It don't happen with a "Regular Scan" or "Quick Scan".
But even there, you see process activity with strace for 2 minutes after the scan has finished. With the "Intense Scan" it never stops. That activity produces 100% CPU load.
I can't remember having the same behavior with x86-64, but i haven't tried with NixOS 20.09 there.
Describe the bug When i have dnsmasq installed on a Raspberry Pi 4 (AARCH64) and do a port scan, it get stuck and consumes 100% CPU forever.
I noticed that when scanning with openvas, but it is also reproducible with nmap.
To Reproduce Steps to reproduce the behavior:
nix run nixpkgs.nmap-graphical -c zenmap
It don't happen with a "Regular Scan" or "Quick Scan".
But even there, you see process activity with strace for 2 minutes after the scan has finished. With the "Intense Scan" it never stops. That activity produces 100% CPU load.
I can't remember having the same behavior with x86-64, but i haven't tried with NixOS 20.09 there.
So maybe it's a NixOS 20.09 problem, or aarch64.
Here is the strace log: https://gist.github.com/davidak/2b41a2301ad1b0e9e4556ef96c28e44c
The process is marked as defunct:
It might be an issue upstream has to fix.
Expected behavior dnsmasq answers the requests and don't do anything further
Screenshots![Screenshot from 2020-11-18 16-56-47](https://user-images.githubusercontent.com/91113/99554059-14d61980-29bf-11eb-8205-0c0e03096b0a.png)
The program is not detected correctly, so nmap probably never got the banner.
Additional context It's the first time i disabled IPv6 on NixOS, but that probably don't cause such issues.
Notify maintainers @fpletz @globin
Metadata
"aarch64-linux"
Linux 4.19.118, NixOS, 20.09.1721.896270d629e (Nightingale)
yes
yes
nix-env (Nix) 2.3.7
"nixos-20.09.1721.896270d629e"
/nix/var/nix/profiles/per-user/root/channels/nixos
Maintainer information: