IZ67282: JAVA JIT COMPILE TIME CRASH ON AIX64 IN THE METHOD DECREFERENCEC OUNT()

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Error Message: A SIGSEGV occurs when the JIT is compiling a
    method. Commonly seen while compiling a method in the package
    "com/ibm/datatools/perf/console/..." but the possibility exists
    that the problem can occur while compiling methods from other
    packages.
    .
    Stack Trace:
    decReferenceCount__16TR_CodeGeneratorFP7TR_Node@AF226_56
    lstoreEvaluator__19TR_PPCTreeEvaluatorFP7TR_NodeP16TR_CodeGenera
    tor
    evaluate__16TR_CodeGeneratorFP7TR_Node
    doInstructionSelection__16TR_CodeGeneratorFv
    generateCodePhase1__16TR_CodeGeneratorFv
    generateCode__16TR_CodeGeneratorFv
    .
    The problem only exists in the 64bit PowerPC JIT compiler. The
    problem is not likely to occur using the default JIT, but has
    been seen a few times when using the compressed references JIT
    (-Xcompressedrefs option). The problem is unlikely to occur on
    Java5.
    

Local fix

  • Disable the compilation of the method that the JIT was compiling
    when the SIGSEGV occurred.
    -Xjit:exclude={<full_method_signature>}
    i.e.
    -Xjit:excldue={package/class.method()V}
    

Problem summary

  • The problem occurs when the JIT attempts to optimize away a long
    divide due to the fact that the divisor is determined to be the
    constant value 1. The problem only occurs when this
    transformation is done at a very late stage. The problem is rare
    because the transformation is almost always done at a much
    earlier stage of the compilation.
    

Problem conclusion

  • This defect will be fixed in:
    6.0.0 SR8
    5.0.0 SR11 FP2
    .
    The JIT was modified so that it handles this transformation
    correctly.
    .
    To obtain the fix:
    Install build 20091231 or later
    

Temporary fix

Comments

APAR Information

  • APAR number

    IZ67282

  • Reported component name

    JAVA 5 JIT

  • Reported component ID

    620500124

  • Reported release

    500

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2009-12-22

  • Closed date

    2010-01-18

  • Last modified date

    2010-04-29

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

    IZ67221

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

Fix information

  • Fixed component name

    JAVA 5 JIT

  • Fixed component ID

    620500124

Applicable component levels

  • R500 PSN

       UP



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Document information


More support for:

Runtimes for Java Technology
Just In Time (JIT) Compiler

Software version:

5.0

Reference #:

IZ67282

Modified date:

2010-04-29

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