Arch pacman -Syu :::: exclude kernel
To avoid having pacman -Syu update the kernel or other packages, add them to the IgnorePkg list.
Edit:
nano /etc/pacman.conf
Set as individual entries, or comma separated list:
IgnorePkg = linux IgnorePkg = linux-headers
references:
From DigitalOcean howto
From ArchLinux wiki