Steps to Capture First Chance Exceptions Using Debug Diagnostic Tool (DebugDiag)

Introduction

 

In the world of software development, debugging is an essential skill. Debug Diagnostic Tool (DebugDiag) is a powerful utility designed to assist in troubleshooting various issues related to application crashes, hangs, and performance bottlenecks. One of the critical functionalities of DebugDiag is capturing first chance exceptions.

 

A first chance exception occurs when an exception is thrown in an application, before it is handled..

 

This blog will walk you through the steps to capture these exceptions effectively.

 

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Understanding First Chance Exceptions

 

 

• When an exception is thrown, it is initially caught by the runtime before any catch blocks are executed. This is considered a "first chance" event.
• If the exception is not handled (caught), it becomes a "second chance" exception when it propagates up the call stack and is eventually unhandled.

 

 

Prerequisites

 

Before we dive into the steps, ensure you have the following:

• Debug Diagnostic Tool (DebugDiag) installed on your system.
• Administrator privileges to configure and run DebugDiag.
• Access to the application or process you intend to monitor.

 

Steps to Capture First Chance Exceptions Using DebugDiag

 

Step 1: Launch DebugDiag

 

First, open the DebugDiag tool. You can find it in the Start menu under "Debug Diagnostic Tool." Ensure you run it with administrator privileges to access all its features.

 

Step 2: Create a New Rule

 

Once DebugDiag is open, you need to create a new rule to capture exceptions:

• Click on the "Rules" tab.
• Select "Add Rule."
• Choose "Crash" as the rule type and click "Next."

 

Step 3: Select the Target Process – IIS Web application pool

 

The next step involves selecting the application or process you want to monitor:

• You can choose from a list of running processes or provide an executable path.
• Select the target process and click "Next."
  
  

   

Step 4: Configure Exceptions

 

In this step, you'll configure the tool to capture first chance exceptions:

• Under advance settings click on Exceptions
• Under "Exceptions," click "Add Exception."
• If you know the exact exception you can type the exception under “Optional Exception Name” or you can select the exception from the given exception name
  
  

   

• Set the "Action Type" to "Full Userdump."
• Set the “Action Limit” to 10
• Click on “Save & Close”
• Click "OK" to save the settings.

 

For example, If you need to configure the exception. Select CLR(.NET) 4.x Exception and mention Exception name as System.Security.Cryptography.CryptographicException.

 

This is how it can be set :

 

In case you are facing issues with your application and you see Exception name as System.Runtime.InteropServices.COMException, you can enable the debug diag for such first chance exception like this :

 

 

Step 5: Specify Advanced Settings

 

DebugDiag offers advanced settings for fine-tuning the capture process:

• You can configure options such as the number of user dumps to capture, the location to save the dump files, and notifications.
• Adjust these settings according to your requirements and click "OK."

 

Step 6: Activate the Rule

 

After configuring the rule, you need to activate it:

• Click "Finish" to complete the rule setup.
• The rule will now appear in the "Rules" tab. Ensure it is checked to activate it.

 

Step 7: Monitor and Capture Exceptions

 

With the rule active, DebugDiag will monitor the selected process for exceptions:

• When a first chance exception occurs, DebugDiag will capture a full user dump of the process.
• You can view the captured dumps in the specified location.

 

Conclusion

 

Capturing first chance exceptions using Debug Diagnostic Tool (DebugDiag) is a crucial step in troubleshooting and resolving application crashes. By following the steps outlined in this blog, you can effectively monitor your applications, capture critical exception data, and analyze the root causes of crashes. This proactive approach will enable you to enhance the stability and reliability of your software, ultimately providing a better experience for your users.

 

List of Common Exceptions

 

Here are some common exceptions you might encounter and want to capture:

• AccessViolationException: Indicates that an invalid memory access occurred.
• NullReferenceException: Occurs when an attempt is made to access a null object reference.
• OutOfMemoryException: Thrown when the system runs out of memory.
• StackOverflowException: Happens when the execution stack overflows due to excessive recursion.
• ArgumentException: Raised when an invalid argument is passed to a method.
• InvalidOperationException: Indicates that a method call is invalid for the object's current state.
• FileNotFoundException: Thrown when an attempt to access a file that does not exist on disk fails.

By capturing and analyzing these exceptions, you can gain deeper insights into application behavior and improve overall software quality.

 

Additional Resources

 

For further reading and resources on DebugDiag and exception handling, consider the following:

• Debug Diagnostic Tool Documentation
• WinDbg Debugging Tool
• Best Practices for Exception Handling in .NET

Happy debugging!