IV16593: JAVA JIT PPC - CRASH IN PPCCREATEMETHODTRAMPOLINE()

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Error Message: SIGSEGV after replacing classes using a java
    agent.
    .
    Stack Trace: {libj9jit23.so}{ppcCreateMethodTrampoline()}
    {libj9jit23.so}{createTrampoline()}
    {libj9jit23.so}{syncTempTrampolines()}
    {libj9jit23.so}{synchronizeTrampolines()}
    {libj9jit23.so}{jitHookGlobalGCEnd()}
    ...
    .
    This problem can only occur on PPC platforms (AIX and LinuxPPC).
    The problem has only even been seen on Java5. The way Java6 (and
    up) handles Java agents has changed making the problem nearly
    impossible to hit in Java6 and up.
    In order to hit this problem there must be no fewer then 2 class
    replace events and the JIT must consume more then one code cache
    (8mb by default).
    A class replace events are normally caused by requesting a Java
    agent to begin profiling a set of methods.
    

Local fix

  • There is no way to avoid this problem other then to avoid
    causing the java agent to replace classes or discontinue to use
    of the java agent completely.
    

Problem summary

  • When a class is replaced the Java5 JIT will discontinue using
    all previously compiled method bodies and revert to the
    interpreter until methods are compiled again. If this event
    occurs twice, there maybe pending long jump trampoline patch
    requests that will fail as the compiled code is no longer
    registered with the JVM.
    

Problem conclusion

  • This defect will be fixed in:
    5.0.0 SR14
    .
    The JIT was modified to handle this case appropriately.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV16593

  • 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

    2012-03-08

  • Closed date

    2012-05-18

  • Last modified date

    2012-05-18

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

    IV16590

  • 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 PSY

       UP



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Document information


More support for:

Runtimes for Java Technology
Just In Time (JIT) Compiler

Software version:

5.0

Reference #:

IV16593

Modified date:

2012-05-18

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