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IV99768: GC ASSERTION IN MM_PARALLELTASK OR MM_PARALLELSCAVENGETASK AFTER SCAVENGER BACKOUT

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APAR status

  • Closed as program error.

Error description

  • Error Message: Crash in
    MM_ParallelTask::synchronizeGCThreadsAndReleaseSingleThread() or
    MM_ParallelTask::synchronizeGCThreadsAndReleaseMaster().
    One of the following Assertion messages occurs:
    04:58:41.796126707  0x1FAC200 j9mm.621             Event
    GC Assertion message:
    MM_ParallelScavengeTask::MM_ParallelScavengeTask at
    0000000036E0F260 from
    synchronizeGCThreadsAndReleaseSingleThread: call from
    (ParallelScavenger.cpp:3563), expected
    (ParallelScavenger.cpp:4085)
    OR
    13:35:03.922196875 *0x2B97FC00 j9mm.621             Event
    GC Assertion message:
    MM_ParallelScavengeTask::MM_ParallelScavengeTask(MM_EnvironmentB
    ase *, MM_Dispatcher *, MM_ParallelScavenger *, MM_CycleState *)
    at 00000050082FBB68 from synchronizeGCThreadsAndReleaseMaster:
    call with syncPointWorkUnitIndex 61, expected 99
    The Snap trace file will also show the following message prior
    to one of the above Assertion messages:
    13:35:03.922180500  0x0 j9mm.63              Event       Set
    scavenger backout flag=true
    .
    Stack Trace: Native stack may be one of the following:
    MM_ParallelTask::synchronizeGCThreadsAndReleaseSingleThread+0x1b
    0 ()
    MM_ParallelScavengeTask::synchronizeGCThreadsAndReleaseSingleThr
    ead+0x41 ()
    MM_ParallelScavenger::workThreadGarbageCollect+0x159 ()
    MM_ParallelDispatcher::slaveEntryPoint+0x8a ()
    dispatcher_thread_proc2+0x198 ()
    j9sig_protect+0x208 ()
    dispatcher_thread_proc+0x48 ()
    OR
    MM_ParallelTask::synchronizeGCThreadsAndReleaseMaster()
    MM_ParallelScavengeTask::synchronizeGCThreadsAndReleaseMaster()
    MM_ParallelScavenger::completeBackOut()
    MM_ParallelScavenger::workThreadGarbageCollect()
    MM_ParallelScavengeTask::run()
    MM_ParallelDispatcher::slaveEntryPoint()
    .
    

Local fix

Problem summary

  • GC threads go out-of-sync during an aborted scavenge cycle.
    

Problem conclusion

  • The GC has been updated to work correctly in this scenario.
    .
    This APAR will be fixed in the following Java Releases:
       8    SR5       (8.0.5.0)
       7 R1 SR4 FP15  (7.1.4.15)
    .
    Contact your IBM Product's Service Team for these Service
    Refreshes and Fix Packs.
    For those running stand-alone, information about the available
    Service Refreshes and Fix Packs can be found at:
               https://www.ibm.com/developerworks/java/jdk/
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV99768

  • Reported component name

    J9 COMMON CODE

  • Reported component ID

    620700127

  • Reported release

    270

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2017-09-11

  • Closed date

    2017-09-11

  • Last modified date

    2018-11-16

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

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

    PH05417

Fix information

  • Fixed component name

    J9 COMMON CODE

  • Fixed component ID

    620700127

Applicable component levels

  • R270 PSY

       UP

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Document Information

Modified date:
22 February 2022