Microsoft KB Archive/187884

= CoCreateInstance Under Stress on Multiple Threads at the Same Time Causes Long Hangs or Returns Failure =

Article ID: 187884

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Server 4.0, Terminal Server Edition
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 4.0 Standard Edition

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This article was previously published under Q187884





SYMPTOMS
Calling CoCreateInstance on multiple threads at the same time causes the computer to not respond (hang) for long periods of time. No desktop activity can be performed during this time. PerfMon logs during the time the computer is not responding show no signs that the computer is stressed. The idle thread has more than 95 percent of the CPU time while the computer is not responding. This problem was originally identified when hosting ASP pages that issue CoCreateInstance requests. When under stress, the computer would cease responding. CoCreateInstance requests would fail with the E_OUTOFMEMORY error leading up to the time when the computer quits responding.



CAUSE
The problem is caused by a shortage in the LPC resource pool. All threads that request LPC pool storage are in a wait (a two-minute timeout) for a free pool request to post that pool storage is available. Explorer.exe threads that need LPC pool storage will also wait. Since no free pool requests come through, all threads wait for two minutes, giving the appearance of a system hang. When the two minute timeout expires, the pool is expanded and all threads begin running again.



RESOLUTION
To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

152734 How to Obtain the Latest Windows NT 4.0 Service Pack



STATUS
Microsoft has confirmed that this is a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.

Additional query words: CoCreateInstance stress hang E_OUTOFMEMORY

Keywords: kbbug kbfix kbqfe KB187884

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