Reason for libbpf rejecting SECTION symbols in 'maps' section

[Toke Høiland-Jørgensen <toke@xxxxxxxxxx>]

Hi Andrii

We ran into an issue with binutils[0] mangling BPF object files, which
makes libbpf sad. Specifically, binutils will create SECTION symbols for
every section in .symtab, which trips this check in
bpf_object__init_user_maps():

if (GELF_ST_TYPE(sym.st_info) == STT_SECTION
    || GELF_ST_BIND(sym.st_info) == STB_LOCAL) {
	pr_warn("map '%s' (legacy): static maps are not supported\n", map_name);
	return -ENOTSUP;
}

Given the error message I can understand why it's checking for
STB_LOCAL, but why is the check for STT_SECTION there? And is there any
reason why libbpf couldn't just skip the SECTION symbols instead of
bugging out?

Hope you can help shed some light on the history here.

-Toke


[0] This happens because rpmbuild has a script that automatically that
runs 'strip' on every object file in an rpm; and so when we package up
the kernel selftests, we end up with mangled object files. Newer
versions of binutils don't do this, but the one on RHEL does.