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Q240955: Multithreaded Program May Wait Forever on WaitForMultipleObjects

Article: Q240955
Product(s): Microsoft Windows NT
Version(s): winnt:4.0 SP4,4.0 SP5,4.0 SP6
Operating System(s): 
Keyword(s): kbWinNT400PreSP7Fix
Last Modified: 08-MAY-2002

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The information in this article applies to:

- Microsoft Windows NT Server versions 4.0 SP4, 4.0 SP5, 4.0 SP6 
- Microsoft Windows NT Workstation versions 4.0 SP4, 4.0 SP5, 4.0 SP6 
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SYMPTOMS
========

Any multithreaded program may wait forever on a WaitForMultipleObjects call when
waiting on multiple mutexes. This behavior occurs when the thread making the API
call is already holding one on the mutexes.

For example, assume a program with two threads and two mutexes. Thread A owns
mutex 1 and thread B owns mutex 2. If thread A calls WaitForMultipleObjects on
both mutex 1 and mutex 2 with bWaitAll=TRUE, the call waits for mutex 2 to be
released by thread B. However, the call never returns, even after thread B
releases mutex 2.

CAUSE
=====

This behavior occurs because the Windows NT kernel is not handling the
WaitForMultipleObjects call correctly for multiple mutexes.

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-language version of this fix should have the following file
attributes or later:

 Date       Time                 Size      File name     Platform
 ----------------------------------------------------------------
 09/01/99   06:11 PM             931,584   Ntoskrnl.exe  Intel
 09/01/99   06:13 PM             951,680   Ntkrnlmp.exe  Intel

 09/01/99   06:10 PM             1,381,824 Ntoskrnl.exe  Alpha
 09/01/99   06:10 PM             1,410,112 Ntkrnlmp.exe  Alpha



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:

======================================================================
Keywords          : kbWinNT400PreSP7Fix 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400search kbWinNT400search kbWinNTW400sp5 kbWinNTW400sp4 kbWinNTSsearch kbWinNTS400sp6 kbWinNTS400sp5 kbWinNTS400sp4 kbWinNTS400search kbWinNTW400sp6
Version           : winnt:4.0 SP4,4.0 SP5,4.0 SP6
Hardware          : ALPHA x86
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

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