libbpf: Make BTF finalization strict

With valid ELF and valid BTF, there is no reason (apart from bugs) why BTF
finalization should fail. So make it strict and return error if it fails. This
makes CO-RE relocation more reliable, as they are not going to be just
silently skipped, if BTF finalization failed.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200708015318.3827358-2-andriin@fb.com

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 88a4836..efd857e 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2473,19 +2473,11 @@ static int bpf_object__finalize_btf(struct bpf_object *obj)
                return 0;
 
        err = btf__finalize_data(obj, obj->btf);
-       if (!err)
-               return 0;
-
-       pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err);
-       btf__free(obj->btf);
-       obj->btf = NULL;
-       btf_ext__free(obj->btf_ext);
-       obj->btf_ext = NULL;
-
-       if (libbpf_needs_btf(obj)) {
-               pr_warn("BTF is required, but is missing or corrupted.\n");
-               return -ENOENT;
+       if (err) {
+               pr_warn("Error finalizing %s: %d.\n", BTF_ELF_SEC, err);
+               return err;
        }
+
        return 0;
 }