diff --git a/libgphoto2_port/libusb1/libusb1.c b/libgphoto2_port/libusb1/libusb1.c
index c6b16aa..74b722f 100644
--- a/libgphoto2_port/libusb1/libusb1.c
+++ b/libgphoto2_port/libusb1/libusb1.c
@@ -84,6 +84,14 @@ static int gp_nrofdevs = 0;
 static struct libusb_device_descriptor	*gp_descs;
 static libusb_device			**gp_devs;
 
+static void
+free_devicelist(void)
+{
+	if (gp_devs != NULL)
+		libusb_free_device_list (gp_devs, 1);
+	gp_devs = NULL;
+}
+
 static ssize_t
 load_devicelist (libusb_context *ctx) {
 	time_t	xtime;
@@ -91,7 +99,7 @@ load_devicelist (libusb_context *ctx) {
 	time(&xtime);
 	if (xtime != gp_devslastchecked) {
 		if (gp_nrofdevs)
-			libusb_free_device_list (gp_devs, 1);
+			free_devicelist();
 		free (gp_descs);
 		gp_nrofdevs = 0;
 		gp_devs = NULL;
@@ -267,12 +275,14 @@ static int gp_port_usb_init (GPPort *port)
 static int
 gp_port_usb_exit (GPPort *port)
 {
+	/* devices must be freed before exiting the USB context */
+	free_devicelist();
+
 	if (port->pl) {
 		libusb_exit (port->pl->ctx);
 		free (port->pl);
 		port->pl = NULL;
 	}
-	if (gp_devs) libusb_free_device_list (gp_devs, 1);
 	free (gp_descs);
 	return (GP_OK);
 }