On 8/6/22 12:40 AM, Hou Tao wrote:
From: Hou Tao <houtao1@xxxxxxxxxx>
During bpf(BPF_LINK_CREATE) for BPF_TRACE_ITER, bpf_iter_attach_map()
has already acquired a map uref, but the uref may be released
by bpf_link_release() during th reading of map iterator.
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@xxxxxxxxxx>
See my previous reply for some wording issue.
Acked-by: Yonghong Song <yhs@xxxxxx>
---
kernel/bpf/hashtab.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index da7578426a46..da8c0177f773 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -2064,6 +2064,7 @@ 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;
@@ -2073,6 +2074,7 @@ 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);
}
