vbetool: mmap /dev/zero: Operation not permitted Failed to initialise LRMI (Linux Real-Mode Interface).

[dreaddy]

Upgrade from 18.04 to 20.04

As root.

mmap /dev/zero: Operation not permitted Failed to initialise LRMI (Linux Real-Mode Interface).

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: vbetool 1.1-4
ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30
Uname: Linux 5.4.0-26-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
Date: Sun Apr 26 15:20:56 2020
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: vbetool
UpgradeStatus: Upgraded to focal on 2020-04-26 (0 days ago)

[dreaddy (dreaddymck)]

[root@thing ~] :) vbetool dpms force off
mmap /dev/zero: Operation not permitted
Failed to initialise LRMI (Linux Real-Mode Interface).

[Paul Sladen (sladen)]

To assist with debugging please try both of these options
(individually) from a clean state:

(a) sudo mount -o remount,exec /dev

(b) sudo setsebool -P mmap_low_allowed

(ie. boot, test, reboot, test the other).

Do either of those work?

[dreaddy (dreaddymck)]

That's a negative:

sudo mount -o remount,exec /dev
sudo reboot

results:
[dreaddy@thing ~] :) sudo /usr/sbin/vbetool dpms off
mmap /dev/zero: Operation not permitted
Failed to initialise LRMI (Linux Real-Mode Interface).

[dreaddy@thing ~] :) sudo setsebool -P mmap_low_allowed

results:
sudo: setsebool: command not found

[dreaddy (dreaddymck)]

Solution found here:
https://askubuntu.com/questions/1120578/how-do-i-edit-grub-to-add-iomem-relaxed

failed as well.

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
to:
GRUB_CMDLINE_LINUX_DEFAULT="iomem=relaxed quiet splash"

[dreaddy (dreaddymck)]

Mistakes were made.

(a) sudo mount -o remount,exec /dev

Works.

The mistake made was rebooting before testing vbetool.

Solution:

sudo mount -o remount,exec /dev
vbetool dpms force off
sudo mount -o remount,noexec /dev

[dreaddy (dreaddymck)]

Solution:

mount -o remount,exec /dev
vbetool dpms force off
mount -o remount,noexec /dev