Bug#865141: more info

[Josip Rodin]

And in turn this makes subsequent kernel upgrades croak:

% sudo dpkg --configure -a
Setting up linux-image-4.9.0-8-amd64 (4.9.144-3.1) ...
/etc/kernel/postinst.d/initramfs-tools:
update-initramfs: Generating /boot/initrd.img-4.9.0-8-amd64
/etc/kernel/postinst.d/zz-update-grub:
/usr/sbin/grub-probe: error: failed to get canonical path of `/dev/mapper/oldvgname-lvroot'.
run-parts: /etc/kernel/postinst.d/zz-update-grub exited with return code 1
dpkg: error processing package linux-image-4.9.0-8-amd64 (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 linux-image-4.9.0-8-amd64

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