[Bugfix] Fix inner_dp_world initialization order for multi-node TP (#35892)

Signed-off-by: Yongye Zhu <zyy1102000@gmail.com>
Signed-off-by: Nick Hill <nickhill123@gmail.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: Nick Hill <nickhill123@gmail.com>
Co-authored-by: Nick Hill <nhill@redhat.com>

tests/distributed/test_multiproc_executor.py

@@ -9,11 +9,11 @@ focusing on executor initialization, RPC calls, and distributed execution.
 
 import multiprocessing
 import os
+import socket
 
 from tests.utils import multi_gpu_test
 from vllm.config import VllmConfig
 from vllm.engine.arg_utils import EngineArgs
-from vllm.utils import get_open_port
 from vllm.v1.core.sched.output import SchedulerOutput
 from vllm.v1.executor.multiproc_executor import MultiprocExecutor
 
@@ -333,7 +333,9 @@ def test_multiproc_executor_multi_node():
     - Node 1 (rank 1): Uses GPUs 2,3 (CUDA_VISIBLE_DEVICES=2,3) with TP=2
     Total world_size = 4, nnodes = 2
     """
-    port = get_open_port()
+    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
+        s.bind(("", 0))
+        port = s.getsockname()[1]
     # symm_mem does not work for simulating multi instance in single node
     os.environ["VLLM_ALLREDUCE_USE_SYMM_MEM"] = "0"