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PK27738: DFHWB0002 0505 FOLLOWED BY DFHSM0002 030D OR OTHER VARIOUS ABENDS MAY OCCUR IF TCPIPSERVICE IS SET IMMCLOSE.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • While a CWXN task is running, the TCPIPService that it is using
    gets set IMMCLOSE.  The storage associated with the STE for this
    task gets FREEMAINED by the IMMCLOSE, but as the task has not
    terminated yet, a pointer to this storage still exists, held as
    the SO token for the task in transaction manager.
    The storage may get used several times before the task pointing
    to the storage finally terminates.
    When it does, during task termination DFHSOXM decrements
    ste_txn_count by 1.  This is at offset x'24' into the STE.
    However, the storage that it is referencing is no longer an STE.
    In the situation which brought about this APAR, the storage was
    now a QPH.  When DFHSOXM decrements the QPH +24, or field
    QPH_FIRST_FREE_CELL, it corrupts this address.  In our case it
    was a QPH for subpool RMOFRMUW, though it could just as well be
    any other subpool or piece of task storage.
    Additional Keywords: MINUS ONE 1 -1 S0C4 ABENDS0C4 MSGDFHWB0002
    WB0002 SUBTRACT OFF LESS
    DFHSM0002 has been seen hitting various subpools:
    LI_PLB XMTRANS LD_CSECT PGLLE PGHTB LD_APES the key is
    the first free QPH+24 always contains an address that is 1 less
    or minus 1 from the address that it should contain.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All.                                         *
    ****************************************************************
    * PROBLEM DESCRIPTION: When a TCPIPSERVICE is set IMMCLOSE,    *
    *                      storage related to the STE is           *
    *                      FREEMAINed, but any remaining CWXN      *
    *                      tasks will attempt to use this storage  *
    *                      at task termination.                    *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    While a CWXN task is running, the TCPIPSERVICE that it is using
    is IMMCLOSEd. The storage associated with the STE for this task
    gets FREEMAINed by the IMMCLOSE, but as the task has not yet
    terminated, a pointer to this storage still exists. When the
    task terminates, DFHSOXM attempts to decrement STE_TXN_COUNT by
    1, but the storage that contains this field is no longer an STE,
    and may have been reused by some other function. DFHSOXM will
    decrement the storage at the address that was previously an STE,
    but its current contents are now unpredictable.
    
    Additional keywords: MINUS ONE 1 -1 MSGDFHWB0002 WB0002 SUBTRACT
    S0C4 ABENDS0C4 0C4 ABEND0C4
    

Problem conclusion

  • DFHSOXM has been changed to check that the STE storage is still
    valid before attempting to decrement STE_TXN_COUNT.
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PK27738

  • Reported component name

    CICSTS 3.1 Z/OS

  • Reported component ID

    5655M1500

  • Reported release

    400

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2006-07-10

  • Closed date

    2006-07-26

  • Last modified date

    2006-08-02

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

    PK26484

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

    UK16522

Modules/Macros

  •    DESSOXM  DFHSOXM
    

Fix information

  • Fixed component name

    CICSTS 3.1 Z/OS

  • Fixed component ID

    5655M1500

Applicable component levels

  • R400 PSY UK16522

       UP06/07/29 P F607

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:
02 August 2006