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PM72757: ABEND0C4 IN DFSAOSW0 DUE TO THE YTIB STORAGE HAS BEEN FREED

A fix is available

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APAR status

  • Closed as program error.

Error description

  • Abend 0C4 in DFSAOSW0 which was due to a YTIB that was released
    from storage. This issue is similiar to PM60750 problem. When
    RRS terminated on the BE, the FE went through Backout processing
    and the YTIB was freed which cause the ABEND0C4. PM60750
    attempted to close this hole, however, obviously there's still a
    timing window.
    

Local fix

  • N/A
    Additional symptom:
    AbendS0C4 DFSAOSW0 in AWAOSEND logic when
    OTMA CM1 transaction runs on BE IMS, replies
    to IOPCB, and also switches to another transaction,
    and then the other transaction is /DEQ'd or removed
    by OEM tool using /DEQ interface.
    The IOPCB response deleted the YTIB at FE IMS, so
    the AWAOSEND for DFS2322 may S0C4 if the YTIB storage
    has been freed.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All IMS V12 OTMA Shared Queues users with    *
    *                 CM1 and AOS='anything but N'.                *
    ****************************************************************
    * PROBLEM DESCRIPTION: ABEND0C4 in DFSAOSW0 attempting to      *
    *                      access YTIB storage that has been       *
    *                      released.                               *
    ****************************************************************
    * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
    ****************************************************************
    When an IMS backend (BE) system sends a DFS error message to an
    IMS frontend (FE) system, it passes the address of the FE YTIB
    in the AWE field AWAOTIBA. However, that address may no longer
    be valid if the FE systems frees the YTIB and releases the
    storage. This results in an potential ABEND0C4 abend in
    DFSAOSW0.
    
    Addition Keywords:
    
    MSGDFS2322I MSGDFS2224I MSGDFS3688I MSGDFS2193I MSGDFS2766I
    

Problem conclusion

  • GEN:
    KEYWORDS:
     SYSPLEXSQ
    
    *** END IMS KEYWORDS ***
    The code has been redesigned so that the BE AWE contains an
    OTMA flag, the TMEMBER and TPIPE name, and the YTIB token so
    that the FE can issue DFSYDST FUNC=FIND TYPE=YTIB to locate the
    YTIB, rather than rely on the address pased in AWAOTIBA. If the
    YTIB is found, the code will proceed as usual. If the YTIB is
    not found, the process will be aborted and the AWE freed.
    
    DFSAOSD was modified to add AOS_OTMA in AOS_FLAG2, and the
    length was increased to add 2 new fields, AOS_TMEMBER &
    AOS_TPIPE, at the end of the dsect.
    
    DFSYTIB & DFSYFD00 were modified to delete an obsolete bit in
    YTIB_FLAG2.
    
    DBFHSQS0, DFSAOSW0, DFSYLUS0, & DFSYSLM0 were modified to set
    AOS_OTMA, AOS_TMEMBER, AOS_TPIPE, & AOS_TIBTOK in the AOSHEAD
    for the AWAOSEND and AWAOSMSG AWE's.
    
    DFSAOSW0 was also modified to issue DFSYDST FUNC=FIND TYPE=YTIB
    if AOS_OTMA is set.
    
    DFSCIO50, DFSRLM10, DFSSLUM0, & DFS6LUS0 were recompiled due to
    the length change in DFSAOSD.
    
    DFSAOA00 & DFSAOAM2 were recompiled due to changes in DFSYTIB.
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PM72757

  • Reported component name

    IMS V12

  • Reported component ID

    5635A0300

  • Reported release

    202

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2012-09-12

  • Closed date

    2013-01-02

  • Last modified date

    2013-02-04

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

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

    PM78609 PM78610 UK90702

Modules/Macros

  •    DBFHSQS0 DFSAOAM2 DFSAOA00 DFSAOSD  DFSAOSW0
    DFSCIO50 DFSRLM10 DFSSLUM0 DFSYFD00 DFSYLUS0 DFSYSLM0 DFSYTIB
    DFS6LUS0
    

Fix information

  • Fixed component name

    IMS V12

  • Fixed component ID

    5635A0300

Applicable component levels

  • R200 PSY UK90702

       UP13/01/05 P F301 Ž

Fix is available

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Document Information

Modified date:
14 December 2020