--- x/drivers/comedi/drivers.c
+++ y/drivers/comedi/drivers.c
@@ -961,7 +961,7 @@ EXPORT_SYMBOL_GPL(comedi_legacy_detach);
 int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 {
 	struct comedi_driver *driv;
-	int ret;
+	int ret, detach;
 
 	lockdep_assert_held(&dev->mutex);
 	if (dev->attached)
@@ -1004,11 +1004,15 @@ int comedi_device_attach(struct comedi_d
 	dev->driver = driv;
 	dev->board_name = dev->board_ptr ? *(const char **)dev->board_ptr
 					 : dev->driver->driver_name;
+	detach = 0;
 	ret = driv->attach(dev, it);
-	if (ret >= 0)
+	if (ret >= 0) {
+		detach = 1;
 		ret = comedi_device_postconfig(dev);
+	}
 	if (ret < 0) {
-		comedi_device_detach(dev);
+		if (detach)
+			comedi_device_detach(dev);
 		module_put(driv->module);
 	}
 	/* On success, the driver module count has been incremented. */