IV61407: INFINITE LOOP IN JDWP

APAR status

• Closed as program error.

Error description

• Error Message: Customer reports JDWP is in infinite loop and it
  consumes high amounts of CPU after shutting down TCPIP on z/OS.
  .
  Stack Trace: The top of the stack iswp124
                                 _fwrite_inline
                            fwrite
                        libj9prt26.so::j9file_write+0xfe
                    libj9prt26.so::j9file_write_text+0x476
                libj9prt26.so::j9file_vprintf+0x8c
            libhyprtshim26.so::hystub_file_printf+and from the
  write, it appears to be reporting:13:39:02.613 ERROR:
  .PacketDispatcher.cpp:95. Run: Exception in: TransportException
  .510/202. socket accept failed or closed (error code:
  -247)......
  .
  Another simple way to reproduce the infinite loop is to run the
  following command with server=y and a negative numbersetting to
  timeout.java
  -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=4747,ti
  meout=-100
  

Local fix

• N/A
  

Problem summary

• In socket accept phase, if it fails and returns due to invalid
  parameters(e.g. timeout) or wrong TCP/IP status before waiting
  in blocking mode, it should not continue to try again in a loop.
  Otherwise, it will cause infinite loop issue.
  

Problem conclusion

• To resolve this issue, JDWP has been updated to check the
  invalid parameters(e.g. timeout) and wrong TCP/IP status
  conditions, then stop any attempts.
  .
  This APAR will be fixed in the following Java Releases:
  
     7    SR7 FP1   (7.0.7.1)
     6    SR16 FP1  (6.0.16.1)
     7 R1 SR1 FP1   (7.1.1.1)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, Java maintenance is available
  from:
             https://www.ibm.com/developerworks/java/jdk/
  

Temporary fix

• N/A
  

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

  JAVA CLASS LIBS

• Fixed component ID

  620700130

Applicable component levels

• R600 PSY

     UP

• R700 PSY

     UP