dhcpcd segfaults - Githubissues

Describe the bug

On my system running NixOS 20.09, the dhcpcd service repeatedly segfaults when it tries to configure a specific interface. From the logs:

Dec 18 13:07:13 nixos dhcpcd[26701]: enp0s20u13u5: leased 169.254.95.120 for 600 seconds
Dec 18 13:07:13 nixos dhcpcd[26701]: enp0s20u13u5: adding route to 169.254.95.0/24
Dec 18 13:07:13 nixos dhcpcd[26701]: enp0s20u13u5: deleting route to 169.254.95.0/24
Dec 18 13:07:13 nixos kernel: dhcpcd[26701]: segfault at 99 ip 0000000000418eb2 sp 00007ffe27674e60 error 4 in dhcpcd[407000+33000]
Dec 18 13:07:13 nixos kernel: Code: 00 e9 33 fa ff ff 83 7c 24 0c 02 0f 85 a7 02 00 00 0f 1f 80 00 00 00 00 48 8b 44 24 20 48 8d 35 48 34 02 00>

I did not configure any network specific options in the NixOS configuration.

My workaround for the issue is to add

networking.useDHCP = false;
networking.interfaces.eno1.useDHCP = true;

to the NixOS configuration, which prevents dhcpcd from configuring the enp0s20u13u5 interface.

Notify maintainers @fpletz @edolstra

Metadata Output of nix-shell -p nix-info --run "nix-info -m":

  /nix/store/ajidkqg53y0zvh0m5cjgqiw3pf9cvlf0-bash-interactive-4.4-p23-dev
copying path '/nix/store/ajidkqg53y0zvh0m5cjgqiw3pf9cvlf0-bash-interactive-4.4-p23-dev' from 'https://cache.nixos.org'...
 - system: `"x86_64-linux"`
 - host os: `Linux 5.4.83, NixOS, 20.09.2290.647cc06986c (Nightingale)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.3.9`
 - channels(root): `"nixos-20.09.2290.647cc06986c"`
 - channels(user): `""`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

NixOS / nixpkgs

dhcpcd segfaults #107149