DOCUMENT:Q172913  22-OCT-2000  [sna]
TITLE   :Server Stops with STOP 0xA in Ibmsync.sys Driver Under Stress
PRODUCT :Microsoft SNA Server
PROD/VER:WINDOWS:2.11,2.11 SP1,2.11 SP2,3.0,3.0 SP1
OPER/SYS:
KEYWORDS:kbnetwork

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

 - Microsoft SNA Server, versions 2.11, 2.11 SP1, 2.11 SP2, 3.0, 3.0 SP1, on platform(s):
    - the operating system: Microsoft Windows NT 
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SYMPTOMS
========

While transferring large amounts of data over the IBM SDLC or IBM X.25 link
service provided with SNA Server, the Windows NT computer may fail with the
following STOP message:

   STOP 0x000A (driver = IBMSYNC.SYS)

This problem was found while testing back-to-back SDLC communications between two
SNA Server computers, each with an IBM SDLC adapter. The SDLC connection was
supporting seven concurrent AFTP conversations where each conversation was
performing continuous "Get" and "Put" file copies across the SDLC link. After
30-45 minutes of operation, the STOP screen was observed.

The contents of the dump file are in the More Information section of this
article.

CAUSE
=====

The problem occurs because the Ibmsync.sys driver runs out of control blocks to
queue up events for a deferred procedure call (DPC). The IBMSYNC driver
allocates a queue size of 20 when it initializes. If all the entries in this
queue are filled up, an access violation occurs in Ibmsync.sys.


RESOLUTION
==========

The Ibmsync.sys DPC queue size has been increased to 100. Since the queue
element size is 16 bytes, this change causes IBMSYNC to reserve an extra 1280
bytes during initialization.

STATUS
======

Microsoft has confirmed this to be a problem in SNA Server version 2.11 (SP1 and
SP2) and 3.0 (including SP1). 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):

   S E R V P A C K


MORE INFORMATION
================

The following is an excerpt from the Windows NT crash dump file when this
problem occurred:

Bugcheck 0000000a : 0000000c 00000018 00000001 fcae3cf0

kd> kv
kv
ChildEBP RetAddr  Args to Child
fee54bb4 fcae3cf0 439cfc80 522aa6e6 fcae1774 NT!_KiTrap0E+0x252 (FPO: [0,0]
TrapFrame @ fee54bb4)
fee54c28 fcae15bc ffb604b8 fee54c5c ffb4f008
IBMSYNC!_SyncPutDPCQueueTail+0x50 (FPO: [1,0,1])
fee54c44 8013c76a ffb4f008 ffb60400 fcae1702 IBMSYNC!_EntryPointISR+0x2ac
(FPO: [EBP 0xfee54c5c] [2,
1,4])
fee54c44 8040445b ffb4f008 ffb60400 fcae1702 NT!_KiInterruptDispatch+0x2a
(FPO: [0,2] TrapFrame @ fe
e54c5c)
fee54ccc 80404310 00000286 8013c65c ffb604b8
hal!HalpHardwareInterrupt03+0x2 (FPO: [0,0,0])
fee54cd4 8013c65c ffb604b8 00000010 ff104902 hal!KfLowerIrql+0x44 (FPO:
[1,1,0])
fee54ce8 fcae315d ffb4f008 fcae3160 ffb604b8
NT!_KeSynchronizeExecution+0x2c
fee54cf8 fcae301c ffb604b8 ffb60624 ffb604b8 IBMSYNC!_Write8273Cmd+0x1d
(FPO: [2,0,0])
fee54d10 fcae313a ffb604b8 ffb604e4 ffb604b8
IBMSYNC!_TxFSMActionXmitNext+0xfc (FPO: [1,0,3])
fee54d24 fcae2de0 ffb604b8 00000000 ffb604b8 IBMSYNC!_TxFSMEvent+0x7a (FPO:
[2,0,3])
fee54d38 fcae313a ffb604b8 ffb4f008 ffb604b8 IBMSYNC!_TxFSMActionEndOK+0x90
(FPO: [1,0,2])
fee54d4c fcae308e ffb604b8 00000001 ffb604b8 IBMSYNC!_TxFSMEvent+0x7a (FPO:
[2,0,3])
fee54d64 fcae0e3c ffb604b8 00000001 00000001
IBMSYNC!_ProtectedTxFSMEvent+0x5e (FPO: [3,1,2])
fee54d78 80137ee3 ffb60474 ffb60400 00000000 IBMSYNC!_DPCRoutine+0xcc (FPO:
[4,0,1])
fee54dac 8010c8ac fee54e00 fc8f218c fc8f0658 NT!KiRetireDpcList+0x31 (FPO:
[0,4,0])
fee54dc4 fc8f6072 ffb5f2c8 0017be78 ff107b9c
NT!_ExpAcquireResourceSharedLite+0xce (FPO: [EBP 0xfee5
4e00] [2,1,4])
fee54e00 00000000 801168d4 00000008 00000293 Npfs!_NpFsdRead+0x62

kd> !trap fee54bb4
!trap fee54bb4
eax=00000000 ebx=ffb604b8 ecx=ffb5ff68 edx=00000388 esi=ffb604b8
edi=00000005
eip=fcae3cf0 esp=fee54c28 ebp=ffb5ff58 iopl=0         nv up ei ng nz na pe
nc
cs=0008  ss=0010  ds=0023  es=0023  fs=0030  gs=0000
efl=00010282
ErrCode = 00000002
fcae3cf0 c7400c00000000   mov     dword ptr [eax+0xc],0x0

kd> u IBMSYNC!_SyncPutDPCQueueTail+0x50
u IBMSYNC!_SyncPutDPCQueueTail+0x50
IBMSYNC!_SyncPutDPCQueueTail+0x50:
fcae3cf0 c7400c00000000   mov     dword ptr [eax+0xc],0x0

Additional query words:

======================================================================
Keywords          : kbnetwork 
Technology        : kbAudDeveloper kbSNAServSearch
Version           : WINDOWS:2.11,2.11 SP1,2.11 SP2,3.0,3.0 SP1
Issue type        : kbbug
Solution Type     : kbfix

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

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