fix CUDA device index issue on cu130

__init__.py

@@ -216,6 +216,40 @@ def unet_offload_device_patched():
     logger.debug(f"[MultiGPU Core Patching] unet_offload_device_patched returning device: {device} (current_unet_offload_device={current_unet_offload_device})")
     return device
 
+# --- cu130 / PyTorch DLPack device-guard patch ---
+# comfy_kitchen's CUDA backend uses tensor.__dlpack__ which requires the current CUDA device
+# to match the tensor's device index. With multi-GPU setups the global current device can differ,
+# causing: BufferError: Can't export tensors on a different CUDA device index.
+def _patch_comfy_kitchen_dlpack_device_guard():
+    try:
+        import comfy_kitchen.backends.cuda as ck_cuda  # type: ignore
+    except Exception:
+        return  # comfy_kitchen not installed or no CUDA backend
+
+    try:
+        orig_wrap = getattr(ck_cuda, "_wrap_for_dlpack", None)
+        if orig_wrap is None or getattr(orig_wrap, "_multigpu_patched", False):
+            return
+
+        def _wrap_for_dlpack_guarded(tensor):
+            try:
+                if torch.cuda.is_available() and hasattr(tensor, "is_cuda") and tensor.is_cuda:
+                    idx = tensor.device.index
+                    if idx is not None:
+                        # Ensure current CUDA device matches the tensor before exporting via DLPack.
+                        torch.cuda.set_device(idx)
+            except Exception:
+                pass
+            return orig_wrap(tensor)
+
+        _wrap_for_dlpack_guarded._multigpu_patched = True  # type: ignore
+        setattr(ck_cuda, "_wrap_for_dlpack", _wrap_for_dlpack_guarded)
+        logger.info("[MultiGPU] Patched comfy_kitchen CUDA DLPack wrapper with device guard.")
+    except Exception as e:
+        logger.debug(f"[MultiGPU] Failed to patch comfy_kitchen DLPack wrapper: {e}")
+
+_patch_comfy_kitchen_dlpack_device_guard()
+
 logger.info(f"[MultiGPU Core Patching] Patching mm.get_torch_device, mm.text_encoder_device, mm.unet_offload_device")
 logger.info(f"[MultiGPU DEBUG] Initial current_device: {current_device}")
 logger.info(f"[MultiGPU DEBUG] Initial current_text_encoder_device: {current_text_encoder_device}")