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WMI Event Registration Leak

Article ID: 327542 - View products that this article applies to.

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.

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CAUSE

When the Winmgmt service tries to call the sink on a client that has quit unexpectedly, an "RPC Server Unavailable (0x800706BA)" 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.

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RESOLUTION

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

(http://support.microsoft.com/kb/260910/EN-US/ )

How to Obtain the Latest Windows 2000 Service Pack

Hotfix Information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site:

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

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

Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language. 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

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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.

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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, "RPC Server Unavailable"). 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

(http://support.microsoft.com/kb/265173/EN-US/ )

The Datacenter Program and Windows 2000 Datacenter Server Product

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