Created attachment 34536 [details]
I'm using the SYNC extension to create a recurring event. The events happen as I expect them to, but the server uses 100% CPU. The server remains responsive and the CPU usage returns to normal when the client exits. I've attached a small program that triggers the problem.
I'm running Debian lenny (xorg 7.3) but I've also observed this behavior on Debian testing (xorg 7.5).
I tried the test program and cannot reproduce the CPU usage. I'm going to close this bug; please provide more info if you still see this using X server master.