why roi_data_loader failed?

[Johumliu]

error info is: INFO net.py: 256: End of model: generalized_rcnn json_stats: {"accuracy_cls": 0.037109375, "bbox_iou": 0.578046441078186, "bbox_iou_pre": 0.581378161907196, "eta": "156 days, 14:28:45", "iter": 0, "loss": 4.357075472828001, "loss_bbox": 0.0108263548463583, "loss_cls": 1.7434967756271362, "loss_mask": 1.8641934394836426, "loss_rpn_bbox_fpn2": 0.017656072974205017, "loss_rpn_bbox_fpn3": 0.027422986924648285, "loss_rpn_bbox_fpn4": 0.00962013378739357, "loss_rpn_bbox_fpn5": 0.0, "loss_rpn_bbox_fpn6": 0.0, "loss_rpn_cls_fpn2": 0.5143534541130066, "loss_rpn_cls_fpn3": 0.12222617119550705, "loss_rpn_cls_fpn4": 0.043131548911333084, "loss_rpn_cls_fpn5": 0.004148534964770079, "loss_rpn_cls_fpn6": 0.0, "lr": 0.006666666828095913, "mb_qsize": 64, "mem": 11154, "time": 75.1695876121521} CRITICAL train.py: 98: roi_data_loader failed INFO loader.py: 126: Stopping enqueue thread Traceback (most recent call last): File "tools/train_net.py", line 132, in main() File "tools/train_net.py", line 114, in main checkpoints = detectron.utils.train.train_model() File "/data/ljh/Detectron-Cascade-RCNN/detectron/utils/train.py", line 64, in train_model handle_critical_error(model, 'roi_data_loader failed') File "/data/ljh/Detectron-Cascade-RCNN/detectron/utils/train.py", line 100, in handle_critical_error raise Exception(msg) Exception: roi_data_loader failed