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IT19148: SIGSEGV from zmuHealthCheck during queue manager shutdown

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APAR status

  • Closed as program error.

Error description

  • During shutdown the queue manager writes failure records in FDC
    files.
    A loss of queue manager function might be experienced, but not
    always.
    
    Details from the FDC files follow:
    
    Probe Id     :- XC130003
    Component     :- xehExceptionHandler
    Program Name      :- amqzmur0
    Arith1      :- 11 (0xb)
    Comment1     :- SIGSEGV: address not mapped(1c)
    
    MQM Function Stack
    amqzmur0
    zmuUtilityManager
    zmuShutdownPhase
    zmuHealthCheck
    xcsFFST
    
    /opt/mqm/lib64/libmqml.so 'zmuHealthCheck+0x674
    [0xffff80ff5447aef4] [Signal 11 (SEGV)]
    /opt/mqm/lib64/libmqml.so 'zmuShutdownPhase+0x2cb
    [0xffff80ff5447793b]
    /opt/mqm/lib64/libmqml.so 'zmuUtilityManager+0x1d37
    [0xffff80ff54473e67]
    /opt/mqm/bin/amqzmur0   'main+0x16b [0x40118b]
    /opt/mqm/bin/amqzmur0   '_start+0x6c [0x400ffc]
    
    
    Also Probe Id ZX103101 is seen.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This can happen while shutting the queue manager down, and is
    rare because it is due to a rare timing condition.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    While working through a list of data blocks, an MQ internal task
    freed one of these blocks, then accessed the memory that was
    just freed.  If in that brief moment another task in the queue
    manager had been given that block, then it had written its own
    data there, and the MQ internal task just mentioned would access
    a null pointer.
    

Problem conclusion

  • The IBM MQ product has been corrected so that the memory just
    freed is no longer accessed in this invalid way.  The FDC is
    therefore avoided.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v9.0 CD    9.0.3
    v9.0 LTS   9.0.0.2
    
    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

    IT19148

  • 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

    2017-02-07

  • Closed date

    2017-03-21

  • Last modified date

    2017-03-21

  • 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

  • R900 PSY

       UP

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Document Information

Modified date:
21 March 2017