IV96648: EBP REGISTER HOLDS INCORRECT VALUE

APAR status

• Closed as program error.

Error description

• Error Message: Various symptoms can occur such as a crash,
  unexpected exceptions or incorrect behaviour.
  .
  Stack Trace: N/A
  .
  This problem can only occur on X86 32-bit systems.
  

Local fix

• The following environment variable needs to be set to avoid the
  problem.
  TR_DisableEBPasGPR=1
  

Problem summary

• The JIT compiler uses the EBP register as both a general purpose
  register as well as for holding JVM internal pointers on X86
  32-bit systems. At various points in a JIT compiled method, EBP
  needs to contain a JVM internal pointer, and so the value it
  previously held as a general purpose register needs to be moved
  and preserved. The JIT compiler was not correctly handling all
  of these cases, so it is possible for the incorrect value to be
  in EBP.
  

Problem conclusion

• The JIT compiler has been updated to no longer use EBP as a
  general purpose register on X86 32-bit systems.
  .
  This APAR will be fixed in the following Java Releases:
     8    SR4 FP6   (8.0.4.6)
     8    SR5 FP10  (8.0.5.10)
  .
  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

APAR Information

• 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