修复就绪屏障位被消费致FTP永不监听；新增栈可观测（水位探针+静态调用图报告）并补FTP实测

test/ftp_speed_test.py

@@ -37,6 +37,33 @@ def send_cmd(sock, cmd):
     time.sleep(0.1)
     return recv_line(sock)
 
+def connect_with_retry(host, port, timeout=15.0, attempts=6, delay=3.0):
+    """连接控制通道（带重试）。
+
+    CH395F 单客户端复用：上一会话未 QUIT 就断开时，服务端可能仍在处理旧连接，
+    新连接会被 RST（WinError 10061）；实测约 30s 后服务端丢弃旧会话并重新 listen。
+    注意不要用裸 TCP 探测端口（探测会占掉唯一会话）。
+    """
+    last_err = None
+    for i in range(1, attempts + 1):
+        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        s.settimeout(timeout)
+        try:
+            s.connect((host, port))
+            return s, None
+        except Exception as e:
+            last_err = e
+            try:
+                s.close()
+            except Exception:
+                pass
+            if i < attempts:
+                print(f"  connect failed ({e}); retry {i}/{attempts - 1} in {delay:.0f}s "
+                      f"(single-client: stale session blocks new connections)")
+                time.sleep(delay)
+    return None, last_err
+
+
 def parse_pasv(resp):
     m = re.search(r"(\d+),(\d+),(\d+),(\d+),(\d+),(\d+)", resp.decode())
     if m:
@@ -80,22 +107,23 @@ def test_speed(host, port, size_kb):
 
     # ---- Connect + Login ----
     print("[Connect] Connecting...")
-    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-    sock.settimeout(60.0)
-    try:
-        sock.connect((host, port))
-    except Exception as e:
-        print(f"  CONNECT FAILED: {e}")
-        check("Connect", False, str(e))
-        return finish(sock)
+    sock, err = connect_with_retry(host, port, timeout=60.0)
+    if sock is None:
+        print(f"  CONNECT FAILED: {err}")
+        check("Connect", False, str(err))
+        return finish(None)
     recv_line(sock)  # 220
-    if not send_cmd(sock, "USER anonymous"):
-        check("Login USER", False)
+    resp = send_cmd(sock, "USER anonymous")
+    if not (resp and resp.startswith(b"230")):
+        check("Login USER 230", False,
+              resp.decode(errors='replace').rstrip() if resp else "no resp")
         return finish(sock)
-    if not send_cmd(sock, "PASS test@test.com"):
-        check("Login PASS", False)
+    resp = send_cmd(sock, "PASS test@test.com")
+    if not (resp and resp.startswith(b"230")):
+        check("Login PASS 230", False,
+              resp.decode(errors='replace').rstrip() if resp else "no resp")
         return finish(sock)
-    check("Login (USER/PASS)", True)
+    check("Login (USER/PASS 230)", True)
     send_cmd(sock, "TYPE I")
 
     # ---- Upload ----