Moving over to the kernel as a userspace process shouldn't be able to cause such a hang regardless of what it does so this looks like a kernel bug (lock related by the looks of it).
** Package changed: lxc (Ubuntu) => linux (Ubuntu) -- 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/linux/+bug/1642767/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
