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Fix Symbol loading for Kernel Driver minidump analysis


You need to have the exact same version of the driver binary (.sys file) and the debug information file (PDB) ready on the machine running the WinDbg session.

Debugging session

First, triple-check that you've got a local symbol cache configured and have the Microsoft Symbol Server referenced in the session:

.sympath cache*D:\symbols;srv*

In this example, my local path where symbols get stored and looked up from is D:\symbols, adjust to your system accordingly. Symbol loading can be sped up tremendously if you keep the same local cache path in between debugging sessions. Then turn on "noisy symbol loading" to get vital details about the symbol loading process:

!sym noisy

All set, now force reloading all symbols, this will spit out a great deal of diagnostics:

.reload /n /f

Once done, look for the first occurrence of a line similar to the following:

SYMSRV:  UNC: d:\symbols\mydriver.sys\620F6CF740000\mydriver.sys - path not found

Where mydriver.sys is replaced with the driver you're debugging. Create the directory structure d:\symbols\mydriver.sys\620F6CF740000\ with PowerShell:

New-Item -Type Directory -Path "d:\symbols\mydriver.sys\620F6CF740000\"

Put the driver binary file mydriver.sys in this directory.

Now we'll determine the location where the debugger will expect the PDB. We can get this information with the symchk tool (included in the Windows Driver SDK, typical location: C:\Program Files (x86)\Windows Kits\10\Debuggers\x64) in PowerShell:

symchk /v /os "D:\symbols\mydriver.sys\620F6CF740000\mydriver.sys"

Look for the first occurrence of this line:

SYMSRV:  UNC: D:\symbols\mydriver.pdb\BBFF36A8FA374D1DAD904AD5AFDD8B441\mydriver.pdb - file not found

Yet again back in PowerShell, create this directory structure:

New-Item -Type Directory -Path "D:\symbols\mydriver.pdb\BBFF36A8FA374D1DAD904AD5AFDD8B441\"

Finally, place the PDB file in this directory.

If you now run the symchk command again, the output should have changed to:

SYMSRV:  PATH: D:\symbols\mydriver.pdb\BBFF36A8FA374D1DAD904AD5AFDD8B441\mydriver.pdb
SYMSRV:  RESULT: 0x00000000

Watch out for mismatched pdb

If you also get a line similar to

DBGHELP: D:\symbols\mydriver.pdb\BBFF36A8FA374D1DAD904AD5AFDD8B441\mydriver.pdb - mismatched pdb
the PDB file used is the wrong version, most probably from a newer or older build and must be replaced with the correct one!

Finally back in WinDbg we can invoke another symbol loading:

.reload /n /f

After these steps, the items in the call stack should be resolved to proper function names:

9: kd> kc
 # Call Site
00 nt!KeBugCheckEx
01 Wdf01000!Mx::MxBugCheckEx
02 Wdf01000!FxVerifierBugCheckWorker
03 Wdf01000!FxVerifierNullBugCheck
04 Wdf01000!imp_WdfObjectGetTypedContextWorker
05 mydriver!WdfObjectGetTypedContextWorker
06 mydriver!DeviceRequestContextGet
07 mydriver!EvtRequestCompletionTimer
08 Wdf01000!FxTimer::TimerHandler
09 Wdf01000!FxTimer::_FxTimerWorkItemCallback
0a Wdf01000!FxSystemWorkItem::WorkItemHandler
0b Wdf01000!FxSystemWorkItem::_WorkItemThunk
0c nt!IopProcessWorkItem
0d nt!ExpWorkerThread
0e nt!PspSystemThreadStartup
0f nt!KiStartSystemThread

3rd party sources