IJ50938: JAVA JIT - CRASH IN TR_HANDLEINJECTEDBASICBLOCK::FINDANDREPLACEREFERENCES()

APAR status

• Closed as program error.

Error description

• Error Message: A SEGSEGV is received when JIT compiling a
  method.
  .
  Stack Trace:
  libj9jit29.so}{TR_HandleInjectedBasicBlock::findAndReplaceRefere
  nces(TR::TreeTop*,TR::Block*,TR::Block*)}
  libj9jit29.so}{OMR::Block::split(TR::TreeTop*,TR::CFG*,bool,bool
  ,TR::ResolvedMethodSymbol*)}
  libj9jit29.so}{splitRuntimeGuardBlock(TR::Compilation*,TR::Block
  *,TR::CFG*)}
  libj9jit29.so}{TR_VirtualGuardHeadMerger::perform()}
  libj9jit29.so}{OMR::Optimizer::performOptimization(const
  OptimizationStrategy*,int,int,int)}
  libj9jit29.so}{OMR::Optimizer::performOptimization(const
  OptimizationStrategy*,int,int,int)}
  libj9jit29.so}{OMR::Optimizer::optimize()}
  libj9jit29.so}{OMR::Compilation::compile()}
  libj9jit29.so}{TR::CompilationInfoPerThreadBase::compile(J9VMThr
  ead*,TR::Compilation*,TR_ResolvedMethod*,T...}
  libj9jit29.so}{TR::CompilationInfoPerThreadBase::wrappedCompile(
  J9PortLibrary*,void*)}
  libj9prt29.so}{omrsig_protect}
  libj9jit29.so}{TR::CompilationInfoPerThreadBase::compile(J9VMThr
  ead*,TR_MethodToBeCompiled*,J9::J9SegmentP...}
  libj9jit29.so}{TR::CompilationInfoPerThread::processEntry(TR_Met
  hodToBeCompiled&,J9::J9SegmentProvider&)}
  libj9jit29.so}{TR::CompilationInfoPerThread::processEntries()}
  libj9jit29.so}{protectedCompilationThreadProc(J9PortLibrary*,TR:
  :CompilationInfoPerThread*)}
  libj9prt29.so}{omrsig_protect}
  libj9jit29.so}{compilationThreadProc(void*)}
  libj9thr29.so}{thread_wrapper}
  .
  The problem can occur with a different stack trace then what is
  shown in this APAR, but it should always show a crash in the
  compiler. We have seen this issue cause a crash in
  GlobalRegisterAllocator as well as VirtualGuardHeadMerger.
  

Local fix

• The problem can be avoided by using the following java command
  line argument:
  -Xjit:disableVirtualGuardHeadMerger
  This option will disable the JIT optimization that has the
  problem. Disabling this optimization should show a minor impact
  on performance.
  

Problem summary

• The JIT optimization VirtualGuardHeadMerger could corrupt the
  compiler's internal representation of the Java code being
  compiled causing the compiler to crash later on in
  VirtualGuardHeadMerger or some other optimization.
  

Problem conclusion

• The JIT was modified so that VirtualGuardHeadMerger will not
  corrupt the internal representation.
  .
  This APAR will be fixed in the following Releases:
  .
  IBM Semeru Runtimes
    21              21.0.4.0
    17              17.0.12.0
    11              11.0.24.0
  IBM SDK, Java Technology Edition
    8    SR8 FP30  (8.0.8.30)
  .
  Downloads and supplementary documentation can be found at the
  following locations:
  - For non z/OS operating systems:
   - IBM Semeru Runtimes, Version 11 and later
     https://www.ibm.com/semeru-runtimes/downloads/
   - IBM SDK, Java Technology Edition, Version 8
     https://www.ibm.com/support/pages/java-sdk-downloads/
  - For the z/OS operating system:
   - Java SDK Products on z/OS
     https://www.ibm.com/support/pages/java-sdk-products-zos
  

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