How do I prevent a redhat kernel module loading at boot time of after?

vaquitasos

Caution is advised whenever making kernel changes.

Also see: dracut(8) - low-level tool for generating an initramfs/initrd image

This is called blacklisting. It prevents a kernel module from loading either dynamically or at boot time.

Edit or create a file.

$ sudo vi /etc/modprobe.d/blacklist.conf

Add the lines to blacklist a kernel module. The kernel install runs /bin/false instead of loading. The blacklist command does not prevent this module loading as a dependency for other kernel modules.

# Blacklists sierra kernel module.
blacklist sierra
install sierra /bin/false

Make a backup of your existing initial ramdisk.

$ sudo cp /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r).bak.$(date +%m-%d-%H%M%S).img

Create a new initial ramdisk.

$ sudo dracut -f -v
dracut: Executing: /usr/bin/dracut -f -v
...
...
...
dracut: *** Including module: shutdown ***
dracut: *** Including modules done ***
dracut: *** Installing kernel module dependencies ***
dracut: *** Installing kernel module dependencies done ***
dracut: *** Resolving executable dependencies ***
dracut: *** Resolving executable dependencies done***
dracut: *** Hardlinking files ***
dracut: *** Hardlinking files done ***
dracut: Could not find 'strip'. Not stripping the initramfs.
dracut: *** Generating early-microcode cpio image ***
dracut: *** Constructing AuthenticAMD.bin ****
dracut: *** Constructing GenuineIntel.bin ****
dracut: *** Store current command line parameters ***
dracut: *** Creating image file '/boot/initramfs-4.18.0-147.5.1.el8_1.x86_64.img' ***
 dracut: *** Creating initramfs image file '/boot/initramfs-4.18.0-147.5.1.el8_1.x86_64.img' done ***

Reboot the system when ready.

$ sudo reboot

Check if kernel module status.

$ lsmod | grep sierra

Demo, what happens if the kernel module load is attempted.

$ sudo modprobe -v sierra
install /bin/false
modprobe: ERROR: Error running install command for sierra
modprobe: ERROR: could not insert 'sierra': Operation not permitted