IV78631: CRASH IN LIBC GETENV DURING JIT COMPILATION

APAR status

• Closed as program error.

Error description

• Error Message: The JVM crashes with a GPF during JIT compilation
  and the javacore shows that the crash happened in getenv.
  .
  Stack Trace: Many different stacks are possible within the JIT
  compiler, but the top entry is always libc getenv:
  4XENATIVESTACK               getenv+0xe9 (0x00007FD617FE9F19
  <OSB>libc.so.6+0x34f19<CSB>)
  .
  Note: This APAR does not fix a problem. It only reduces the
  chances of hitting a problem caused by external native code
  executing within the java process (i.e. JNI).
  

Local fix

Problem summary

• The problem is caused by native methods adding to the
  environment variables in a multi-threaded application (Java
  applications are always multi-threaded). The libc getenv and
  putenv functions are not thread safe so while a putenv call is
  running a concurrent call to getenv is likely to encounter
  inconsistent data and fail. The JIT is one of several components
  that reads environment variables, but since it does so more
  often than most it is frequently the point of failure reported
  when this sort of crash occurs.
  

Problem conclusion

• A new option has been provided to prevent the JIT from
  attempting to read environment variables:
  -XX:doNotProcessJitEnvVars
  This will prevent JIT calls to getenv which might otherwise be
  impacted by concurrent putenv calls.
  Note that the use of this option can not completely guarantee
  crashes in getenv will no longer occur as other parts of the JVM
  and application code may still be using getenv, but it should
  greatly reduce the frequency of crashes. By using this option
  the JIT will no longer respond to any debugging environment
  variables.
  .
  This APAR will be fixed in the following Java Releases:
     6    SR16 FP20 (6.0.16.20)
     6 R1 SR8 FP20  (6.1.8.20)
     7 R1 SR3 FP30  (7.1.3.30)
     7    SR9 FP30  (7.0.9.30)
     8    SR2 FP10  (8.0.2.10)
  .
  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

• R600 PSY

     UP

• R260 PSY

     UP

• R130 PSY

     UP