IJ35496: JAVA JIT COMPILE TIME SOF IN TR_INDUCTIONVARIABLEANALYSIS::GETENTRYVALUE()

APAR status

• Closed as program error.

Error description

• Error Message: A SIGSEGV is received when JIT compiling a large
  method (likely a machine generated java method).
  .
  Stack Trace:
  {libj9jit29.so}{getUseDefAliasesBV__Q2_3OMR15SymbolReferenceFbT1
  } <OSB>0x10020d401c0<CSB>
  {libj9jit29.so}{getTRAliases_impl__24TR_NodeAliasSetInterfaceXSP
  1_FbT1} <OSB>0x10020d402a0<CSB>
  {libj9jit29.so}{contains__20TR_AliasSetInterfaceXT24TR_NodeAlias
  SetInterfaceXSP1__FUiPQ2_2TR11Compilation}
  <OSB>0x10020d40380<CSB>
  {libj9jit29.so}{getEntryValue__28TR_InductionVariableAnalysisFPQ
  2_2TR5BlockPQ2_2TR15SymbolReferenceP12TR_BitVectorR8TR_ArrayXTPQ
  2_2TR4Node_} <OSB>0x10020d40450<CSB>
  {libj9jit29.so}{getEntryValue__28TR_InductionVariableAnalysisFPQ
  2_2TR5BlockPQ2_2TR15SymbolReferenceP12TR_BitVectorR8TR_ArrayXTPQ
  2_2TR4Node_} <OSB>0x10020d405e0<CSB>
  {libj9jit29.so}{getEntryValue__28TR_InductionVariableAnalysisFPQ
  2_2TR5BlockPQ2_2TR15SymbolReferenceP12TR_BitVectorR8TR_ArrayXTPQ
  2_2TR4Node_} <OSB>0x10020d40770<CSB>
  --- The getEntryValue() frames will repeat hundreds or thousands
  of times ---
  The crashing method is irrelevant, the crash will occur in
  whatever method overflows the stack. It's the repeated
  getEntryValue() frames that is unique to this issue.
  .
  The problem can occur on any OpenJ9 based JVM (all platforms).
  Typically it occurs when a large amount of code is between the
  definition of a variable and it's use in a loop as an induction
  variable to control the loop.
  

Local fix

• The problem can be avoid by disabling the compilation of the
  affected method(s):
  -Xjit:exclude={<affected_method_signature>}
  The <affected_method_signature> can be obtained from the java
  console crash data output when the problem occurred.
  

Problem summary

• The JIT uses a recursive function during induction variables
  analysis. This can cause a SOF (stack overflow) if the method is
  very large and the definition of a variable related to a loop is
  far from the start of the loop it's self.
  

Problem conclusion

• The JIT was modified to give up looking for a variable
  definition when the depth of the recursion reaches a limit.
  .
  This APAR will be fixed in the following Java Releases:
   8 SR7 (8.0.7.0)
  .
  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