IBM Support

PI15453: AIO TCP CHANNEL COULD HANG ON MICROSOFT WINDOWS OPERATING SYSTEMS

Fixes are available

8.5.5.2: WebSphere Application Server V8.5.5 Fix Pack 2
7.0.0.33: WebSphere Application Server V7.0 Fix Pack 33
8.0.0.9: WebSphere Application Server V8.0 Fix Pack 9
PI15453: AIO TCP channel could hang on Microsoft Windows operating systems
8.5.5.3: WebSphere Application Server V8.5.5 Fix Pack 3
7.0.0.35: WebSphere Application Server V7.0 Fix Pack 35
8.5.5.4: WebSphere Application Server V8.5.5 Fix Pack 4
8.0.0.10: WebSphere Application Server V8.0 Fix Pack 10
7.0.0.37: WebSphere Application Server V7.0 Fix Pack 37
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
8.0.0.11: WebSphere Application Server V8.0 Fix Pack 11
8.5.5.7: WebSphere Application Server V8.5.5 Fix Pack 7
7.0.0.39: WebSphere Application Server V7.0 Fix Pack 39
8.5.5.8: WebSphere Application Server V8.5.5 Fix Pack 8
8.0.0.12: WebSphere Application Server V8.0 Fix Pack 12
8.5.5.9: WebSphere Application Server V8.5.5 Fix Pack 9
7.0.0.41: WebSphere Application Server V7.0 Fix Pack 41
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
8.0.0.13: WebSphere Application Server V8.0 Fix Pack 13
7.0.0.43: WebSphere Application Server V7.0 Fix Pack 43
8.5.5.12: WebSphere Application Server V8.5.5 Fix Pack 12
8.0.0.14: WebSphere Application Server V8.0 Fix Pack 14
8.5.5.13: WebSphere Application Server V8.5.5 Fix Pack 13
7.0.0.45: WebSphere Application Server V7.0 Fix Pack 45
8.0.0.15: WebSphere Application Server V8.0 Fix Pack 15
7.0.0.45: Java SDK 1.6 SR16 FP60 Cumulative Fix for WebSphere Application Server
7.0.0.35: Java SDK 1.6 SR16 FP1 Cumulative Fix for WebSphere Application Server
7.0.0.37: Java SDK 1.6 SR16 FP3 Cumulative Fix for WebSphere Application Server
7.0.0.39: Java SDK 1.6 SR16 FP7 Cumulative Fix for WebSphere Application Server
7.0.0.41: Java SDK 1.6 SR16 FP20 Cumulative Fix for WebSphere Application Server
7.0.0.43: Java SDK 1.6 SR16 FP41 Cumulative Fix for WebSphere Application Server
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Due to a problem introduced by APAR PM95795, threads may hang
    and an application server may stop responding to requests on
    version V7.0.0.31 or V8.0.0.8.  This can happen when
    Asynchronous I/O (AIO) is enabled, which it is by default, and
    it can only occur on Windows operating systems.
    .
    Javacores and the SystemOut.log (WSVR0605W messages) may show
    many threads hung with a stack trace similar to the following:
    .
    Java callstack:
     at
    com/ibm/io/async/AsyncLibrary.terminateIOCB(AsyncLibrary.java:78
    8(Compiled Code))
     at
    com/ibm/io/async/AsyncSocketChannel.close(AsyncSocketChannel.jav
    a:314(Compiled Code))
     at
    com/ibm/ws/tcp/channel/impl/AioSocketIOChannel.close(AioSocketIO
    Channel.java:435(Compiled Code))
     at
    com/ibm/ws/tcp/channel/impl/TCPConnLink.destroy(TCPConnLink.java
    :530(Compiled Code))
     at
    com/ibm/wsspi/channel/base/OutboundConnectorLink.close(OutboundC
    onnectorLink.java:50(Compiled Code))
     at
    com/ibm/ws/tcp/channel/impl/TCPConnLink.close(TCPConnLink.java:5
    06(Compiled Code))
     at
    com/ibm/ws/http/channel/inbound/impl/HttpInboundLink.close(HttpI
    nboundLink.java:785(Compiled Code))
     at
    com/ibm/ws/http/channel/inbound/impl/HttpICLReadCallback.error(H
    ttpICLReadCallback.java:141)
     at
    com/ibm/ws/tcp/channel/impl/AioReadCompletionListener.futureComp
    leted(AioReadCompletionListener.java:220(Compiled Code))
     at
    com/ibm/io/async/AbstractAsyncFuture.invokeCallback(AbstractAsyn
    cFuture.java:217(Compiled Code))
     at
    com/ibm/io/async/AsyncChannelFuture.fireCompletionActions(AsyncC
    hannelFuture.java:161(Compiled Code))
     at
    com/ibm/io/async/AbstractAsyncFuture.completed(AbstractAsyncFutu
    re.java:170)
     at
    com/ibm/io/async/ResultHandler.complete(ResultHandler.java:213(C
    ompiled Code))
     at
    com/ibm/io/async/ResultHandler.runEventProcessingLoop(ResultHand
    ler.java:775(Compiled Code))
     at
    com/ibm/io/async/ResultHandler$2.run(ResultHandler.java:905(Comp
    iled Code))
     at
    com/ibm/ws/util/ThreadPool$Worker.run(ThreadPool.java:1660(Compi
    led Code))
    .
    These threads are blocked by another thread with the following
    stack trace:
    .
    Java callstack:
     at com/ibm/io/async/AsyncLibrary.aio_cancel2(Native Method)
     at com/ibm/io/async/AsyncLibrary.cancel2(AsyncLibrary.java:462)
     at
    com/ibm/io/async/AbstractAsyncChannel.cancel(AbstractAsyncChanne
    l.java:287)
     at
    com/ibm/io/async/AsyncChannelFuture.cancel(AsyncChannelFuture.ja
    va:114)
     at
    com/ibm/io/async/AsyncSocketChannelHelper$tCallback.timerTrigger
    ed(AsyncSocketChannelHelper.java:116)
     at
    com/ibm/io/async/Timer.checkForTimeouts(Timer.java:426(Compiled
    Code))
     at com/ibm/io/async/Timer.run(Timer.java:241(Compiled Code))
    

Local fix

  • AIO can be disabled to prevent the problem.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  IBM WebSphere Application Server Full       *
    *                  Profile Versions 7.0.0.31 and 8.0.0.8       *
    *                  users of AIO and on Microsoft Windows       *
    *                  operating systems                           *
    ****************************************************************
    * PROBLEM DESCRIPTION: A thread could hang when processing a   *
    *                      timeout                                 *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    A thread could hang when processing a possible timeout of  a
    TCP read/write operation due to thread synchronization issues.
    This could occur, when trying to confirm a read/write had been
    successfully cancelled and the operation could be truly
    declared a timeout. This problem was introduced with PM95795
    

Problem conclusion

  • To avoid the hang, polling code was added to the TCP AIO code
    to monitor the state of the cancel operation
    
    The fix for this APAR is currently targeted for inclusion in
    fix packs 7.0.0.33, 8.0.0.9 and 8.5.5.2.  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

    PI15453

  • Reported component name

    WEBS APP SERV N

  • Reported component ID

    5724H8800

  • Reported release

    850

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2014-04-08

  • Closed date

    2014-04-24

  • Last modified date

    2014-04-24

  • 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 APP SERV N

  • Fixed component ID

    5724H8800

Applicable component levels

  • R700 PSY

       UP

  • R800 PSY

       UP

  • R850 PSY

       UP



Document information

More support for: WebSphere Application Server
General

Software version: 850

Reference #: PI15453

Modified date: 24 April 2014