how to Get kernel debug messages

I have installed the kernel debug symbols for my system

sudo apt install linux-image-5.11.0-17-generic-dbgsym

Also

$ sysctl kernel.printk
kernel.printk = 7 4 1 7

But when typing

sudo dmesg -wH

I get just real error messages. I do not get any debug info.

What am I missing?

1 Answer

You have installed the debug symbols, which are not related to debug messages.

With the debug symbols you can use debuggers, like gdb.

In order to read debug messages you need to compile the kernel/kernel module with the DEBUG define.