IBM Support

IT25945: FDC with xecS_I_PRIVATE_MEMORY_ERROR and probe ID XC006001 when consuming large message with async consume and GMO_CONVERT

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APAR status

  • Closed as program error.

Error description

  • When using asynchronous consume to retrieve a large message over
    a server connection channel and requesting that the message be
    converted, if the converted message is larger than the
    unconverted message, the consume may fail with a Failure Data
    Capture (FDC) record with the following features:
    
    Component     :- xcsFreeMemFn
    Major Errorcode  :- xecS_I_PRIVATE_MEMORY_ERROR
    Arith1      :- 140193638268248 (0x7f8160023d58)
    Comment1     :- invalid head tag
    
    MQM Function Stack ends with:
    rstHandleMsgExpansion
    ccxStageReAlloc
    xcsFreeMemFn
    xcsFFST
    
    The consuming application receives MQRC_CONNECTION_BROKEN
    (2009). This issue also affects the MQ classes for Java and MQ
    classes for JMS which internally use asynchronous consume to
    service synchronous GET requests.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This affects users of MQ applications which connect over a
    server-connection channel and use GMO_CONVERT as part of an
    asynchronous consumption of messages with an MQCB.
    
    It also affects users of the MQ classes for Java and MQ classes
    for JMS, which implicity use async consume for MQGET operations.
    
    The issue is seen only when receiving messages > 4KB, and where
    the conversion causes the message to grow in size, such as
    converting from a single-byte to double-byte character set.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    When performing internal memory management to convert a message
    larger than 4KB, the server-connection channel could free memory
    using an incorrectly offset pointer, resulting in the internal
    xecS_I_PRIVATE_MEMORY_ERROR error code, and the FDC record
    described above.
    

Problem conclusion

  • The MQ channel logic has been corrected to use the correct
    pointer offset when freeing this memory as part of message
    conversion.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    V9.0 CD    9.0.5
    v9.0 LTS   9.0.0.6
    
    
    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

    IT25945

  • Reported component name

    IBM MQ BASE M/P

  • Reported component ID

    5724H7261

  • Reported release

    900

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2018-08-13

  • Closed date

    2018-08-16

  • Last modified date

    2018-10-04

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

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

    PH01793

Fix information

  • Fixed component name

    IBM MQ BASE M/P

  • Fixed component ID

    5724H7261

Applicable component levels

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"9.0","Edition":"","Line of Business":{"code":"LOB36","label":"IBM Automation"}}]

Document Information

Modified date:
04 October 2018