Okay, this is interesting: the view of the memory map layout seen in some detail in the preceding figure is exactly what our aforementioned procmap utility provides! As promised earlier, let's now see screenshots of the kernel VAS when running procmap (earlier, we showed screenshots of the user VAS).
To keep in sync with the immediate discussion, we will now show screenshots of procmap providing a "visual" view of the kernel VAS on the very same Raspberry Pi 3B+ system (we could specify the --only-kernel switch to show only the kernel VAS; we don't do so here, though). As we have to run procmap on some process, we arbitrarily choose systemd PID 1; we also use the --verbose option switch. However, it seems to fail:
Why did it fail to build the kernel module (that's part of the procmap project)? I mention this in the project...