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PM93389: TIGHT LOOP IN DFHMRXM AFTER ABEND IN DFHSMGF

A fix is available

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APAR status

  • Closed as program error.

Error description

  • CICS joblog(s) shows abends occurred as follows:
    
    DFHSM0001 AN ABEND (CODE 0C4/AKEA) HAS OCCURRED AT OFFSET
              X'09F0' IN MODULE DFHSMGF.
    DFHAP0002 A SEVERE ERROR (CODE X'0595') HAS OCCURRED IN MODULE
              DFHAPXM.
    DFHAP0001 AN ABEND (CODE 0C4/AKEA) HAS OCCURRED AT OFFSET
              X'01C0' IN MODULE DFHMRXM
    DFHAP0001 AN ABEND (CODE 0C4/AKEA) HAS OCCURRED AT OFFSET
              X'029A' IN MODULE DFHMRXM.
    .
    The last DFHAP0001 is repeated until the region is terminated.
    .
    A user transid is being attached. The SM0001 and AP0002 are
    related to a getmain for the task's TCA. The program check 0C4
    in DFHSMGF causes the getmain to fail so we do NOT have a TCA
    for this task. The KE stack shows an abend in DFHDSKE, the stack
    is corrupt. A Segentry forward pointer has been overlayed (the
    cause is unknown). DFHMRXM is entered to perform recovery.
    When entering DFHMRXM it assumes that the TASENTRY has a valid
    TCA at offset 0028. However, this isn't the case, because of the
    abend in DFHSMGF, there is no TCA. RegC is loaded from the
    TASENTRY with 00000000. causing an abend 0C4 at offset x'1C0'.
    .
    The recovery routine in DFHMRXM (RECOVERY_ROUTINE), issues the
    message but then returns to the mainline code at MRXM_RETURN
    where it uses RegC, again, assuming it contains the TCA.
    It now abends at offset X'029A'.
    We drive the recovery routine in DFHMRXM (RECOVERY_ROUTINE)
    and a tight loop occurs around the abend and its recovery.
    

Local fix

  • Prevent abend SM0001
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All.                                         *
    ****************************************************************
    * PROBLEM DESCRIPTION: Recursive abend in DFHMRXM causes CICS  *
    *                      to crash.                               *
    ****************************************************************
    * RECOMMENDATION:                                            . *
    ****************************************************************
    In the reported problem, 2 CICS systems ( SYSA and SYSB ) were
    connected via IRC.  The transaction routing program ( DFHRTE )
    was activated by CRTE on SYSA so a transaction entered on SYSA
    was routed to SYSB.  When SYSB received the request, DFHAPXM
    was driven for transaction attach and in doing so, attempted
    to GETMAIN a TCA.  The GETMAIN failed but a codepath exists
    whereby processing continued and DFHMRXM was driven to notify
    the primary client that the transaction would wait forever.
    DFHMRXM abended ( because of no TCA ) and its recovery routine
    was driven. Control returned to DFHMRXM mainline logic where
    the abend sequence was repeated. SYSB was in a recursive abend
    situation.
    

Problem conclusion

  • DFHXMTA has been modified to not call DFHMRXM in the
    aforementioned scenario.
    

Temporary fix

  •             *********
                * HIPER *
                *********
    FIX AVAILABLE BY PTF ONLY
    

Comments

APAR Information

  • APAR number

    PM93389

  • Reported component name

    CICS TS Z/OS V4

  • Reported component ID

    5655S9700

  • Reported release

    600

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-07-19

  • Closed date

    2013-09-09

  • Last modified date

    2013-10-03

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

    PM86992

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

    PM93391 UK97501 UK97502

Modules/Macros

  •    DFHXMTA
    

Fix information

  • Fixed component name

    CICS TS Z/OS V4

  • Fixed component ID

    5655S9700

Applicable component levels

  • R600 PSY UK97501

       UP13/09/21 P F309

  • R700 PSY UK97502

       UP13/09/21 P F309

Fix is available

  • Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.

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Document Information

Modified date:
03 October 2013