Windows Media Unicast Service May Become Unresponsive and No Longer Serve Content (266752)


The information in this article applies to:

  • Microsoft Windows Media Services 4.0
  • Microsoft Windows Media Services 4.1
This article was previously published under Q266752

SYMPTOMS

The Windows Media Services Unicast Service may become unresponsive and no longer serve content.

CAUSE

This problem occurs because there is a race condition deadlock between two server threads, one of which is in the process of shutting down a client previously connected to a shared (broadcast) source, while the other is in the process of connecting a new client to the same shared source. Each thread enters two critical sections, but in opposite orders.

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 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/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 fix for Windows NT 4.0 and Windows 2000 can be obtained at:

http://download.microsoft.com/download/winmediatech40/Update/24957/NT45/EN-US/WMSU24957.EXE

The English version of this fix should have the following file attributes or later:
   Date        Time    Version      Size    File name  Platform
   --------------------------------------------------------------------
    06/29/2000  11:07 4.1.0.3858    440,288  Nsum.exe  x86 Windows NT
    06/29/2000  12:26 4.1.0.3920    440,800  NSum.exe  x86 Windows 2000

STATUS

Microsoft has confirmed that this is a problem in Windows Media Services.

MORE INFORMATION

The fix avoids taking one of the critical sections on one of the threads, so that the ordering problem (and therefore the potential for deadlock) is eliminated. This fix is fairly low risk, as it simply involves moving one buffer allocation from a method to the two calling sites, in order to allow a call to that method to occur outside of a critical section.

For additional information about how to install Windows 2000 and Windows 2000 hotfixes at the same time, click the article number below to view the article in the Microsoft Knowledge Base:

249149 Installing Microsoft Windows 2000 and Windows 2000 Hotfixes

Modification Type:MajorLast Reviewed:4/7/2006
Keywords:kbQFE KBHotfixServer kbdownload kbbug kbfix kbWin2000PreSP2Fix KB266752
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