IBM Support

IT17583: SIGSEGV in MQ application, occurring within the MQ API library code in function xlsPostEvent

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APAR status

  • Closed as program error.

Error description

  • SIGSEGV memory exception in MQ application, occurring within the
    MQ API library code.
    The function at the top of the stack (the function running that
    causes the SIGSEGV) is xlsPostEvent.
    If the call stack can be captured from a core file, it looks
    like this (there might be slight differences but xlsPostEvent
    will always be at the top):
    #0  in xlsPostEvent
    #1  in xcsSubtaskExtendSet
    #2  in xcsAllocateMemBlockFn
    #3  in xcsAllocateQuickCellFn
    #4  in xlsThreadPreInitialization
    #5  in xlsThreadInitialization
    #6  in xcsConnectSharedSubpool
    #7  in InitSharedSubpool
    #8  in xcsInitializeEx
    #9  in ziiConnectToAgent
    #10 in ziiMQCONN
    #11 in zstMQConnect
    #12 in zstMQCONNX
    #13 in MQCONNX_Server_Call
    #14 in zswGetEntryPointsByName
    #15 in zswMQCONNX_Call
    An MQ Failure Data Capture (FDC) record with a similar call
    stack will be generated to report the SIGSEGV if the application
    has not overridden MQ's signal handler.
    If this issue is encountered in an IBM Integration Bus
    environment, then the bipbroker and bipservice processes
    terminate with BIP2013E and BIP2002W
    errors due to the SIGSEGV signal from MQ. Errors similar to the
    following will be observed within IBM Integration Bus
    BIP2013E: The IBM Integration Bus service detected that
    executable bipbroker terminated, signal 6.
    BIP2002W: The IBM Integration Bus service has stopped. Please
    find attached abend file that got generated.
    The IBM Integration Bus abend file will identify that a SIGSEGV
    was generated while MQ was in the xlsPostEvent.

Local fix

Problem summary

  • ****************************************************************
    Potentially all users of IBM MQ.  But note that this is a rare
    condition, only ever seen on an application thread that
    repeatedly connects and disconnects from the queue manager every
    5 seconds.
    The issue was observed when such an application was deployed as
    part of an IBM Integration Bus flow, however the issue exists
    within MQ product code, and not IBM Integration Bus.
    Platforms affected:
    At the time an application was making a new connection to the
    queue manager, it was obtaining access to a new block of shared
    memory.  During this activity a null pointer was accessed,
    leading to a SIGSEGV memory exception.

Problem conclusion

  • The IBM MQ product code has been corrected to prevent this null
    pointer access.
    The fix is targeted for delivery in the following PTFs:
    Version    Maintenance Level
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    If the maintenance level is not yet available information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'

Temporary fix


APAR Information

  • APAR number


  • Reported component name


  • Reported component ID


  • Reported release


  • Status


  • PE




  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date


  • Closed date


  • Last modified date


  • 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


  • Fixed component ID


Applicable component levels

  • R800 PSY


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

Document Information

Modified date:
10 March 2017