Re: [PATCH bpf-next v1 4/6] bpf: selftests: Move test_ksyms_weak test to lskel, add libbpf test

On Thu, Oct 7, 2021 at 1:46 PM Kumar Kartikeya Dwivedi [off-list ref] wrote:

[...]

quoted

quoted

 /* typeless symbols, default to zero. */

@@ -38,7 +37,7 @@ int pass_handler(const void *ctx)
        /* tests existing symbols. */
        rq = (struct rq *)bpf_per_cpu_ptr(&runqueues, 0);
        if (rq)
-               out__existing_typed = rq->cpu;
+               out__existing_typed = 0;

Why do we need this change?

Since they share the same BPF object for generating skeleton, it needs to remove
dependency on CO-RE which gen_loader does not support.

If it is kept, we get this:
...
libbpf: // TODO core_relo: prog 0 insn[5] rq kind 0
libbpf: prog 'pass_handler': relo #0: failed to relocate: -95
libbpf: failed to perform CO-RE relocations: -95
libbpf: failed to load object 'test_ksyms_weak'

I see. Thanks for the explanation.

Song