On Thu, Jan 18, 2024 at 05:58:20PM +0200, Eduard Zingerman wrote:
On Thu, 2024-01-18 at 19:58 +0800, Shung-Hsi Yu wrote:
Compilation of lsm_cgroup.c will fail if the vmlinux.h comes from a kernel that does _not_ have CONFIG_PACKET=y. The reason is that the definition of struct sockaddr_ll is not present in vmlinux.h and the compiler will complain that is has an incomplete type.
CLNG-BPF [test_maps] lsm_cgroup.bpf.oprogs/lsm_cgroup.c:105:21: error: variable has incomplete type 'struct sockaddr_ll' 105 | struct sockaddr_ll sa = {}; | ^ progs/lsm_cgroup.c:105:9: note: forward declaration of 'struct sockaddr_ll' 105 | struct sockaddr_ll sa = {}; | ^ 1 error generated.
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Hi Shung-Hsi,
One option is to use CO-RE, e.g. as at the bottom of this email (not sure if people would agree with me). But that would not produce usable test anyways, as load would fail with unresolved CO-RE relocation.
But what is your final goal?
Final goal would be have BPF selftests compiled and test against our own kernel, without having to come up with a specific kernel flavor that is used to build and run the selftest. For v5.14 and v5.19-based kernel it works: compilation is successful and I was able to run the verifier tests. (Did not try running the other tests though)
As far as I understand, selftests are supposed to be built and run using specific configuration, here is how config for x86 CI is prepared:
./scripts/kconfig/merge_config.sh \ ./tools/testing/selftests/bpf/config \ ./tools/testing/selftests/bpf/config.vm \ ./tools/testing/selftests/bpf/config.x86_64
(root is kernel source). I'm not sure if other configurations are supposed to be supported.
Would it make sense to have makefile target that builds/runs a smaller subset of general, config-agnostic selftests that tests the core feature (e.g. verifier + instruction set)?
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