The SMAP is used to prevent the supervisor mode from unintentionally reading/writing into
memory pages in the user space, it is enabled by default since Linux kernel 3.7.
But it could be disabled through kernel boot parameters.
Ensure that Supervisor Mode Access Prevention (SMAP) is not disabled by
the nosmap boot paramenter option.
Check that the line GRUB_CMDLINE_LINUX="..."
within /etc/default/grub
doesn't contain the argument nosmap.
Run the following command to update command line for already installed kernels:
# grubby --update-kernel=ALL --remove-args="nosmap"