@user_123454321 my  pytorch version is 1.6.0 and OS is ubuntu 16.04. I tried different GPU models but the issue persists. By the way, may I know your pytorch version?
Some updates: I found the output fc(t.cuda()) equals to the bias of the Linear layer. When I set bias=False, calling fc(t.cuda()) will raise an error RuntimeError: copy_if failed to synchronize: an illegal memory access was encountered. I guess it is probably related to the implementation of torch.addmm() but could not find out.