`modprobe -r` Example Problems

incfex

In Chapter 26: Kernel Modules -> Module Utilities.
The tutorial uses 'modprobe -r e1000e' as example, which removed the Intel network driver from the system, making all the SSH connections dropped. I would assume that this would cause some confusions around students who are not so familiar with Linux.
Thus, I purpose to use a more "harmless" module as the exmaple. Or at least warn about possible outcomings.

coop

It is true that NIC drivers can be removed even when being used (unlike almost any other kernel module) as they have been explicitly constructed that way so you don 't have to bring the entire network down to reload them. It is not guaranteed, but modprobe e1000e right after removal should keep everything working again, as most applications and services (including ssh) are built to withstand temporary network outages.

jbalamtlf

the student maybe not on a local machine, and if so, this maybe complicated. the snd-pcm-oss module is a pretty good generally harmless alternative, tho im unsure of its availability on all target systems. also i havnt reached this point in the lesson, i maybe missing some context.

luisviveropena

Hi @jbalamtlf, from the beginning of the course we encourage students to have their own test environment. So we are not talking about removing a kernel module in a running server, but in a virtual machine or in a native hardware specific for this course.

For another hand, I verified that Ubuntu 20.04.4 LTS doesn't include the snd-pcm-oss module, so I bet it's not available in all distros.

Regards,
Luis.

coop

I've never seen a system without the e1000 modules which is why they were chosen. Every other choice we have used over many years has presented exactly what Luis is pointing out. So nothing is going to change