Commit a0f2b7ac authored by Hangbin Liu's avatar Hangbin Liu Committed by Alexei Starovoitov
Browse files

libbpf: Close map fd if init map slots failed 



Previously we forgot to close the map fd if bpf_map_update_elem()
failed during map slot init, which will leak map fd.

Let's move map slot initialization to new function init_map_slots() to
simplify the code. And close the map fd if init slot failed.

Reported-by: default avatarAndrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: default avatarHangbin Liu <liuhangbin@gmail.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201006021345.3817033-2-liuhangbin@gmail.com
parent dca4121c

tools/lib/bpf/libbpf.c

+34 −21
Original line number Diff line number Diff line
@@ -4203,6 +4203,36 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map) 
	return 0;

}



static int init_map_slots(struct bpf_map *map)

{

	const struct bpf_map *targ_map;

	unsigned int i;

	int fd, err;



	for (i = 0; i < map->init_slots_sz; i++) {

		if (!map->init_slots[i])

			continue;



		targ_map = map->init_slots[i];

		fd = bpf_map__fd(targ_map);

		err = bpf_map_update_elem(map->fd, &i, &fd, 0);

		if (err) {

			err = -errno;

			pr_warn("map '%s': failed to initialize slot [%d] to map '%s' fd=%d: %d\n",

				map->name, i, targ_map->name,

				fd, err);

			return err;

		}

		pr_debug("map '%s': slot [%d] set to map '%s' fd=%d\n",

			 map->name, i, targ_map->name, fd);

	}



	zfree(&map->init_slots);

	map->init_slots_sz = 0;



	return 0;

}



static int

bpf_object__create_maps(struct bpf_object *obj)

{
@@ -4245,28 +4275,11 @@ bpf_object__create_maps(struct bpf_object *obj) 
		}



		if (map->init_slots_sz) {

			for (j = 0; j < map->init_slots_sz; j++) {

				const struct bpf_map *targ_map;

				int fd;



				if (!map->init_slots[j])

					continue;



				targ_map = map->init_slots[j];

				fd = bpf_map__fd(targ_map);

				err = bpf_map_update_elem(map->fd, &j, &fd, 0);

				if (err) {

					err = -errno;

					pr_warn("map '%s': failed to initialize slot [%d] to map '%s' fd=%d: %d\n",

						map->name, j, targ_map->name,

						fd, err);

			err = init_map_slots(map);

			if (err < 0) {

				zclose(map->fd);

				goto err_out;

			}

				pr_debug("map '%s': slot [%d] set to map '%s' fd=%d\n",

					 map->name, j, targ_map->name, fd);

			}

			zfree(&map->init_slots);

			map->init_slots_sz = 0;

		}



		if (map->pin_path && !map->pinned) {