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Viewing UMDF Objects

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Warning

UMDF 2 is the latest version of UMDF and supersedes UMDF 1. All new UMDF drivers should be written using UMDF 2. No new features are being added to UMDF 1 and there is limited support for UMDF 1 on newer versions of Windows 10. Universal Windows drivers must use UMDF 2.

The archived UMDF 1 samples can be found in the Windows 11, version 22H2 - May 2022 Driver Samples Update.

For more info, see Getting Started with UMDF.

This topic describes how you can use the Wudfext.dll debugger extensions to view information about objects used by a User-Mode Driver Framework (UMDF) version 1 driver.

Starting with UMDF version 2, you should instead use the Wdfkd.dll debugger extensions. For more info, see Windows Driver Framework Extensions (Wdfkd.dll).

You can perform the following steps to view information about UMDF version 1 objects:

  1. Use one of the following UMDF debugger extensions to view device stacks that are in the host process:

    • !wudfext.umdevstacks

    • !wudfext.umdevstack as shown in the following example:

      !wudfext.umdevstack <dev-stack-addr>

      The information includes driver objects and device objects for each driver. Currently, UMDF allows only one device stack in a host process so there is no difference between the outputs of these two extensions.

  2. View the complete object tree by using the !wudfext.wudfobject UMDF debugger extension, as in the following example:

    !wudfext.wudfobject <IWDFDriver*> 1

  3. Use the !wudfext.wudfdevice UMDF debugger extension as shown in the following example to determine the Plug and Play (PnP) and power-management state of the device:

    !wudfext.wudfdevice <IWDFDevice*>

  4. Perform the following steps to determine the queues that are associated with the device:

    1. Use the !wudfext.wudfdevicequeues UMDF debugger extension to view the queues that are associated with the device. This extension shows queue properties, queue state, and driver-owned requests.

    2. Use the !wudfext.wudfqueue UMDF debugger extension as shown in the following example to obtain information about each queue:

      !wudfext.wudfqueue <IWDFIoQueue*>

  5. Use the !wudfext.wudfrequest UMDF debugger extension to obtain information about a particular request. This information includes the underlying user-mode I/O request packet (IRP). From the user-mode IRP information, you can determine where the request is currently being processed in the stack. You can also use the !wudfext.umirp UMDF debugger extension to obtain this user-mode IRP information.

  6. Determine all I/O targets by:

    1. Using the !wudfext.wudfobject UMDF debugger extension to view the child objects of the device object. I/O target objects are child objects of the device object.

    2. Using the !wudfext.wudfiotarget UMDF debugger extension as shown in the following example to view information about each I/O target object:

      !wudfext.wudfiotarget <IWDFTarget*>

      This extension shows the target's state and the list of sent requests.

    There is currently no UMDF debugger extension that allows you to view all I/O targets.

  7. Use the following UMDF debugger extensions to view information about file objects:

    !wudfext.wudfrequest or !wudfext.umirp
    Use the !wudfext.wudfrequest or the !wudfext.umirp UMDF debugger extension to view files that are child objects of device objects.

    !wudfext.wudffile
    Use the !wudfext.wudffile UMDF debugger extension as shown in the following example to view information about a framework file:

    !wudfext.wudffile <IWDFFile*>

    !wudfext.umfile
    Use the !wudfext.umfile UMDF debugger extension as shown in the following example to view information about a UMDF intra-stack file (that is, a file object that a driver in the stack created as opposed to a file object that was created by an application or by a driver in another stack):

    !wudfext.umfile <addr>

    In some cases, there might not be a corresponding framework file, and user-mode IRP information might include a UMDF intra-stack file.

    Information that !wudfext.umfile displays includes any IRPs that are queued to the UMDF intra-stack file. Only driver-created files track user-mode IRPs that are queued to those files. For application-created files, the I/O manager tracks the kernel-mode IRPs.

    !wudfext.umdevstacks and !wudfext.umdevstack
    Use the output from the !wudfext.umdevstacks and !wudfext.umdevstack UMDF debugger extensions to view outstanding UMDF intra-stack files that correspond to driver-created files.