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I'm porting a legacy filter driver that does File Encryption to minifilter.
Lately I started using Driver Verifier (the old legacy driver failed passing it). I went solving various problems thanks to it.
But I'm stuck on this one, I've disabled all my FLT_OPERATION_REGISTRATION Callbacks so now I'm not filtering any I/Os and while I shutdown the computer this message appears :
FILTER VERIFIER WARNING: A filter has set a completion context for a callback data which will be lost. Probable cause of this is that no post-operation callback was requested or routine was registered for this operation or the request was being pended or completed. (Filter = FFFFC902E4C59010 (driver_name_here), Cbd = FFFFC902E8705998) Break, ignore, zap or remove ?
In windbg I can print the FLT_CALLBACK_DATA structure and the FLT_IO_PARAMETER_BLOCK and the IO_STATUS_BLOCK :
kd> dt !_flt_callback_data FFFFC902E8705998 FLTMGR!_FLT_CALLBACK_DATA +0x000 Flags : 2 +0x008 Thread : 0xffffc902`e7f40040 _KTHREAD +0x010 Iopb : 0xffffc902`e87059f0 _FLT_IO_PARAMETER_BLOCK +0x018 IoStatus : _IO_STATUS_BLOCK +0x028 TagData : (null) +0x030 QueueLinks : _LIST_ENTRY [ 0x00000000`00000000 - 0x00000000`00000000 ] +0x040 QueueContext :  (null) +0x030 FilterContext :  (null) +0x050 RequestorMode : 0 '' kd> dx -id 0,0,ffffc902e2aaf080 -r1 ((FLTMGR!_FLT_IO_PARAMETER_BLOCK *)0xffffc902e87059f0) ((FLTMGR!_FLT_IO_PARAMETER_BLOCK *)0xffffc902e87059f0) : 0xffffc902e87059f0 [Type: _FLT_IO_PARAMETER_BLOCK *] [+0x000] IrpFlags : 0x0 [Type: unsigned long] [+0x004] MajorFunction : 0x10 [Type: unsigned char] [+0x005] MinorFunction : 0x0 [Type: unsigned char] [+0x006] OperationFlags : 0x0 [Type: unsigned char] [+0x007] Reserved : 0x0 [Type: unsigned char] [+0x008] TargetFileObject : 0x0 [Type: _FILE_OBJECT *] [+0x010] TargetInstance : 0xffffc902e69c1010 [Type: _FLT_INSTANCE *] [+0x018] Parameters [Type: _FLT_PARAMETERS] kd> dx -id 0,0,ffffc902e2aaf080 -r1 (*((FLTMGR!_IO_STATUS_BLOCK *)0xffffc902e87059b0)) (*((FLTMGR!_IO_STATUS_BLOCK *)0xffffc902e87059b0)) [Type: _IO_STATUS_BLOCK] [+0x000] Status : -1 [Type: long] [+0x000] Pointer : 0xffffffff [Type: void *] [+0x008] Information : 0x0 [Type: unsigned __int64]
But they are quite empty...
And since I'm not filtering any I/Os where can I be using a FLT_CALLBACK_DATA ?
Without Driver Verifier it goes to shutdown normally (no BSOD or freezes).
If anybody has ever encountered this message ... any help appreciated !
(I also registered some callback in pDriverObject->MajorFunction to communicate with the driver, but I don't think it can come from this).
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