DOCUMENT:Q284215 08-MAY-2002 [winnt] TITLE :Non-Paged Pool Leak in TimerQueue Active List Cleanup PRODUCT :Microsoft Windows NT PROD/VER::4.0 OPER/SYS: KEYWORDS:kbWinNT400PreSP7Fix ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server version 4.0 ------------------------------------------------------------------------------- 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 described in this article and should be applied only to systems experiencing this specific problem. This fix may receive additional testing at a later time, to further ensure product quality. 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, please go to the following address on the World Wide Web: http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS NOTE: In special cases, charges that are normally incurred for support calls may be canceled, if a Microsoft Support Professional determines that a specific update will resolve your problem. Normal 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 this to be a problem in the Microsoft products that are listed at the beginning of this article. Additional query words: ====================================================================== Keywords : kbWinNT400PreSP7Fix Technology : kbWinNTsearch kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 Version : :4.0 Hardware : ALPHA x86 Issue type : kbbug Solution Type : kbfix ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.