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PI39495: WMQ Z/OS:LOOP OCCURRED WHEN STOPPING WAS SERVER AFTER ADMIN STRUCTURE FULL CONDITION.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • There is a loop problem when stopping WAS server
    after Admin Structure Full condition.
    The error in the recovery processing for the initial 5C6 abend
    can lead to an ACE being incorrectly left on the VLCA chain for
    the application address space. When the Servant region was
    subsequently  stopped, CSQMCTXE added the context ACE to the
    VLCA chain, however  because it was already on the chain, this
    led to the reported loop  condition.
    
    
    Additional Symptom(s) Search Keyword(s):
    

Local fix

  • n/a
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 *
    *                 Release 0 Modification 1 and Release 1       *
    *                 Modification 0.                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: High CPU loop in MQ application address *
    *                      space during termination processing     *
    *                      following an earlier abend in RRS exit  *
    *                      processing for that address space.      *
    *                      The application address space hangs and *
    *                      cannot be canceled.                     *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    While an MQ RRS Exit is processing a RRS context (for example,
    to prepare or commit work done under the context) on behalf of
    an RRS application e.g. WSAS, the context ACE is added to the
    VLCA allied ACE chain for the address space.
    If the RRS exit abends, CSQ3RRSF is invoked to provide recovery
    processing, including removing the ACE from the VLCA chain,
    however an error in this recovery routine can lead to the ACE
    being incorrectly left on the chain.
    If the ACE is subsequently used again (for example during end
    context processing), it can be added to the VLCA chain again,
    leading to a loop being introduced to the chain.
    When the chain is subsequently processed, for example by end of
    task processing, or other RRS exits for the address space, the
    loop in the VLCA chain results in processing looping, causing
    high cpu.
    A latch is held while processing the VLCA chain, so any other
    tasks attempting to use this chain will be suspended due to
    the looping task holding this latch. This can result in the
    address space failing to end correctly, even when canceled.
    

Problem conclusion

  • CSQ3RRSF is changed to correctly remove the context ACE from the
    VLCA chain when needed.
    010Y
    100Y
    CSQ3RRSF
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PI39495

  • Reported component name

    WMQ Z/OS V7

  • Reported component ID

    5655R3600

  • Reported release

    010

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2015-04-20

  • Closed date

    2015-04-29

  • Last modified date

    2015-07-01

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

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

    PI39731 UI27171 UI27172

Modules/Macros

  • CSQ3RRSF
    

Fix information

  • Fixed component name

    WMQ Z/OS V7

  • Fixed component ID

    5655R3600

Applicable component levels

  • R010 PSY UI27171

       UP15/06/03 P F506 ¢

  • R100 PSY UI27172

       UP15/06/03 P F506 ¢

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 2015