Hey @lzkzls could you please share a minimal reproduce-able example code?
The first error picture does not seem to be a DDP error. Does the code run correctly without DDP? Looks like the autograd graph generating d_real_loss and d_fake_loss share some operators/parameters.
The second error picture seems to suggest the generator_model is a None object? It will be helpful to see a self-contained repro of this error.