The problem:
I’ve developed a USB WDM driver that doesn’t fall in any device
category, so I’m trying testing it with the “universal” test suite. As
soon as I select it in the HCT “Test Selection Wizard” window, and I
click on ok, the driver will not unload any more.
What’s happening:
knowing that this kind of problems are caused by leaky references to the
device or driver object, I did my homework following the directions
provided by Eliyas (“Debugging a Failed Driver Unload” in the WinDbg
online help), looking for a mismatching
ObReferenceObject/ObDereferenceObject couple in my driver. I indeed
found one, but it’s not in my driver: it’s in kitdevis.sys, that appears
to be part of the HCT distribution. It seems that for some reason,
between two calls to my IRP_MN_QUERY_CAPABILITIES handler, kitdevis.sys
increments the reference counter of my device obejct, and after that it
never decrements it.
A thing to mention is that I’m borrowing the PNP handling code from
Walter Oney’s WDM book, without any modification.
Another thing to mention is that I never experienced any problem in
unloading the driver, in months of developing and testing. It only
happens when I click “ok” in the Test Selection Wizard.
Now, I know I must be missing something obvious, because it’s impossible
that the HCT suite has such a macroscopic problem, but for the moment
I’ve no idea what. Does anybody know what could cause this behavior?
Thanks in advance!
Loris