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CbFs crashing in CbFsDeleteFileFunc

Also by EldoS: CallbackRegistry
A component to monitor and control Windows registry access and create virtual registry keys.
Posted: 01/13/2011 09:31:41
by Robert Baer (Basic support level)
Joined: 11/08/2010
Posts: 46


thanks for that hint. I inserted the line

to my code. Unfortunately, the problem occured again after this modification.
It is still the file control block that is NULL in CbFsWriteCB (see posting #3).

How should we proceed?

Posted: 01/13/2011 12:35:50
by Eugene Mayevski (EldoS Corp.)

Then unfortunately we need to ask you to create a test case that reproduces the problem and submit it to us. We can't go further without a way to reproduce the issue.
Posted: 01/13/2011 12:57:38
by Vladimir Cherniga (EldoS Corp.)

We run into the problem that some internal structure address (Fcb - file control block) was overwritten by your code or by a mistake in our internal callback code. In any case it is hard to find the source of the problem without ability to reproduce it locally from our side. If you could provide a sample code to reproduce the problem or describe the steps that will produce the same results with existent Mapper sample, it would be much easier. From our side i can provide a modified debug driver binary (win32) with an additional debug messages helps to trace the cases if user mode Fcb structures has Null value. You may trace it with well-known DebugView utility from sysinternals.com

[ Download ]
Posted: 01/24/2011 02:31:36
by Robert Baer (Basic support level)
Joined: 11/08/2010
Posts: 46

Hello Vladimir,

thanks a lot for providing a debug version. Strangely, debugview didn't show any information when the problem occured. Debugview should work correctly as my own OutputDebugStrings are traced. Possibly none of the inserted debug messages were executed?
At the moment the problem does not occur anymore. Perhaps my last changes corrected the fault or the timing is different now. I will get back to you if the error occurs again.

Posted: 01/24/2011 06:05:01
by Volodymyr Zinin (EldoS Corp.)

Debug messages are "suppressed" in the case you use Windows Vista or Seven. In order to switch it on open the key "HKLM\SYSTEM\CCS\Control\Session Manager\Debug Print Filter". Under this key, create a DWORD value with the name "DEFAULT" and set it to 0xF. And reboot the machine.
Posted: 01/24/2011 06:11:14
by Volodymyr Zinin (EldoS Corp.)

BTW try to use the latest CallbackFS build. There have been some corrections that perhaps "fixed" the problem with zeroed FCB.
Posted: 01/24/2011 06:26:14
by Vladimir Cherniga (EldoS Corp.)

Possibly none of the inserted debug messages were executed?

This may be the signal that this problem not touching the code executing in driver. This may be a problem in user mode part.
Also by EldoS: CallbackProcess
A component to control process creation and termination in Windows and .NET applications.



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