[Pkg-xfce-devel] Bug#770885: Bug#770885: lightdm: Restart, Suspend, Hibernate, Shut Down all greyed out and nonfunctional

[Adam Bolte]

Hi believe I'm running into the same issue.

$ apt-cache policy lightdm cgmanager policykit-1 systemd-shim systemd libpam-systemd sysvinit-core libvirt-daemon-system | grep -E -A1 '^[^[:space:]]+' | grep -v '^--$'
lightdm:
Installed: 1.10.3-3
cgmanager:
Installed: 0.33-2+deb8u2
policykit-1:
Installed: 0.105-8
systemd-shim:
Installed: 9-1
systemd:
Installed: 215-17+deb8u2
libpam-systemd:
Installed: 215-17+deb8u2
sysvinit-core:
Installed: 2.88dsf-59
libvirt-daemon-system:
Installed: 1.2.9-9+deb8u1

Also:

$ dpkg -S /sbin/init
sysvinit-core: /sbin/init

Since I'm not running systemd but I am using libvirt, I have the following set:

$ cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-3.19.0 root=/dev/sda2 ro cgroup_enable=memory quiet

(note the "cgroup_enable=memory" bit) as well as:

$ sed -n '/^[^#]/p' /etc/default/libvirtd
start_libvirtd="yes"
mount_cgroups=yes

This mounts cgroups nicely, as advertised:

$ mount | grep ^cgroup
cgroup on /sys/fs/cgroup type tmpfs (rw,relatime,size=12k)
cgroup_root on /sys/fs/cgroup type tmpfs (rw,relatime)
cgroup_cpuset on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset,release_agent=/run/cgmanager/agents/cgm-release-agent.cpuset,clone_children)
cgroup_cpu on /sys/fs/cgroup/cpu type cgroup (rw,nosuid,nodev,noexec,relatime,cpu,release_agent=/run/cgmanager/agents/cgm-release-agent.cpu)
cgroup_cpuacct on /sys/fs/cgroup/cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpuacct,release_agent=/run/cgmanager/agents/cgm-release-agent.cpuacct)
cgroup_devices on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices,release_agent=/run/cgmanager/agents/cgm-release-agent.devices)
cgroup_freezer on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer,release_agent=/run/cgmanager/agents/cgm-release-agent.freezer)
cgroup_net_cls on /sys/fs/cgroup/net_cls type cgroup (rw,nosuid,nodev,noexec,relatime,net_cls,release_agent=/run/cgmanager/agents/cgm-release-agent.net_cls)
cgroup_blkio on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio,release_agent=/run/cgmanager/agents/cgm-release-agent.blkio)
cgroup_perf_event on /sys/fs/cgroup/perf_event type cgroup (rw,nosuid,nodev,noexec,relatime,perf_event,release_agent=/run/cgmanager/agents/cgm-release-agent.perf_event)
cgroup_memory on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory,release_agent=/run/cgmanager/agents/cgm-release-agent.memory)

However, according to #760640, these cgroups are created by hand and
not via cgmanager. This is clear by inspecting how
/etc/init.d/libvirtd works.

This is where some guesswork on my part comes into being, since I'm
not entirely clear on how this is all supposed to fit together. I'm
guessing lightdm is relying on policykit, which in turn is using
cgmanager and libpam-systemd. When cgroups are manually created as per
#760640 for virtd, it somehow borks cgmanager, and thus policykit, and
thus lightdm.

You can also observe NetworkManager doesn't allow state to be changed
by the user in this situation.

So if my theory is correct, #760640 is a blocker for resolving
this. I'm happy to run any tests anyone might suggest to verify this,
but it seems easily reproducible on the few boxes I have tested
with. Simply set mount_cgroups=yes in /etc/default/libvirtd and the
lightdm shutdown drop-down options become grayed out. At least libvirt
cgroup support is supposed to start working though. :/

Related bugs seem to be:

#760640 - Should use cgmanager
#769494 - Please mount cgroup automatically
#601757 - Please mount cgroup automatically

So the only real option to have lightdm/NetworkManager and
libvirt+cgroups working is to use systemd. But I can't use that yet
due to other systemd bugs, and I'd rather not use it anyway.

If anyone has a work-around/hack to have libvirtd register cgroup
mounts via cgmanager, please do tell.
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