From: Rhys Rustad-Elliott me@rhysre.net
[ Upstream commit cba41bb78d70aad98d8e61e019fd48c561f7f396 ]
Commit d937bc3449fa ("bpf: make uniform use of array->elem_size everywhere in arraymap.c") changed array_map_gen_lookup to use array->elem_size instead of round_up(map->value_size, 8) as the element size when generating code to access a value in an array map.
array->elem_size, however, is not set by bpf_map_meta_alloc when initializing an BPF_MAP_TYPE_ARRAY_OF_MAPS or BPF_MAP_TYPE_HASH_OF_MAPS. This results in array_map_gen_lookup incorrectly outputting code that always accesses index 0 in the array (as the index will be calculated via a multiplication with the element size, which is incorrectly set to 0).
Set elem_size on the bpf_array object when allocating an array or hash of maps to fix this.
Fixes: d937bc3449fa ("bpf: make uniform use of array->elem_size everywhere in arraymap.c") Signed-off-by: Rhys Rustad-Elliott me@rhysre.net Link: https://lore.kernel.org/r/20230602190110.47068-2-me@rhysre.net Signed-off-by: Martin KaFai Lau martin.lau@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/bpf/map_in_map.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/map_in_map.c b/kernel/bpf/map_in_map.c index 38136ec4e095a..fbc3e944dc747 100644 --- a/kernel/bpf/map_in_map.c +++ b/kernel/bpf/map_in_map.c @@ -81,9 +81,13 @@ struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) /* Misc members not needed in bpf_map_meta_equal() check. */ inner_map_meta->ops = inner_map->ops; if (inner_map->ops == &array_map_ops) { + struct bpf_array *inner_array_meta = + container_of(inner_map_meta, struct bpf_array, map); + struct bpf_array *inner_array = container_of(inner_map, struct bpf_array, map); + + inner_array_meta->index_mask = inner_array->index_mask; + inner_array_meta->elem_size = inner_array->elem_size; inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1; - container_of(inner_map_meta, struct bpf_array, map)->index_mask = - container_of(inner_map, struct bpf_array, map)->index_mask; }
fdput(f);