ROS2 Topic Re-Publisher crashes with segfault in Jazzy due to JumpHandler initialization

[tizianofiorenzani]

Labels

• bug
• ros2
• jazzy

Description

Environment

• ROS Distribution: ROS2 Jazzy
• PlotJuggler Version: 3.15.0 (from apt: ros-jazzy-plotjuggler-ros 2.3.1)
• OS: Ubuntu 24.04 (Noble)
• Plugin: libTopicPublisherROS2.so

Problem

The ROS2 Topic Re-Publisher plugin crashes with a segmentation fault when enabled in ROS2 Jazzy. The same plugin works correctly in ROS2 Humble.

Steps to Reproduce

1. Install PlotJuggler on ROS2 Jazzy: sudo apt install ros-jazzy-plotjuggler-ros
2. Launch PlotJuggler: ros2 run plotjuggler plotjuggler
3. Load any ROS2 bag file
4. Enable topic re-streaming by clicking the checkbox in the toolbar
5. Crash occurs immediately with segfault

Stack Trace

Stack trace (most recent call last):
#3  Source "publisher_ros2.cpp", line 112, in TopicPublisherROS2::setEnabled(bool)
#2  Source "publisher_ros2.cpp", line 65, in TopicPublisherROS2::updatePublishers()
    Source "generic_publisher.h", line 54, in GenericPublisher::create(...)
    Source "generic_publisher.h", line 31, in GenericPublisher::GenericPublisher(...)
#1  Object "/opt/ros/jazzy/lib/librclcpp.so", in rclcpp::PublisherBase::PublisherBase(..., PublisherEventCallbacks const&, bool)
#0  Object "/opt/ros/jazzy/lib/librclcpp.so", in rclcpp::JumpHandler::JumpHandler(...)
Segmentation fault (Signal sent by the kernel [(nil)])

[tizianofiorenzani]

I solved it locally and I generated an (AI) summary of what I have done:

Complete Guide: Fixing PlotJuggler ROS2 Topic Re-Publisher Crash in Jazzy

Problem Summary

PlotJuggler's ROS2 Topic Re-Publisher plugin crashed with a segmentation fault when enabled in ROS2 Jazzy. The same plugin worked correctly in ROS2 Humble.

Error: Segfault in rclcpp::JumpHandler::JumpHandler() when creating publishers.

Root Cause Analysis

The Investigation Process

1. Initial Symptoms

   • Crash occurred immediately when enabling topic re-streaming checkbox
   • Stack trace showed crash in JumpHandler::JumpHandler() called from PublisherBase constructor
   • No crash in ROS2 Humble with identical code

2. Deep Dive into the Code

   • Located the issue in src/TopicPublisherROS2/generic_publisher.h
   • The GenericPublisher class inherited from rclcpp::PublisherBase
   • Used conditional compilation for Humble vs. Jazzy constructors

3. The Root Cause

   // Original problematic code
   #ifdef ROS_HUMBLE
       : rclcpp::PublisherBase(node_base, topic_name, type_support, rcl_publisher_get_default_options())
   #else
       : rclcpp::PublisherBase(node_base, topic_name, type_support, rcl_publisher_get_default_options(), callbacks_, true)
   #endif

   In Jazzy, the 5-parameter PublisherBase constructor always initializes a JumpHandler for time synchronization. This crashes because:

   • PlotJuggler already has an initialized ROS2 context
   • The JumpHandler receives invalid pointers when called in this context
   • Result: Segmentation fault

Why Simple Fixes Failed

Attempt 1: Change use_intra_process_comm from true to false

• Result: Still crashed
• Reason: The constructor initializes JumpHandler regardless of this parameter

Attempt 2: Use the 4-parameter constructor

• Result: Still crashed
• Reason: C++ overload resolution in Jazzy picks the 5-parameter version anyway

Attempt 3: Remove PublisherEventCallbacks

• Result: Compilation errors
• Reason: Jazzy's librclcpp.so ABI requires it

The Breakthrough

The solution was to stop inheriting from PublisherBase entirely and use ROS2's built-in rclcpp::GenericPublisher factory function instead.

The Solution

Step 2: Rewrite generic_publisher.h

Replace the entire contents of src/plotjuggler_fix/plotjuggler-ros-plugins/src/TopicPublisherROS2/generic_publisher.h with:

// Copyright 2018, Bosch Software Innovations GmbH.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef GENERIC_PUBLISHER_H
#define GENERIC_PUBLISHER_H

#include <memory>
#include <string>
#include <rclcpp/rclcpp.hpp>

// JAZZY FIX: Use rclcpp::GenericPublisher instead of inheriting from PublisherBase
// This avoids the JumpHandler initialization that causes segfault in Jazzy
class GenericPublisher
{
public:
  GenericPublisher(std::shared_ptr<rclcpp::GenericPublisher> publisher)
    : publisher_(publisher)
  {
  }

  virtual ~GenericPublisher() = default;

  void publish(std::shared_ptr<rmw_serialized_message_t> message)
  {
    // Use the GenericPublisher's publish method
    rclcpp::SerializedMessage serialized_msg(*message);
    publisher_->publish(serialized_msg);
  }

  static std::shared_ptr<GenericPublisher> create(rclcpp::Node& node, const std::string& topic_name,
                                                  const std::string& topic_type)
  {
    // Use rclcpp's built-in create_generic_publisher which doesn't trigger JumpHandler
    rclcpp::QoS qos(10);
    qos.reliable();
    qos.durability_volatile();
    
    auto generic_pub = node.create_generic_publisher(topic_name, topic_type, qos);
    return std::make_shared<GenericPublisher>(generic_pub);
  }

private:
  std::shared_ptr<rclcpp::GenericPublisher> publisher_;
};

#endif  // GENERIC_PUBLISHER_H

Step 3: Build the Fixed Plugin

cd src/plotjuggler_fix/plotjuggler-ros-plugins
bash -c "source /opt/ros/jazzy/setup.bash && colcon build --packages-select plotjuggler_ros --cmake-args -DCMAKE_BUILD_TYPE=Release"

Expected output:

Starting >>> plotjuggler_ros
Finished <<< plotjuggler_ros [30.7s]
Summary: 1 package finished [30.9s]

Step 4: Install the Fixed Plugin

sudo cp install/plotjuggler_ros/lib/plotjuggler_ros/libTopicPublisherROS2.so \
         /opt/ros/jazzy/lib/plotjuggler_ros/libTopicPublisherROS2.so

Step 5: Test the Fix

ros2 launch avas_mission_manager plotjuggler.launch.xml

Then in PlotJuggler:

1. Load a rosbag file
2. Click the topic re-streaming checkbox in the toolbar
3. Select topics to republish
4. Success! No crash, topics are republished

Technical Details

Why This Fix Works

1. No PublisherBase inheritance: Avoids the problematic constructor entirely
2. Uses node.create_generic_publisher(): ROS2's built-in factory function that doesn't trigger JumpHandler
3. Wrapper pattern: Maintains API compatibility with existing code
4. Proper QoS settings: Configures reliable, volatile durability for compatibility

Key Changes

Aspect	Before	After
Inheritance	class GenericPublisher : public rclcpp::PublisherBase	class GenericPublisher (no inheritance)
Constructor	Calls PublisherBase constructor (triggers JumpHandler)	Wraps rclcpp::GenericPublisher
Publisher Creation	Manual construction with type support	Uses node.create_generic_publisher()
Message Publishing	Direct rcl_publish_serialized_message()	Uses GenericPublisher::publish()

Compatibility

• ✅ ROS2 Jazzy: Works perfectly (tested)
• ✅ ROS2 Humble: Should still work (uses same API)
• ✅ Backward compatible: No changes to calling code needed

Files Modified

• Source: src/plotjuggler_fix/plotjuggler-ros-plugins/src/TopicPublisherROS2/generic_publisher.h
• Installed: /opt/ros/jazzy/lib/plotjuggler_ros/libTopicPublisherROS2.so

Backup and Rollback

Backup Original Plugin

sudo cp /opt/ros/jazzy/lib/plotjuggler_ros/libTopicPublisherROS2.so \
         /opt/ros/jazzy/lib/plotjuggler_ros/libTopicPublisherROS2.so.original

Rollback if Needed

sudo cp /opt/ros/jazzy/lib/plotjuggler_ros/libTopicPublisherROS2.so.original \
         /opt/ros/jazzy/lib/plotjuggler_ros/libTopicPublisherROS2.so

Troubleshooting

Build Fails

Issue: Missing dependencies

cd src/plotjuggler_fix/plotjuggler-ros-plugins
rosdep update
rosdep install --from-paths . --ignore-src --rosdistro=jazzy -y

Plugin Not Loading

Issue: Wrong library path

# Verify the plugin exists
ls -la /opt/ros/jazzy/lib/plotjuggler_ros/libTopicPublisherROS2.so

# Check PlotJuggler can find it
ros2 run plotjuggler plotjuggler 2>&1 | grep TopicPublisher

Still Crashes

Issue: Old plugin cached

# Clear PlotJuggler cache
rm -rf ~/.local/share/PlotJuggler
rm -rf ~/.config/PlotJuggler

# Restart PlotJuggler

Upstream Contribution

This fix should be contributed back to the PlotJuggler project. The GitHub issue template is available in github_issue_plotjuggler.md.

Submit to Upstream

1. Fork: https://github.com/PlotJuggler/plotjuggler-ros-plugins
2. Create branch: git checkout -b fix/jazzy-segfault
3. Apply the fix to src/TopicPublisherROS2/generic_publisher.h
4. Commit: git commit -m "Fix segfault in Jazzy by using create_generic_publisher"
5. Push and create Pull Request

Summary

The PlotJuggler ROS2 Topic Re-Publisher crash in Jazzy was caused by ABI changes in rclcpp::PublisherBase that always initialize JumpHandler. The solution was to completely avoid PublisherBase inheritance and use ROS2's built-in create_generic_publisher() factory function instead.

Result: ✅ Plugin works perfectly in Jazzy, maintaining full functionality for scrubbing through rosbag timelines while republishing topics.

[facontidavide]

fixed

[tizianofiorenzani]

Great, thanks!