It appears to be the NVIDIA drivers.
See this post + answer for troubleshooting:
NMI watchdog: BUG: soft lockup - CPU#2 stuck for 23s! [nvidia-smi:566] and
https://askubuntu.com/a/934850/949723:
At startup, edit the Grub menu entry and append the kernel parameter "nomodeset" or modprobe.blacklist=nouveau
to the existing parameters quiet splash
.
So I edited the file /etc/default/grub, and edited the GRUB_CMDLINE_LINUX_DEFAULT
line to this:
GRUB_CMDLINE_LINUX_DEFAULT="nomodeset"
Afterwards I ran sudo update-grub
. That's it, 8 seconds the boot time, no beep sound, I am so happy, no CPU stuck on journalctl
anymore! :)
Warning! Adding "nomodeset" permanently to /etc/default/grub
will disable NVidia drivers. This option is useful only if the system doesn't boot correctly with Nouveau.
After you install the NVidia drivers, this parameter should be removed.