Can't get message of subsceriber:Trying to serialize 13944 in 508 MTU stream

[Junming-Liang]

Issue template

• Hardware description: STM32F40726T6
• RTOS: FreeRTOS
• Installation type: micro_ros_setup

• Version or commit hash: foxy

  Steps to reproduce the issue

  I aspire to garner the reception of three topics disseminated from the superior machine by establishing micro nodes. Within these triplet transmissions, a duo operates in an expected manner, yet one topic concerning the path planning module seems to have encountered certain complications during its initialisation phase. This is key code:

  rcl_subscription_t trajectory_subscription;
  ...
  devastator_planning_msgs__msg__TargetTrajectory trajectorysubmsg;
  ...
  void get_rosidl_runtime_c_String_memory(rosidl_runtime_c__String *str,
                                      int len) {
  str->capacity = len;
  str->data = (char *)malloc(str->capacity * sizeof(char));
  str->size = 0;
  }
  void get_msgbuff_memory(void) {
  // get localization msg memory
  ...
  // get chassis msg memory
  ...
  // get trajectory msg memory
  get_rosidl_runtime_c_String_memory(&trajectorysubmsg.header.frame_id,
                                   STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(
    &trajectorysubmsg.sensor_timestamp.localization_header.frame_id,
    STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(
    &trajectorysubmsg.sensor_timestamp.prediction_header.frame_id,
    STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(
    &trajectorysubmsg.sensor_timestamp.chassis_header.frame_id,
    STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(
    &trajectorysubmsg.sensor_timestamp.traffic_light_header.frame_id,
    STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(
    &trajectorysubmsg.sensor_timestamp.cone_header.frame_id,
    STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(
    &trajectorysubmsg.sensor_timestamp.map_header.frame_id,
    STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(
    &trajectorysubmsg.sensor_timestamp.padmsg_header.frame_id,
    STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(
    &trajectorysubmsg.sensor_timestamp.routing_header.frame_id,
    STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(
    &trajectorysubmsg.sensor_timestamp.start_planning_header.frame_id,
    STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(
    &trajectorysubmsg.sensor_timestamp.finish_planning_header.frame_id,
    STRING_BUFFER_LEN);
  
  trajectorysubmsg.trajectory_point.capacity = MAX_trajectoryPOINTS;
  trajectorysubmsg.trajectory_point.data =
    (devastator_planning_msgs__msg__TrajectoryPoint *)malloc(
        trajectorysubmsg.trajectory_point.capacity *
        sizeof(devastator_planning_msgs__msg__TrajectoryPoint));
  for (int i = 0; i < MAX_trajectoryPOINTS; i++) {
  get_rosidl_runtime_c_String_memory(
      &trajectorysubmsg.trajectory_point.data[i].path_point.lane_id, 1);
  }
  trajectorysubmsg.trajectory_point.size = 0;
  
  trajectorysubmsg.path_point.capacity = 5;
  trajectorysubmsg.path_point.data =
    (devastator_planning_msgs__msg__PathPoint *)malloc(
        trajectorysubmsg.path_point.capacity *
        sizeof(devastator_planning_msgs__msg__PathPoint));
  for (int i = 0; i < MAX_trajectoryPOINTS; i++) {
  get_rosidl_runtime_c_String_memory(
      &trajectorysubmsg.path_point.data[i].lane_id, 1);
  }
  trajectorysubmsg.path_point.size = 0;
  
  get_rosidl_runtime_c_String_memory(&trajectorysubmsg.gear, STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(&trajectorysubmsg.estop_reason,
                                   STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(&trajectorysubmsg.stop_pose.lane_id,
                                   STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(&trajectorysubmsg.stop_reason,
                                   STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(&trajectorysubmsg.replan_reason,
                                   STRING_BUFFER_LEN);
  
  // get commond msg memory
  get_rosidl_runtime_c_String_memory(&commond_pubmsg.header.frame_id,
                                   STRING_BUFFER_LEN);
  get_rosidl_runtime_c_String_memory(&commond_pubmsg.protocol_version,
                                   STRING_BUFFER_LEN);
  }
  void appMain(void *argument) {
  
  rcl_allocator_t allocator = rcl_get_default_allocator();
  rclc_support_t support;
  RCCHECK(rclc_support_init(&support, 0, NULL, &allocator));
  rcl_node_t node;
  RCCHECK(rclc_node_init_default(&node, "control_node", "", &support));
  RCCHECK(rclc_publisher_init_default(
    &control_commond_publisher, &node,
    ROSIDL_GET_MSG_TYPE_SUPPORT(devastator_control_msgs, msg,
                                VehicleControlCommand),
    "/control/vehicle_control_command"));
  printf(" the min free heap size is %d \r\n", (int32_t)xPortGetFreeHeapSize());
  printf(" the min free stack size is %d \r\n",
       (int32_t)uxTaskGetStackHighWaterMark(NULL));
  RCCHECK(rclc_subscription_init_default(
    &localization_estimate_subscription, &node,
    ROSIDL_GET_MSG_TYPE_SUPPORT(devastator_localization_msgs, msg,
                                LocalizationEstimate),
    "/localization/localization_estimate"));
  printf("xixi\n");
  printf(" the min free heap size is %d \r\n", (int32_t)xPortGetFreeHeapSize());
  printf(" the min free stack size is %d \r\n",
       (int32_t)uxTaskGetStackHighWaterMark(NULL));
  RCSOFTCHECK(rclc_subscription_init_default(
    &chassis_report_subscription, &node,
    ROSIDL_GET_MSG_TYPE_SUPPORT(devastator_control_msgs, msg,
                                VehicleReportCommon),
    "/sensor/vehicle_report_common"));
  printf(" the min free heap size is %d \r\n", (int32_t)xPortGetFreeHeapSize());
  printf(" the min free stack size is %d \r\n",
       (int32_t)uxTaskGetStackHighWaterMark(NULL));
  RCSOFTCHECK(rclc_subscription_init_best_effort(
    &trajectory_subscription, &node,
    ROSIDL_GET_MSG_TYPE_SUPPORT(devastator_planning_msgs, msg,
                                TargetTrajectory),
    "/planning/trajectory_path"));
  
  printf(" the min free heap size is %d \r\n", (int32_t)xPortGetFreeHeapSize());
  printf(" the min free stack size is %d \r\n",
       (int32_t)uxTaskGetStackHighWaterMark(NULL));
  rcl_timer_t timer;
  RCCHECK(rclc_timer_init_default(&timer, &support, RCL_MS_TO_NS(200),
                                control_commond_pub_callback));
  rclc_executor_t executor;
  RCCHECK(rclc_executor_init(&executor, &support.context, 4, &allocator));
  RCCHECK(rclc_executor_add_timer(&executor, &timer));
  RCCHECK(rclc_executor_add_subscription(
    &executor, &localization_estimate_subscription,
    &localization_estimate_submsg, &localization_estimate_callback,
    ON_NEW_DATA));
  RCCHECK(rclc_executor_add_subscription(&executor, &trajectory_subscription,
                                       &trajectorysubmsg,
                                       &trajectory_callback, ON_NEW_DATA));
  RCCHECK(rclc_executor_add_subscription(
    &executor, &chassis_report_subscription, &chassis_submsg,
    &chassis_report_callback, ON_NEW_DATA));
  
  get_msgbuff_memory();
  
  printf(" the min free heap size is %d \r\n", (int32_t)xPortGetFreeHeapSize());
  printf(" the min free stack size is %d \r\n",
       (int32_t)uxTaskGetStackHighWaterMark(NULL));
  while (1) {
  rclc_executor_spin_some(&executor, RCL_MS_TO_NS(10));
  usleep(10000);
  }
  RCCHECK(rcl_publisher_fini(&control_commond_publisher, &node));
  RCCHECK(rcl_node_fini(&node));
  }

  The node looks like work well:

  
  $ ros2 node info /control_node              
  /control_node
  Subscribers:
  /localization/localization_estimate: devastator_localization_msgs/msg/LocalizationEstimate
  /planning/trajectory_path: devastator_planning_msgs/msg/TargetTrajectory
  /sensor/vehicle_report_common: devastator_control_msgs/msg/VehicleReportCommon
  Publishers:
  /control/vehicle_control_command: devastator_control_msgs/msg/VehicleControlCommand
  Service Servers:
  
  Service Clients:
  
  Action Servers:
  
  Action Clients:

But when I send the msg TargetTrajectory, rosagent out put is:
```shell
[1692612714.928269] warning  | OutputStream.hpp   | push_submessage          | serialization warning  | Trying to serialize 13944 in 508 MTU stream
[1692612715.028242] warning  | OutputStream.hpp   | push_submessage          | serialization warning  | Trying to serialize 13944 in 508 MTU stream

And the program never get inside the callback function of TargetTrajectory subscriber. This is my msg information:

std_msgs/Header header
SensorTime sensor_timestamp
float64 start_gnss_time

float64 total_path_length # in meters​​
float64 total_path_time # in seconds​​

# ============================================
TrajectoryPoint[] trajectory_point
PathPoint[] path_point
string gear 
# ============================================

bool is_estop
string estop_reason

bool is_stop
PathPoint stop_pose
string stop_reason

bool is_replan
string replan_reason

bool car_in_dead_end

# ============================================
uint8 TRACETYPE_GO_STRAIGHT=0 
uint8 TRACETYPE_TURN_LEFT=1
uint8 TRACETYPE_TURN_RIGHT=2
uint8 TRACETYPE_CHANGELINE_LEFT=3
uint8 TRACETYPE_CHANGELINE_RIGHT=4

bool high_beam
bool low_beam
bool horn
bool emergency_light
uint8 trace_type

I eagerly await your response.

[Junming-Liang]

This issue is due to the message size exceeding the MTU size. When using a best effort subscriber, messages are buffered in memory up to the MTU size. Solutions are to adjust the MTU size or switch to using a default subscriber. I will close this issue, but welcome everyone to continue the discussion.