diff --git a/hw/usb.c b/hw/usb.c
index bacdc81bfc4676a11dce4b4b4fb60de7d8449c1e..9976f81bd7d189c0ec16a9eb19bb73f62152d5d9 100644
--- a/hw/usb.c
+++ b/hw/usb.c
@@ -315,6 +315,10 @@ int usb_handle_packet(USBDevice *dev, USBPacket *p)
 {
     int ret;
 
+    if (dev == NULL) {
+        return USB_RET_NODEV;
+    }
+
     assert(p->owner == NULL);
     ret = usb_device_handle_packet(dev, p);
     if (ret == USB_RET_ASYNC) {