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
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Document Information
Modified date:
20 April 2012