can: af_can: Fix error path of can_init()

This patch add error path for can_init() to avoid possible crash if some
error occurs.

Fixes: 0d66548a ("[CAN]: Add PF_CAN core module")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

net/can/af_can.c

@@ -952,6 +952,8 @@ static struct pernet_operations can_pernet_ops __read_mostly = {
 
 static __init int can_init(void)
 {
+	int err;
+
 	/* check for correct padding to be able to use the structs similarly */
 	BUILD_BUG_ON(offsetof(struct can_frame, can_dlc) !=
 		     offsetof(struct canfd_frame, len) ||
@@ -965,15 +967,31 @@ static __init int can_init(void)
 	if (!rcv_cache)
 		return -ENOMEM;
 
-	register_pernet_subsys(&can_pernet_ops);
+	err = register_pernet_subsys(&can_pernet_ops);
+	if (err)
+		goto out_pernet;
 
 	/* protocol register */
-	sock_register(&can_family_ops);
-	register_netdevice_notifier(&can_netdev_notifier);
+	err = sock_register(&can_family_ops);
+	if (err)
+		goto out_sock;
+	err = register_netdevice_notifier(&can_netdev_notifier);
+	if (err)
+		goto out_notifier;
+
 	dev_add_pack(&can_packet);
 	dev_add_pack(&canfd_packet);
 
 	return 0;
+
+out_notifier:
+	sock_unregister(PF_CAN);
+out_sock:
+	unregister_pernet_subsys(&can_pernet_ops);
+out_pernet:
+	kmem_cache_destroy(rcv_cache);
+
+	return err;
 }
 
 static __exit void can_exit(void)