[Bugfix] Release GPU memory after diffusion execution failures (#6385)

Signed-off-by: nagisa <1434936049@qq.com>
Signed-off-by: nagisa-kun <1434936049@qq.com>
Co-authored-by: Hongsheng Liu <liuhongsheng4@huawei.com>

tests/diffusion/test_diffusion_worker_broadcast.py

@@ -71,6 +71,45 @@ def test_recv_message_waits_indefinitely():
     worker_proc.mq.dequeue.assert_called_once_with(indefinite=True)
 
 
+def test_busy_loop_releases_failed_rpc_traceback_and_device_cache(monkeypatch):
+    original = RuntimeError("model execution failed")
+    worker_proc = WorkerProc.__new__(WorkerProc)
+    worker_proc.gpu_id = 0
+    worker_proc.mq = Mock()
+    worker_proc.mq.dequeue.side_effect = [
+        {
+            "type": "rpc",
+            "method": "execute_model",
+            "args": (),
+            "kwargs": {},
+            "output_rank": 0,
+            "exec_all_ranks": False,
+            "collect_rank_status": False,
+        },
+        {"type": "shutdown"},
+    ]
+    worker_proc.worker = Mock()
+    worker_proc.worker.execute_method.side_effect = original
+    worker_proc.result_mq = object()
+    worker_proc._return_result = Mock()
+    worker_proc.wake_event = None
+    worker_proc._running = True
+
+    gc_collect = Mock()
+    mock_platform = Mock()
+    monkeypatch.setattr(diffusion_worker_module.gc, "collect", gc_collect)
+    monkeypatch.setattr(diffusion_worker_module, "current_omni_platform", mock_platform)
+
+    worker_proc._worker_busy_loop()
+
+    worker_proc._return_result.assert_called_once_with(
+        {"status": "error", "error": "model execution failed", "wave_id": None}
+    )
+    assert original.__traceback__ is None
+    gc_collect.assert_called_once_with()
+    mock_platform.empty_cache.assert_called_once_with()
+
+
 def test_busy_loop_preserves_order_when_overflow_payload_is_delayed(monkeypatch):
     """A consumed overflow marker must not be abandoned on a socket timeout."""
     writer = MessageQueue(