Error in iterating through dataloader

1 
for data, transf_data,target in data_bar:

File “/root/anaconda3/envs/gcn/lib/python3.11/site-packages/tqdm/std.py”, line 1178, in iter
for obj in iterable:
File “/root/anaconda3/envs/gcn/lib/python3.11/site-packages/torch/utils/data/dataloader.py”, line 633, in next
data = self._next_data()
^^^^^^^^^^^^^^^^^
File “/root/anaconda3/envs/gcn/lib/python3.11/site-packages/torch/utils/data/dataloader.py”, line 1345, in _next_data
return self._process_data(data)
^^^^^^^^^^^^^^^^^^^^^^^^
File “/root/anaconda3/envs/gcn/lib/python3.11/site-packages/torch/utils/data/dataloader.py”, line 1371, in _process_data
data.reraise()
File “/root/anaconda3/envs/gcn/lib/python3.11/site-packages/torch/_utils.py”, line 644, in reraise
raise exception
RuntimeError: Caught RuntimeError in DataLoader worker process 0.
Original Traceback (most recent call last):
File “/root/anaconda3/envs/gcn/lib/python3.11/site-packages/torch/utils/data/_utils/worker.py”, line 308, in _worker_loop
data = fetcher.fetch(index)
^^^^^^^^^^^^^^^^^^^^
File “/root/anaconda3/envs/gcn/lib/python3.11/site-packages/torch/utils/data/_utils/fetch.py”, line 51, in fetch
data = [self.dataset[idx] for idx in possibly_batched_index]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “/root/anaconda3/envs/gcn/lib/python3.11/site-packages/torch/utils/data/_utils/fetch.py”, line 51, in
data = [self.dataset[idx] for idx in possibly_batched_index]
~~~~~~~~~~~~^^^^^
File “/home/rani1/graph_mv/nn_linear/dataset.py”, line 14, in getitem
feature = self.features[idx]
~~~~~~~~~~~~~^^^^^
RuntimeError: CUDA error: initialization error
Compile with TORCH_USE_CUDA_DSA to enable device-side assertions.

2

You didn’t describe your use case and what exactly triggers the error, so I speculate you are using CUDATensors inside your Dataset and are then using multiple workers in your DataLoader, which will try to re-initialize the CUDA context.
If so, use CPUTensors or the spawn start method in multiprocessing.

3

Yes , just solved it, by num_worker = 0