How to Fix the “Include linux/init.h not found” Error

Resolving the ‘linux/init.h: No such file or directory’ Error

If you’re trying to build a kernel module for your class and encountering a cascade of errors, the ‘No such file or directory’ error at the top can be a frustrating roadblock. This error typically affects files like init.h, module.h, and kernel.h. In your code, you’ve included these headers as follows:

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

Let’s explore some solutions to address this issue and get your kernel module building successfully.

1. Kernel Header Installation

The ‘No such file or directory’ error often indicates that the necessary kernel headers are not installed on your system. You can resolve this by installing the appropriate kernel headers. You mentioned trying the following command:

sudo apt-get install linux-headers-generic

However, it seems you encountered an issue with this command. You can try the following steps instead:

• Determine your kernel version by running uname -r. It will display something like 5.4.0-xx-generic.
• Install the kernel headers specific to your version. Replace xx with the appropriate version number in the following command:

  sudo apt-get install linux-headers-5.4.0-xx-generic

This command should install the necessary kernel headers for your current kernel version.

2. Correcting Header Paths

In your code, you attempted to include headers using paths like /usr/include/linux/init.h. This is not the standard way to include kernel headers, and it can lead to issues. Instead, rely on the system’s include paths, as you did with #include <linux/init.h>.

Ensure that your code uses the correct include statements without specifying full paths.

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

3. Makefile Configuration

It’s essential to have a proper Makefile to build kernel modules. The Makefile should be configured to build your module correctly. Here’s a simple example of a Makefile:

obj-m += your_module_name.o

all:
    make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

clean:
    make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

Replace your_module_name with the name of your module. This Makefile will compile your module using the appropriate kernel build system.

Conclusion

By installing the correct kernel headers, fixing your include paths, and configuring a proper Makefile, you should be able to resolve the ‘linux/init.h: No such file or directory’ error and successfully build your kernel module. Remember to adapt the commands and paths to your specific system configuration. Good luck with your kernel module development!