IV67654: LINUX CORE DUMP MISSING HEAP MEMORY WHEN USING HUGE PAGES

APAR status

• Closed as program error.

Error description

• Error Message: A core dump triggered on Linux via the operating
  system (not via the JVM dump agents) was smaller than expected.
  When opened with a tool such as jdmpview or Memory Analyser the
  core dump did not contain the memory for the Java heap.
  .
  Stack Trace: N/A
  .
  This issue only affects core dumps created by unhandled signals
  that cause a core dump to be generated by the operating
  system.If the JVM generates a core dump itself via the JVM dump
  agents and reports:"JVMDUMP032I JVM requested System dump ..."on
  the console it will have ensured the large pages are in the core
  dump.
  

Local fix

• Writing the string "0x7F" to the coredump_filter for a process
  will force Linux to include all the pages of memory in any core
  dump generated by the operating system for that process.The
  coredump_filter can be set for a running JVM by identifying the
  process id (pid) of the JVM and running:> echo 0x7F >
  /proc/<pid>/coredump_filterThe setting for a running process can
  be checked by running:> cat /proc/<pid>/coredump_filter
  

Problem summary

• The problem was caused by the JVM resetting the value of
  coredump_filter incorrectly.
  

Problem conclusion

• The JVM has been updated to set coredump_filter to 0x7F at
  startup.
  .
  This APAR will be fixed in the following Java Releases:
     7 R1 SR2 FP10  (7.1.2.10)
     6    SR16 FP3  (6.0.16.3)
     6 R1 SR8 FP3   (6.1.8.3)
     7    SR8 FP10  (7.0.8.10)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the 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

  J9 COMMON CODE

• Fixed component ID

  620700127

Applicable component levels

• R270 PSY

     UP

• R600 PSY

     UP

• R260 PSY

     UP