IV20339: SYSTEM Z JIT-COMPILED CODE CRASH AFTER CATCHING AN EXCEPTION

PM63541: SHIP SDK APARS IV18371+IV19615+IV20339 AS WSAS IFIX

APAR status

• Closed as program error.

Error description

• Error Message: A SIGSEGV or ABEND occurs in a JIT-compiled
  method after an inlined method throws an exception which is
  caught by a handler in the JIT-compiled method.
  The catch is often implicit, caused by the exception being
  thrown out of a synchronize block, which requires the JVM to
  unlock an object before continuing to look for a suitable catch
  block down the call stack. Hence, in some cases, the crash point
  can be in the native function jitMonitorExit.
  .
  Stack Trace:
  .
  This failure only occurs on a z196 system running z/OS or
  z/Linux.
  

Local fix

• This issue can be avoided by using the -Xjit:disableZGryphon
  option.
  

Problem summary

• The crash or ABEND occurs when program execution jumps to a
  wrong exception handler, due to an incorrectly specified
  exception range in the exception table of the JIT-compiled
  method.
  This problem is caused by a z196-specific optimization that
  exploits conditional move instructions to eliminate unnecessary
  branches. When the branch being eliminated comes from a basic
  block that can throw exceptions, the JIT compiler fails to mark
  the end of the exception range properly, and eventually
  generates a corrupt exception table.
  

Problem conclusion

• This defect will be fixed in:
  6.0.1 SR2 FP1
  7.0.0 SR2
  .
  The JIT compiler has been updated to generate correct exception
  ranges in this scenario.
  

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:

  PM74205

Fix information

• Fixed component name

  JIT

• Fixed component ID

  620700124

Applicable component levels

• R260 PSY

     UP