broken pipe when sending distributed run

[mrT23]

i am trying to send a distributed run via 'launch' script:
python -m fastai2.launch train.py --model_name=xresnet
on a 1xV100 machine, then run succeed
on a 2xV100 machine, the run fails and i get an error message:

File "/opt/conda/lib/python3.6/site-packages/fastai2/distributed.py", line 91, in begin_fit
self.learn.model = DistributedDataParallel(self.model, device_ids=[self.cuda_id], output_device=self.cuda_id)
File "/opt/conda/lib/python3.6/site-packages/torch/nn/parallel/distributed.py", line 298, in init
self.broadcast_bucket_size)
File "/opt/conda/lib/python3.6/site-packages/torch/nn/parallel/distributed.py", line 480, in _distributed_broadcast_coalesced
dist._broadcast_coalesced(self.process_group, tensors, buffer_size)
RuntimeError: Broken pipe

i pulled the latest version of fastai2 from 25.11

[sgugger]

This is too vague an error message and could come from multiple things (it basically says there was an error...) Unless you debug it more to point us to something in the library that is the cause, ther eis nothing we can do to help.