Bug#845161: udev: "mount: invalid option --" when busybox is not installed

[Simon McVittie]

Package: udev
Version: 232-5
Severity: important

To reproduce:

* Build a minimal sid qemu virtual machine for autopkgtest as described in
  autopkgtest-virt-qemu(1)
* Have udev 232-5 (232-4 not tested but should also be affected)
* Boot the system

Because udev's initramfs hook now does "mount --move", it doesn't work with
klibc mount, which is used when busybox isn't installed:

Begin: Running /scripts/local-bottom ... done.
Begin: Running /scripts/init-bottom ... mount: invalid option --
done.
run-init: opening console: No such file or directory
Target filesystem doesn't have requested /sbin/init.
run-init: opening console: No such file or directory
run-init: opening console: No such file or directory
run-init: opening console: No such file or directory
run-init: opening console: No such file or directory
run-init: opening console: No such file or directory
No init found. Try passing init= bootarg.

I was tempted to give this RC severity, but it can only happen on systems
that ignore initramfs-tools-core's Recommends: busybox. However, that's
quite annoying for automated testing, where installing Recommends would
frequently hide bugs.

Feel free to bump this up to RC if you think it ought to be.

Regards,
    S