cargo bpf build failure on Fedora

[kbknapp]

Just compiling the hello example on fedora gives the error:

$ cargo bpf build
[ .. snip .. ]
   Compiling redbpf-probes v1.0.1
error: failed to run custom build command for `redbpf-probes v1.0.1`

Caused by:
  process didn't exit successfully: `/mnt/storage/Projects/hello-bpf/target/bpf/release/build/redbpf-probes-a7fe94a0d7f9d765/build-script-build` (exit code: 101)
  --- stderr
  /lib/modules/5.7.12-200.fc32.x86_64/source/include/net/flow_offload.h:304:4: error: use of undeclared identifier 'KBUILD_MODNAME'
  /lib/modules/5.7.12-200.fc32.x86_64/source/include/net/flow_offload.h:338:3: error: use of undeclared identifier 'KBUILD_MODNAME'
  /lib/modules/5.7.12-200.fc32.x86_64/source/include/net/flow_offload.h:342:3: error: use of undeclared identifier 'KBUILD_MODNAME'
  /lib/modules/5.7.12-200.fc32.x86_64/source/include/net/flow_offload.h:304:4: error: use of undeclared identifier 'KBUILD_MODNAME', err: true
  /lib/modules/5.7.12-200.fc32.x86_64/source/include/net/flow_offload.h:338:3: error: use of undeclared identifier 'KBUILD_MODNAME', err: true
  /lib/modules/5.7.12-200.fc32.x86_64/source/include/net/flow_offload.h:342:3: error: use of undeclared identifier 'KBUILD_MODNAME', err: true
  thread 'main' panicked at 'failed to generate bindings: ()', /home/kevin/.cargo/registry/src/github.com-1ecc6299db9ec823/redbpf-probes-1.0.1/build.rs:74:10
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
error: failed to compile the `block_http' program

Following the exact same instructions on Ubuntu 20.04 yields a successful build.

[alessandrod]

Thanks for reporting the issue!

I think the latest kernel version we run on CI is 5.4, so there's probably a little porting work we need to do for newer kernels. What fedora version is this?

[kbknapp]

Fedora 32 which currently ships with kernel 5.7.14. I tried it on a few 5.7.x kernels but all had the same result.

[rsdy]

Everything up to 5.6 should work. Unfortunately I haven't had time to track the changes made in 5.7 onwards yet, and I can't put an ETA on it right now, but it doesn't seem like a huge piece of work.

[rsdy]

@kbknapp I've merged a PR that will enable compilation on 5.7 onwards. Let me know if you have any issues on Fedora in 1.1.