diff --git a/repos/dde_linux/src/drivers/usb_modem/main.cc b/repos/dde_linux/src/drivers/usb_modem/main.cc
index 490a8c291a..9f295bb45f 100644
--- a/repos/dde_linux/src/drivers/usb_modem/main.cc
+++ b/repos/dde_linux/src/drivers/usb_modem/main.cc
@@ -199,6 +199,11 @@ Driver::Device::~Device()
 {
 	driver.devices.remove(&le);
 	if (udev) unregister_device();
+
+	while (usb.source()->ack_avail()) {
+		Usb::Packet_descriptor p = usb.source()->get_acked_packet();
+		usb.source()->release_packet(p);
+	}
 }