Bluetooth: Fix memory leaks from discovery filter UUID list

In case of failure or when unplugging a controller, the allocated
memory for the UUID list of the discovery filter is not freed. Use
the newly introduced helper for reset the discovery filter and with
that also freeing existing memory.
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NJohan Hedberg <johan.hedberg@intel.com>

net/bluetooth/hci_core.c

@@ -4255,6 +4255,7 @@ void hci_unregister_dev(struct hci_dev *hdev)
 	hci_remote_oob_data_clear(hdev);
 	hci_bdaddr_list_clear(&hdev->le_white_list);
 	hci_conn_params_clear_all(hdev);
+	hci_discovery_filter_clear(hdev);
 	hci_dev_unlock(hdev);
 
 	hci_dev_put(hdev);

net/bluetooth/mgmt.c

@@ -3870,9 +3870,12 @@ static int start_discovery(struct sock *sk, struct hci_dev *hdev,
 		goto failed;
 	}
 
+	/* Clear the discovery filter first to free any previously
+	 * allocated memory for the UUID list.
+	 */
+	hci_discovery_filter_clear(hdev);
+
 	hdev->discovery.type = cp->type;
-	hdev->discovery.rssi = HCI_RSSI_INVALID;
-	hdev->discovery.uuid_count = 0;
 
 	hci_req_init(&req, hdev);
 
@@ -3957,6 +3960,11 @@ static int start_service_discovery(struct sock *sk, struct hci_dev *hdev,
 		goto failed;
 	}
 
+	/* Clear the discovery filter first to free any previously
+	 * allocated memory for the UUID list.
+	 */
+	hci_discovery_filter_clear(hdev);
+
 	hdev->discovery.type = cp->type;
 	hdev->discovery.rssi = cp->rssi;
 	hdev->discovery.uuid_count = uuid_count;