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PM15519: DFHLD0001 AN ABEND (CODE 0C4/AKEX) HAS OCCURRED AT OFFSET X'0980' IN MODULE DFHLDLD1.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • You receive DFHLDLD1 abend (code 0C4/AKEX) has occurred at
    offset X'0980' in module DFHLDLD1. This was most likely caused
    by doing a mass Discard of all the DB2ENTRYs.
    You suffer an overlay of the APE (Active Program Element) block
    in CICS.
    What is bad about it is +X'18' ( APE_NEXT) is a value of
    x'00000000'. This results in the ABEBD0C4.
    Additional symptoms:   A word of storage is overlayed with
    binary zeroes . This overlayed word is at one of several
    offsets into a page of ECDSA storage.  The potential
    offsets are 0E8 1B0 278 340 408 4D0 598 660 728 7F0 8B8 980 A48
    B10 BD8 CA0 D68 E30 EF8 or FC0 .
    .
    This problem happens when a DB2ENTRY resource is discarded.
    When that happens, the DFHD2ENT control block representing
    the DB2ENTRY is freemained . At that time, the chain of
    CSUBs anchored in that DFHD2ENT at RCT_FREE_CONN_CHAIN
    (DFHD2ENT+X'B8' should be made to no longer point back to
    the just freed DFHD2ENT . But that sometimes does not
    happen.  Later, this page of storage that used to contain
    DFHD2ENTs can be used for a different control block.  And
    then later, a free CSUB (which points into the old
    page of DFHD2ENTs) can be picked up off the GLB_FREE_CONN_CHAIN
    at which point the unchain code will clear the word of
    storage at what used to be DFHD2ENT+X'B8'.  This can cause
    any type of ECDSA storage to get overlayed sometimes days
    after the discard of the DB2ENTRY.
    .
    The offset above are based on the offsets of the beginning of
    the DFHD2ENTs in a page of DFHD2ENTs +X'B8' which
    is RCT_FREE_CONN_CHAIN
    .
    zeros X'00000000'
    

Local fix

  • KIXREVRJL
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All.                                         *
    ****************************************************************
    * PROBLEM DESCRIPTION: Abend 0C4/AKEX in DFHLDLD1.             *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    This problem presented as an abend 0C4 in DFHLDLD1.
    Prior to the abend, a DISCARD of DB2ENTRYs had occurred which
    in turn caused the DB2ENTRY control blocks to be freed.
    
    As part of freeing the DB2ENTRY control blocks, DFHD2TM should
    have freed 2 CSUB chains anchored from the DB2ENTRY, the
    protected CSUB chain and the global free CSUB chain.
    However, DFHD2TM cleared the anchor pointer to the global free
    CSUB chain as part of freeing the CSUBs on the protected chain
    all as part of freeing the DB2ENTRY.
    
    As a consequence, CSUBs on the global free chain were available
    for reuse but containing invalid pointer references to storage
    that was once a DB2ENTRY but was now ( for example ) an LD_APE,
    thus causing the 0C4 when these invalid pointer references are
    used.
    
    Keywords: abend0C4 abendS0C4 S0C4 LD0001 msgDFHLD0001 DFHLD0001
    

Problem conclusion

  • DFHD2TM has been modified and will not orphan the CSUBs on
    the global free chain.
    

Temporary fix

  • FIX AVAILABLE BY PTF ONLY
    

Comments

APAR Information

  • APAR number

    PM15519

  • Reported component name

    CICSTS V3 Z/OS

  • Reported component ID

    5655M1500

  • Reported release

    500

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-05-28

  • Closed date

    2010-06-24

  • Last modified date

    2010-07-01

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

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

    PM16615 UK58263

Modules/Macros

  •    DESD2TM  DFHD2TM
    

Fix information

  • Fixed component name

    CICSTS V3 Z/OS

  • Fixed component ID

    5655M1500

Applicable component levels

  • R500 PSY UK58263

       UP10/07/01 P F006

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:
01 July 2010