[PATCH] Reorganise sock init in rpcsvc to avoid races.

If one of the callback (e.g. data ready) is called
before socket setup is complete, oops may occur.

With this patch, socket is kept SK_BUSY until all is
ready to avoid this.

Also some code is moved around to make it cleaner.

net/sunrpc/svcsock.c

@@ -627,7 +627,7 @@ svc_udp_sendto(struct svc_rqst *rqstp)
 	return error;
 }
 
-static int
+static void
 svc_udp_init(struct svc_sock *svsk)
 {
 	svsk->sk_sk->data_ready = svc_udp_data_ready;
@@ -643,9 +643,8 @@ svc_udp_init(struct svc_sock *svsk)
 			    3 * svsk->sk_server->sv_bufsz,
 			    3 * svsk->sk_server->sv_bufsz);
 
+	set_bit(SK_DATA, &svsk->sk_flags); /* might have come in before data_ready set up */
 	set_bit(SK_CHNGBUF, &svsk->sk_flags);
-
-	return 0;
 }
 
 /*
@@ -773,19 +772,14 @@ svc_tcp_accept(struct svc_sock *svsk)
 	dprintk("%s: connect from %u.%u.%u.%u:%04x\n", serv->sv_name,
 			NIPQUAD(sin.sin_addr.s_addr), ntohs(sin.sin_port));
 
-	if (!(newsvsk = svc_setup_socket(serv, newsock, &err, 0)))
-		goto failed;
-
 	/* make sure that a write doesn't block forever when
 	 * low on memory
 	 */
 	newsock->sk->sndtimeo = HZ*30;
 
-	/* Precharge. Data may have arrived on the socket before we
-	 * installed the data_ready callback. 
-	 */
-	set_bit(SK_DATA, &newsvsk->sk_flags);
-	svc_sock_enqueue(newsvsk);
+	if (!(newsvsk = svc_setup_socket(serv, newsock, &err, 0)))
+		goto failed;
+
 
 	/* make sure that we don't have too many active connections.
 	 * If we have, something must be dropped.
@@ -1006,7 +1000,7 @@ svc_tcp_sendto(struct svc_rqst *rqstp)
 	return sent;
 }
 
-static int
+static void
 svc_tcp_init(struct svc_sock *svsk)
 {
 	struct sock	*sk = svsk->sk_sk;
@@ -1017,6 +1011,7 @@ svc_tcp_init(struct svc_sock *svsk)
 	if (sk->state == TCP_LISTEN) {
 		dprintk("setting up TCP socket for listening\n");
 		sk->data_ready = svc_tcp_listen_data_ready;
+		set_bit(SK_CONN, &svsk->sk_flags);
 	} else {
 		dprintk("setting up TCP socket for reading\n");
 		sk->state_change = svc_tcp_state_change;
@@ -1035,9 +1030,8 @@ svc_tcp_init(struct svc_sock *svsk)
 				    3 * svsk->sk_server->sv_bufsz);
 
 		set_bit(SK_CHNGBUF, &svsk->sk_flags);
+		set_bit(SK_DATA, &svsk->sk_flags);
 	}
-
-	return 0;
 }
 
 void
@@ -1258,6 +1252,18 @@ svc_setup_socket(struct svc_serv *serv, struct socket *sock,
 	memset(svsk, 0, sizeof(*svsk));
 
 	inet = sock->sk;
+
+	/* Register socket with portmapper */
+	if (*errp >= 0 && pmap_register)
+		*errp = svc_register(serv, inet->protocol,
+				     ntohs(inet_sk(inet)->sport));
+
+	if (*errp < 0) {
+		kfree(svsk);
+		return NULL;
+	}
+
+	set_bit(SK_BUSY, &svsk->sk_flags);
 	inet->user_data = svsk;
 	svsk->sk_sock = sock;
 	svsk->sk_sk = inet;
@@ -1271,23 +1277,9 @@ svc_setup_socket(struct svc_serv *serv, struct socket *sock,
 
 	/* Initialize the socket */
 	if (sock->type == SOCK_DGRAM)
-		*errp = svc_udp_init(svsk);
+		svc_udp_init(svsk);
 	else
-		*errp = svc_tcp_init(svsk);
-if (svsk->sk_sk == NULL)
-	printk(KERN_WARNING "svsk->sk_sk == NULL after svc_prot_init!\n");
-
-	/* Register socket with portmapper */
-	if (*errp >= 0 && pmap_register)
-		*errp = svc_register(serv, inet->protocol,
-				     ntohs(inet_sk(inet)->sport));
-
-	if (*errp < 0) {
-		inet->user_data = NULL;
-		kfree(svsk);
-		return NULL;
-	}
-
+		svc_tcp_init(svsk);
 
 	spin_lock_bh(&serv->sv_lock);
 	if (!pmap_register) {
@@ -1302,6 +1294,9 @@ if (svsk->sk_sk == NULL)
 
 	dprintk("svc: svc_setup_socket created %p (inet %p)\n",
 				svsk, svsk->sk_sk);
+
+	clear_bit(SK_BUSY, &svsk->sk_flags);
+	svc_sock_enqueue(svsk);
 	return svsk;
 }