bpf: Acquire map uref in .init_seq_private for hash map iterator
authorHou Tao <houtao1@huawei.com>
Wed, 10 Aug 2022 08:05:31 +0000 (16:05 +0800)
committerAlexei Starovoitov <ast@kernel.org>
Wed, 10 Aug 2022 17:12:47 +0000 (10:12 -0700)
commitef1e93d2eeb58a1f08c37b22a2314b94bc045f15
tree0b6f8ba11a3d23591f83266c8d40d607d71b195d
parentf76fa6b338055054f80c72b29c97fb95c1becadc
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: d6c4503cc296 ("bpf: Implement bpf iterator for hash maps")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220810080538.1845898-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
kernel/bpf/hashtab.c