Deadlock condition may occur when a large number of DFS clients connect to a shared folder for the first time (824909)

SYMPTOMS

When many Distributed File System (DFS) clients connect to a server and access a shared folder for the first time, you may find that a deadlock condition occurs in the server message block (SMB) redirector component or in the Terminal Services redirector component. Therefore, the server does not return a referral to the DFS client, and the DFS client cannot connect to the shared folder.

For example, a deadlock condition in the Terminal Services redirector component may result when many DFS clients connect to the server in a Terminal Services session and access different \\ServerName\ShareName shares, where an entry does not exist for any one of the shares in the DFS referral cache.

CAUSE

This problem may occur if both the following conditions are true:

The number of network file access requests is larger than the number of available critical worker threads.
The network file access requests are for \\ServerName\ShareName shares that are accessed by the DFS client for the first time. That is, share entries do not exist in the DFS referral cache.

The DFS client (Mup.sys) posts network file access requests to the critical work queue on the server. Because the DFS client does not throttle work items, a deadlock condition may occur in situations where the redirector components require worker threads to complete the transport connection operations, and the worker threads are exhausted by the DFS client.

RESOLUTION

To resolve this issue, obtain the latest service pack for Windows Server 2003.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

889100 How to obtain the latest service pack for Windows Server 2003

Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Windows Server 2003 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

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

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 usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Prerequisites

This hotfix requires Windows Server 2003.

Restart requirement

You must restart your computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix 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
-------------------------------------------------------
22-Jul-2003  19:10  5.2.3790.71  106,496  Mup.sys
22-Jul-2003  18:58  5.2.3790.71  304,640  Mup.sys  IA-64