Rebuilding a kernel module(driver) with debugging

Question

I have been trying for the past day to rebuild my iwlwifi modules with debugging enabled. The way to do this is to build with the .config param CONFIG_IWLWIFI_DEBUG=y. If I was building a new kernel this would be easy, but I want to keep using the installed ubuntu kernel. At the moment I don’t care about installing the modules. I just want to see the .ko files build, insmod them, and check for /sys/modules/iwlwifi/parameters/debug which should exist if the modules are built for debugging. What’s the official ubuntu way of doing this?

So far, this is what I’m doing:

My kernel is 4.15.0-43-generic, headers are already installed in /usr/src/linux-headers-4.15.0-43-generic

1. Installed /usr/src/linux-source-4.15.0 with apt-get and unpacked it to ~/

2. Set CONFIG_IWLWIFI_DEBUG=y in ~/linux-4.15.0/.config and /usr/src/linux-headers-4.15.0-43-generic/.config because I’m not sure which would be used.

3. In ~/linux-4.15.0/drivers/net/.../iwlwifi, I run make -C /lib/modules/$(uname -r)/build M=$(pwd) modules

4. ko modules build, but they aren’t debug-enabled

Answer 1

Turns out I needed to run make scripts in the headers dir. It exits with failure, but I guess it does whatever it needs to with the build params first.