IV45074: JEXTRACT HANGS WHEN RUNNING AGAINST A LINUX CORE FILE

APAR status

• Closed as program error.

Error description

• Error Message: When the jextract tool is run against a Linux
  core file it does not terminate.
  If a java stack trace is obtained from the jextract process by
  triggering a javacore then the stack trace for the main method
  will appear to remain the same. The GC History section will show
  that objects are being freed and indicate that the tool is doing
  work but comparing stack traces across several javacores will
  show no progress is made on the main thread.
  .
  Stack Trace: 3XMTHREADINFO3           Java callstack:
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/ClosingFileReader.readFully(ClosingFile
  Reader.java:447(Compiled Code))
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/ClosingFileReader.readInt(ClosingFileRe
  ader.java:385(Compiled Code))
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/DumpReader.readInt(DumpReader.java:33(C
  ompiled Code))
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/LittleEndianDumpReader.readInt(LittleEn
  dianDumpReader.java:26(Compiled Code))
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/NewElfDump$ElfFile.readInt(NewElfDump.j
  ava:752(Compiled Code))
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/NewElfDump$ElfFile.readNote(NewElfDump.
  java:701(Compiled Code))
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/NewElfDump$ElfFile.readNotes(NewElfDump
  .java:695(Compiled Code))
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/NewElfDump$ElfFile.readProgramHeader(Ne
  wElfDump.java:687)
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/NewElfDump$ElfFile.readFile(NewElfDump.
  java:617)
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/NewElfDump$Elf32File.<init>(NewElfDump.
  java:967)
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/NewElfDump.readModules(NewElfDump.java:
  1219)
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/NewElfDump.buildProcess(NewElfDump.java
  :1145)
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/NewElfDump.readProcess(NewElfDump.java:
  1138)
  4XESTACKTRACE                at
  com/ibm/dtfj/corereaders/NewElfDump.extract(NewElfDump.java:1879
  )
  4XESTACKTRACE                at
  com/ibm/jvm/j9/dump/extract/Main.<init>(Main.java:430)
  4XESTACKTRACE                at
  com/ibm/jvm/j9/dump/extract/Main.main(Main.java:318)
  .
  

Local fix

Problem summary

• The problem was caused when a core file is damaged or contains
  unexpected data.
  

Problem conclusion

• This defect will be fixed in:
  7.0.0 SR5
  6.0.1 SR6
  6.0.0 SR14
  .
  The jextract tool has been updated with an additional validity
  check on the contents of the file that will prevent this
  unexpected data causing it not to terminate.
  

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

• R260 PSY

     UP

• R600 PSY

     UP