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  • Blog Post: Windows Troubleshooting – Special Pool

    The Windows Support team has a new YouTube channel, “ Windows Troubleshooting ”.  The first set of videos cover debugging blue screens. In this video, Bob Golding, Senior Escalation Engineer, describes how the Special Pool Windows diagnostics tool ...read more
  • Blog Post: Bugchecking a Computer on A Usermode Application Crash

    Hello my name is Gurpreet Singh Jutla and I would like to share information on how we can bugcheck a box on any usermode application crash. Set the application as a critical process when the application crash is reproducible. We may sometimes need a complete ...read more
  • Blog Post: Debugging a Windows 8.1 Store App Crash Dump (Part 2)

    In Part 1 , we covered the debugging of a Windows Store Application crash dump that contains a Stowed Exceptions Version 1 (SE01) structure.   This post continues on from Part 1, covering the changes introduced in March 2014. These Windows Updates ...read more
  • Blog Post: Debugging a Windows 8.1 Store App Crash Dump

    Quality reports on the App Summary page Microsoft provides triage dumps of your Windows Store application’s crashes and hangs through the Quality section of the App Summary page on the Dev Center - Windows Store apps portal.   Back in June 2012, ...read more
  • Blog Post: Understanding Pool Corruption Part 3 – Special Pool for Double Frees

    In Part 1 and Part 2 of this series we discussed pool corruption and how special pool can be used to identify the cause of such corruption.  In today’s article we will use special pool to catch a double free of pool memory.   A double free of ...read more
  • Blog Post: How To Deadlock Yourself (Don’t Do This)

    Some APIs should come with a warning in big red letters saying “ DANGER! ”, or perhaps more subtly “ PROCEED WITH CAUTION ”.  One such API is ExSetResourceOwnerPointer . Although the documentation contains an explanation of what limited activity ...read more
  • Blog Post: Call Stacks for Pool Allocations

    Hello, it's the Debug Ninja back again for another NtDebugging Blog article.   For as long as I can remember user mode debuggers have had an easy way to get call stacks for heap allocations.   On more recent versions of Windows this has been ...read more
  • Blog Post: Debugging a Crash, Found a Trojan

    Hi, I'm Manish from Global Escalation Services. I would like to present a multiple random bug check issue, which was caused by malicious code (trojan) running on the machine. This is the walkthrough of how we found the virus on the server. In this particular ...read more
  • Blog Post: The Compiler Did What?

    I was recently investigating a crash in an application.  As I researched the issue I found a very old defect in the code that was only recently being exposed by the compiler.   The crash occurred at the below instruction because the ebx register ...read more
  • Blog Post: Debugging a Debugger to Debug a Dump

    Recently I came across an instance where my debugger did not do what I wanted.  Rarely do computers disobey me, but this one was unusually stubborn.  There was no other option; I had to bend the debugger to my will.   There are many ways ...read more
  • Blog Post: Fixing an ICorDebugUnmanagedCallback induced hang

    Hi debuggers, Andrew Richards here with a NTDebugging post that is a little different to what is usually posted.   Instead of talking about debugging, I’m going to talk about an issue I just faced while writing a debugger.   This debugger work ...read more
  • Blog Post: Debugging Backwards: Proving root cause

    Matt Burrough here again.   On rare occasions when debugging, we'll actually know (or strongly suspect) what the root cause of a problem is at the beginning of our analysis - but we still need to investigate to confirm our assertion.   The following ...read more
  • Blog Post: Debugging a CLOCK_WATCHDOG_TIMEOUT Bugcheck

    Hi debuggers, Andrew Richards here for my first NT Debugging post. I thought I’d share a recent case that used a lot of discovery techniques to uncover the details of what was going on. Most bugchecks give you the information you need as arguments, but ...read more
  • Blog Post: Where Did My Disk I/O Go?

    Hello, Mr. Ninja back again.   I recently discovered that although my team often tracks I/O from the file system through to the disk controller, we have never publicly documented the steps required to do this.   This seems like a great opportunity ...read more
  • Blog Post: Commitment Failures, Not Just a Failed Love Story

    I was working on a debug the other day when I ran the “!vm” command and saw that the system had some 48,000 commit requests that failed. This was strange as the system was not out of memory and the page file was not full. I was left scratching my head ...read more
  • Blog Post: Leaving the Do Not Disturb Sign on the Door Will Cause the KERNEL_APC_PENDING_DURING_EXIT Bugcheck

    This is Ron Stock from the Global Escalation Services team and I recently worked with a customer to determine which misbehaving driver was crashing their critical server. This particular crash was a STOP 0x00000020 which maps to KERNEL_APC_PENDING_DURING_EXIT ...read more
  • Blog Post: What Did Storport Do With My I/O?

    In a previous article I showed how to track an I/O request from the filesystem, through the class driver, and to the storage driver.  In that article I concluded with " From this data we can usually assume that the request has been sent to the ...read more
  • Blog Post: Configuring a Hyper-V VM For Kernel Debugging

    Yesterday's blog prompted some questions about how to set up a debugger for a Windows OS running in a Hyper-V VM.   I was surprised that I wasn't able to find good, publicly available, Microsoft issued documentation for this configuration.   ...read more
  • Blog Post: My Kernel Debugger Won't Connect

    Hello ntdebugging readers, the Debug Ninja is back again with a quick blog this holiday season.   I recently encountered a situation where the kernel debugger could not connect to a Windows Server 2008 R2 system running in a Hyper-V virtual machine ...read more
  • Blog Post: Understanding Pool Corruption Part 1 – Buffer Overflows

    Before we can discuss pool corruption we must understand what pool is.  Pool is kernel mode memory used as a storage space for drivers.  Pool is organized in a similar way to how you might use a notepad when taking notes from a lecture or a ...read more
  • Blog Post: Use Caution When Implementing IPC for Performance Counters

      Recently I was working with a developer who had created performance counters that work in Performance Monitor but are never collected in a user defined data collector set.  The customer explained that their counters update named shared memory ...read more
  • Blog Post: How the Clipboard Works, Part 1

    Recently I had the opportunity to debug the clipboard in Windows, and I thought I’d share some of the things I learned.   The clipboard is one of those parts of Windows that many of us use dozens (hundreds?) of times a day and don’t really think ...read more
  • Blog Post: Determining the source of Bug Check 0x133 (DPC_WATCHDOG_VIOLATION) errors on Windows Server 2012

    What is a bug check 0x133? Starting in Windows Server 2012, a DPC watchdog timer is enabled which will bug check a system if too much time is spent in DPC routines. This bug check was added to help identify drivers that are deadlocked or misbehaving.  ...read more
  • Blog Post: Debugging a Generation 2 Virtual Machine

    Hyper-V is based on the 440BX (PCI) chipset for emulation. The decision to use this chipset started years ago with Connectix Virtual PC.  The advantage of using an emulated chipset based on a popular motherboard like the 440BX, along with associated ...read more
  • Blog Post: Stop 0x19 in a Large Pool Allocation

    Hello all, Scott Olson here again to share another interesting issue I recently debugged with pool corruption and found that using special pool does not work with large pool allocations ( pool allocations greater than a PAGE_SIZE ).   Here is an ...read more