Created attachment 21646 [details] [review]
proposed fix

In xdg-screensaver, do_resume() and track_window() both call
cleanup_suspend() to remove the tracking process from the status file.
cleanup_suspend() removes the process using a grep -v for the window
id.  This means there is a race condition after the first removal
where a new tracking process can be created and then removed from the
status file while it's still active.

I think this can be fixed by either (1) looking for the process id
in the status file or (2) removing one of the
calls to cleanup_suspend().

The attached patch does (1).