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authorHou Tao <houtao1@huawei.com>2022-08-10 11:05:31 +0300
committerAlexei Starovoitov <ast@kernel.org>2022-08-10 20:12:47 +0300
commitef1e93d2eeb58a1f08c37b22a2314b94bc045f15 (patch)
tree0b6f8ba11a3d23591f83266c8d40d607d71b195d /kernel
parentf76fa6b338055054f80c72b29c97fb95c1becadc (diff)
downloadlinux-ef1e93d2eeb58a1f08c37b22a2314b94bc045f15.tar.xz
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/hashtab.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 4d793a92301b..6c530a5e560a 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -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);
}