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IV50392: JIT-COMPILED LOOP CAUSES INCORRECT PROGRAM BEHAVIOUR

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APAR status

  • Closed as program error.

Error description

  • Error Message: The Java JIT compiler may incorrectly optimize a
loop that performs one bitwise operation (AND, OR, XOR) on
arrays, using two loop indices (or induction variables). After
the execution of an affected loop, the second induction variable
will be incorrectly updated or corrupted. This may in turn cause
a variety of incorrect program behaviour. In particular, a
program attempting to create a SSL connection may encounter an
unexpected javax.crypto.BadPaddingException due to this problem.
.
Stack Trace: N/A
.

Local fix

  • The -Xjit:disableIdiomRecognition option will work around this
issue.

Problem summary

  • The JIT compiler is able to recognize small loops and turn them
into CISC instructions available on System z hardware. In the
case of a loop that performs a single bitwise operation using
two induction variables, this optimization may produce incorrect
code.

Problem conclusion

  • This defect will be fixed in:
7.0.0 SR6
6.0.1 SR7
6.0.0 SR15
.
The JIT optimization has been corrected to update the second
induction variable appropriately.

Temporary fix

  • 



Comments


    

  • 



APAR Information




    

  • APAR number
    IV50392
    • 

  • Reported component name
    JIT
    • 

  • Reported component ID
    620700124
    • 

  • Reported release
    260
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Special Attention
    NoSpecatt
    • 

  • Submitted date
    2013-10-04
    • 

  • Closed date
    2013-10-04
    • 

  • Last modified date
    2013-10-04
    • 





    

  • 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
    • 








      
              
                            

              

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Document Information


            

            


                        

            Modified date:
            

            04 October 2013
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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