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IT26218: Access Violation FDC reported with Probe Id XC130031 in functionxcsRequestThreadMutexSem.

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APAR status

  • Closed as program error.

Error description

  • Initially a failure data capture (FDC) record  is generated,
    with the following Probe Id, Component, and Function Stack:
    Probe Id          :- CO000003
    Component         :- ccxAllocMem
    Major Errorcode   :- rrcE_BAD_PARAMETER
    Probe Description :- AMQ6125: An internal IBM MQ error has
    occurred.
    
    MQM Function Stack
    cciReceiveThread
    ccxReceiveThreadFn
    cciProcessOne
    cciReceiveOne
    cciSendHeartbeat
    ccxAllocMem
    xcsFFST
    
    Moments later, an Access Violation FDC record is generated, with
    the following Probe Id, Component, and Function Stack:
    Probe Id          :- XC130031
    Component         :- xehExceptionHandler
    Probe Description :- AMQ6109: An internal IBM MQ error has
    occurred.
    Comment1          :- Access Violation at address
    0000000000000008 when reading.
    .
    MQM Function Stack
    cciReceiveThread
    ccxReceiveThreadFn
    cciProcessOne
    cciReceiveOne
    cciSendHeartbeat
    ccxFreeMem
    xcsRequestThreadMutexSem
    xcsFFST
    

Local fix

  • Disable heartbeating on the SVRCONN channel
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This issue affects users of clients which connect via
    server-connection (SVRCONN) channels and have heartbeating
    enabled.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    Due to a coding error, when freeing a memory buffer used for the
    sending of heartbeat flows, a small timing window existed where
    the client could attempt to access an invalid memory address.
    This resulted in an access violation on Microsoft Windows, or a
    SIGSEGV on UNIX platforms.
    
    It was possible for the timing window to occur at either the
    client or queue manager side of the channel.
    

Problem conclusion

  • The MQ client logic, and the queue manager channel logic, have
    been updated to prevent this invalid memory access.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v9.0 LTS   9.0.0.7
    v9.1 CD    9.1.3
    v9.1 LTS   9.1.0.2
    
    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

    IT26218

  • 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

    2018-09-07

  • Closed date

    2019-03-18

  • Last modified date

    2019-03-18

  • 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 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:
18 March 2019