Microsoft KB Archive/152947

= XCON: Err Msg: Suspected Deadlock =

Article ID: 152947

Article Last Modified on 10/28/2006

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APPLIES TO


 * Microsoft Exchange Server 4.0 Standard Edition

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This article was previously published under Q152947



SYMPTOMS
The Microsoft Exchange Message Transfer Agent (MTA) is still alive but it fails to handle any additional incoming or outgoing messages via the Microsoft Exchange X.400 TCP/IP Connector. Several 9405 Event IDs appear in the Windows NT Event Log:

Error: suspected deadlock BASE KERNEL 29 (16) and MAIN BASE 1 (16)



CAUSE
The OPVRECON semaphore and the Kernel Control Block (CB) KPSEMID semaphore are acquired in a different order by two threads, causing a deadlock. This occurs when a message for an previously freed CB is sent into Platform, due to a close race condition, while the root thread is trying to acquire the same CB for a new connection.



STATUS
Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 4.0. This problem was corrected in the latest Microsoft Exchange Service Pack. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

Keywords: kbusage KB152947

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