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IV34699: GARBAGE COLLECTOR ASSERT WITH AN OBJECT REFERENCE HALF ZEROED-OU T

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APAR status

  • Closed as program error.

Error description

  • Error Message: 0000000000E7AD00: Object neither in heap nor
    stack-allocated in thread Thread-22
       0000000000E7AD00: O-Slot=0000000000E8AAD0
       0000000000E7AD00: O-Slot value=00002B7E00000000
       0000000000E7AD00: PC=00002B7E85C5297D
       0000000000E7AD00: framesWalked=8
       0000000000E7AD00: arg0EA=0000000000E8ACC0
       0000000000E7AD00: walkSP=0000000000E8A900
       0000000000E7AD00: literals=00002B7E88C86C48
       0000000000E7AD00: jitInfo=00002B7E860EAED0
       0000000000E7AD00: method=00002B7E88D40DB0
    (org/apache/derby/impl/sql/compile/FromBaseTable.bindNonVTITable
    s(Lorg/apache/derby/iapi/sql/dictionary/DataDictionary;Lorg/apac
    he/derby/impl/sql/compile/FromList;)Lorg/apache/derby/impl/sql/c
    ompile/ResultSetNode;) (JIT)
       0000000000E7AD00: stack=0000000000E841B0-0000000000E8B210
       16:03:28.106 0x814800    j9mm.479    *   ** ASSERTION FAILED
    ** at ParallelScavenger.cpp:2390:
    ((MM_StackSlotValidator(MM_StackSlotValidator::NOT_ON_HEAP,
    *slotPtr, stackLocation, walkState).validate(_env)))
    Note the "O-Slot value=00002B7E00000000".  This example is from
    a little-endian platform, so the low-order half of this slot is
    all zeros, while the high-order half looks like half a pointer.
    On a big-endian platform, it might be the high-order half that
    contains zeros.
    .
    Stack Trace: N/A
    .
    

Local fix

  • -Xjit:disableEscapeAnalysis
    

Problem summary

  • Escape analysis sometimes used the wrong field information to
    initialize a field of a stack-allocated object.  This allowed it
    to generate a 4-byte store to initialize an 8-byte field, which
    is incorrect.
    

Problem conclusion

  • This defect will be fixed in:
    7.0.0 SR4
    6.0.1 SR5
    6.0.0 SR13
    5.0.0 SR16
    .
    Escape analysis was fixed so it would always use the right field
    information.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV34699

  • Reported component name

    JIT

  • Reported component ID

    620700124

  • Reported release

    260

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-01-14

  • Closed date

    2013-01-14

  • Last modified date

    2013-02-28

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

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

    IV34700

Fix information

  • Fixed component name

    JIT

  • Fixed component ID

    620700124

Applicable component levels

  • R260 PSY

       UP

  • R600 PSY

       UP

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Document Information

Modified date:
28 February 2013