Knowledge Base

Access Violation in SNA Host Account Cache (SNAUDB) Service

Article ID: 242876

Article Last Modified on 6/24/2004

APPLIES TO

Microsoft SNA Server 3.0 Service Pack 4
Microsoft SNA Server 4.0
Microsoft SNA Server 3.0 Service Pack 2
Microsoft SNA Server 3.0 Service Pack 3
Microsoft SNA Server 3.0 Service Pack 4
Microsoft SNA Server 4.0
Microsoft SNA Server 4.0 Service Pack 1
Microsoft SNA Server 4.0 Service Pack 2
Microsoft SNA Server 4.0 Service Pack 3

This article was previously published under Q242876

SYMPTOMS

The SNA Host Account Cache (Snaudb.exe) may stop unexpectedly. When this occurs, the following Host Security features may stop functioning until the service is restarted:

Single Sign-On (SSO)
Password Replication to/from a host (for example, Mainframe, AS/400) system

If Drwtsn32.exe is configured as the default debugger on the Windows NT Server running the SNA Host Account Cache service, a Drwtsn32.log file similar to the following is generated in the Windows NT system directory:

Application exception occurred:
App: exe\snaudb.dbg (pid=<process ID>)
When: <date> @ <time>
Exception number: c0000005 (access violation)

[data omitted]

function: SendRegisterMessage
6178c4e7 6a01 push 0x1
6178c4e9 6894a07961 push 0x6179a094
6178c4ee 68c2030000 push 0x3c2
6178c4f3 682ca27961 push 0x6179a22c
6178c4f8 ffd3 call ebx
6178c4fa 85c0 test eax,eax
6178c4fc 0f84cc000000 je SendRegisterMessage+0x38e (6178c5ce)
6178c502 a1d4ed7961 ds:6179edd4=00000000 mov eax,[g_pfnProcessRequest+0x14 (6179edd4)]
6178c507 8d542428 lea edx,[esp+0x28] ss:0239cc1f=????????
6178c50b 52 push edx
FAULT ->6178c50c 8b8800250000 mov ecx,[eax+0x2500] ds:00002500=????????
6178c512 51 push ecx
6178c513 6850a27961 push 0x6179a250
6178c518 56 push esi
6178c519 e8a25cffff call PreAsyncTrace (617821c0)
6178c51e 83c410 add esp,0x10
6178c521 e9a8000000 jmp SendRegisterMessage+0x38e (6178c5ce)
6178c526 8b15c4117861 ds:617811c4=6020fcdc mov edx,[_imp____dwEnabledTraces (617811c4)]
6178c52c f60202 test byte ptr [edx],0x2 ds:0138e244=53
6178c52f 7431 jz SendRegisterMessage+0x322 (6178c562)
6178c531 6a02 push 0x2
6178c533 6894a07961 push 0x6179a094

----> Stack Back Trace <----*

FramePtr ReturnAd Param#1 Param#2 Param#3 Param#4 Function Name
0138fc40 6178bca0 010ec3f0 0110665c 602012a0 00000102 snarpc!SendRegisterMessage (FPO: [EBP 0x602012a0] [2,1670,4])
0138fe64 6178b9c4 010ec3f0 00000000 00230000 002416f0 snarpc!RegisterServer (FPO: [EBP 0x602012a0] [2,130,4])

In addition, an event similar to the following is logged in the Windows NT application event log when the Access Violation error occurs:

Event ID: 4097
Source: DrWatson
Description: The application, exe\snaudb.dbg, generated an application error. The error occurred on <date> @ <time>. The exception generated was c0000005 at address 6178c50c (SendRegisterMessage).

CAUSE

The Access Violation error occurs if a Host Security component (for example, the Backup Host Account Cache service, SNA WinNT Account Synchronization service, and so on) attempts to register with the Master (or Primary) SNA Host Account database immediately after the component un-registers itself with the Master Host Account database.

RESOLUTION

To resolve this problem, obtain the latest service pack for SNA Server 4.0. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

215838 How to Obtain the Latest SNA Server Version 4.0 Service Pack

STATUS

Microsoft has confirmed that this is a problem in Microsoft SNA Server versions 3.0, 3.0 SP1, 3.0 SP2, 3.0 SP3, 3.0 SP4, 4.0, 4.0 SP1, 4.0 SP2, 4.0 SP3.

This problem was first corrected in SNA Server 4.0 Service Pack 4.

MORE INFORMATION

This fix corrects the timing window that can cause the Access Violation error to occur when a Host Security component tries to register itself with the Master Database (MDB) immediately after it un-registers itself.

The following is an excerpt from a SNA Host Account Cache internal message trace (Udbmsg1.atf) that captures a UDI_REGISTER message that immediately follows a UDI_UNREGISTER message from a backup SNA Host Account Cache Database:

MSG_OUTGOING to ServerType: MDB, Address: 0x27e4b0
Message Type: UDI_UNREGISTER. Sequence Number: 0
Request: Number of UnRegistration Vectors: 1, Status: 0
RegistrationVector #0: DomainName: USPASS, ResourceType: SDB, Address: USFLPK1DEVPD05
____________________________________________________________
MSG_OUTGOING to ServerType: MDB, Address: 0x27ed50
Message Type: UDI_REGISTER. Sequence Number: 0
Request: Number of Registration Vectors: 1, Status: 0
RegistrationVector #0: DomainName: USPASS, ResourceType: SDB, Address: USFLPK1DEVPD05
MSG_OUTGOING to ServerType: MDB - Error: ErrorCode: 1722
MSG_OUTGOING to ServerType: MDB - Error: ErrorCode: 1722
___________________________________________________________

The ResourceType of Secondary Database (SDB) correlates to a Backup SNA Host Account Cache service.

The timestamps in the trace file show that these messages were received at approximately the same time.

Keywords: kbbug kbfix kbsna400presp4fix kbqfe kbsna400sp4fix KB242876

Microsoft KB Archive/242876

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