DOCUMENT:Q292041  20-MAY-2002  [winnt]
TITLE   :Heap Coruption in Windows NT RPCSS Service with DCOM Calls
PRODUCT :Microsoft Windows NT
PROD/VER::4.0,4.0 SP6a
OPER/SYS:
KEYWORDS:kbWinNT400PreSP7Fix

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The information in this article applies to:

 - Microsoft Windows NT Server versions 4.0, 4.0 SP6a 
 - Microsoft Windows NT Server, Enterprise Edition versions 4.0, 4.0 SP6a 
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SYMPTOMS
========

Rpcss.exe may generate an access violation (C0000005) in the RtlAllocateHeap
function when activating or deactivating an ATL DCOM EXE server.

CAUSE
=====

This problem can occur when the DCOM garbage collector frees some heap memory
that is allocated for the static endpoint structure at a wrong address. This
corrupts the heap free list for the process.

RESOLUTION
==========

A supported fix is now available from Microsoft, but it is only intended to
correct the problem described in this article and should be applied only to
systems experiencing this specific problem.

To resolve this problem, 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

NOTE: In special cases, charges that are normally incurred for support calls may
be canceled, if a Microsoft Support Professional determines that a specific
update will resolve your problem. Normal support costs will apply to additional
support questions and issues that do not qualify for the specific update in
question.

The English version of this fix should have the following file attributes or
later:

   File name
   ---------
   Ole32.dll
   Rpcss.exe



WORKAROUND
==========

To work around this problem, use any of the following methods:

 - The heap corruption does not occur if you use dynamic endpoints in the DCOM
   configuration.

 - Maintain DCOM alive by using a client connection. This avoids the DCOM
   garbage collector cleanup.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products that are
listed at the beginning of this article.



Additional query words:

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Keywords          : kbWinNT400PreSP7Fix 
Technology        : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400 kbWinNTS400sp6 kbWinNTS400search kbWinNTS400 kbWinNTSEnt400SP6a
Version           : :4.0,4.0 SP6a
Hardware          : ALPHA x86
Issue type        : kbprb

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