IBM Support

IT36729: FDC from xcsFreeMemFn in amqrmppa process reporting xecS_I_PRIVATE_MEMORY_ERROR FROM during thread cleanup

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APAR status

  • Closed as program error.

Error description

  • With IT34004 applied, a problem persists where an invalid
    pointer may still be accessed during thread cleanup operations.
    
    Failure data capture (FDC) records with the following
    characteristics may also be observed:
    
    Probe Id          :- XC130003
    Component     :- xehExceptionHandler
    Thread            :- nn    RemoteResponder
    MQM Function Stack
    ccxResponder
    rrxResponder
    ccxReceiveThreadFn
    ccxReceiveThreadCleanup
    cciEndConv
    rriAsyncConvControl
    rriFreeSess
    ccxStageFree
    xcsFFST
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Client or Channel applications on MQ version 9.2.0.2 with
    SHARECONV(1), that may experience network interruptions.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    A network socket error in cciTcpSend function causes the socket
    to be closed and the ccxReceiveThreadCleanup function to perform
    cleanup tasks.
    IT34004 addressed the problem where a timing condition existed
    where some memory freed during the cleanup operation may be
    double freed at a later stage in the cleanup process. There
    remained a possibility the freed memory pointer could be
    accessed without first checking it was valid and so a code path
    existed where an attempt to access the pointer caused a segment
    violation or xecS_I_PRIVATE_MEMORY_ERROR error FDC to be
    captured.
    

Problem conclusion

  • An extra check has been added to ensure the memory pointer is
    validated before use.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v9.0 LTS   9.0.0.12
    v9.1 LTS   9.1.0.9
    v9.2 LTS   9.2.0.3
    v9.x CD    9.2.3
    
    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

    IT36729

  • 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

    2021-04-28

  • Closed date

    2021-07-06

  • Last modified date

    2021-07-16

  • 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":"LOB36","label":"IBM Automation"},"Business Unit":{"code":"BU053","label":"Cloud \u0026 Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"910"}]

Document Information

Modified date:
18 July 2021