Multiple problems trying to unmount loop device mounts 1. If lock-break support is compiled in, the system freezes instantly if umount is issued 2. If lock-break is disabled ( either the kernel is not patched or the option is not activated in config ) umount /dev/loop? gives "device busy" error. umount /mountpoint seems to work, but actual loop device stays locked and has to be manualy unlocked using losetup. The only place I found so far where this is causing real trouble is when trying to convert system to LVM. The lvmcreate_initrd script fails. Also there might be some nasty surprises when writing CDs.
Sorry, forgot the versions kernel: 2.4.16 ( preempt, lock-break, XFS and ACPI applied ) glibc, gcc etc. from the current portage tree without any modifications
Try merging baselayout-1.7.0 (on rsync in 1/2 hr -- we're using a real /etc/mtab instead of a symlink) and using kernel 2.4.18_pre3 which includes loopback device fixes. This should change things dramatically for the better. I'm marking this as fixed; resubmit a bug if you still have problems.