Subject: cgroupfs-mount: Cannot remove cgroupfs-mount

From: Ryutaroh Matsumoto <[email-masked]>
Date: Sat, 25 Apr 2020 04:56:02 +0900 (JST)

Package: cgroupfs-mount
Version: 1.4
Severity: normal

Dear Maintainer,

After installation of cgroupfs-mount, tring to remove it gives

Removing cgroupfs-mount (1.4) ...
Unmounting cgroupfs hierarchyumount: /sys/fs/cgroup/elogind: target is busy.
invoke-rc.d: initscript cgroupfs-mount, action "stop" failed.
dpkg: error processing package cgroupfs-mount (--remove):
 installed cgroupfs-mount package pre-removal script subprocess returned error exit status 32
Errors were encountered while processing:
 cgroupfs-mount
E: Sub-process /usr/bin/dpkg returned an error code (1)

Best regards, Ryutaroh Matsumoto

-- System Information:
Distributor ID:	Debian
Description:	Devuan GNU/Linux 3 (beowulf)
Release:	3
Codename:	beowulf
Architecture: x86_64

Kernel: Linux 4.19.0-8-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=C.UTF-8 (charmap=locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
UTF-8), LANGUAGE=en_US:en (charmap=locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)
LSM: AppArmor: enabled

Versions of packages cgroupfs-mount depends on:
ii  lsb-base  10.2019051400

cgroupfs-mount recommends no packages.

cgroupfs-mount suggests no packages.

-- debconf information:
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
	LANGUAGE = "en_US:en",
	LC_ALL = (unset),
	LC_CTYPE = "C.UTF-8",
	LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory

---

From: Mark Hindley <[email-masked]>
Date: Sat, 25 Apr 2020 10:00:16 +0100

Control: tags -1 debian

Ryutaroh,

> E: Sub-process /usr/bin/dpkg returned an error code (1)

Thanks. Yes I bumped into this a couple of days ago.

The problem appears to be that /usr/bin/cgroupfs-umount tries to unmount all the
cgroups, even if it didn't originally create them. elogind creates its own cgroupfs and is
still using it.

As cgroupfs-mount is not a forked package and Devuan uses Debian's package
directly it needs to be fixed in Debian. There is already a Debian bug about it
at https://bugs.debian.org/950986.

I do have a workaround: cgroupfs-mount removes cleanly in single user mode (when
elogind is not running), or you can stop elogind first and then remove
cgroupfs-mount. However, this will also lose your logind sessions which may or
may not matter to you. Obviously new ones are created once elogind is restarted
and you log back in.

Mark