[Nix-dev] Two approaches to kmod migration

[Peter Simons]

Hi Yury,

I don't understand all the fine details of this issue, so please take my
comments with a grain of salt.

I agree with you that the introduction of a $MODULE_DIR variable seems
pointless. I don't see what the purpose of that variable might be. The
module path is inherently bound to the currently running kernel, so it's
fine to have modules located underneath /var/run/current-system, and
that's it. If the active system is switched, then the module path
changes transparently, too. The kernel may or may not be able to use
those new modules, but worrying about that is the responsibility of the
system administrator, IMHO.

However, I don't want an impure /lib/modules path either. I appreciate
that introducing that path would make life easier for people who package
kernel modules, but that convenience comes at a price, namely the risk
that impure builds will erroneously succeed and will end up building
software that crashes the machine or something. I like NixOS because it
goes a long way to try and avoid those kind of risks, and I am willing
to accept the additional effort of fixing kernel module build systems if
it means that those kernel modules can be relied on afterward.

I trust you'll correct me in case I misunderstood the situation, but
from what I know by now, those are my 2 cents.

Take care,
Peter