SNA 4.0 SP2 May Cause Trap in Function RamWrite or CheckInboundQ[sna]
ID: Q225108    CREATED: 02-APR-1999   MODIFIED: 08-APR-1999
WINDOWS:4.0SP2
WINDOWS
PUBLIC | kbfaq

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft SNA Server, version 4.0SP2 
-------------------------------------------------------------------------------

SYMPTOMS
========

An application exception (trap) may occur at some point after installing Service
Pack 2 for SNA Server 4.0. The function reporting the problem has been seen in
either function RamWrite or function CheckInboundQ.

If you have Dr. Watson (Drwtsn32.exe) configured as the default debugger, a
Drwtsn32.log file will be created in the [NTROOT] directory.

In addition to the Dr. Watson, a Snadump.log file will be created in the
[SNAROOT\traces] directory. Both an event 4097 and 624 will get created in the
application log of the Event Viewer with this occurs.

Drwtsn32.log example showing an exception in function RamWrite:

Application exception occurred:
        App: exe\snalink.dbg (pid=pid #)
        When: 3/16/1999 @ 14:45:28.559
        Exception number: c0000005 (access violation)
[..]
[..]
State Dump for Thread Id [Thread Id]

eax=85a3a2a8 ebx=6726acf0 ecx=b2c0b7e8 edx=00000001 esi=9706fb1c edi=00000002
eip=6722d085 esp=00bcfcbc ebp=00bcfcdc iopl=0         nv up ei pl zr na po nc
cs=001b  ss=0023  ds=0023  es=0023  fs=0038  gs=0000             efl=00000246

function: RamWrite
        6722d062 895004           mov     [eax+0x4],edx          ds:86ca8cae=8b045089
        6722d065 8b0b             mov     ecx,[ebx]              ds:6726acf0=01010054
        6722d067 8b35c8ac2667     mov     esi,[BmD (6726acc8)]   ds:6726acc8=01010000
        6722d06d 8b4128           mov     eax,[ecx+0x28]         ds:b3e7a1ee=3328418b
        6722d070 33c9             xor     ecx,ecx
        6722d072 894df8           mov     [ebp-0x8],ecx          ss:01e3e6e2=????????
        6722d075 894d10           mov     [ebp+0x10],ecx         ss:01e3e6e2=????????
        6722d078 8d0cc0           lea     ecx,[eax+eax*8]        ds:85a3a2a8=????????
        6722d07b 8945f4           mov     [ebp-0xc],eax          ss:01e3e6e2=????????
        6722d07e 8db4cedc3b0000   lea     esi,[esi+ecx*8+0x3bdc] ds:b2c0f3c4=????????
FAULT ->6722d085 395610           cmp     [esi+0x10],edx         ds:982de522=????????

DRWTSN32.LOG example showing an exception in function CheckInboundQ:

Application exception occurred:
        App: exe\mngagent.dbg (pid=pid #)
        When: 11/3/1998 @ 7:28:50.734
        Exception number: c0000005 (access violation)
[..]
[..]
State Dump for Thread Id [Thread Id]

eax=00000000 ebx=00000000 ecx=033fffb0 edx=033fffa8 esi=77f1c67a edi=77f674e0
eip=67226860 esp=033fff5c ebp=033fff64 iopl=0         nv up ei pl zr na po nc
cs=001b  ss=0023  ds=0023  es=0023  fs=0038  gs=0000             efl=00000246

function: CheckInboundQ
        67226850 55               push    ebp
        67226851 8bec             mov     ebp,esp
        67226853 51               push    ecx
        67226854 a1d85c2667       mov  eax,[BmD+0x10 (67265cd8)] ds:67265cd8=00000000
        67226859 56               push    esi
        6722685a 8945fc           mov     [ebp-0x4],eax          ss:0460e96a=????????
        6722685d 8b45fc           mov     eax,[ebp-0x4]          ss:0460e96a=????????
FAULT ->67226860 f0ff00           lock    inc dword ptr [eax]    ds:00000000=????????

NOTE: For this particular problem, the access violations can appear in a number
of different SNA components (for example, Snaservr.exe, Snabase.exe,
Snalink.exe, Snaprint.exe, and so on). This will be indicated by the Pid # in
the Drwtsn32.log file.

CAUSE
=====

This problem was due to a regression in the Snadmod.dll introduced in Service
Pack 2.

RESOLUTION
==========

A supported fix that corrects this problem is now available from Microsoft, but
it 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 4.0 service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services
to obtain the fix. 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/support/supportnet/default.asp

The English version of this fix should have the following file attributes or
later:

+--------------------------------+
| File name   | Date     | Time  | 
+--------------------------------+
| Snadmod.dll | 03/31/99 | 11:01 | 
+--------------------------------+

NOTE: Because of file dependencies, the most recent fix that contains the above
files may also contain additional files.


STATUS
======

Microsoft has confirmed this to be a problem in SNA Server 4.0 SP2.