Proc socket stats use sk_prot->inuse_idx value to record inuse sock stats.
We currently do not set this correctly from sockmap side. The result is
reading sock stats '/proc/net/sockstat' gives incorrect values. The
socket counter is incremented correctly, but because we don't set the
counter correctly when we replace sk_prot we may omit the decrement.
Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: John Fastabend <john.fastabend@xxxxxxxxx>
---
net/core/sock_map.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 60decd6420ca..016ea5460f8f 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -222,6 +222,9 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk)
struct bpf_prog *msg_parser = NULL;
struct sk_psock *psock;
int ret;
+#ifdef CONFIG_PROC_FS
+ int idx;
+#endif
/* Only sockets we can redirect into/from in BPF need to hold
* refs to parser/verdict progs and have their sk_data_ready
@@ -293,9 +296,15 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk)
if (msg_parser)
psock_set_prog(&psock->progs.msg_parser, msg_parser);
+#ifdef CONFIG_PROC_FS
+ idx = sk->sk_prot->inuse_idx;
+#endif
ret = sock_map_init_proto(sk, psock);
if (ret < 0)
goto out_drop;
+#ifdef CONFIG_PROC_FS
+ sk->sk_prot->inuse_idx = idx;
+#endif
write_lock_bh(&sk->sk_callback_lock);
if (stream_parser && stream_verdict && !psock->saved_data_ready) {
--
2.25.1
