exiting vm os after kernal debugging..

Question

I assume it is normal that the virtual machine's os freezes when it is under kernal debugging..  How can get access to vm so that I can shut it down when I am done with debugging?  Is there a command in WinDbg that tell the vm to shutdown? 

Answer 1

If the OS isn't compromised by your bugs, you could just 'go' and then shut it down.  If the OS is compromised by your bug, you can '.reboot' it.

Answer 2

Offhand I'd say that it isn't "normal" that the os freezes when it is under kernel debugging. At least with VMWare the VM guest OS runs normally unless it encounters a fault of some sort. If a fault is encountered I've found that the best thing to do is to use the VM IDE to Reset the guest OS. When the guest OS restarts there is usually a message that allows you to start normally, run repair, etc.

The WinDbg .reboot command, suggested by Phil, doesn't work reliably for me. After .reboot the guest VM often hangs and requires yet another reboot to actually come back up.

Your mileage can vary. FWIW.

Thomas F. Divine

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Thomas F. Divine http://www.pcausa.com

Answer 3

It depends on the VM technology. Most have some 'DOM0' control interface that will allow you to shutdown/restart the VM without having to do anything from within the VM.

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Mark Roddy Windows Driver and OS consultant www.hollistech.com

Answer 4

Thank you all for your response, however, I am still unable to get things working. My virtual machine locks up when I start WinDbg on my host machine.  I followed the instruction on how to usb WinDBG to inspect Kernel-Mode Code from http://www.personal.psu.edu/jdl5225/blogs/eportfolio/Instruction_Set.pdf.  some specific details I did is as follow:

As stated previously, I compiled my driver source (using Window Driver Kit x86 free build environment) and generated a .inf file for my driver. I installed the driver and there is a yellow exclamation point right next to my hardware indicating error code 31.  Thus I want to debug my driver so I started my path down using WinDBG and I did the below.  Can someone help me identify what I am doing wrong?  Why is my target machine locking up?  Is my symbols loaded up properly?

1. My VM is a XP so I went to Run->msconfig, enabled debug, set debug com to COM1, and set baud to 115200. 
2. On my host machine, I started WinDBG and proceed setting the following:

Answer 5

VirtualPc?

VmWare?

Xen?

Hyper-V?

VirtualBox?

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Mark Roddy Windows Driver and OS consultant www.hollistech.com

Answer 6

Virtual Box

Answer 7

Download and install VirtualKd on your host system and install the client piece on your vm. Works great.

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Mark Roddy Windows Driver and OS consultant www.hollistech.com

Answer 8

Hi Mark,

I am trying to get VirtualKD to work on my machine.  My system is as follow:

- Win 7 64 bit with VirtualBox having target machine as XP Pro.

I am following the directions on http://articles.sysprogs.org/visualddk/firstdriver/.  However, I am running into an issue installing the VisualDDK.  The error message I get is that "Installation aborted".  Would you know how I can overcome this issue?  The sysprog.org forum is very slow in their response.  Also, how can I install the 32-bit debugging tools on my 64-bit machine per the article.  Please help..

Answer 9

VirtualDDK is completely separate from VirtualKd. Don't bother with VirtualDDK. Just install VirtualKd using the documentation  for VirtualKd.

I can't help you with VirtualDDK. If you want to go down that path, and I have no idea why you would want to do that, I suggest you ask the authors on their support forum.

Frequently we lose sight of the problem we were trying to solve.

You can install either the 32bit or the 64bit version of windbg on a 64 bit system. For the 32bit version select the 32bit installer.

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Mark Roddy Windows Driver and OS consultant www.hollistech.com

Answer 10

the reason I went down the VirtualDDk route was becasue I cannot get VirtualKD to work properly.  I installed the VirtualKD and the client on the VM machine.  I can kick off vmon.exe but my VM machine goes blank during startup.  Also, the "start windbg automatically" is disabled.  A snapshot of what I see is as follow:  Please help!

Answer 11

thank you guys for all your support...  communicating back and forth with you has got me going.  I set my debugger path via vmon and now I am in debug mode with my virtual machine.  The challenge now is to decipher the messages and try to figure out what is wrong with my driver.  thanks!