Comment 2 for bug 1894591

Performing verification:

First, reproducing on older kernel:

$ uname -rv
4.4.0-190-generic #220-Ubuntu SMP Fri Aug 28 23:02:15 UTC 2020
$ grep "clocksource" /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="clocksource=tsc"
$ cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-4.4.0-190-generic root=UUID=f6c72a0a-003a-4b81-9550-ba49a547e32d ro clocksource=tsc
$ cat /sys/devices/system/clocksource/clocksource0/current_clocksource
kvm-clock

kvm-clock is the default, even though we explicitly asked for tsc. We can reproduce.

Now, I enabled -proposed and installed 4.4.0-191-generic:

$ uname -rv
4.4.0-191-generic #221-Ubuntu SMP Fri Sep 18 13:34:04 UTC 2020
$ grep "clocksource" /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="clocksource=tsc"
$ cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-4.4.0-191-generic root=UUID=f6c72a0a-003a-4b81-9550-ba49a547e32d ro clocksource=tsc
$ cat /sys/devices/system/clocksource/clocksource0/current_clocksource
tsc
$ dmesg | grep defer
[ 0.870439] clocksource: Override clocksource tsc is not currently HRT compatible - deferring

We have our requested clocksource, tsc, and we did not need to force override the reliability checks from the watchdog.

The kernel in -proposed, 4.4.0-191-generic, fixes the problem, and I am happy to mark the bug verified.