Index: uspace/drv/bus/usb/xhci/endpoint.c
===================================================================
--- uspace/drv/bus/usb/xhci/endpoint.c	(revision 275f5292c04445b3d6aa69f11b56f74b81bcb074)
+++ uspace/drv/bus/usb/xhci/endpoint.c	(revision e439f46861706be55b5ae3dec82cfd42d38f5cf5)
@@ -68,4 +68,10 @@
 	}
 
+	fibril_mutex_lock(&ep->guard);
+	ep->hc_data.data = NULL;
+	ep->hc_data.toggle_get = NULL;
+	ep->hc_data.toggle_set = NULL;
+	fibril_mutex_unlock(&ep->guard);
+
 	usb_log_debug("Endpoint %d:%d destroyed.", ep->address, ep->endpoint);
 }