Unhashed kernel memory addresses

[stephank]

As of NixOS 22.05, this is logged at startup:

kernel: **********************************************************
kernel: **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
kernel: **                                                      **
kernel: ** This system shows unhashed kernel memory addresses   **
kernel: ** via the console, logs, and other interfaces. This    **
kernel: ** might reduce the security of your system.            **
kernel: **                                                      **
kernel: ** If you see this message and you are not debugging    **
kernel: ** the kernel, report this immediately to your system   **
kernel: ** administrator!                                       **
kernel: **                                                      **
kernel: **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
kernel: **********************************************************

This is apparently caused by the slub_debug=FP kernel parameter set by the hardened profile.

We already have other workarounds in place on top of the hardened profile, and I'm not sure if it's better we just copy over and tweak the profile instead of using it directly.

I think the upstream issue is: NixOS/nixpkgs#90704