I was able to reproduce this bug on Debian unstable (lxc=2.0.7-2, libpam-cgfs=2.0.6-1, systemd=232-22, linux-image-4.9.0-2-amd64=4.9.18-1 or even using 4.11.0-rc6-1, libpam-cgm not installed, cgmanager not installed) with Debian Jessie unprivileged container (created using download template [1]). Systemd version in the container: 215-17+deb8u6.
In addition to the three symptoms listed in the bug description, here is another: in the container "/sys/fs/cgroup/systemd" isn't mounted (systemctl command fails and any attempt to manually mount it will hangs forever). It appears there are two problems: 1. When using umask, create lxc cgroups before running lxc-start: $ mkdir /sys/fs/cgroup/systemd/user.slice/user-$UID.slice/session-$XDG_SESSION_ID.scope/lxc $ mkdir /sys/fs/cgroup/{freezer,memory}/user/$USER/0/lxc # replace <subgid> $ sudo chgrp <subgid> /sys/fs/cgroup/systemd/user.slice/user-$UID.slice/session-$XDG_SESSION_ID.scope/lxc $ sudo chgrp <subgid> /sys/fs/cgroup/{freezer,memory}/user/$USER/0/lxc $ chmod g+x /sys/fs/cgroup/systemd/user.slice/user-$UID.slice/session-$XDG_SESSION_ID.scope/lxc $ chmod g+x /sys/fs/cgroup/{memory,freezer}/user/$USER/0/lxc Start the container, systemd will be able to mount /sys/fs/cgroup/systemd/: $ lxc-start -n <name> And lxc-stop works, host is able to reboot without hard reset. 2. About the kernel related problem: systemd try to mount "/sys/fs/cgroup/systemd/" twice ([2]: mount_table and mount_setup): once using "none,name=systemd,xattr" options then if the first try fails there is another using "none,name=systemd". The first try returns "permission denied" and then systemd become stuck at the second try. Without manually creating the lxc cgroups, I was able to reproduce this problem using unprivileged container Alpine edge (Alpine doesn't use systemd): $ lxc-attach -n alpine_container --clear-env # mount -t tmpfs tmpfs /sys/fs/cgroup # mkdir /sys/fs/cgroup/systemd # mount -t cgroup -o none,name=systemd cgroup /sys/fs/cgroup/systemd -> mount command hangs, lxc-stop hangs, host needs a hard reset [1] http://images.linuxcontainers.org/ [2] https://github.com/systemd/systemd/blob/1b59cf04aee20525179f81928f1e1794ce970551/src/core/mount-setup.c#L104 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1642767 Title: starting any container with umask 007 breaks host system shutdown. lxc-stop just hangs. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lxc/+bug/1642767/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs