IBM Support

PI80719: Websocket race condition on writing data while closing can hang a thread

Fixes are available

9.0.0.4: WebSphere Application Server traditional V9.0 Fix Pack 4
9.0.0.5: WebSphere Application Server traditional V9.0 Fix Pack 5
9.0.0.6: WebSphere Application Server traditional V9.0 Fix Pack 6
9.0.0.7: WebSphere Application Server traditional V9.0 Fix Pack 7
17.0.0.2: WebSphere Application Server Liberty 17.0.0.2
17.0.0.3: WebSphere Application Server Liberty 17.0.0.3
17.0.0.4: WebSphere Application Server Liberty 17.0.0.4
18.0.0.1: WebSphere Application Server Liberty 18.0.0.1
18.0.0.2: WebSphere Application Server Liberty 18.0.0.2
9.0.0.8: WebSphere Application Server traditional V9.0 Fix Pack 8
9.0.0.9: WebSphere Application Server traditional V9.0 Fix Pack 9
18.0.0.3: WebSphere Application Server Liberty 18.0.0.3
9.0.0.10: WebSphere Application Server traditional V9.0 Fix Pack 10
18.0.0.4: WebSphere Application Server Liberty 18.0.0.4
19.0.0.1: WebSphere Application Server Liberty 19.0.0.1
19.0.0.2: WebSphere Application Server Liberty 19.0.0.2
19.0.0.3: WebSphere Application Server Liberty 19.0.0.3
9.0.0.11: WebSphere Application Server traditional V9.0 Fix Pack 11
19.0.0.4: WebSphere Application Server Liberty 19.0.0.4
19.0.0.5: WebSphere Application Server Liberty 19.0.0.5
9.0.5.0: WebSphere Application Server traditional Version 9.0.5 Refresh Pack
19.0.0.6: WebSphere Application Server Liberty 19.0.0.6
19.0.0.7: WebSphere Application Server Liberty 19.0.0.7
19.0.0.8: WebSphere Application Server Liberty 19.0.0.8
9.0.5.1: WebSphere Application Server traditional Version 9.0.5 Fix Pack 1
19.0.0.9: WebSphere Application Server Liberty 19.0.0.9
19.0.0.10: WebSphere Application Server Liberty 19.0.0.10
19.0.0.11: WebSphere Application Server Liberty 19.0.0.11
9.0.5.2: WebSphere Application Server traditional Version 9.0.5 Fix Pack 2
19.0.0.12: WebSphere Application Server Liberty 19.0.0.12
20.0.0.1: WebSphere Application Server Liberty 20.0.0.1
20.0.0.2: WebSphere Application Server Liberty 20.0.0.2
9.0.5.3: WebSphere Application Server traditional Version 9.0.5 Fix Pack 3
20.0.0.3: WebSphere Application Server Liberty 20.0.0.3
20.0.0.4: WebSphere Application Server Liberty 20.0.0.4
20.0.0.5: WebSphere Application Server Liberty 20.0.0.5
20.0.0.6: WebSphere Application Server Liberty 20.0.0.6
9.0.5.4: WebSphere Application Server traditional Version 9.0.5 Fix Pack 4
20.0.0.7: WebSphere Application Server Liberty 20.0.0.7
20.0.0.8: WebSphere Application Server Liberty 20.0.0.8
9.0.5.5: WebSphere Application Server traditional Version 9.0.5 Fix Pack 5
20.0.0.9: WebSphere Application Server Liberty 20.0.0.9
20.0.0.10: WebSphere Application Server Liberty 20.0.0.10
20.0.0.11: WebSphere Application Server Liberty 20.0.0.11
20.0.0.12: WebSphere Application Server Liberty 20.0.0.12
9.0.5.6: WebSphere Application Server traditional Version 9.0.5 Fix Pack 6

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • websocket race condition on writing data while closing can
    hang a thread
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server Liberty - Channel Framework          *
    ****************************************************************
    * PROBLEM DESCRIPTION: Thread leak can occur when a websocket  *
    *                      session is writing data and the client  *
    *                      closes the socket before closing the    *
    *                      session                                 *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    There is a race condition that has a small chance of happening
    when the websocket server is writing a message and the client
    closes the connection without properly closing the websocket
    session with a close frame.  This race condition does not affect
    the program's functionality, but will cause a thread to hang,
    and the hanging thread can be see in a javacore.
    

Problem conclusion

  • The problem was fixed by programatically removing the race
    condition, and to better handle the case where the websocket
    session is closed abruptly by the client when the client does
    not send a websocket close frame.
    
    The fix for this APAR is currently targeted for inclusion in fix
    pack 17.0.0.2  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 number

    PI80719

  • Reported component name

    WAS LIBERTY COR

  • Reported component ID

    5725L2900

  • Reported release

    CD0

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2017-04-27

  • Closed date

    2017-05-18

  • Last modified date

    2017-05-18

  • 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

    WAS LIBERTY COR

  • Fixed component ID

    5725L2900

Applicable component levels

  • RCD0 PSY

       UP

[{"Line of Business":{"code":"LOB36","label":"IBM Automation"},"Business Unit":{"code":"BU053","label":"Cloud \u0026 Data Platform"},"Product":{"code":"SSD28V","label":"WebSphere Application Server Liberty Core"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"CD0"}]

Document Information

Modified date:
07 September 2021