IJ47085: JAVA JIT: SIG_SEGV IN SETHANDLERINFOWITHOUTBCINFO()

APAR status

• Closed as program error.

Error description

• Error Message: A SIG_SEGV while JIT compiling a method
  The javacore will have a line like this:
  1XHEXCPMODULE  Compiling method: ...
  .
  Stack Trace:
  {libj9jit29.so}{setHandlerInfoWithOutBCInfo__Q2_3OMR5BlockFUiUcU
  sP17TR_ResolvedMethodPQ2_2TR11Compilat...}
  {libj9jit29.so}{processBytecodeAndGenerateCFG__21TR_J9EstimateCo
  deSizeFP13TR_CallTargetRQ2_2TR6RegionR...}
  {libj9jit29.so}{realEstimateCodeSize__21TR_J9EstimateCodeSizeFP1
  3TR_CallTargetP12TR_CallStackbRQ2_2TR6...}
  {libj9jit29.so}{estimateCodeSize__21TR_J9EstimateCodeSizeFP13TR_
  CallTargetP12TR_CallStackb}
  {libj9jit29.so}{calculateCodeSize__19TR_EstimateCodeSizeFP13TR_C
  allTargetP12TR_CallStackb}
  {libj9jit29.so}{estimateAndRefineBytecodeSize__16TR_J9InlinerUti
  lFP11TR_CallSiteP13TR_CallTargetP12TR_...}
  {libj9jit29.so}{applyPolicyToTargets__14TR_InlinerBaseFP12TR_Cal
  lStackP11TR_CallSite}
  {libj9jit29.so}{getSymbolAndFindInlineTargets__14TR_InlinerBaseF
  P12TR_CallStackP11TR_CallSiteb}
  {libj9jit29.so}{inlineCallTargets__28TR_MultipleCallTargetInline
  rFPQ2_2TR20ResolvedMethodSymbolP12TR_...}
  {libj9jit29.so}{performInlining__14TR_InlinerBaseFPQ2_2TR20Resol
  vedMethodSymbol}
  {libj9jit29.so}{perform__10TR_InlinerFv}
  {libj9jit29.so}{performOptimization__Q2_3OMR9OptimizerFPC20Optim
  izationStrategyiN22}
  {libj9jit29.so}{optimize__Q2_3OMR9OptimizerFv}
  {libj9jit29.so}{compile__Q2_3OMR11CompilationFv}
  ...
  .
  The problem can occur on any platform when using the IBM JVM,
  but the issue can only occur when compiling a method that is
  very close to the JVM method size limit of 65536 bytes. I
  believe the issue might be limited to method that are not
  compiled using javac, like auto generated methods.
  

Local fix

• The issue can only be avoided by preventing the JIT from
  attempting to compile the method which triggers the issue to
  occur. This can be achieved by using the following java command
  line option with the method name that is seen in the javacore on
  the "1XHEXCPMODULE  Compiling method" line.
  -Xjit:exclude={full_method_name_from_javacore}
  

Problem summary

• The JIT was using 16bit variables to hold the offset to try
  region and catcher bytecodes. In some rare cases where (after
  being loaded by the VM) a method size can exceed 65536 bytes,
  and if the bytecode offset of a try region or a catch bock is
  greater then 65536, truncation will occur leading to a SIG_SEGV.
  

Problem conclusion

• The JIT was modified so that the try region and catch block
  offsets are held in 32bit variables.
  See:
  https://github.com/eclipse/omr/pull/6999
  https://github.com/eclipse-openj9/openj9/pull/17469
  .
  This APAR will be fixed in the following Releases:
  .
  IBM SDK, Java Technology Edition
     8    SR8 FP10  (8.0.8.10)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the available
  maintenance can be found at:
             https://www.ibm.com/support/pages/java-sdk
  

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