Fix ChildFailedError

✅ Solution

ChildFailedError in Unsloth with multi-GPU setups usually arises from issues during the synchronization of model parameters across GPUs in the distributed training process, specifically when using `torch.distributed.launch`. To fix it, try using `torchrun` instead of `torch.distributed.launch` to launch your training script. Ensure all GPUs are visible and properly configured via `CUDA_VISIBLE_DEVICES` environment variable prior to launching the process.