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-rw-r--r--include/net/sock.h2
-rw-r--r--net/l2tp/l2tp_core.c19
2 files changed, 14 insertions, 7 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index 5db02546941c..e0517ecc6531 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -323,7 +323,7 @@ struct sk_filter;
* @sk_tskey: counter to disambiguate concurrent tstamp requests
* @sk_zckey: counter to order MSG_ZEROCOPY notifications
* @sk_socket: Identd and reporting IO signals
- * @sk_user_data: RPC layer private data
+ * @sk_user_data: RPC layer private data. Write-protected by @sk_callback_lock.
* @sk_frag: cached page frag
* @sk_peek_off: current peek_offset value
* @sk_send_head: front of stuff to transmit
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 7499c51b1850..754fdda8a5f5 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1150,8 +1150,10 @@ static void l2tp_tunnel_destruct(struct sock *sk)
}
/* Remove hooks into tunnel socket */
+ write_lock_bh(&sk->sk_callback_lock);
sk->sk_destruct = tunnel->old_sk_destruct;
sk->sk_user_data = NULL;
+ write_unlock_bh(&sk->sk_callback_lock);
/* Call the original destructor */
if (sk->sk_destruct)
@@ -1469,16 +1471,18 @@ int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
sock = sockfd_lookup(tunnel->fd, &ret);
if (!sock)
goto err;
-
- ret = l2tp_validate_socket(sock->sk, net, tunnel->encap);
- if (ret < 0)
- goto err_sock;
}
+ sk = sock->sk;
+ write_lock(&sk->sk_callback_lock);
+
+ ret = l2tp_validate_socket(sk, net, tunnel->encap);
+ if (ret < 0)
+ goto err_sock;
+
tunnel->l2tp_net = net;
pn = l2tp_pernet(net);
- sk = sock->sk;
sock_hold(sk);
tunnel->sock = sk;
@@ -1504,7 +1508,7 @@ int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
setup_udp_tunnel_sock(net, sock, &udp_cfg);
} else {
- sk->sk_user_data = tunnel;
+ rcu_assign_sk_user_data(sk, tunnel);
}
tunnel->old_sk_destruct = sk->sk_destruct;
@@ -1518,6 +1522,7 @@ int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
if (tunnel->fd >= 0)
sockfd_put(sock);
+ write_unlock(&sk->sk_callback_lock);
return 0;
err_sock:
@@ -1525,6 +1530,8 @@ err_sock:
sock_release(sock);
else
sockfd_put(sock);
+
+ write_unlock(&sk->sk_callback_lock);
err:
return ret;
}