SNA 3.0 Service Pack 2 Hang or Access Violation in SNA Server or SnaBase
Article ID: 175271
Article Last Modified on 9/22/2005
APPLIES TO
- Microsoft SNA Server 3.0 Service Pack 2
This article was previously published under Q175271
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.
This problem was corrected in the latest SNA Server version 3.0 U.S.
Service Pack. For information on obtaining this Service Pack, query on
the following word in the Microsoft Knowledge Base (without the spaces):
Keywords: kbbug kbfix kbqfe kbhotfixserver KB175271