PI22215: LIBERTY PROFILE SERVER USES EXCESSIVE CPU WHEN TCPIP IS STOPPED

8.5.5.4: WebSphere Application Server V8.5.5 Fix Pack 4
8.5.5.5: WebSphere Application Server V8.5.5 Fix Pack 5
8.5.5.6: WebSphere Application Server V8.5.5 Fix Pack 6
8.5.5.7: WebSphere Application Server V8.5.5 Fix Pack 7
8.5.5.8: WebSphere Application Server V8.5.5 Fix Pack 8
8.5.5.9: WebSphere Application Server V8.5.5 Fix Pack 9
8.5.5.10: WebSphere Application Server V8.5.5 Fix Pack 10
8.5.5.11: WebSphere Application Server V8.5.5 Fix Pack 11
8.5.5.12: WebSphere Application Server V8.5.5 Fix Pack 12
8.5.5.13: WebSphere Application Server V8.5.5 Fix Pack 13
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.15: WebSphere Application Server V8.5.5 Fix Pack 15
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
8.5.5.20: WebSphere Application Server V8.5.5.20
8.5.5.18: WebSphere Application Server V8.5.5 Fix Pack 18
8.5.5.19: WebSphere Application Server V8.5.5 Fix Pack 19
8.5.5.16: WebSphere Application Server V8.5.5 Fix Pack 16
8.5.5.21: WebSphere Application Server V8.5.5.21

APAR status

• Closed as program error.

Error description

• After TCPIP is stopped, the liberty Server uses lots of CPU.
  It continues to use alot of CPU even after TCPIP is restarted.
  The Liberty Server must be restarted to stop the CPU usage.
  
  A dump of the Liberty Server shows 1 thread is using all the
  CPU.  The thread is kernel-command-listener and has this java
  stack trace:
  sun/nio/ch/ServerSocketChannelImpl.accept()
     source: ServerSocketChannelImpl.java:311
  com/ibm/ws/kernel/launch/internal/platform/
   ServerCommandListener.acceptAndExecuteCommand()
     source: ServerCommandListener.java:257
  com/ibm/ws/kernel/launch/internal/platform/
   ServerCommandListener$2.run()
     source: ServerCommandListener.java:237
  

Local fix

• Stop the Liberty Server before TCPIP is stopped
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server                                      *
  *                  Liberty Profile                             *
  ****************************************************************
  * PROBLEM DESCRIPTION: Excessive CPU usage when server socket  *
  *                      is closed from external causes, e.g.    *
  *                      turning off TCPIP                       *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The loop processing server commands (from the startup script)
  did
  not distinguish between (unrecoverable) errors from the socket
  becoming unusable (e.g. closed due to TCPIP turned off) and
  (recoverable) errors processing a single command
  

Problem conclusion

• We now detect when the socket is closed or otherwise unusable
  due to external factors and stop trying to read commands from
  it.
  
  The fix for this APAR is currently targeted for inclusion in fix
  pack 8.5.5.4. Please refer to the Recommended Updates page for
  delivery information:
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

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

  LIBERTY - Z/OS

• Fixed component ID

  5655W6514

Applicable component levels

• R850 PSY

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