APAR status
Closed as program error.
Error description
Error Message: When this problem is encountered it may manifest itself as an exception relating to invalid program data or as incorrect program output. . Stack Trace: N/A . The problem occurs in rare circumstances where data is being copied between overlapping source and destination subranges in a single Java array using a loop. The code generated by the JIT compiler in these rare circumstances on x86 and POWER systems can result in incorrect values being placed in the destination range of array elements.
Local fix
The issue can be worked around by using the -Xjit:disableIdiomRecognition option. Note that this will likely cause a performance degradation.
Problem summary
The problem occurs when a Java application is copying array elements between overlapping source and destination subranges of a single array using a loop. In some rare circumstances, the JIT may generate an optimized implementation of the loop that is not functionally equivalent to the original Java loop when executed on x86 and POWER systems. This can result in data corruption in the array during the copy operation.
Problem conclusion
The JIT has been modified to ensure that code generated is always functionally equivalent to the original Java loop and will not produce any incorrect values. . This APAR will be fixed in the following Java Releases: 6 SR16 FP2 (6.0.16.2) 6 R1 SR8 FP2 (6.1.8.2) 7 R1 SR2 (7.1.2.0) 7 SR8 (7.0.8.0) . Contact your IBM Product's Service Team for these Service Refreshes and Fix Packs. For those running stand-alone, Java maintenance is available from: https://www.ibm.com/developerworks/java/jdk/
Temporary fix
Comments
APAR Information
APAR number
IV64048
Reported component name
JIT
Reported component ID
620700124
Reported release
600
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2014-08-27
Closed date
2014-08-27
Last modified date
2014-08-27
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
R600 PSY
UP
R260 PSY
UP
R130 PSY
UP
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Document Information
Modified date:
27 August 2014