diff --git a/sys/dev/ciss/ciss.c b/sys/dev/ciss/ciss.c
index c8dee7059aa4..9553fb4de6ac 100644
--- a/sys/dev/ciss/ciss.c
+++ b/sys/dev/ciss/ciss.c
@@ -3429,13 +3429,17 @@ ciss_name_device(struct ciss_softc *sc, int bus, int target)
 			     target, 0);
 
     if (status == CAM_REQ_CMP) {
+	mtx_lock(&sc->ciss_mtx);
 	xpt_path_lock(path);
 	periph = cam_periph_find(path, NULL);
-	sprintf(sc->ciss_logical[bus][target].cl_name, "%s%d",
-		periph->periph_name, periph->unit_number);
 	xpt_path_unlock(path);
+	mtx_unlock(&sc->ciss_mtx);
 	xpt_free_path(path);
-	return(0);
+	if (periph != NULL) {
+		sprintf(sc->ciss_logical[bus][target].cl_name, "%s%d",
+			periph->periph_name, periph->unit_number);
+		return(0);
+	}
     }
     sc->ciss_logical[bus][target].cl_name[0] = 0;
     return(ENOENT);