IJ04875: JAVA JIT: CRASH IN JIT LIBRARY FUNCTION FINDCLASSINFO()

APAR status

• Closed as program error.

Error description

• Error Message: A SIGSEGV is received while executing
  findClassInfo() when the JIT is compiling a method.
  .
  Stack Trace:
  TR_PersistentCHTable::findClassInfo(TR_OpaqueClassBlock*)()
  TR_PersistentInfo::isObsoleteClass(void*,TR_FrontEnd*)()
  TR_PPCPrivateLinkage::buildVirtualDispatch(...)()
  ...
  .
  The issue is only known to occur on PowerPC machines. The issue
  is unlikely to occur on architectures that have strong memory
  coherency (like X86 or ZSeries).
  

Local fix

• Depending on the release of Java, one of the following java
  command line options can be used to avoid the problem:
  Java 6/7.0: -Xjit:disableCHTable,disableCHOpts
  Java 7.1/8: -Xjit:disableCHOpts
  The use of the above options will have some effect on the
  execution performance of JIT compiled code.
  

Problem summary

• The JIT compiler failed to use locking to prevent a compiler
  thread from reading from an internal data structure at the same
  time that another compiler thread is adding to the structure
  which can lead to a crash in findClassInfo() on architectures
  that have weak memory coherency.
  

Problem conclusion

• The JIT was modified so that proper locking is used to prevent
  concurrent access to a JIT internal data structure.
  .
  This APAR will be fixed in the following Java Releases:
   7 SR10 FP25 (7.0.10.25)
   7 R1 SR4 FP25 (7.1.4.25)
   6 R1 SR8 FP65 (6.1.8.65)
   8 SR5 FP11 (8.0.5.11)
  .
  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:

• Fixed component name

  JIT

• Fixed component ID

  620700124

Applicable component levels