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OA24775: IKTXINIT LOOP ISSUING RECEIVE DURING LOGON TO TSO

A fix is available

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APAR status

  • Closed as program error.

Error description

  • During logon IKTXINIT sends a query to the device that is
    logging on.  The loop occurs when the query reply returns with
    too much data.  IKTXINIT has a fixed size for the QUERY reply
    data.  When the length of data to be received exceeds that fixed
    size, then IKTXINIT loops repeating its RECEIVE SPECIFIC at
    offset x'1286'.  In this case IKTXINIT was V1R9 base.
    While the LU is sending in the too large query reply, IKTXINIT
    should not loop.  The APAR is taken to correct the loop.
    IKTXINIT initiates the loop by issuing the RECEIVE.  Other
    modules are in the loop, processing the RECEIVE.  System
    trace shows the following repeating sequence.
    ----------------------------------------------------------------
    DSP      070C0000 80C96400 00000000 00000001 00006C68 00000000
    >>> Address 80C96400 is in ISTAICI2+1A18 (label cckriuwt).
    SVC    1 070C0000 80C96400 00000000 00000001 00006C68 Wait
    SVCR   1 070C0000 80C96400 809FFF98 00000001 00006C68
    SRB      070C0000 A8E75150 FFFF00BD 22D7B44C 22D7B390       00
                               009FFB00 00
    >>> Address A8E75150 is the entry of ISTAPCAD (VTAM dispatcher).
    SSRV 129          A8E74558 00006C68 00000000 00000000 Post
                               00000000
    >>> Address A8E74558 is in ISTAICPT+11B8 (after 05EF to POST).
    ----------------------------------------------------------------
    The looping address space has name "unknown".
    The VTAM internal trace will show the repeating sequence of
    entries:
             REQS, REQS, AI1, AI2, QUE TSIR, RELS, REQS,
             DSP TSIR, UP, RELS, VPST ISTAICPT, EXIT TSIR
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All TSO users.                               *
    ****************************************************************
    * PROBLEM DESCRIPTION: IKTXINIT loop issuing RECEIVE macro     *
    *                      to receive the query data during the    *
    *                      logon to TSO.                           *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    This problem is described as follows:
      1. User tried to logon to TSO.
      2. IKTXINIT received control to process the logon.
      3. It issued the SEND macro to get the query data from
         the terminal to determine the device characteristics.
      4. It issued the RECEIVE macro to receive the query data
         from the terminal.
      5. Terminal responded with the invalid very large query
         data information and its data length was higher than
         4096 bytes.
      6. IKTXINIT received 4096 bytes of data from the terminal.
      7. It issued RECEIVE macro again to receive the remaining
         data with the RPL length of zero bytes and invalid
         buffer address.
      8. VTAM returned to IKTXINIT with the zero bytes of data.
      9. IKTXINIT repeated the steps 7 and 8 forever. This caused
         the loop in IKTXINIT and VTAM.
    

Problem conclusion

  • IKTXINIT has been changed to receive the query data up to
    4096 bytes. If the query reply is longer than 4096 bytes,
    it will reject the logon with the new message IKT125I and
    issue an ABEND0AB RC 204 to end the user address space.
    IKTMSGS, IKTTVMSG and ISTVTMEU have been changed to add a
    new message IKT125I.
    -------------------------------------------------------------
    The request for the publication change has been submitted
    as follows:
       Title: z/OS Communications Server: IP and SNA Codes
       Release: z/OS V1R7 and higher.
       Document Number: SC31-8791-05
    
    In the Chapter 7 - VTAM abend codes, under the topic of
    Abend code 0AB:
    
    Add the register 15 return code 204 after the return code
    203 as follows:
      0204
          During a logon for the TSO application, TSO/VTAM issued
          a QUERY 3270 data stream to determine the characteristics
          of the terminal. The response to the query was more than
          4096 bytes.
    
    -------------------------------------------------------------
    The request for the publication change has been submitted
    as follows for another book:
       Title: z/OS Communications Server SNA Messages
       Release: z/OS V1R7 and higher.
       Document Number: SC31-8790-05
    
    In the Chapter 3 - IKT messages for TSO/VTAM network operators
    
    Add a new message IKT125I after IKT124I as follows:
    
    
    IKT125I TSO LOGON REJECTED: QUERY REPLY TOO LARGE - TERMINAL
            ID termid
    
    Explanation:
    During a logon for the TSO application, TSO/VTAM issued a QUERY
    3270 data stream to determine characteristics of the terminal.
    The response to the query was more than allowed 4096 bytes.
    
      termid is the LU name of the terminal.
    
    System Action:
    The user address space ends and ABEND0AB RC 204 is issued.
    System processing continues.
    
    Operator Response:
    Save the dump and system log for problem determination. Contact
    the System Programmer.
    
    System Programmer Response:
    If you can not determine the cause of the problem from the
    output provided or need additional assistance, contact the IBM
    software support center.
    
    Routing code: 1,8
    

Temporary fix

  • *********
    * HIPER *
    *********
    

Comments

APAR Information

  • APAR number

    OA24775

  • Reported component name

    VTAM V4 MVS/ESA

  • Reported component ID

    569511701

  • Reported release

    190

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2008-04-16

  • Closed date

    2008-05-09

  • Last modified date

    2008-06-03

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

    UA41007 UA41008 UA41009 UA41010

Modules/Macros

  • IKTMSGS  IKTTVMSG IKTXINIT ISTVTMEU
    

Publications Referenced
SC31879007SC31879107SC31879006SC31879106SC31879005
SC31879105SC31879008SC31879108  

Fix information

  • Fixed component name

    VTAM V4 MVS/ESA

  • Fixed component ID

    569511701

Applicable component levels

  • R1A0 PSY UA41007

       UP08/05/31 P F805 Ž

  • R170 PSY UA41008

       UP08/05/29 P F805 Ž

  • R180 PSY UA41009

       UP08/05/29 P F805 Ž

  • R190 PSY UA41010

       UP08/05/29 P F805 Ž

Fix is available

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Document Information

Modified date:
03 June 2008