Add a goddamn max length parameter to your tokenizer.

tokenizer_config.json

@@ -46,10 +46,10 @@
   "cls_token": "<s>",
   "eos_token": "</s>",
   "mask_token": "<mask>",
-  "model_max_length": 1000000000000000019884624838656,
+  "model_max_length": 512,
   "pad_token": "<pad>",
   "sep_token": "</s>",
   "sp_model_kwargs": {},
   "tokenizer_class": "XLMRobertaTokenizer",
-  "unk_token": "<unk>"
+  "unk_token": "<unk>",
 }