Q195998: SNA Server Fails With Access Violation in Routine s1pxsnd()
Article: Q195998
Product(s): Microsoft SNA Server
Version(s): WINDOWS:3.0,3.0SP1,3.0SP2,3.0SP3,4.0,4.0SP1
Operating System(s):
Keyword(s):
Last Modified: 20-MAY-2002
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The information in this article applies to:
- Microsoft SNA Server, versions 3.0, 3.0 SP1, 3.0 SP2, 3.0 SP3, 4.0, 4.0 SP1
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SYMPTOMS
========
The SNA Server service may fail with an access violation after receiving a badly
formatted message from the SNA client APPC DLL (Wappc32.dll). This may occur if
the client application issues both [MC_]ALLOCATE and RECEIVE_ALLOCATE from the
same process.
If Drwtsn32.exe is configured as the default debugger on the SNA Server system,
the Drwtsn32.log file may contain an entry similar to the following when this
access violation occurs:
Application exception occurred:
App: <path>snaservr.exe (pid=<process ID #>)
When: <date> @ <time>
Exception number: c0000005 (access violation)
[...]
State Dump for Thread Id 0xd3
eax=012d007e ebx=012d036e ecx=012d5405 edx=017d88b8 esi=017d1451
edi=017d89bd
eip=003edcf6 esp=0118ff3c ebp=00000000 iopl=0
nv up ei pl nz na po cy
cs=001b ss=0023 ds=0023 es=0023 fs=0038 gs=0000 efl=00000207
function: s1pxsnd
003edcd9 b101 mov cl,0x1
003edcdb 8b5004 mov edx,[eax+0x4]
003edcde 668b5a06 mov bx,[edx+0x6]
003edce2 8bea mov ebp,edx
003edce4 662b5d04 sub bx,[ebp+0x4]
003edce8 6643 inc bx
003edcea 663b5c2412 cmp bx,[esp+0x12]
003edcef 7d19 jge s1pxsnd+0xa8a
003edcf1 8b6d00 mov ebp,[ebp]
003edcf4 fec1 inc cl
FAULT ->003edcf6 668b4506 mov ax,[ebp+0x6]
003edcfa 662b4504 sub ax,[ebp+0x4]
*----> Stack Back Trace <----*
FramePtr ReturnAd Param#1 Param#2 Param#3 Param#4 Function Name
00000000 00000000 00000000 00000000 00000000 00000000 snaservr!s1pxsnd
In addition, the Windows NT Application Event Log may contain the following event
which coincides with the same failure time as indicated in the drwtsn32.log
entry.
Event ID: 624
Source: SNA Server
Description: Creating dump file <snaroot>\snadump.log for Snaservr.exe
CAUSE
=====
In a rare condition, the SNA Windows NT or Windows 95/98 client APPC DLL
(Wappc32.dll) may send a badly formatted message to the SNA Server if the client
application issues both [MC_]ALLOCATE and RECEIVE_ALLOCATE from the same
process. The SNA Server fails with an access violation when receiving this badly
formatted message.
RESOLUTION
==========
SNA Server 3.0
--------------
A supported fix that corrects this problem is now available from Microsoft, but
has not been fully regression-tested and should be applied only to systems
experiencing this specific problem. If you are not severely affected by this
specific problem, Microsoft recommends that you wait for the next Microsoft SNA
Server version 3.0 service pack that contains this fix.
To resolve this problem immediately, contact Microsoft Product Support Services
to obtain the fix. The updated Wappc32.dll must be applied to all SNA Server
client computers that access the SNA Server.
For a complete list of Microsoft Product Support Services phone numbers and
information on support costs, please go to the following address on the World
Wide Web:
http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS
The English version of this fix should have the following file attributes or
later:
File Name Date Time
----------------------------------
Wappc32.dll
NOTE: The Date and Time information for the above file will be provided in this
article as soon as it becomes available.
NOTE: Due to file dependencies, the most recent fix that contains the above files
may also contain additional files.
SNA Server 4.0
--------------
This problem was corrected in the latest SNA Server version 4.0 U.S. Service
Pack. For information on obtaining this Service Pack, query on the following
word in the Microsoft Knowledge Base (without the spaces):
S E R V P A C K
STATUS
======
Microsoft has confirmed this to be a problem in SNA Server versions 3.0, 3.0
Service Pack 1, 3.0 Service Pack 2, 3.0 Service Pack 3, 4.0, and 4.0 Service
Pack 1.
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Keywords :
Technology : kbAudDeveloper kbSNAServSearch kbSNAServ300 kbSNAServ400 kbSNAServ300SP3 kbSNAServ300SP1 kbSNAServ400SP1 kbSNAServ300SP2
Version : WINDOWS:3.0,3.0SP1,3.0SP2,3.0SP3,4.0,4.0SP1
Issue type : kbbug
Solution Type : kbfix
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