This is a note to let you know that I've just added the patch titled libbpf: Apply map_set_def_max_entries() for inner_maps on creation to the 6.6-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-apply-map_set_def_max_entries-for-inner_maps-.patch and it can be found in the queue-6.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 96d17f72f8025af973fd583fd25a452834c29d12 Author: Andrey Grafin <conquistador@xxxxxxxxxxxxxx> Date: Wed Jan 17 16:06:18 2024 +0300 libbpf: Apply map_set_def_max_entries() for inner_maps on creation [ Upstream commit f04deb90e516e8e48bf8693397529bc942a9e80b ] This patch allows to auto create BPF_MAP_TYPE_ARRAY_OF_MAPS and BPF_MAP_TYPE_HASH_OF_MAPS with values of BPF_MAP_TYPE_PERF_EVENT_ARRAY by bpf_object__load(). Previous behaviour created a zero filled btf_map_def for inner maps and tried to use it for a map creation but the linux kernel forbids to create a BPF_MAP_TYPE_PERF_EVENT_ARRAY map with max_entries=0. Fixes: 646f02ffdd49 ("libbpf: Add BTF-defined map-in-map support") Signed-off-by: Andrey Grafin <conquistador@xxxxxxxxxxxxxx> Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Acked-by: Yonghong Song <yonghong.song@xxxxxxxxx> Acked-by: Hou Tao <houtao1@xxxxxxxxxx> Link: https://lore.kernel.org/bpf/20240117130619.9403-1-conquistador@xxxxxxxxxxxxxx Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index de08b920a149d..e238e6b824393 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -70,6 +70,7 @@ static struct bpf_map *bpf_object__add_map(struct bpf_object *obj); static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog); +static int map_set_def_max_entries(struct bpf_map *map); static const char * const attach_type_name[] = { [BPF_CGROUP_INET_INGRESS] = "cgroup_inet_ingress", @@ -5121,6 +5122,9 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b if (bpf_map_type__is_map_in_map(def->type)) { if (map->inner_map) { + err = map_set_def_max_entries(map->inner_map); + if (err) + return err; err = bpf_object__create_map(obj, map->inner_map, true); if (err) { pr_warn("map '%s': failed to create inner map: %d\n",