Microsoft KB Archive/327542

= WMI Event Registration Leak =

Article ID: 327542

Article Last Modified on 2/24/2007

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APPLIES TO


 * Microsoft Windows 2000 Server
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Professional Edition

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This article was previously published under Q327542



SYMPTOMS
Windows Management Instrumentation (WMI) does not tear down temporary event registrations when the corresponding sink becomes invalid. An invalid sink can occur in the following scenarios:
 * A client did not cancel the event registration (IWbemServices::CancelAsyncCall).
 * The sink object was deleted before the reference count reached zero.
 * Hardware failure.
 * The client process was not gracefully ended.

Because of the invalid sink, events are continually generated to be queued for the consumer until the Winmgmt service is restarted. As a result, the Winmgmt process uses a large amount of CPU and memory resources.



CAUSE
When the Winmgmt service tries to call the sink on a client that has quit unexpectedly, an &quot;RPC Server Unavailable (0x800706BA)&quot; error occurs. (Alternatively, this behavior also occurs in Unsecapp.exe if the callback is made through an IUnsecuredApartment interface.) WMI cannot distinguish if the event delivery was unsuccessful because of a temporary network issue or because the client system quit unexpectedly. This error indicates that the target for the call was not currently available. Because the client did not cancel the event registration, WMI continues to call the client hoping to get events through when network connectivity is reestablished. Each event is timed out and discarded in the internal WMI event queue for the consumer, but the registration itself does not get timed out.



Service Pack Information
To resolve this problem, obtain the latest service pack for Microsoft Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

260910 How to Obtain the Latest Windows 2000 Service Pack

Hotfix Information
A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Windows 2000 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

  Date         Time   Version        Size     File name 25-Sep-2002 10:40  1.50.1085.88   643,146  Wbemcore.dll



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Microsoft Windows 2000 Service Pack 4.



MORE INFORMATION
When you apply this hotfix, the Windows 2000 WMI Event Sub-System cancels an event subscription when an remote procedure call (RPC) type error is detected during event delivery (for example, &quot;RPC Server Unavailable&quot;). The hotfix does not involve any real time monitoring of the connection. If an event consumer loses connectivity with WMI (Winmgmt), the event subscriptions are torn down the next time an event delivery is tried. WMI continues to use CPU resources to handle polling and intrinsic event registrations until an event delivery is tried. CPU resources are not impacted for real and extrinsic events. This solution is the same solution that was incorporated into Windows XP and later versions of Windows.

For additional information about how to obtain a hotfix for Windows 2000 Datacenter Server, click the article number below to view the article in the Microsoft Knowledge Base:

265173 The Datacenter Program and Windows 2000 Datacenter Server Product

Keywords: kbhotfixserver kbqfe kbqfe kbwin2ksp4fix kbsysadmin kbbug kbfix kbwin2000presp4fix KB327542

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