IBM Support

PI30924: TITLE: CSQ1,ABN=5C6-00E50002,U=SYSOPR,C=R3600.710.ASMC-CSQVUNLX,M=CSQVLFRR,LOC=CSQMLPLM.CSQMTAPB+0000 IN A 14/12/17 PTF PECHANGE

A fix is available

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • In a shared queue environment, the customer receives:
    .
    TITLE: CSQ1,ABN=5C6-00E50002,U=SYSOPR,C=R3600.710.ASMC-CSQVUNLX,
    M=CSQVLFRR,LOC=CSQMLPLM.CSQMTAPB+00000792
    .
    00E50002 means UNLATCH REQUEST AND LATCH NOT OWNED BY REQUESTING
    EB.
    .
    The PSW is in CSQVXUL0+65A (UK79464) where the unlatch request
    came from CSQMTAPB+00000792 (UI19124).
    .
    The change team can see from the queue manager trace that while
    CSQMTAPB was waiting for a request to the structure task to open
    a shared queue to be processed, while it was holding the IVSA
    latch, the IVSA was freed by DB2/CF resync processing
    (CSQEDB2R), and then later reallocated by the message expiry
    control task for use by another queue. Therefore when CSQMTAPB
    tried to free the IVSA latch it abended with 5C6-00E50002 as
    the IVSA had been cleared.  There needs to be more serialization
    between CSQMTAPB and CSQEDB2R to prevent this from occurring.
    
    Additional symptoms:
    IXL041E CONNECTOR NAME ... HAS NOT RESPONDED TO THE
            DISCONNECTED/FAILED CONNECTION EVENT
    IXL049E HANG RESOLUTION ACTION FOR CONNECTOR ...
            SYSTEM WILL TAKE ACTION
    IXL013I IXLCONN REQUEST FOR STRUCTURE ...
            IXLCONN RETURN CODE: 0000000C,  REASON CODE: 0201
            CONNECTIONS TO THE STRUCTURE ARE BEING PREVENTED
              CONADIAG0:   00000002
              CONADIAG1:   00000008
              CONADIAG2:   00000C27
    IXL050I CONNECTOR NAME ... HAS NOT PROVIDED A REQUIRED
            RESPONSE AFTER 1029 SECONDS.
            TERMINATING CONNECTOR TASK TO RELIEVE THE HANG.
    IEA794I SVC DUMP HAS CAPTURED:
              DUMPID=002 REQUESTED BY JOB (ssidMSTR)
              DUMP TITLE=ssid,ABN=026-08110102,U=SYSOPR,
              C=R3600.710.ASMC-CSQVSRX,M=CSQVSRRX
    IXL048I THE RESPONSE REQUIRED FROM CONNECTOR NAME ...
            FOR THE DISCONNECTED/FAILED CONNECTION EVENT
            ... IS NO LONGER EXPECTED.
            REASON: CONNECTOR HAS DISCONNECTED/FAILED.
    
    A structure task hung when CSQEDB2R called CSQILOC2 to locate
    the IVSA of a queue that needs deleting. The hang occurs when
    the synonym chain latch is requested - it is not safe for this
    to be requested on a structure task due to the risk of deadlocks
    between the latch holder and the structure task. This APAR
    removes the CSQILOC2 call that PI14223 incorrectly added to
    CSQEDB2R.
    .
    Additional keywords:
     Latch waiter: STRTSKnn
     Latch owner:  XCFWRK01 latch held (11)SSSCONN/DMCSEGAL
                                        (8)DMCITREE
     5C6-00D40047 ABEND5C6 ABENDS5C6 S5C6 S05C6
    

Local fix

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: Abend 5C6-00E50002 occurs in CSQMTAPB   *
    *                      when connecting to a structure holding  *
    *                      a shared queue that is being deleted on *
    *                      another queue manager in the queue      *
    *                      sharing group.                          *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    CSQMTAPB was called to process a notification that the last
    input handle on a shared queue had been closed on another queue
    manager, and proceeded to locate the IVSA for the shared queue
    and obtain a latch on it.
    While CSQMTAPB held the latch, the shared queue was deleted on
    another queue manager, and while this delete was still in
    progress the local queue manager connected to the structure
    containing the shared queue, causing CSQEDB2R to resync
    information about shared queues with DB2.
    CSQEDB2R detected the partially deleted queue and the code added
    by PI14223 deleted the local control blocks associated with the
    queue, including the IVSA. When CSQMTAPB subsequently attempted
    to release the IVSA latch the IVSA storage had been reused,
    leading to the reported abend.
    

Problem conclusion

  • CSQEDB2R is changed to schedule the deletion of the queue
    control blocks using CSQEKATM, ensuring that the deletion is
    serialised with CSQMTAPB processing.
    010Y
    100Y
    CSQEDB2R
    CSQEKATM
    CSQE197N
    CSQIDDEL
    CSQIDEL5
    CSQIERS3
    CSQIEXP1
    CSQILEPL
    CSQILOC2
    CSQMOAQ1
    

Temporary fix

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

Comments

APAR Information

  • APAR number

    PI30924

  • Reported component name

    WMQ Z/OS V7

  • Reported component ID

    5655R3600

  • Reported release

    100

  • Status

    CLOSED PER

  • PE

    YesPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2014-12-04

  • Closed date

    2015-01-16

  • Last modified date

    2015-05-06

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

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

    UI24439 UI24440

Modules/Macros

  • CSQEDB2R CSQEKATM CSQE197N CSQIDDEL CSQIDEL5
    CSQIERS3 CSQIEXP1 CSQILEPL CSQILOC2 CSQMOAQ1
    

Fix information

  • Fixed component name

    WMQ Z/OS V7

  • Fixed component ID

    5655R3600

Applicable component levels

  • R010 PSY UI24439

       UP15/02/04 P F502 «

  • R100 PSY UI24440

       UP15/02/04 P F502 «

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.

[{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG19M","label":"APARs - z\/OS environment"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.1","Edition":"","Line of Business":{"code":"","label":""}}]

Document Information

Modified date:
06 May 2015