diff --git a/ros/ros_comm/roscpp/include/ros/subscription.h b/ros/ros_comm/roscpp/include/ros/subscription.h
index 5b01f08..dce5fdd 100644
--- a/ros/ros_comm/roscpp/include/ros/subscription.h
+++ b/ros/ros_comm/roscpp/include/ros/subscription.h
@@ -268,6 +268,7 @@ class ROSCPP_DECL Subscription : public boost::enable_shared_from_this<Subscript
 
   std::vector<PublisherLinkPtr> get_publisher_links()
   {
+    boost::mutex::scoped_lock lock(publisher_links_mutex_);
     return publisher_links_;
   }
 };
diff --git a/ros/ros_comm/roscpp/src/libros/shm_manager.cpp b/ros/ros_comm/roscpp/src/libros/shm_manager.cpp
index ccd15f5..663e212 100644
--- a/ros/ros_comm/roscpp/src/libros/shm_manager.cpp
+++ b/ros/ros_comm/roscpp/src/libros/shm_manager.cpp
@@ -136,7 +136,7 @@ void ShmManager::threadFunc()
           if (g_config_comm.topic_white_list.find(topic) != 
             g_config_comm.topic_white_list.end() || 
             shm_map_.find(topic) != shm_map_.end() ||
-            (*it)->get_publisher_links().size() == 0)
+            (*it)->getNumPublishers() == 0)
           {
             continue;
           }
@@ -243,7 +243,7 @@ void ShmManager::threadFunc()
 
                   // Block needs to be allocated
                   if (read_index == sharedmem_transport::ROS_SHM_SEGMENT_WROTE_NUM ||
-                    shm_map_[topic].shm_sub_ptr->get_publisher_links().size() == 0)
+                    shm_map_[topic].shm_sub_ptr->getNumPublishers() == 0)
                   {
                     {
                       boost::mutex::scoped_lock lock(shm_map_mutex_);
diff --git a/ros/ros_comm/roscpp/src/libros/topic_manager.cpp b/ros/ros_comm/roscpp/src/libros/topic_manager.cpp
index 08d4025..b9e9f57 100644
--- a/ros/ros_comm/roscpp/src/libros/topic_manager.cpp
+++ b/ros/ros_comm/roscpp/src/libros/topic_manager.cpp
@@ -229,6 +229,7 @@ SubscriptionPtr TopicManager::lookupSubscription(const std::string& topic)
 
 L_Subscription  TopicManager::getAllSubscription()
 {
+  boost::mutex::scoped_lock lock(subs_mutex_);
   return subscriptions_ ;
 }