Microsoft KB Archive/284215

= Non-Paged Pool Leak in TimerQueue Active List Cleanup =

PSS ID Number: 284215

Article Last Modified on 10/16/2002

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The information in this article applies to:


 * Microsoft Windows NT Server 4.0

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This article was previously published under Q284215



SYMPTOMS
Netbt.sys may send many broadcast messages from a Windows NT 4.0-based server (by using UdpSendNSBcast). The absence of a response to particular broadcast messages causes a Netbt timer function to expire after a retry period. Typically, a timer cleanup routine moves expired list entries from an active list to a free list, and list entry memory blocks are reused. In the situation that is described in this article, however, expired memory blocks are being abandoned. The result is a non-paged pool leak of 0xA0 (160 bytes) for each abandoned entry. After many ignored broadcast messages and several weeks, non-paged pool may be exhausted.



CAUSE
A special condition causes expired timer memory blocks to be abandoned and not moved to the free list for reuse. This special condition has been modified to prevent the problem.



RESOLUTION
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 NT 4.0 service pack that contains this fix.

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/default.aspx?scid=fh;EN-US;CNTACTMS

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 should have the following file attributes or later:   Date         Time     Size      File name   Platform 02/12/2001  08:51p   124,720   Netbt.sys   Intel



WORKAROUND
To work around this problem, review network broadcasts and determine if broadcasts are being ignored. Monitor non-paged pool by using Perfmon, and cycle the servers before before non-paged pool is exhausted. Use this method until you can apply this hotfix.



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

Keywords: kbbug kbQFE KB284215

Technology: kbWinNT400search kbWinNTS400 kbWinNTS400search kbWinNTsearch kbWinNTSsearch

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