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

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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 number

    IT21856

  • Reported component name

    WEBS MQ NSS ITA

  • Reported component ID

    5724A3902

  • Reported release

    531

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2017-08-04

  • Closed date

    2017-08-23

  • Last modified date

    2017-08-23

  • 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

       UP

[{"Line of Business":{"code":"LOB36","label":"IBM Automation"},"Business Unit":{"code":"BU053","label":"Cloud \u0026 Data Platform"},"Product":{"code":"SSFKSJ","label":"WebSphere MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"5.3.1"}]

Document Information

Modified date:
27 September 2021