First ran into this problem after upgrading from Ubuntu 18.04 to 20.04 in an old HP Pavillion laptop (dv7-2185dx): the system was stuck at a blank screen sometimes after a boot/reboot. After editing grub to enable debug mode (linux /boot/vmlinuz-5.4.0.58-generic root=... ro debug
), I see that whenever the boot sequence hangs, it is always after "random: fast init done" or random: crng init done
(or both). Sample output below:
snapshot: boot halts after crng init done
I have checked previous questions on similar issues, e.g.: Ubuntu installation stuck at random crng init done Boot - very slow start "random: fast init done"
However, the solutions there don't work in my case: I have no SD cards to remove, I boot from an internal SSD and my UUIDs in blkid
and fstab
agree, my system does not use a swap partition but rather a swap file in the same partition as the system, I tried installing rng-tools
and haveged
but the situation was not resolved. I also did a fresh 20.04 installation and this problem occurred there too.
Curiously, I have Ubuntu 18.04 in another partition of the same disk which always boots fine. Both systems seem to use the same initrd
image version (initrd.img-5.4.0-58-generic
).
I am baffled at this point, hence the request for help. The problem is not even well-reproducible, it happens randomly but quite frequently. Any ideas what might be going on, or at least any pointers on how to troubleshoot?
Happy to provide more info as necessary...