Issues with Custom Kernel Module on Ubuntu 22.04: 'Module Not Found' Error During Boot
I'm currently trying to load a custom kernel module on my Ubuntu 22.04 system, but I've encountered an issue where the module fails to load during the boot process. The kernel module is properly compiled and resides in `/lib/modules/$(uname -r)/extra/my_module.ko`. However, when I check the boot logs, I see the following error: ``` modprobe: FATAL: Module my_module not found in modules.dep ``` I verified that the module was built for the current kernel by using `uname -r`, and I ran `depmod` after placing the module in the directory. The output of `depmod` shows that it recognizes my module: ``` $ depmod -n my_module.ko ``` However, when I attempt to load the module manually using `modprobe my_module`, it works just fine. It seems that the problem arises only during boot time. To troubleshoot, I checked the `/etc/modules` file to ensure my module is listed there, which it is: ``` # /etc/modules my_module ``` I also examined the systemd journal logs for any additional context: ``` journalctl -b | grep my_module ``` The logs show that the module loading process fails, but there are no explicit reasons given. I'm unsure if there are other dependencies or conflicts that might be causing this issue or if there's a specific timing issue during the boot process. I would appreciate any insights on what might be going wrong or how to further diagnose this issue. Has anyone else experienced similar problems with custom kernel modules not loading at boot on Ubuntu? What steps can I take to resolve this?