On Thu, Nov 19, 2020 at 03:22:42PM -0800, Andrii Nakryiko wrote:
[ ... ]
> +static int load_module_btfs(struct bpf_object *obj)
> +{
> + struct bpf_btf_info info;
> + struct module_btf *mod_btf;
> + struct btf *btf;
> + char name[64];
> + __u32 id, len;
> + int err, fd;
> +
> + if (obj->btf_modules_loaded)
> + return 0;
> +
> + /* don't do this again, even if we find no module BTFs */
> + obj->btf_modules_loaded = true;
> +
> + /* kernel too old to support module BTFs */
> + if (!kernel_supports(FEAT_MODULE_BTF))
> + return 0;
> +
> + while (true) {
> + err = bpf_btf_get_next_id(id, &id);
> + if (err && errno == ENOENT)
> + return 0;
> + if (err) {
> + err = -errno;
> + pr_warn("failed to iterate BTF objects: %d\n", err);
> + return err;
> + }
> +
> + fd = bpf_btf_get_fd_by_id(id);
> + if (fd < 0) {
> + if (errno == ENOENT)
> + continue; /* expected race: BTF was unloaded */
> + err = -errno;
> + pr_warn("failed to get BTF object #%d FD: %d\n", id, err);
> + return err;
> + }
> +
> + len = sizeof(info);
> + memset(&info, 0, sizeof(info));
> + info.name = ptr_to_u64(name);
> + info.name_len = sizeof(name);
> +
> + err = bpf_obj_get_info_by_fd(fd, &info, &len);
> + if (err) {
> + err = -errno;
> + pr_warn("failed to get BTF object #%d info: %d\n", id, err);
close(fd);
> + return err;
> + }
> +
> + /* ignore non-module BTFs */
> + if (!info.kernel_btf || strcmp(name, "vmlinux") == 0) {
> + close(fd);
> + continue;
> + }
> +
[ ... ]
> @@ -8656,9 +8815,6 @@ static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name,
> else
> err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC);
>
> - if (err <= 0)
> - pr_warn("%s is not found in vmlinux BTF\n", name);
> -
> return err;
> }
>
> @@ -8675,6 +8831,9 @@ int libbpf_find_vmlinux_btf_id(const char *name,
> }
>
> err = __find_vmlinux_btf_id(btf, name, attach_type);
> + if (err <= 0)
> + pr_warn("%s is not found in vmlinux BTF\n", name);
> +
Please explain this move in the commit message.
> btf__free(btf);
> return err;
> }
> --
> 2.24.1
>
