AppArmor must be enabled at boot time in your bootloader configuration to ensure that the controls it provides are not overridden.
Solution
For grub2 based systems edit /etc/default/grub and remove all instances of apparmor=0 from all CMDLINE_LINUX parameters: GRUB_CMDLINE_LINUX_DEFAULT='quiet' GRUB_CMDLINE_LINUX='' Run the following command to update the grub2 configuration: # update-grub