This is a note to let you know that I've just added the patch titled libbpf: Close map fd if init map slots failed to the 5.8-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: libbpf-close-map-fd-if-init-map-slots-failed.patch and it can be found in the queue-5.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 87843e88da06fbe6fcf011f0f8a678343ce25087 Author: Hangbin Liu <liuhangbin@xxxxxxxxx> Date: Tue Oct 6 10:13:43 2020 +0800 libbpf: Close map fd if init map slots failed [ Upstream commit a0f2b7acb4b1d29127ff99c714233b973afd1411 ] 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: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> Signed-off-by: Hangbin Liu <liuhangbin@xxxxxxxxx> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx> Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Link: https://lore.kernel.org/bpf/20201006021345.3817033-2-liuhangbin@xxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index e4d304247c1ba..3e71c2f69afe8 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -3677,6 +3677,36 @@ 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) { @@ -3719,28 +3749,11 @@ 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); - goto err_out; - } - pr_debug("map '%s': slot [%d] set to map '%s' fd=%d\n", - map->name, j, targ_map->name, fd); + err = init_map_slots(map); + if (err < 0) { + zclose(map->fd); + goto err_out; } - zfree(&map->init_slots); - map->init_slots_sz = 0; } if (map->pin_path && !map->pinned) {