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IV81731: JAVA JIT: CRASH IN JIT COMPILED CODE

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APAR status

  • Closed as program error.

Error description

  • Error Message: SIGSEGV in JIT compiled code
.
Stack Trace: N/A
.
The problem can occur on any platform as long as you are using
the gencon or optavgpause gc policies, the problem is related to
"write barriers" which are only used with the parallel mark GC
phase.
This problem does NOT exist in Java 6.0 (J9VM R24) or earlier.

Local fix

  • The problem is best avoided by using the following Java command
line option to disable on JIT optimization phase:
-Xjit:disableLoopVersioner
The problem can also be avoid by using the flatheap GC policy.
Both options will have some effect on performance but the JIT
option is not likely to have a noticeable effect on performance
and therefore it is the work-around we would suggest in most
cases.

Problem summary

  • When the JIT compiler is duplicating code (JIT IL nodes) it can
forget to reset the NULL and Non-NULL flags, this potentially
leads the JIT to conclude that some code can be removed
resulting in a store to a NULL pointer and a crash.

Problem conclusion

  • The JIT was modified so that it correctly clears the
NULL/Non-NULL flags when duplicating code (JIT IL nodes) for use
with write barriers.
.
This APAR will be fixed in the following Java Releases:
   8    SR3       (8.0.3.0)
   7    SR9 FP40  (7.0.9.40)
   7 R1 SR3 FP40  (7.1.3.40)
   6 R1 SR8 FP25  (6.1.8.25)
.
Contact your IBM Product's Service Team for these Service
Refreshes and Fix Packs.
For those running stand-alone, information about the available
Service Refreshes and Fix Packs can be found at:
           https://www.ibm.com/developerworks/java/jdk/

Temporary fix

  • 



Comments


    

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APAR Information




    

  • APAR number
    IV81731
    • 

  • Reported component name
    JIT
    • 

  • Reported component ID
    620700124
    • 

  • Reported release
    130
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Special Attention
    NoSpecatt / Xsystem
    • 

  • Submitted date
    2016-02-22
    • 

  • Closed date
    2016-02-24
    • 

  • Last modified date
    2016-02-29
    • 





    

  • 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


    

  • R130  PSY
       UP
    • 

  • R260  PSY
       UP
    • 








      
              
                            

              

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Document Information


            

            


                        

            Modified date:
            

            29 February 2016
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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