Windows System Software -- Consulting, Training, Development -- Unique Expertise, Guaranteed Results

Sept/Oct 2019 Issue of The NT Insider available

Download PDF here:

It’s a particularly BIG issue, too: 40 pages of technical goodness, ranging from WDF to Minifilters. Check it out.
Before Posting...
Please check out the Community Guidelines in the Announcements and Administration Category.

Can't see output from DbgPrint

Michael_RolleMichael_Rolle Member - All Emails Posts: 135

This is certainly WinDbg 101 stuff, but the things I read in the Help file aren't sufficient.
1. Fired up WinDbg. Opened a window to local Kernel (File->Kernel Debug...->Local tab->OK).
2. ed Kd_IHVDRIVER_Mask, value is already 0xffffffff.
3. In the DriverEntry function, I call DbgPrintEx (DPFLTR_IHVDRIVER_ID, DPFLTR_INFO_LEVEL, fmt, args...);
4. Start the driver using the SC START command.
5. Nothing in the WinDbg session window.
6. !dbgprint says the DbgPrint buffer is empty.

By the way, if I close the session window, File->Kernel Debug... remains grayed out, and I have to quit WinDbg and start it again if I want to repeat the above. What am I doing wrong here, and is this a clue regarding the missing debug output?

I have WinDbg 10.0.17763.1 AMD64, and Windows 10 OS 1803.


Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Upcoming OSR Seminars
Writing WDF Drivers 21 Oct 2019 OSR Seminar Space & ONLINE
Internals & Software Drivers 18 Nov 2019 Dulles, VA
Kernel Debugging 30 Mar 2020 OSR Seminar Space
Developing Minifilters 27 Apr 2020 OSR Seminar Space & ONLINE