Hostname should also be passed through safe_str

celery/apps/worker.py

@@ -199,7 +199,7 @@ class Worker(WorkController):
 
         banner = BANNER.format(
             app=appr,
-            hostname=self.hostname,
+            hostname=safe_str(self.hostname),
             version=VERSION_BANNER,
             conninfo=self.app.connection().as_uri(),
             concurrency=concurrency,