diff --git a/drivers/char/rocket.c b/drivers/char/rocket.c
index f585bc8..1b3fc6f 100644
--- a/drivers/char/rocket.c
+++ b/drivers/char/rocket.c
@@ -1433,29 +1433,38 @@
 {
 	struct r_port *info = (struct r_port *) tty->driver_data;
 	void __user *argp = (void __user *)arg;
+	int ret = 0;
 
 	if (cmd != RCKP_GET_PORTS && rocket_paranoia_check(info, "rp_ioctl"))
 		return -ENXIO;
 
+	lock_kernel();
+
 	switch (cmd) {
 	case RCKP_GET_STRUCT:
 		if (copy_to_user(argp, info, sizeof (struct r_port)))
-			return -EFAULT;
-		return 0;
+			ret = -EFAULT;
+		break;
 	case RCKP_GET_CONFIG:
-		return get_config(info, argp);
+		ret = get_config(info, argp);
+		break;
 	case RCKP_SET_CONFIG:
-		return set_config(info, argp);
+		ret = set_config(info, argp);
+		break;
 	case RCKP_GET_PORTS:
-		return get_ports(info, argp);
+		ret = get_ports(info, argp);
+		break;
 	case RCKP_RESET_RM2:
-		return reset_rm2(info, argp);
+		ret = reset_rm2(info, argp);
+		break;
 	case RCKP_GET_VERSION:
-		return get_version(info, argp);
+		ret = get_version(info, argp);
+		break;
 	default:
-		return -ENOIOCTLCMD;
+		ret = -ENOIOCTLCMD;
 	}
-	return 0;
+	unlock_kernel();
+	return ret;
 }
 
 static void rp_send_xchar(struct tty_struct *tty, char ch)