SNA Link Access Violation in ibmx25!os_wtime

• Microsoft SNA Server, versions 3.0, 3.0SP1, and 3.0SP2

SYMPTOMS

The SNA Link Service (snalink.exe) may fail with an access violation in ibmx25!os_wtime when the X.25 link to the host is down for an extended period of time. Also, an Event ID 320 with an error code of 0xc0000023 (STATUS_BUFFER_TOO_SMALL) may be logged in the Windows NT Event Viewer Application log.

The failure may be recorded in the <ntroot>\DRWTSN32.LOG file as follows:

   Application exception occurred:
        App: exe\snalink.DBG (pid=120)
        When: 9/24/1997 @ 17:26:12.627
        Exception number: c0000005 (access violation)

   [...]

   State Dump for Thread Id 0x7f

   eax=00000000 ebx=00000000 ecx=00000000 edx=67274840 esi=00000000

   eip=007d75ab esp=0119ff4c ebp=000000ff iopl=0    nv up ei pl zr na po nc
   cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000

   function: os_wtime
           007d75a0 6a01             push    0x1
           007d75a2 e859fdffff       call    os_ftask (007d7300)
           007d75a7 8b4c2404         mov     ecx,[esp+0x4]

   FAULT ->007d75ab c70003000000     mov     dword ptr [eax],0x3

           007d75b1 894808           mov     [eax+0x8],ecx

           007d75b4 c20400           ret     0x4
           007d75b7 cc               int     3
           007d75b8 cc               int     3
           007d75b9 cc               int     3
           007d75ba cc               int     3
           007d75bb cc               int     3
           007d75bc cc               int     3
           007d75bd cc               int     3
           007d75be cc               int     3
           007d75bf cc               int     3

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

   FramePtr ReturnAd Param#1  Param#2  Param#3  Param#4  Function Name
   000000ff 00000000 00000000 00000000 00000000 00000000 ibmx25!os_wtime

   000000ff 00000000 00000000 00000000 00000000 00000000

CAUSE

The Event 320 error indicates that the device driver is unable to transmit a frame for the X.25 link service because its transmission buffers are full. The access violation occurs when the link service tries to recover

 after this error.

STATUS

Microsoft has confirmed this to be a problem in SNA Server versions 3.0, 3.0 Service Pack 1 (SP1), and 3.0 SP2. A supported fix is now available, but has not been fully regression tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information. The new file is