Commit 229fae38 authored by Shuyi Cheng's avatar Shuyi Cheng Committed by Andrii Nakryiko
Browse files

libbpf: Add "bool skipped" to struct bpf_map 



Fix error: "failed to pin map: Bad file descriptor, path:
/sys/fs/bpf/_rodata_str1_1."

In the old kernel, the global data map will not be created, see [0]. So
we should skip the pinning of the global data map to avoid
bpf_object__pin_maps returning error. Therefore, when the map is not
created, we mark “map->skipped" as true and then check during relocation
and during pinning.

Fixes: 16e0c35c ("libbpf: Load global data maps lazily on legacy kernels")
Signed-off-by: default avatarShuyi Cheng <chengshuyi@linux.alibaba.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
parent b69c5c07

tools/lib/bpf/libbpf.c

+8 −3
Original line number Diff line number Diff line
@@ -431,6 +431,7 @@ struct bpf_map { 
	char *pin_path;

	bool pinned;

	bool reused;

	bool skipped;

	__u64 map_extra;

};
@@ -5087,8 +5088,10 @@ bpf_object__create_maps(struct bpf_object *obj) 
		 * kernels.

		 */

		if (bpf_map__is_internal(map) &&

		    !kernel_supports(obj, FEAT_GLOBAL_DATA))

		    !kernel_supports(obj, FEAT_GLOBAL_DATA)) {

			map->skipped = true;

			continue;

		}



		retried = false;

retry:
@@ -5717,8 +5720,7 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) 
			} else {

				const struct bpf_map *map = &obj->maps[relo->map_idx];



				if (bpf_map__is_internal(map) &&

				    !kernel_supports(obj, FEAT_GLOBAL_DATA)) {

				if (map->skipped) {

					pr_warn("prog '%s': relo #%d: kernel doesn't support global data\n",

						prog->name, i);

					return -ENOTSUP;
@@ -7926,6 +7928,9 @@ int bpf_object__pin_maps(struct bpf_object *obj, const char *path) 
		char *pin_path = NULL;

		char buf[PATH_MAX];



		if (map->skipped)

			continue;



		if (path) {

			int len;