Which PyTorch version are you using?
I cannot reproduce this error using a dummy code snippet as:
model = GraphConvolution().to(device)
print(model.weight.device)
model = torch.nn.DataParallel(model)
out = model(torch.randn(8, 100).cuda(), torch.zeros(20, 1).cuda())

Note that device is not properly defined, as you should push the model to the default device (one device only).
nn.DataParallel will then split the input data in the batch dimension and push each chunk to the right device.
Could you post an executable code snippet to reproduce this error (using random tensors), please? 
PS: I don’t think it’s a good idea to tag certain people, as this might discourage others to post an answer.