Linux Kernel Development Diary 2

Second Tutorial

This diary refers to the second FLUSP’s tutorial on Linux Kernel development basics.
Entitled “Building and booting a custom Linux kernel for ARM using kw”, it is possible to infer what this entry is about.

In this tutorial we cloned the IIO tree, the subsystem we will work in the current discipline cycle.
We then used kw to help modifying, building and deploying the custom kernel we built during the tutorial. The customization revolved around changing the kernel name, adding a suffix of the student’s preference (I chose “-REVSTU”).

Before explaining the difficulties arosed when following this tutorial, I must first explain briefly the script to activate the virtual environment.
The “activate.sh” contains some function definitions that help create and initialize a VM. These functions have definitions about image locations, filesystem path and others. For building and deploying a custom kernel, to change some of these definitions was necessary.
With this in mind, everything went well until the creation of the VM with the custom kernel.
After running the function defined on the virtual environment script named “create_vm_virsh()”, altered in this tutorial, the VM would simply not load. Even though I tried to connect with SSH and virsh, nothing worked. I could not get the VM’s IP address nor the virsh console would work.
In front of these complications, I followed the first tutorial again - partialy - so I could run the VM again and try the second tutorial once more. It worked.
As a precaution, I now keep a “backup.sh” in case everything stops working again.