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PM37806: EXCLUSIVE CONTROL CONFLICTS MAY OCCUR BETWEEN THE SMLOCK AND THE DUSYSDMP LOCKS.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • In this case there are 2 transactions abending with storage
    violations at the same time.  One is running on an L8 TCB and
    the other on the QR.
      Transaction #1 on the QR has entered the dump process and has
    acquired the DUSYSDMP lock.  It then calls DFHRSDU that in turn
    requests a STOP_DUMP.  The next request is a FCFR FREE_STORAGE
    that needs the SMLOCK.
      At the same time, transaction #2 on the L8 has performed a
    freemain and owns the SMLOCK.  A storage overlay is discovered
    and dump processing is entered.  The DUSYSDUMP lock is requested
    but transaction #1 owns it.
      Both transactions enter LMQUEUE waits.  Transaction #1 owns
    the DUSYSDMP lock and needs the SMLOCK while Transaction #2 owns
    the SMLOCK and needs the DUSYSDMP lock.  The system begins to
    back up with many tasks waiting in LMQUEUE waits for the SMLOCK.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All CICS users.                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: Deadlock between two tasks requesting   *
    *                      the SMLOCK and DUSYSDMP locks.          *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    DFHSMMF FREEMAIN processing obtains the SMLOCK. If a storage
    violation is detected, DFHSMMF calls DU Domain to take a
    dump and this requires the DUSYSDMP lock.
    
    As part of taking a dump, DU domain calls DFHRSDU STOP_DUMP
    which issues a DFHFCFR FREE_STORAGE request. The FREE_STORAGE
    function includes a call to SM Domain that requires the
    SMLOCK.
    
    If two transactions are abending at the same time, it is
    possible for one to have obtained the DUSYSDMP lock and be
    waiting for the SMLOCK and the other to have obtained the
    SMLOCK and be waiting for the DUSYSDMP.
    
    Additional keywords: DFHSM0102 SM0102 MSGDFHSM0102
    

Problem conclusion

  • DFHSMMF and DFHSMGF have been changed to release the SMLOCK
    when a storage violation is being processed and a dump is to be
    taken by DU domain.
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PM37806

  • 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

    2011-04-26

  • Closed date

    2011-08-23

  • Last modified date

    2011-10-03

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

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

    PM44983 UK71156

Modules/Macros

  •    DESSMGF  DESSMMF  DFHSMGF  DFHSMMF
    

Fix information

  • Fixed component name

    CICS TS Z/OS V4

  • Fixed component ID

    5655S9700

Applicable component levels

  • R600 PSY UK71156

       UP11/09/07 P F109

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 2011