DOCUMENT:Q150795  13-JUN-2001  [sna]
TITLE   :SNA Server Exception 0xC0000194 (Possible Deadlock)
PRODUCT :Microsoft SNA Server
PROD/VER:WINDOWS:2.11
OPER/SYS:
KEYWORDS:

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft SNA Server, version 2.11, on platform(s):
    - the operating system: Microsoft Windows NT 
-------------------------------------------------------------------------------


SYMPTOMS
========

After ending a user-written SNA Server application that submitted three
concurrent TRANSFER_MS_DATA calls to submit an alert to NetView, the SNA Server
will fail with Event 624. You will get the following Drwtsn32.log exception
error:

   Application exception occurred:
   App: snaservr.DBG (pid=223)
   Exception number: c0000194 (possible deadlock)

CAUSE
=====

Under certain conditions, the application shutdown was causing an internal SNA
Server buffer pool mutex to be left in a signaled state, causing the SNA Server
to wait indefinitely for the mutex to be released.


RESOLUTION
==========


To avoid this deadlock, the internal buffer pool mutex time-out interval is now
configurable, with the default still set to infinite. Instead of waiting forever
for the pool event to be signaled, the code now retries to lock the pool mutex
each time the time-out expires.

WARNING: Using Registry Editor incorrectly can cause serious, system-wide
problems that may require you to reinstall Windows NT to correct them. Microsoft
cannot guarantee that any problems resulting from the use of Registry Editor can
be solved. Use this tool at your own risk.

An updated Snadmod.dll now supports a configurable time-out setting using the
following new registry parameter:

    HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/SnaBase
          /Parameters/ 

    PoolMutexTimeout:REG_DWORD:<time-out in milliseconds>

Valid values are 100ms through 0xFFFFFFF (infinite). 1000ms is the recommended
setting if this problem is being encountered.

STATUS
======

Microsoft has confirmed this to be a problem in SNA Server version 2.11. This
problem was corrected in the latest SNA Server for Windows NT version 2.11 U.S.
Service Pack. For information on obtaining this update, query on the following
word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K


Additional query words:

======================================================================
Keywords          :  
Technology        : kbAudDeveloper kbSNAServSearch
Version           : WINDOWS:2.11
Issue type        : kbbug
Solution Type     : kbfix

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2001.