SNA 3.0 SP2 Hang or Access Violation in SNA Server or SnaBase

 Last reviewed: February 3, 1998
Article ID: Q175271
The information in this article applies to:
  • Microsoft SNA Server, version 3.0 Service Pack 2

SYMPTOMS

After you upgrade to Microsoft SNA Server 3.0 Service Pack 2, one of the following symptoms may occur while the server is running:

- Users who have active sessions may find their computer suddenly hangs or 

   stops responding (3270 users may receive perpetual XCLOCK), and new user
   connection attempts to either the SnaBase or SNA Server service may
   fail.
- The SnaBase or SNA Server service may terminate unexpectedly with the 
  following error messages:
Windows NT application event log error: 

   Event: 624
   Source: SNA Server  (or SnaBase)
   Description: Creating dump file C:\SNA\traces\snadump.log for
   Snaservr.exe [or snabase.exe]
Also, an <Ntroot>\Drwtsn32.log entry may be created, indicating the following failure: 

  Application exception occurred:
     App: snaservr.DBG (pid=<process ID>)
     When: <date and time>
     Exception number: c0000005 (access violation)

  The fault entry indicated in routine ntdll!RtlAllocateHeap, or
  ntdll!RtlDestroyHeap.

CAUSE

In SNA Server 3.0 Service Pack 2, client logon requests are now handled from multiple threads within the SnaBase or SNA Server service. If two concurrent client logon requests occur that both use the LSA authentication method (that is, Windows 3.x clients, or Windows NT services that run under the local system account), the SnaBase or SNA Server memory heap may become corrupted. This occurs because LSA logon is not thread-safe, so two concurrent LSA logon requests from the same process can result in memory corruption.

STATUS

Microsoft has confirmed this to be a problem in SNA Server version 3.0 Service Pack 2. A supported fix is now available, but has not been fully regression tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information. 

Keywords          : prodsna snabaseservice snaserverservice kbbug3.00.sp2
Version           : WINDOWS:3.0SP2
Platform          : WINDOWS
Issue type        : kbbug
Solution Type     : kbfix kbpatch

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

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.

Last reviewed: February 3, 1998
© 1998 Microsoft Corporation. All rights reserved. Terms of Use.