Commit ef1e93d2 authored by Hou Tao's avatar Hou Tao Committed by Alexei Starovoitov
Browse files

bpf: Acquire map uref in .init_seq_private for hash map iterator 



bpf_iter_attach_map() acquires a map uref, and the uref may be released
before or in the middle of iterating map elements. For example, the uref
could be released in bpf_iter_detach_map() as part of
bpf_link_release(), or could be released in bpf_map_put_with_uref() as
part of bpf_map_release().

So acquiring an extra map uref in bpf_iter_init_hash_map() and
releasing it in bpf_iter_fini_hash_map().

Fixes: d6c4503c ("bpf: Implement bpf iterator for hash maps")
Signed-off-by: default avatarHou Tao <houtao1@huawei.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220810080538.1845898-3-houtao@huaweicloud.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent f76fa6b3

kernel/bpf/hashtab.c

+2 −0
Original line number Diff line number Diff line
@@ -2060,6 +2060,7 @@ static int bpf_iter_init_hash_map(void *priv_data, 
		seq_info->percpu_value_buf = value_buf;

	}



	bpf_map_inc_with_uref(map);

	seq_info->map = map;

	seq_info->htab = container_of(map, struct bpf_htab, map);

	return 0;
@@ -2069,6 +2070,7 @@ static void bpf_iter_fini_hash_map(void *priv_data) 
{

	struct bpf_iter_seq_hash_map_info *seq_info = priv_data;



	bpf_map_put_with_uref(seq_info->map);

	kfree(seq_info->percpu_value_buf);

}