Ignore invalid UTF-8 data.

qutebrowser/utils/ipc.py

@@ -97,12 +97,14 @@ class IPCServer(QObject):
         """Read json data from the client."""
         while self._socket.canReadLine():
             data = bytes(self._socket.readLine())
+            try:
                 decoded = data.decode('utf-8')
+            except UnicodeDecodeError:
+                return
             try:
                 args = json.loads(decoded)
             except ValueError:
                 return
-            else:
             app = objreg.get('app')
             app.process_args(args)