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IT29123: Queue manager process suffers deadlock when handling memory exception (SIGBUS)

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APAR status

  • Closed as program error.

Error description

  • Queue manager process suffers a deadlock when handling a memory
    exception, generating signal SIGBUS. The SIGUSR2 FDCs generated
    show one or more MQ threads with the following O/S Call Stack.
    
    O/S Call Stack for current thread
    
    /opt/mqm/lib64/libmqmcs.so'xcsPrintStackForCurrentThread+0xe8
    ...
    /opt/mqm/lib64/libmqmcs.so'signalHandlerInternal+0x3c
    /opt/mqm/lib64/libmqmcs.so'PrepareDumpAreas+0x140
    /opt/mqm/lib64/libmqmcs.so'xcsFFSTFn+0x3398
    /opt/mqm/lib64/libmqmcs.so'xcsFFSTSFn+0x1dc
    /opt/mqm/lib64/libmqmcs.so'xehProduceDebugInfo+0x194
    /opt/mqm/lib64/libmqmcs.so'xehAsySignalMonitor+0x1350
    ...
    /lib/sparcv9/libc.so.1'_lwp_start+0x0 [0xffffffff4c44931c]
    
    The stack trace generated for the affected process contains the
    following at
    the top of the stack.
    
    lwp_park (0, 0, 0)
    malloc (1e0, ffffffff4c591a50, 9a50, ffffffff4c588000, 1a13ec,
    9800) + 50
    xcsGetMemFn (a, 1002e4e80, 2, 4, ffffffffffffffff,
    ffffffff6feba398) + 22c
    xcsBuildDumpPtrFmt (ffffffff6feba398, 1, ffffffff0ace6090,
    100000000, 1000, 0) + 1f0
    xehExceptionHandler (a, ffffffff6feba9d0, ffffffff6feba6d0, 0,
    0, 0) + 19c
    __sighndlr (a, ffffffff6feba9d0, ffffffff6feba6d0,
    ffffffff0a90d350, 0, ffffffff4c588000) + c
    call_user_handler (ffffffff78613240, ffffffff6feba9d0, 7e27f857,
    fffffff0, 0, a) + 364
    sigacthandler (a, ffffffff6feba9d0, ffffffff6feba6d0, 14c0c4,
    ffffffff4c588000, a) + 5c
    --- called from signal handler with signal 10 (SIGBUS) ---
    ...
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    All users of MQ
    
    
    Platforms affected:
    AIX, HP-UX Itanium, Linux on Power, Linux on S390, Linux on
    x86-64, Linux on zSeries, Solaris SPARC, Solaris x86-64, IBM
    iSeries, Linux on x86
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    When handling the SIGBUS signal, MQ called malloc resulting in a
    potential hang.
    

Problem conclusion

  • The MQ code which handles SIGBUS signal has been modified to
    resolve the problem.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v9.0 LTS   9.0.0.8
    v9.1 CD    9.1.3
    v9.1 LTS   9.1.0.3
    
    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

    IT29123

  • 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

    2019-05-13

  • Closed date

    2019-06-07

  • Last modified date

    2019-06-07

  • 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:
07 June 2019