Commit 02cc5aa2 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Daniel Borkmann
Browse files

bpf: Remove prealloc-only restriction for sleepable bpf programs. 



Since hash map is now converted to bpf_mem_alloc and it's waiting for rcu and
rcu_tasks_trace GPs before freeing elements into global memory slabs it's safe
to use dynamically allocated hash maps in sleepable bpf programs.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220902211058.60789-15-alexei.starovoitov@gmail.com
parent dccb4a90

kernel/bpf/verifier.c

+0 −23
Original line number Diff line number Diff line
@@ -12586,14 +12586,6 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env, 
	return err;

}



static int check_map_prealloc(struct bpf_map *map)

{

	return (map->map_type != BPF_MAP_TYPE_HASH &&

		map->map_type != BPF_MAP_TYPE_PERCPU_HASH &&

		map->map_type != BPF_MAP_TYPE_HASH_OF_MAPS) ||

		!(map->map_flags & BPF_F_NO_PREALLOC);

}



static bool is_tracing_prog_type(enum bpf_prog_type type)

{

	switch (type) {
@@ -12608,15 +12600,6 @@ static bool is_tracing_prog_type(enum bpf_prog_type type) 
	}

}



static bool is_preallocated_map(struct bpf_map *map)

{

	if (!check_map_prealloc(map))

		return false;

	if (map->inner_map_meta && !check_map_prealloc(map->inner_map_meta))

		return false;

	return true;

}



static int check_map_prog_compatibility(struct bpf_verifier_env *env,

					struct bpf_map *map,

					struct bpf_prog *prog)
@@ -12669,12 +12652,6 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env, 
		case BPF_MAP_TYPE_LRU_PERCPU_HASH:

		case BPF_MAP_TYPE_ARRAY_OF_MAPS:

		case BPF_MAP_TYPE_HASH_OF_MAPS:

			if (!is_preallocated_map(map)) {

				verbose(env,

					"Sleepable programs can only use preallocated maps\n");

				return -EINVAL;

			}

			break;

		case BPF_MAP_TYPE_RINGBUF:

		case BPF_MAP_TYPE_INODE_STORAGE:

		case BPF_MAP_TYPE_SK_STORAGE: