Index: uspace/lib/usbdev/src/devdrv.c
===================================================================
--- uspace/lib/usbdev/src/devdrv.c	(revision 4ee52726789edb40f954a15caac430e9a866cd8e)
+++ uspace/lib/usbdev/src/devdrv.c	(revision 95d5dca71e430f7fef179a3a26aec6e0a1692788)
@@ -506,5 +506,6 @@
 	    EXCHANGE_ATOMIC, handle, IPC_FLAG_BLOCKING);
 	int ret = usb_device_get_info(sess, &h, &iface_no);
-	async_hangup(sess);
+	if (sess)
+		async_hangup(sess);
 	if (ret != EOK)
 		return NULL;