IT21856: PREVENTING THE HANGING OF CONNECTING APPLICATIONS WHEN UNEXPECTED ERROR BY 'PTHREAD_MUTEX_LOCK' IS ENCOUNTERED.

WebSphere MQ for HP NonStop Server V5.3.1 fix pack 5.3.1.14

APAR status

• Closed as program error.

Error description

• Following a cpu down/up event (non core processes). When
  Applications then tried to connect to the qmgr an FFST regarding
   an unexpected error by 'pthread_mutex_lock' occured and the
  connecting application began to hang during its open request to
  the lqma process. This also happened with other newly started
  applications when they tried to connect until the queue manager
  was restarted.
  

Local fix

• To resolve the situation without restarting the qmgr, stop the
  LQMA not handling its open requests. (Using pstate of
  application hanging).
  

Problem summary

• Should a call to 'pthread_mutex_lock'
  fail with error 4022 during the processing of an open message on
  $RECEIVE, the message is discarded but no REPLY is sent to the
  opening process, resulting in it not returning from its open
  call and appearing to hang indefinitely during MQCONN.
  

Problem conclusion

• Since unexpected errors caused by
  failing mutex function calls are not recoverable, the product
  has been changed as such that processes will now terminate in
  a controlled fashion in such situations.
  

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

  WEBS MQ NSS ITA

• Fixed component ID

  5724A3902

Applicable component levels

• R531 PSY

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