IV19966: NON-ATOMIC VARIABLE-LENGTH ARRAYSET

Subscribe to this APAR

By subscribing, you receive periodic emails alerting you to the status of the APAR, along with a link to the fix after it becomes available. You can track this item individually or track all items by product.

Notify me when this APAR changes.

Notify me when an APAR for this component changes.

APAR status

  • Closed as program error.

Error description

  • Error Message: The following assertion in the GC was observed:
    0xf69800    j9mm.107    *   ** ASSERTION FAILED ** at
    MarkingScheme.cpp:299: ((isHeapObject(objectPtr)))
    .
    Stack Trace: N/A
    .
    

Local fix

  • This issue can be avoided using the
    -Xjit:disableIdiomRecognition,disableSequentialStoreSimplificati
    on,disableLoopReduction option. This option may cause a
    noticeable performance degradation.
    

Problem summary

  • The inlined sequence for variable-length non-byte arrayset
    generated by the Java JIT Compiler includes a single-byte XC
    instruction to handle residual (<256 bytes) elements.  As a
    result of this single byte clearing, a partially cleared and
    invalid element value may be visible to other threads
    concurrently examining that array.
    This issue only impacts JDKs on Linux on Z and zOS.
    

Problem conclusion

  • This defect will be fixed in:
    6.0.1 SR2
    7.0.0 SR1
    .
    The JVM has been updated to remove the single-byte XC
    instruction and generate an atomic sequence for all arrayset.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV19966

  • Reported component name

    JIT

  • Reported component ID

    620700124

  • Reported release

    260

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-04-20

  • Closed date

    2012-04-20

  • Last modified date

    2012-04-20

  • 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



Rate this page:

(0 users)Average rating

Document information


More support for:

Runtimes for Java Technology
Just In Time (JIT) Compiler

Software version:

260

Reference #:

IV19966

Modified date:

2012-04-20

Translate my page

Machine Translation

Content navigation