swapoff failed: Cannot allocate memory

[efa]

my memory situation is this:
4 GB ram total
2 GB used
8 GB swap partition in sda5
about 0 GB swap used

running command swapoff I got always the error below:

$ sudo swapoff -a
swapoff: /dev/sda5: swapoff failed: Cannot allocate memory

Seems swapoff always failed, when 'overcommit' is disabled (in my case for deterministic behave reasons)

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: mount 2.31.1-0.4ubuntu3.3
ProcVersionSignature: Ubuntu 4.18.0-16.17~18.04.1-generic 4.18.20
Uname: Linux 4.18.0-16-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
CurrentDesktop: MATE
Date: Thu Mar 7 23:38:20 2019
InstallationDate: Installed on 2016-12-01 (826 days ago)
InstallationMedia: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
SourcePackage: util-linux
UpgradeStatus: Upgraded to bionic on 2018-09-23 (165 days ago)

[efa (efa)]

to disable overcommit:
echo 2 > /proc/sys/vm/overcommit_memory
echo 100 > /proc/sys/vm/overcommit_ratio

Or better for persistence, put values in /etc/sysctl.conf
vm.overcommit_memory=X and run sysctl -p. No need to reboot

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[efa (efa)]

happen on 18.04.3 LTS bionic too

[efa (efa)]

$ uname -a
Linux 02cor2130 5.0.0-32-generic #34~18.04.2-Ubuntu SMP Thu Oct 10 10:36:02 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux