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PM91512: WMQ LATCH IS NOT FREED PROPERLY AFTER ALLIED ADDRESS SPACE FAILS

A fix is available

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APAR status

  • Closed as program error.

Error description

  • A WebSphere MQ latch may not be freed properly after an allied
    address space terminates. In the APAR'd case an abend occurred
    in a WebSphere Application Server address space, for a TCB which
    was executing in CSQMCPRH.  The abend happened while in code
    which acquires and releases the VLCAALA latch.  The recovery
    routine which receives control after the abend does not release
    the latch.
    
    This leaves the MQ control blocks in the WAS address space in an
    inappropriate state.  Later, when the WAS address space is
    forced, the MQ end-of-memory exit gets suspended because of the
    retained latch.  When this exit gets abended by z/OS, the MQ
    qmgr terminates with reason code 00E50054.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of WebSphere MQ Version 7          *
    *                 Release 1 Modification 0.                    *
    ****************************************************************
    * PROBLEM DESCRIPTION: After an abend in CSQMCPRH, the         *
    *                      application address space hangs during  *
    *                      termination and will not end until      *
    *                      forced.                                 *
    *                                                              *
    *                      End of memory processing after the      *
    *                      force results in abend 30D and the      *
    *                      queue manager terminates with abend     *
    *                      6C6-00E50054.                           *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    An application which is connected to MQ using an RRS-enabled
    interface abends in CSQMCPRH.  If the abend occurs while the
    task holds an address-space level latch (VLCAALA), the recovery
    code may not release the latch.
    
    Other tasks in the application address space which require the
    latch will hang waiting for the latch to be released.  This can
    result in the application being unable to terminate, and cancel
    of the address space does not resolve the hang.
    
    If the address space is forced, the MQ End of memory processing
    may also hang.  When this is detected by z/OS, abend 30D is
    issued and the queue manager is terminated with abend 6C6 reason
    00E50054.
    
    In some cases MQ may detect that the latch has not been
    released, resulting in queue manager termination with abend
    6C6-00F30801.
    

Problem conclusion

  • Recovery code in CSQMCPRH has been modified to correctly release
    the VLCAALA latch if an abend occurs while the latch is held.
    100Y
    CSQMCPRH
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PM91512

  • Reported component name

    WMQ Z/OS V7

  • Reported component ID

    5655R3600

  • Reported release

    100

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2013-06-20

  • Closed date

    2013-07-22

  • Last modified date

    2014-08-01

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

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

    UK96026

Modules/Macros

  • CSQMCPRH
    

Fix information

  • Fixed component name

    WMQ Z/OS V7

  • Fixed component ID

    5655R3600

Applicable component levels

  • R100 PSY UK96026

       UP13/08/23 P F308 Ž

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 August 2014