IBM Support

IV20274: JIT INTERNAL STRUCTURE MISALIGNMENT CAUSING CRASHES

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APAR status

  • Closed as program error.

Error description

  • Error Message: The JVM crashes while dereferencing an invalid
    pointer during Java JIT Meta Data walking.  The problem occurs
    when 2 threads try to perform the meta data walking at the same
    time and access (both read and write into) the same internal JIT
    data structure at the same time.
    .
    Stack Trace: N/A
    .
    

Local fix

Problem summary

  • The problem occurs when an internal Java JIT structure becomes
    misaligned on 64-bit platforms.  This is a timing issue caused
    when an internal structure address is written at the same time
    that it is loaded by another thread and so the read would only
    pick up half of the changed address.
    

Problem conclusion

  • This defect will be fixed in:
    6.0.1 SR1
    7.0.0 SR1
    6.0.0 SR11
    .
    The JVM has been updated to fix the misaligned internal JIT data
    structures.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV20274

  • Reported component name

    JIT

  • Reported component ID

    620700124

  • Reported release

    260

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-04-26

  • Closed date

    2012-04-26

  • Last modified date

    2012-04-26

  • 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

    JIT

  • Fixed component ID

    620700124

Applicable component levels

  • R260 PSY

       UP

  • R600 PSY

       UP



Document information

More support for: Runtimes for Java Technology
Just In Time (JIT) Compiler

Software version: 260

Reference #: IV20274

Modified date: 26 April 2012