Client RPC Call for Remote APPC LU List Causes SNABASE Error

Last reviewed: February 1, 1996
Article ID: Q137382

The information in this article applies to:

Microsoft SNA Server for Windows NT, Versions 2.1 and 2.11

SYMPTOMS

SNA Server generates a Dr. Watson error in SNABASE.EXE when a client does a RPC call to get a list of Remote APPC LUs which are paired with a Local APPC LU. The SNA Server logs an Event ID 624 in the Windows NT Application Log (as shown in the Event Viewer) indicating that a SNADUMP.LOG was created for SNABASE.EXE. The error also generates a DRWTSN32.LOG when it occurs. The following is an excerpt from a DRWTSN32.LOG that was created following one of the SNABASE errors:

   Application exception occurred:
   App: C:\SNA\system\snabase.exe (pid=139)
   When: 8/7/1995 @ 10:38:21.884
   Exception number: c0000005 (access violation)

Your DRWTSN32.LOG file will appear somewhat different than this example.

NOTE: If using Windows NT Server 3.5, you will have to load the Windows NT Symbols to get a proper Dr. Watson log when using SNA Server.

After the SNABASE error occurs, the SNA Server stops accepting sessions from SNA Server clients until the SNA Server is shutdown and restarted.

CAUSE

This error is caused when SNA Server tries to copy (read) a larger range of memory than is in a memory buffer. This happens when a client makes an RPC call to get the list of Remote APPC LUs partnered with a particular Local APPC LU and the number of Remote APPC LUs exceed the size of the client's buffer. The error only occurs if the memory buffer is located at the end of a 4K page and the extra memory that SNA Server attempts to read is located on the next uncommitted page. The buffer size is usually less than one hundred bytes so the probability of this error is quite small.

RESOLUTION

Microsoft has modified the files, SNABASE.EXE and SNADMOD.DLL, to correct this problem.

STATUS

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

   S E R V P A C K

KBCategory: kbnetwork kbbug2.10 kbbug2.11
KBSubcategory: ntnetserv
Additional reference words: 2.10 2.11 prodsna DRWTSN32.LOG SNADUMP.LOG trap

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Last reviewed: February 1, 1996
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