diff --git a/src/server.c b/src/server.c
index ff848aa..413d9b9 100644
--- a/src/server.c
+++ b/src/server.c
@@ -475,8 +475,7 @@ main(int argc, char **argv) {
         if (!LIST_EMPTY(&server->clients)) {
             struct tty_client *client;
             LIST_FOREACH(client, &server->clients, list) {
-                if (client->running) {
-                    pthread_mutex_lock(&client->mutex);
+                if (client->running && pthread_mutex_trylock(&client->mutex)) {
                     if (client->state != STATE_DONE)
                         lws_callback_on_writable(client->wsi);
                     else