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Q182110: IIS Access Violates Calling Local COM Server

Article: Q182110
Product(s): Internet Information Server
Version(s): WINNT:3.0,4.0
Operating System(s): 
Keyword(s): 
Last Modified: 20-MAY-2002

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The information in this article applies to:

- Microsoft Windows NT Server version 4.0 
- Microsoft Internet Information Server versions 3.0, 4.0 
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SYMPTOMS
========

Internet Information Server (IIS) may access violate when using an in- process
COM object to expose methods for a local COM server that is running as a
service. The access violation is more likely to occur on multi- processor
servers that are extremely busy. The access violation will occur in seemingly
unrelated areas because the problem affects several areas of the COM support
code.

The debug stack will look similar to the following example:

  Example Stack:
  DbgBreakPoint
  RtlpBreakPointHeap
  RtlpValidateHeapEntry
  RtlDebugSizeHeap
  RtlSizeHeap
  CRetailMalloc_GetSize
  MemSize(void * 0xfeeefeee)
  MemFree(void * 0xfeeefeee)
  CTypeLib2::~CTypeLib2() line 56 + 15 bytes
  CTypeLib2::`scalar deleting destructor'() + 20 bytes
  CTypeLib2::Release(CTypeLib2 * const 0x0344e428)
  CTypeInfo2::Release(CTypeInfo2 * const 0x0344eac8)
  CreateRealProxy
  CProxyWrapper::Connect
  ConnectIPIDEntry@CStdMarsha
  MakeCliIPIDEntry@CStdMarshal
  UnmarshalIPID@CStdMarshal
  RemQIAndUnmarshal@CStdMarshal
  QueryRemoteInterfaces@CStdMarshal
  QueryMultipleInterfaces@CInternalUnk
  QueryInterface@CInternalUnk@CStdIdentity
  CreateInstance
  CreateInstance
  ::FinalConstruct()

CAUSE
=====

The ref count for a contained local servers Type Library can be incorrectly set
when the OLE automation code is set to multithreading. As a result, the Type
Library is released too soon.

The access violation occurs when the in-process object creates or references
methods in the local server after the Type Library has been released.

This problem only occurs when the multiprocessor IIS computer is under stress and
the time frame of the ref counter is incorrectly set too small.

RESOLUTION
==========

A supported fix that corrects this problem is now available from Microsoft, but
has not been fully regression tested and should be applied only to systems
experiencing this specific problem. If you are not severely affected by this
specific problem, Microsoft recommends that you wait for the next service pack.

To resolve this problem immediately, contact Microsoft Product Support Services
to obtain the fix. For a complete list of Microsoft Product Support Services
phone numbers and information on support costs, please go to the following
address on the World Wide Web:

  http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS


STATUS
======

Microsoft has confirmed this to be a problem in Windows NT version 4.0.

MORE INFORMATION
================

A fix was made to the Oleaut32.dll file to add additional thread synchronization
so that the ref counter is protected when it is under stress.
======================================================================
Keywords          :  
Technology        : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 kbiisSearch kbiis400 kbiis300
Version           : WINNT:3.0,4.0
Issue type        : kbbug
Solution Type     : kbfix

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