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Drv_2_Drv Communication!!!

NtDev_GeekNtDev_Geek Member - All Emails Posts: 125

Hi All,

I am trying to establish a communication between my mini-filter and disk lower filter driver using ExCallback APIs. The implementation is as per the buddy driver tutorial, and things are working fine, except the callback in my mini-filter is not called.

Disk Filter:
1. success call to ExCreateCallback in disk filter.
2. Notifying Minifilter with ExNotifyCallback along with context.

1. Sucess call to ExCreateCallback in mini-filter (The obj pointer matched).
2. Registering callback success.
3. Custom callback never called.

I am trying to send some data from my disk filter to mini-filter and want to act accordingly in the InstanceSetup. But the registered custom callback was never invoked. Since the notification call is sync in nature, then why was my custom callback function never invoked?

Can anyone give me some pointers? I appreciate any help you can provide.


  • Scott_Noone_(OSR)Scott_Noone_(OSR) Administrator Posts: 3,529

    No idea...You'll have to debug it. Have you stepped into your call to ExNotifyCallback? You'll be in assembly but that's where I'd start. There are also plenty of code examples on Google.


  • NtDev_GeekNtDev_Geek Member - All Emails Posts: 125

    Thank you for the information.

    As you said, I tried digging it and stepped into the debugger while keeping a breakpoint in my custom callback routine, but no luck.

  • Scott_Noone_(OSR)Scott_Noone_(OSR) Administrator Posts: 3,529

    You can post the relevant code somewhere I can try to spot the problem. It really should "just work"


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