Enabling kernel debugging on Windows 7 x64 | Tech Off

jujitsu_sickness

Hi all.

I'm having a really hard time enabling kernel debugging on Win7.

I've tried the following:

bcdedit /debug on
bcdedit /bootdebug on
bcdedit /dbgsettings 1394 /start active

And also without /bootdebug, and with /start disable, and also with /noumex. Nothing works. The system hangs straight after I log in, or it hangs after a short while. It's far from the simple recommended "bcdedit /debug on"!

Does anyone have any hints and tips? It's driving me insane!

Thanks.

Matthew van Eerde
AKA Maurits

What is the output of:
bcdedit
bcdedit /dbgsettings
?

What command are you using on the host computer to connect to the target?

jujitsu_sickness

In reply to Matthew van Eerde

#Jan 28th @ 7:10 PM

C:\Users\coca>bcdedit /dbgsettings
debugtype               1394
debugstart              Disable
noumex                  Yes
The operation completed successfully.

However I only want to do local kernel debugging. Thanks for your reply.

Matthew van Eerde
AKA Maurits

In reply to jujitsu_sickness

#Jan 28th @ 9:03 PM

I see - you want to do "live" kd? I assume you're doing "kd -kl" to connect. What's the output of that command?

I thought to do 1394 debugging you had to specify a channel: "bcdedit /dbgsettings 1394 CHANNEL:17"

Matthew van Eerde
AKA Maurits

> The system hangs straight after I log in, or it hangs after a short while

Sounds like you're running into problems too severe for live kd. How feasible is it for you to get a second machine w/ 1394 and do two-machine debugging?

Valentin

> The system hangs straight after I log in, or it hangs after a short while

It may be a bit late, but I'd bet you got Skype starting up with Windows. Well, that was at least the case when my machine froze/hung for no apparent reason. Took me some time (+Nullmodemcable and WinDbg running on another machine) to realize that Skype initiated user-mode exceptions caused the freeze. The NOUserModeEXceptions parameter did the job for me, but I've read that it is buggy so it might not work on your machine .

If you don't want to restart your PC every time just to use Skype OR debug, you can always use the "/start disable" dbgsettings parameter and activate the debugger using kdbgctrl and disabling user-mode exceptions from there (-du switch).

I hope i wasn't wrong and it isn't yet to late to help you out ;-D

Cheers

Valentin