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PH39957: MQ Z/OS ABN=602 OCCURS DURING QMGR STARTUP IF THE AMSM ADDRESS SPACE FAILS TO START

A fix is available

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APAR status

  • Closed as program error.

Error description

  • The client complained that CSQ1MSTR took the following dump
    during restart due to a JCL error with CSQ1AMSM however the
    qmgr does not terminate as expected :
    CSQV086E CSQ1 QUEUE MANAGER ABNORMAL TERMINATION
    REASON=00E80100
    IEA794I SVC DUMP HAS CAPTURED: DUMPID=019 REQUESTED BY JOB
    (CSQ1MSTR) DUMP TITLE=CSQ1,ABN=602-00000000,U=SYSOPR
    ,C=MQ900.910.SSSC-CSQ1AMI2,M=CSQGFRCV,PSW=470C100081789BE4,ASID=
    01A3
    The 602 abend occurs due to a race condition between noticing
    that the AMS address space did not start successfully, and
    posting it that MQ startup has reached a given point.
    MQ should not be abending in this situation, and should instead
    rely on the existing logic for checking the existence of the
    AMSM address space.
    .
    Additional Keywords:
    ABEND602 ABENDS602
    

Local fix

  • N/A
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of IBM MQ for z/OS Version 9       *
    *                 Release 1 Modification 0 and Release 2       *
    *                 Modification 0.                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: If AMS fails to start, it is possible   *
    *                      that the QMGR will abend with an        *
    *                      incorrect code (S602).                  *
    ****************************************************************
    If AMS fails to start or terminates unexpectedly, the QMGR
    should abend with S6C6.
    A race condition can occur, where an ECB is posted to the AMS
    address space without checking the existence of the AMS address
    space.
    

Problem conclusion

  • The QMGR startup routine was changed to always check the
    AMS address space exists before posting an ECB to it.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PH39957

  • Reported component name

    IBM MQ Z/OS V9

  • Reported component ID

    5655MQ900

  • Reported release

    100

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2021-08-18

  • Closed date

    2021-12-10

  • Last modified date

    2022-03-01

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

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

    UI78486 UI78487

Modules/Macros

  • CSQ3AMI2
    

Fix information

  • Fixed component name

    IBM MQ Z/OS V9

  • Fixed component ID

    5655MQ900

Applicable component levels

  • R100 PSY UI78487

       UP22/02/10 P F202

  • R200 PSY UI78486

       UP22/02/10 P F202

Fix is available

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Document Information

Modified date:
02 March 2022