Comment 2 for bug 1731543

I ended up kill -9'ing the process. and eventually it went on (not even recording an error).

Then the subsequent 'apt-get autoremove' hung again.

Reading package lists...
Building dependency tree...
Reading state information...
The following packages will be REMOVED:
  linux-headers-4.4.0-96 linux-headers-4.4.0-96-generic
  linux-image-4.4.0-96-generic linux-image-extra-4.4.0-96-generic
0 upgraded, 0 newly installed, 4 to remove and 0 not upgraded.
                                                              After this operation, 339 MB disk space will be freed.
(Reading database ... 170214 files and directories currently installed.)
Removing linux-headers-4.4.0-96-generic (4.4.0-96.119) ...
Removing linux-headers-4.4.0-96 (4.4.0-96.119) ...
Removing linux-image-extra-4.4.0-96-generic (4.4.0-96.119) ...
run-parts: executing /etc/kernel/postinst.d/apt-auto-removal 4.4.0-96-generic /boot/vmlinux-4.4.0-96-generic
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 4.4.0-96-generic /boot/vmlinux-4.4.0-96-generic
update-initramfs: Generating /boot/initrd.img-4.4.0-96-generic
W: mdadm: /etc/mdadm/mdadm.conf defines no arrays.