Verification fail on Ubuntu 20.04

[vituluss]

When I initially compiled and ran the program, the verification failed for "cannot call GPL-restricted function from non-GPL compatible program." I changed the license to "GPL" and it fixed this issue, but then a new verification issue occured. I'm guessing the new issue is because of the older kernel, but if this is possible to be fixed, that'd be nice. Attached is the logs: xdp-loader.log.

OS: Ubuntu 20.04.4 LTS
Kernel: 5.4.0-216-generic
Clang: 10.0.0-4.focal

[Outfluencer]

First of all, i am not really sure why there are any GPL-restricted function, there a non called in the code.

And you are using a pretty old version of clang, i have always compiled it with llvm/clang 20 and have updated it today to 21.

this is the installation from the github workflow

sudo apt update
sudo apt install -y gcc-multilib wget gnupg software-properties-common git libbpf-dev
wget https://apt.llvm.org/llvm.sh
chmod +x llvm.sh
sudo ./llvm.sh 21 all
sudo update-alternatives --install /usr/bin/clang clang /usr/lib/llvm-21/bin/clang 100
sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/lib/llvm-21/bin/clang++ 100
sudo update-alternatives --set clang /usr/lib/llvm-21/bin/clang
sudo update-alternatives --set clang++ /usr/lib/llvm-21/bin/clang++
sudo update-alternatives --install /usr/bin/llvm-strip llvm-strip /usr/lib/llvm-21/bin/llvm-strip 100
sudo update-alternatives --set llvm-strip /usr/lib/llvm-21/bin/llvm-strip

maybe try that.