bng.p4 is too large to be loaded into the kernel

[fruffy]

I have been trying out NIKSS and I ran into some issues with bng.p4. Trying to load it using the command ./nikss-ctl pipeline load id 1 out.o fails.

I attached the log. My kernel is 6.9.3-76060903-generic. Any idea what could be happening here?

tmp.txt

[tatry]

Which version of clang you use to compile generated c code? Can you try clang-10?

I would say that the issue is with clang, not the kernel verifier nor p4c. Some time ago I tested some newer versions of clang. From these test, looks like there are some problems with newer versions of clang (new optimization passes? changed behavior of passes?) that prevent some P4 programs from loading into kernel. The only version of clang I know it is working well is clang-10. Unfortunately, I don't know the exact reason and how to fix it properly.

[fruffy]

Which version of clang you use to compile generated c code? Can you try clang-10?

clang-20, the earliest version I have readily available is clang-11, but that also seems to have problems.

[tatry]

Hmm, ebpf bytecode is not not need to be compiled on the same machine as for running. Maybe have you another machine / VM / docker image which have clang-10 and use it to build bng? Of course, just for test purpose.