LOOP_SET_STATUS: invalid argument

["Daniel M. Debertin" <katdan@mninter.net>]

Has anyone else tried the kernel patches from ftp.kerneli.org? The
"International kernel patch" contains quite a bit of strong crypto, and
surprisingly, they keep their patches up to date (i.e. they are for
something newer than 2.0.11 ;). Anyway, while fooling around with the
latest patch (for 2.2.5), I have come up with the most pernicious problem.
After compiling the kernel with this patch (hoping someone on the
tclug-list is familiar with it), you have to make patches to mount and
losetup. Easy enough; they even compile without too many gotchas. Trying
to use them, however, results in failure:
# dd if=/dev/zero of=test.img bs=1024 count=1000
# modprobe des.o
# losetup -e DES /dev/loop0 test.img
[asks for password, etc....]
ioctl: LOOP_SET_STATUS: invalid argument

This happens no matter what encryption type I select, except for XOR,
which is, cryptographically, a joke. I've been rtfm'ing all night, and it
seems this is a common problem, but nobody has a solution (well, at least
on usenet, nobody that speaks something besides Hungarian ;-). 

Does anybody know anything about this?

Thanks.
Dan Debertin
katdan@mninter.net