IBM Support

IT39029: MQCONN fails in application using isolated bindings. FDC probe ZC037020, component zcsAllocateAgent is written

Subscribe to this APAR

By subscribing, you receive periodic emails alerting you to the status of the APAR, along with a link to the fix after it becomes available. You can track this item individually or track all items by product.

Notify me when this APAR changes.

Notify me when an APAR for this component changes.

 

APAR status

  • Closed as program error.

Error description

  • An MQ queue manager generates a failure data capture (FDC)
    record with the following characteristics:
    
    Probe Id          :- ZC037020
    Component         :- zcsAllocateAgent
    Major Errorcode   :- MQRC_UNEXPECTED_ERROR
    
    MQM Function Stack
    MQCONN
    zswGetEntryPointsByName
    MQCONN
    zstMQCONN
    zstMQConnect
    zisMQCONN
    zisConnectToAgent
    zcsAllocateAgent
    xcsFFST
    
    Error text in first dump area: "Operation not permitted"
    
    Socket filename in second dump area similar to:
    "/var/mqm/sockets/qmname/zsocketapp/hostname/Z.14038.6"
    
    Looking at that file Z.14038.6 using ls -l, it is owned by a
    user different from the user running the application.
    

Local fix

  • It is likely that starting a new application will result in a
    new pid being used, and this will in most cases mean the problem
    situation is averted.
    
    Only perform these tasks if this problem occurs perpetually and
    a fix cannot be installed:
    - End the queue manager.
    - Log on as mqm or root and remove any Z.nnnnn.mm files in the
    /var/mqm/sockets/qmname/zsocketapp/hostname/ directory.
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Applications that connect on the same machine as the queue
    manager, using isolated bindings, on Linux, UNIX and IBM i
    platforms.
    
    
    Platforms affected:
    AIX, IBM iSeries, Linux on Power, Linux on x86-64, Linux on
    zSeries, Solaris SPARC, Solaris x86-64
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    A prior failure occurred in which an isolated bindings
    connection failed to be established during the early handshaking
    between MQ code in the application program and the queue
    manager.  This resulted in a UNIX-domain socket file remaining
    in the /var/mqm/sockets/qmname/zsocketapp/hostname/ directory.
     The socket filename is of the form Z.n.m where n is the pid of
    the application process, and m is a number representing the MQ
    hconn number (a number increasing from 1).
    
    Later, a new application is given the same pid by the operating
    system, and so the MQ code performing the isolated bindings
    MQCONN needs to unlink (delete) the socket file from the file
    system and recreate it.  The unlink() call fails, leading the
    MQCONN call to fail.
    

Problem conclusion

  • The "sticky bit" is set on the directory
    /var/mqm/sockets/qmname/zsocketapp/hostname/ meaning only the
    owner of the directory (mqm) and the owner of the file may
    unlink (delete) the socket filename.
    
    A subroutine has been added to the IBM MQ code that runs when
    the isolated bindings listener starts, to unlink (delete) any
    unneeded socket filenames from this directory.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v9.1 LTS   9.1.0.11
    v9.2 LTS   9.2.0.5
    v9.x CD    9.3.0.0
    
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
    
    If the maintenance level is not yet available information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
    ---------------------------------------------------------------
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT39029

  • Reported component name

    IBM MQ BASE MP

  • Reported component ID

    5724H7271

  • Reported release

    910

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2021-11-09

  • Closed date

    2022-01-18

  • Last modified date

    2022-04-13

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

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

Fix information

  • Fixed component name

    IBM MQ BASE MP

  • Fixed component ID

    5724H7271

Applicable component levels

[{"Line of Business":{"code":"LOB45","label":"Automation"},"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"910"}]

Document Information

Modified date:
14 April 2022