avoid possible null-pointer dereference in error-path

diff --git a/hmcfgusb.c b/hmcfgusb.c
index 0e118661fa7007397f19c52b647f96299c9c1e22..83c9719b04b0d71e7324343a4aa75e7f147d3f87 100644 (file)
--- a/hmcfgusb.c
+++ b/hmcfgusb.c
@@ -285,8 +285,11 @@ static void LIBUSB_CALL hmcfgusb_interrupt(struct libusb_transfer *transfer)
        if (err != 0) {
                fprintf(stderr, "Can't re-submit transfer: %s\n", usb_strerror(err));
                libusb_free_transfer(transfer);
-               cb_data->dev->transfer = NULL;
-               free(cb_data);
+               if (cb_data) {
+                       if (cb_data->dev)
+                               cb_data->dev->transfer = NULL;
+                       free(cb_data);
+               }
        }
 }