urlgrabber fails to close one of its fds on exception, causing livecd-creator to be unable to unmount the chroot and cleanup after itself. More details here: https://lists.dulug.duke.edu/pipermail/yum-devel/2007-November/004644.html Backported patch attached.
Created attachment 272791 [details] urlgrabber-3.0.0-cleanup.patch
Building for rawhide now.