Bluetooth: conn: Fix invalid state transition

When initiating a disconnection conn_disconnect would be called to send
HCI_Disconnect but the controller may be quick enough to send Disconnect
Complete event before setting BT_CONN_DISCONNECT which will then cause
the invalid transition from BT_CONN_DISCONNECTED to BT_CONN_DISCONNECT
and the connection won't be freed properly.

Signed-off-by: Luiz Augusto von Dentz <[email protected]>

Author: Vudentz

subsys/bluetooth/host/conn.c

@@ -2041,7 +2041,9 @@ static int conn_disconnect(struct bt_conn *conn, uint8_t reason)
 		return err;
 	}
 
-	bt_conn_set_state(conn, BT_CONN_DISCONNECT);
+	if (conn->state == BT_CONN_CONNECTED) {
+		bt_conn_set_state(conn, BT_CONN_DISCONNECT);
+	}
 
 	return 0;
 }