1 files changed, 37 insertions, 33 deletions

diff --git a/net/tipc/server.c b/net/tipc/server.c
index 8ee5e86b7870..c0d331f13eee 100644
--- a/net/tipc/server.c
+++ b/net/tipc/server.c
@@ -132,10 +132,11 @@ static struct tipc_conn *tipc_conn_lookup(struct tipc_server *s, int conid)
 
         spin_lock_bh(&s->idr_lock);
         con = idr_find(&s->conn_idr, conid);
-        if (con && test_bit(CF_CONNECTED, &con->flags))
-                conn_get(con);
-        else
-                con = NULL;
+        if (con) {
+                if (!test_bit(CF_CONNECTED, &con->flags) ||
+                    !kref_get_unless_zero(&con->kref))
+                        con = NULL;
+        }
         spin_unlock_bh(&s->idr_lock);
         return con;
 }
@@ -183,35 +184,28 @@ static void tipc_register_callbacks(struct socket *sock, struct tipc_conn *con)
         write_unlock_bh(&sk->sk_callback_lock);
 }
 
-static void tipc_unregister_callbacks(struct tipc_conn *con)
-{
-        struct sock *sk = con->sock->sk;
-
-        write_lock_bh(&sk->sk_callback_lock);
-        sk->sk_user_data = NULL;
-        write_unlock_bh(&sk->sk_callback_lock);
-}
-
 static void tipc_close_conn(struct tipc_conn *con)
 {
         struct tipc_server *s = con->server;
+        struct sock *sk = con->sock->sk;
+        bool disconnect = false;
 
-        if (test_and_clear_bit(CF_CONNECTED, &con->flags)) {
-                if (con->sock)
-                        tipc_unregister_callbacks(con);
-
+        write_lock_bh(&sk->sk_callback_lock);
+        disconnect = test_and_clear_bit(CF_CONNECTED, &con->flags);
+        if (disconnect) {
+                sk->sk_user_data = NULL;
                 if (con->conid)
                         s->tipc_conn_release(con->conid, con->usr_data);
-
-                /* We shouldn't flush pending works as we may be in the
-                 * thread. In fact the races with pending rx/tx work structs
-                 * are harmless for us here as we have already deleted this
-                 * connection from server connection list.
-                 */
-                if (con->sock)
-                        kernel_sock_shutdown(con->sock, SHUT_RDWR);
-                conn_put(con);
         }
+        write_unlock_bh(&sk->sk_callback_lock);
+
+        /* Handle concurrent calls from sending and receiving threads */
+        if (!disconnect)
+                return;
+
+        /* Don't flush pending works, -just let them expire */
+        kernel_sock_shutdown(con->sock, SHUT_RDWR);
+        conn_put(con);
 }
 
 static struct tipc_conn *tipc_alloc_conn(struct tipc_server *s)
@@ -248,9 +242,10 @@ static struct tipc_conn *tipc_alloc_conn(struct tipc_server *s)
 
 static int tipc_receive_from_sock(struct tipc_conn *con)
 {
-        struct msghdr msg = {};
         struct tipc_server *s = con->server;
+        struct sock *sk = con->sock->sk;
         struct sockaddr_tipc addr;
+        struct msghdr msg = {};
         struct kvec iov;
         void *buf;
         int ret;
@@ -271,12 +266,15 @@ static int tipc_receive_from_sock(struct tipc_conn *con)
                 goto out_close;
         }
 
-        s->tipc_conn_recvmsg(sock_net(con->sock->sk), con->conid, &addr,
-                             con->usr_data, buf, ret);
-
+        read_lock_bh(&sk->sk_callback_lock);
+        if (test_bit(CF_CONNECTED, &con->flags))
+                ret = s->tipc_conn_recvmsg(sock_net(con->sock->sk), con->conid,
+                                           &addr, con->usr_data, buf, ret);
+        read_unlock_bh(&sk->sk_callback_lock);
         kmem_cache_free(s->rcvbuf_cache, buf);
-
-        return 0;
+        if (ret < 0)
+                tipc_conn_terminate(s, con->conid);
+        return ret;
 
 out_close:
         if (ret != -EWOULDBLOCK)
@@ -525,11 +523,17 @@ bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, u32 lower,
 void tipc_topsrv_kern_unsubscr(struct net *net, int conid)
 {
         struct tipc_conn *con;
+        struct tipc_server *srv;
 
         con = tipc_conn_lookup(tipc_topsrv(net), conid);
         if (!con)
                 return;
-        tipc_close_conn(con);
+
+        test_and_clear_bit(CF_CONNECTED, &con->flags);
+        srv = con->server;
+        if (con->conid)
+                srv->tipc_conn_release(con->conid, con->usr_data);
+        conn_put(con);
         conn_put(con);
 }