2. Are there any bugs that have been filed? Is there any information that could help lead to a solution?
  3. What is a possible resolution for this issue?

Example 2

Follow these steps:

  • What sticks out in the Crashing Threads table? Anything noticeable?
  • Any bug reports filed?
  • Note their Firefox version.

Challenge questions

  1. What software is causing the problem?
  2. Does the Modules tab show anything suspicious?
  3. Any bugs filed?

Advanced: Filing a crash bug

Are you the first to notice more than one crash with a similar signature? Awesome, file a bug for that crash with a link to the question and add what you know from the description of the crash. To make things easier, you can submit a bug report directly from the site.

How to read

What does each component mean?

  • Signature: What line in the source code Firefox crashed on?
  • UUID: Universally Unique Identifier.
  • Uptime: How long Firefox was open before it crashed.
  • Product: What Mozilla product they are using.
  • Version: What version of the Mozilla product they’re running.
  • Build ID: The time and date that the product was built.
  • Release Channel: What channel that Mozilla product is on e.g. Beta, Nightly etc.
  • OS: What operating system they’re running.
  • Build Architecture: 32 or 64-bit processor.
  • App Notes: Internal Firefox Settings.
  • System Memory Use Percentage: How much memory that product was using.

Where to look first:

Version: The version will be on top of the crash.

Extension tab: Use this to find out what add-ons are installed.

Check the version of the operating system that the crash report was sent from with the tag in the forum.

Signature of the last frame module: The search time period is important to take note of if you notice a trend of crash reports.

Search: These are advanced reports.

UUID: The crash report id number.

Process Type: Used to figure out what caused the problem. This will include the module's file type. For example, typically it will say plugin or Firefox crash.

Build Architecture: This is the type of processor. This can be AMD, Intel, etc.

Crash reason: This is a generic error that is defined in the code of Firefox that is returned when an error occurs. For example, bad write may mean it could not write some data to the computer's memory.

Apps Notes: These are the vendor ids. This includes the make, model and version of the computer's video card. For example,

  • NVIDIA: 900.XXX.XX

The information after that will have a "+" or "-" sign describing if it's on or off.

Processor Notes: What computer saved the report.

Make the support count! This is a great example where this all comes together!

This being concluded, you are now familiar with crash reports. Gather as much information as you can and if there is no bug filed yet, see the Contributors Guide to Writing a Good Bug.

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