I am trying to compile a kernel module from this example, on a Debian 12 system which was just installed.

The example code requires the following header files, and of course these header files also include many other header files:

#include <linux/init.h>
#include <linux/module.h>

So I installed the linux-headers-amd64 package because it has the kernel headers I need to compile. The problem is that the kernel headers get installed into /usr/src/linux-headers-6.1.0-21-common/include/linux/. So I get the following error when I try to compile:

fatal error: linux/init.h: No such file or directory
    1 | #include <linux/init.h>
      |          ^~~~~~~~~~~~~~

I could just create a symbolic link called linux in /usr/include/ except that there is already a directory there with that name. So I tried changing my #include statement like this:

#include "/usr/src/linux-headers-6.1.0-21-common/include/linux/init.h"

But then all the other included header files are not found:

fatal error: linux/compiler.h: No such file or directory
    5 | #include <linux/compiler.h>
      |          ^~~~~~~~~~~~~~~~~~

So, how is this supposed to work? Did I install the wrong package for the kernel header files? How can I compile this without completely rearranging every header file on my system?