IJ19897: SEGMENTATION ERROR IN JIT COMPILED METHOD JAVA/LANG/J9VMINTERNALS.FASTIDENTITYHASHCODE

APAR status

• Closed as program error.

Error description

• Error Message: A SIGSEGV/GPF is received
  .
  Stack Trace: Java stack from javacore
            Java callstack:
                  at
  java/lang/J9VMInternals.fastIdentityHashCode(J9VMInternals.java:
  360(Compiled Code))
                  at
  java/lang/Object.hashCode(Object.java:119(Compiled Code))
  .
  This problem was introduced in Java 8.0.5.22 and fixed in Java
  8.0.5.35. It effects all platforms.
  

Local fix

• This issue can be worked around using the -Xjit:disableUnsafe
  option. Note however that this may have performance impact.
  

Problem summary

• The JIT may query the constant pool entry twice to decide what
  intermediate representation to use for a call. During the two
  queries, the state of the constant pool entry may change from
  unresolved to resolved, causing a mismatch in information the
  JIT gets from the two queries, which then results in an
  unexpected intermediate representation that can be transformed
  into bad machine code.
  

Problem conclusion

• The JIT has been updated to re-read all the information from
  constant pool entry if the entry is resolved at the second
  query.
  .
  This APAR will be fixed in the following Java Releases:
     8    SR5 FP35  (8.0.5.35)
  .
  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