FYI, using the same BKM (Best Known Method) I succeeded in running my ioctl.ko on my rpi3mb platform.

My next move is to develop an IOCTL app to very my IOCTL kernel module.

Your building steps work for me. I have been looking for such solutions for a while; yours is the simplest one. Thanks.

Now I am encountering an insmod problem:

insmod ./hell0_world.ko

Bill Van Leeuwen · 2023-03-19T17:30:36.796Z

This blog follows my previous one on Setting Up Networking and an HTTP Server on the BeagleBone Black with Buildroot. This is part of my independent study course on Embedded Linux and follows from many of my past blogs. My final unit is an intro to D...

ERROR: could not load module ./hell0_world.ko: No such file or directory

I am using buildroot master branch in my ubuntu host. My KDIR string is
/home/tclee/buildroot/output/build/linux-custom

tclee@tclee-Latitude-E6230:~/buildroot/output/build/linux-custom$ make kernelversion 6.12.20

My rpi3mb target is running a different kernel version:

Linux buildroot 6.12.20-v7 #1 SMP Tue Jun 3 20:03:35 PDT 2025 armv7l GNU/Linux

I am wondering if the kernel version difference is the cause of this failure.

I am resolving this problem; your comment is welcome.

I did not change my setting. After lunch I tried the steps again. It surprisingly works:

The rpi3mb console log shows:

[427889.087724] Hello World!
[427915.237325] Goodbye World

My next move is the replacement of hello_work.c with my ioctl.ko.

Tommy Lee Hi Tommy, I'm happy that these instructions worked out for you! I'm sorry I was so slow to respond. I do not monitor my blog often.

Thanks for the interaction :) I hope the best for you in the future!

Writing and Inserting a 'Hello World' Kernel Module for the Beaglebone Black (Buildroot)

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insmod ./hell0_world.ko

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Writing and Inserting a 'Hello World' Kernel Module for the Beaglebone Black (Buildroot)

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insmod ./hell0_world.ko