Need to use RUnlock for RLock.

cmd/dwelling-radio/main.go

@@ -63,7 +63,7 @@ func main() {
 		}
 
 		lstnrs.RLock()
-		defer lstnrs.Unlock()
+		defer lstnrs.RUnlock()
 		web.Index(&currentSong, lst, *songListLen, lstnrs, r).Render(context.Background(), w)
 	})
 

internal/http/dj_handlers.go

@@ -140,7 +140,7 @@ func (dj *DJHandlers) Status(w http.ResponseWriter, r *http.Request) {
 	}
 
 	dj.listeners.RLock()
-	defer dj.listeners.Unlock()
+	defer dj.listeners.RUnlock()
 	err = json.NewEncoder(w).Encode(&struct {
 		Current   *radio.Song  `json:"current_song,omitempty"`
 		Listeners int64        `json:"listeners"`