How NixOS decides to compile the Linux kernel? And is there a way to avoid it?

shico · August 25, 2024, 12:43pm

Compiling the Linux kernel when running nixos-rebuild takes so much time, and freezes my PC in the meantime. How NOT to build the Linux kernel?

TLATER · August 25, 2024, 12:48pm

That means you’re either overriding something that changes the kernel, or you’re using a channel that isn’t being serviced by hydra, either because it’s very outdated or too new.

What is your config, and what’s the output of nix-shell -p nix-info --run "nix-info -m"?

shico · August 25, 2024, 1:53pm

It happens when I set hardware.bumblebee.enable to true.

The output is

these 6 paths will be fetched (0.75 MiB download, 10.20 MiB unpacked):
  /nix/store/iw9x2m9lxk566qvcn13ypwyb6f2x7kdy-file-5.45
  /nix/store/i9x2sifgd2r28jmvm9yfnykjsmv9xbm9-gnu-config-2024-01-01
  /nix/store/6x42kczk505372wqayhjvwbmjwvxrrkp-gnumake-4.4.1
  /nix/store/s4xysdp2cx1r4zzqqr3c9v2z8q0g5zlj-patchelf-0.15.0
  /nix/store/bc0as359y5y067dfp7afrq1f011m9ny3-stdenv-linux
  /nix/store/x5pfxw8jkaifsbqqhf4lahjxlkm5mfqf-update-autotools-gnu-config-scripts-hook
copying path '/nix/store/i9x2sifgd2r28jmvm9yfnykjsmv9xbm9-gnu-config-2024-01-01' from 'https://cache.nixos.org'...
copying path '/nix/store/6x42kczk505372wqayhjvwbmjwvxrrkp-gnumake-4.4.1' from 'https://cache.nixos.org'...
copying path '/nix/store/s4xysdp2cx1r4zzqqr3c9v2z8q0g5zlj-patchelf-0.15.0' from 'https://cache.nixos.org'...
copying path '/nix/store/iw9x2m9lxk566qvcn13ypwyb6f2x7kdy-file-5.45' from 'https://cache.nixos.org'...
copying path '/nix/store/x5pfxw8jkaifsbqqhf4lahjxlkm5mfqf-update-autotools-gnu-config-scripts-hook' from 'https://cache.nixos.org'...
copying path '/nix/store/bc0as359y5y067dfp7afrq1f011m9ny3-stdenv-linux' from 'https://cache.nixos.org'...
 - system: `"x86_64-linux"`
 - host os: `Linux 6.1.105, NixOS, 24.05 (Uakari), 24.05.20240822.797f7dc`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.18.5`
 - channels(shico): `""`
 - nixpkgs: `/nix/store/5z81la6av4j0ckp0w1949lxiwjyyykks-source`

TLATER · August 25, 2024, 3:04pm

In that case you’ll build the nvidia kernel module, which might look similar to building the kernel, but it’s just doing some builds for the nvidia driver - no way around this, since it’s proprietary upstream can’t republish it, so the download has to happen on your computer and subsequently built for the kernel you’re running.

That said, it should not be freezing your PC, or take particularly long. While the build is running, can you keep an eye on your system stats to see if you run out of memory or something? This might be caused by mounting /tmp as a tmpfs, for example.

Bumblebee also might not actually be what you need, what GPU/CPU are you using? Is this actually a PC or a laptop?

You’re using the latest NixOS stable commit, but his seems suspicious, what about:

$ nix-channel --list
$ sudo nix-channel --list

shico · August 25, 2024, 5:05pm

Installing the nvidia driver without bumblebee does not trigger a Linux kernel compilation though. Doing what was suggested in this comment fixed my issue

github.com/NixOS/nixpkgs

bumblebee: should not depend on broken nvidia_11_legacy390

opened 02:45PM - 14 Jun 24 UTC

t-gebauer

0.kind: bug

### Describe the bug NixOS at 24.05 and above refuses to build `bumbleee`. >… error: Package ‘nvidia-x11-390.157’ in /nix/store/4jz704ypzh80nk0p00613dd7d0n1n9n3-nixos-24.05/nixos/pkgs/os-specific/linux/nvidia-x11/generic.nix:237 is marked as broken, refusing to evaluate. ### Steps To Reproduce 1. build `bumblebee` ### Expected behavior No build failures. ### Additional context The same issue exists for `primus`: https://github.com/NixOS/nixpkgs/issues/306786 The packages is marked as broken only for kernel versions 6.2 and above: https://github.com/NixOS/nixpkgs/commit/0b14e79f1ca4b1722d222d8a089f5ee961be1a91 Interesting is also, that for `bumblebee` (and `primus`) the `nvidia-x11` package is only required with `libsOnly = true`: https://github.com/NixOS/nixpkgs/blob/cc54fb41d13736e92229c21627ea4f22199fee6b/pkgs/top-level/all-packages.nix#L35276 Could it be that in this context the package is not actually broken even at kernels above 6.1? ### Workaround Pin the kernel to version 6.1. However, the usual `boot.kernelPackages` way does not work (why?). But overriding the default `linuxPackages` attribute with an overlay works: ``` nixpkgs.overlays = [ (self: super: { linuxPackages = super.linuxPackages_6_1; }) ]; ``` ### Notify maintainers  @abbradar ### Metadata Please run `nix-shell -p nix-info --run "nix-info -m"` and paste the result. ```console [user@system:~]$ nix-shell -p nix-info --run "nix-info -m" - system: `"x86_64-linux"` - host os: `Linux 6.1.93, NixOS, 24.05 (Uakari), 24.05.1409.cc54fb41d137` - multi-user?: `yes` - sandbox: `yes` - version: `nix-env (Nix) 2.18.2` - channels(root): `"nixos-24.05"` - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos` ``` --- Add a :+1: [reaction] to [issues you find important]. [reaction]: https://github.blog/2016-03-10-add-reactions-to-pull-requests-issues-and-comments/ [issues you find important]: https://github.com/NixOS/nixpkgs/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc

nix-channel --list returns nothing.

sudo nix-channel --list:

nixos https://nixos.org/channels/nixos-23.11
nixpkgs-unstable https://nixos.org/channels/nixpkgs-unstable

nrdxp · August 25, 2024, 5:43pm

If your hardeware is new enough, I would recommend not using bumblebee and instead configuring prime render offload, which solves the same problem as bubblebee, but directly in the driver (and officially supported).

shico · August 25, 2024, 5:52pm

My hardware isn’t new. I would have expected bumblebee to work as it is basically abandoned software now and doesn’t change. But with every NixOS update, a new problem with bumblebee comes up .-.

TLATER · August 25, 2024, 11:05pm

That has been deprecated for months now, pretty sure there have been several critical CVEs since, you should upgrade to 24.05.

shico · August 25, 2024, 11:15pm

Idk if it’s used though, my configuration uses flakes with the updated version. Should I remove these channels if I primarily use flakes or update them instead?

TLATER · August 26, 2024, 12:34am

Ah, I see, that also explains the empty channels in nix-info.

I’d suggest removing them, commands like nix-shell could in theory still use your channels, although nixpkgs.flake.setNixPath should override what your commands use these days. If nothing else, it saves a bit of disk space.

Brisingr05 · August 26, 2024, 4:12am

Also, use nixos-unstable instead of nixpkgs-unstable (unless you know what you’re doing).