One of my clients came across an issue with (only) one of their SharePoint servers recently when applying the Project Server (August 2011) hotfix. The error involved the hung SharePoint Search Service. These steps are originally referenced in a Project Server Programming through PSI blog posting and found on the ProjectServerBlogs. Thanks to those all with contributing postings.
Project Errors and solutions:
1.Try to stop and restart the service:
Net stop osearch
Net start osearch
2.Try to kill the current processes
Stsadm –o osearch –action stop
Stsadm –o osearch –action start
3.Try killing the processes from task manager. The processes will be processing by the search service user.
4.Stop the service and kill the processes (1&2) and then go to your sqlServer and open the Activity job. Kill all processes which are using your crawling user which will be the processes which are hanging your server. Then restart the service.
Really hope this saves you time as this can be a bit unsettling to those that come across this for the 1st time (especially when they are performing this on Production after successfully running on their Development environment without seeing this).