Thursday, June 7, 2012

Part 5: Setup WinDBG as a server to solve BSOD

Part 5: Setting up WINDBG as a Server.
I am assuming here you have gone through installation and already setup windbg. Now I am going to setup WINDBG as a server so you need not to install Windbg on every crashed system, no need to download symbols again and again and also no need to copy dump files on WinDBG server. All I want to do is everything Hassle free. Here I am utilizing D drive. Where windbg is installed
  • ·         Create a folder D:\windbg. (on the windbgserver)
  • ·         Share it on the network. Give administrators full permissions. 

  • ·        Select all files from "C:\Program Files (x86)\Windows Kits\8.0\Debuggers\x64" and copy them in  D:\windbg
  • ·         Copy c:\symbol folder inside d:\windbg as well

Above is the windbg topology, Now what you need to do is log into your desktop or laptop with admin rights (also having admin rights to windbgserver and memberserver) with internet connectivity. Here I am going to use KD.exe (commandline tool to windbg).

Map shared WinDBG folder from windbgserver on your desktop, let's map it to W: (you can use another drive,  if W: is already mapped)

Open start>computer> and select Map network drive for lower menu bar

Change drive to W: and use \\\windbg, click finish. (if it ask for network credentials provide it admin username and password)
Open command prompt.  start>run>cmd. Type below commands.

Once it is done reading minidump file type !analyze -v  as shown and press enter.

Now in next screen you can clearly see what is the root cause of BSOD.

So next time you find any "bug" file on your windows system, I am sure you know how to kill it.
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Wednesday, June 6, 2012

Part 4: Setup WinDBG as a server to solve BSOD

Part 4: Troubleshoot if dump file not generating.
There might be some unexpected reboot you might found but does not find dump files, for troubleshoot check system debugging information, it is set correctly, sometimes dump file located on partition (could be separate HDD) fails or does not have enough space or if the partition hosted on network drive and Ethernet card or iscsi/HBA device fails.
Check link for more info
Or sometimes WinDBG is not able to give you root cause, check you symbol files path, check internet connectivity. Also check if some has powercycle server. These are the some of possible reasons.
check this link as well:

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Part 3: Setup WinDBG as a server to solve BSOD

Part 3: Configuration

WinDBG is setup and ready, now we need memory dump file to analyze. When I started writing this demo, I didn’t have any real world dump file, but in the end I found one and you can see demo in the last. for Here there is a trick, you can have dump file, by crashing  system manually. Source
I tried to download Notmyfault utility from, but it is not available there I found the software on download and unzip it under c:\notmyfault folder (create notmyfault folder under c drive).
Run NotMyfault.exe from c:\Notmyfault\x64.

Congrats you have just crashed your system and created memory dump file.
Note: Do not try this on your pc or production systems I am here crashing it in virtual machine Lab.
Once it will done writing to dump file, system will restart automatically.
Currently my dump setting is set to minidump file, and I crashed my computer twice, it has created 2 files. You can set dump file settings to full memory dump or kernel memory dump and see the results.

After installation, you will find new programs installed under  Start>All Programs>Windows Kits>Debugging tools for windows
Click WinDBG (X64). WinDBG is a pure debugger tool, specially designed for Microsoft application developers. 

What are symbol files?
In next stage you need symbols in order to be able to do effective debugging. I will call it as WinDBG dictionary from where WinDBG decode dump files.

Next  you need to configure Symbol files location and server path
You can alter the symbols store location, you can set it to another drive. Here I am using srv*c:\symbols* which will save symbols files to c:\symbols and download from,

There are also symbols available from citrix if you want check bug files generated on citrix server. Below is the list.

  1. Value for non-Microsoft employees:
For Microsoft employees:
  1. 2.       Symbol Server (Citrix):
Click file>Open Crash Dump  or press Ctrl+D.
Navigate to c:\dump\minidump and select latest memory dump file. Press open.

It will download partial necessary symbol files to decode dump file. It will take time depending on your internet speed.  you can check the c:\symbols folder size later as it is growing slowly.

As from above screenshot Windbg detected myfault.sys file is the culprit. Now you can google or search files and folders for the filename on your computer and determine what driver or software is associated to myfault.sys. when we run notmyfault.exe check the other file name located in the same folder. Once you get what application or driver is causing error upgrade it to stable version or also check Hardware relying on drivers or software.

Here we have successfully postmortem'ed minidump file. Now we are going to capture Kernel memory dump file. For this change write debugging information and dump file location.
This time I will show you another method of crashing system, and don’t need any utility, simply go to Task manager and end process tree of csrss.

This will generate BSOD and create Memory.dump file under c:\dump. After restart open WinDGB>file> open crash dump> Navigate to c:\dump and open Memory.dump file.

Once the cmd prompt opened type !analyze - v command for detailed debug logs.
As you can see csrss.exe caused BSOD.

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Tuesday, June 5, 2012

Part 2: Setup WinDBG as a server to solve BSOD

Part 2: Dowanload and install WinDBG.

WinDBG is a part of Windows drivers kit (619MB ISO) also called WDK and Windows Software Development Kit (SDK), Here I am using  SDK to download. go to and download sdksetup.exe file.
Downloaded file is just a 701 kb in size, before starting installation make sure your internet connection is working as it will download component and required softwares from internet, You must be a administrator to install this file, right click and run as administrator
Installation will start downloading Microsoft .net framework 4 and setup it to proceed, which will be downloaded from internet, (if you have already installed .net 4 it will not download), check I accept the Microsoft .NET Framework license terms and click Accept & Install.  
It will take time depending on your internet speed.
Once installation completes, It will ask you where to store setup package files on the server (I am choosing this option incase in future if I need to install WinDBG on another server, and don't have to download it again), I have created Temp folder under C drive and store all the setup files, and will manually do installation once download finished. Click next to proceed.
I am keeping defaults here and clicking next.
 Select Debugging tools for windows and deselect other selection. Now you will see it will be downloading 115 MB of data, this is why I chose SDK (around 250 MB) over windows drivers kit WDK (619.8 MB). Click download to start it.
Once the download completes you are ready to install WinDBG, open c:\temp folder (backup or copy c:\temp folder to central location in case if you need to install the same on another computer, no need to download it again) and run sdksetup.exe (you must be an administrator to install it) or right click and click run as administrator.
I am keeping all the defaults and pressing next

As we are not going to install .net framework 4.5 SDK you can ignore warning and press next.
Accept the license agreement
Start installation by pressing Accept.

All you have done now. Windbg is downloaded and installed successfully, all you need to do is configure it.

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Part 1: Setup WinDBG as a server to solve BSOD

Setup WinDBG as a server

Have you ever faced BSOD (Blue screen of death) problem on your system and ever want a root cause why it is happening, well I will try here to solve the problem.

Note: for your information, I will not suggest you  to use your daily using systems or production environment, Her I have done all tests and labs on my virtual environment. I won't be responsible for any damage.

In this demo I am using 2 windows 2008 64 bit VM and 1 windows 7 VM which is set up on vmware workstation.

Part1:  What is WinDBG?

What is BSOD?
System OS crashed or halted by unrecoverable error.

What are these errors?
This could be (Faulty/incompatible) Hardware, outdated BIOS & firmware, (buggy) softwares, (could include (buggy/out dated) Drivers, incompatible patch).

How can I determine what is causing error? And what softwares are used?
WinDBG is a free debugger tool, which reads dump file.

What is dump file?
Whenever system is crashed it create dump file, and this dump file has all the answer. It contains data, (Memory Map) that was in the memory when system crashed, you can use it as a point in time to see what was in memory when system crashed.
 There are 3 types of dump files which are used for analyses:  
  • Complete memory dump saved in %SystemRoot%\MEMORY.DMP,
  • Kernel memory dump saved in %SystemRoot%\MEMORY.DMP
  • Small memory dump (64 KB) saved  %SystemRoot%\Minidump
* %systemroot% is path equal to "C:\windows" for windows 2003 and later operating system.
Read Microsoft KB on for detailed information about memory dump files

You can configure windows settings which dump file you want to generate
Simply Go to start, right click computer, choose properties
Click "Advance system settings"
 Click on setting  under Startup and Recovery.
 Create a "Dump" folder under C drive, Here I am changing the path of each memory dump file path to C:\Dump, for better management and easy portability of dump files Rather than keeping default.

If you have more than 2 GB of ram you will not able to see complete memory dump in drop down list. By default system will create Kernel memory dump file, you can use drop down list and select which dump file you want to create.  

Select small memory dump (256 KB) and set dump file location to c:\dump\minidump.

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