IV24866: CRASH IN JIT RUN-TIME LIBRARY IN REPLACETRAMPOLINE

APAR status

• Closed as program error.

Error description

• Error Message: A SIGSEGV/GPF is raised by the Java JIT run-time
  library code that manages code caches. This crash only occurs if
  the JVM is running on a 64-bit x86-based processor.
  .
  Stack Trace: TR_MCCCodeCache::replaceTrampoline
  TR_MCCManager::replaceTrampoline
  mcc_replaceTrampoline
  amd64CodePatching
  TR_MCCCodeCache::patchTrampoline
  TR_MCCCodeCache::patchCallPoint
  mcc_callPointPatching_unwrapper
  jitCallCFunction
  mergedStaticGlueCallFixer
  .
  

Local fix

• N/A
  

Problem summary

• On x86-64, if a JIT-compiled method calls an interpreted method,
  the JIT compiler generates a special data structure in the
  current code cache. If another code cache becomes current before
  the compilation has completed, the data structure in the
  original current code cache becomes obsolete, and future
  searches for this data structure in the current code cache will
  fail, which will cause the JVM to crash.
  

Problem conclusion

• This defect will be fixed in:
  6.0.0 SR11
  .
  The JIT compiler has been modified to re-reserve space for a new
  data structure for the interpreter dispatch if it detects that
  the current code cache has been switched.
  

Temporary fix

• The problem can be avoided by configuring the JIT to use a
  single code cache. However, since the maximum size of an
  individual cache is 32 MBytes the total amount of code that can
  be JIT compiled will be reduced from the default when using this
  option, and this may lead to reduced performance for some
  applications.
  
  -Xjit:code=32768,codetotal=32768
  

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

• R600 PSY

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