Why is there a segmentation fault here?

[SylarAnh]

Stack trace (most recent call last):
#21 Object "/usr/lib/x86_64-linux-gnu/ld-2.31.so", at 0xffffffffffffffff, in
#20 Object "/home/jcwang/code/ws_di-lui-sam/src/di_lui_sam/cmake-build-debug/devel/lib/multi_proxy/multi_proxy_subMapFusion", at 0x555555600ead, in start
#19 Source "../csu/libc-start.c", line 308, in libc_start_main [0x7ffff45e6082]
#18 Source "/home/jcwang/code/ws_di-lui-sam/src/di_lui_sam/src/subMapFusion.cpp", line 2235, in main [0x555555601305]
2232: std::thread OptThread(&SubMapFusion::globalOptimizationThread, &SubMapF);
2233: std::thread pubLoopThread(&SubMapFusion::publishSCWithCloudThread, &SubMapF);
2234:
>2235: ros::spin();
2236:
2237: pubDesOtherThread.join();
2238: pubMapThread.join();
#17 Object "/opt/ros/noetic/lib/libroscpp.so", at 0x7ffff7f2a21e, in ros::spin()
#16 Object "/opt/ros/noetic/lib/libroscpp.so", at 0x7ffff7f41fce, in ros::SingleThreadedSpinner::spin(ros::CallbackQueue*)
#15 Object "/opt/ros/noetic/lib/libroscpp.so", at 0x7ffff7eee882, in ros::CallbackQueue::callAvailable(ros::WallDuration)
#14 Object "/opt/ros/noetic/lib/libroscpp.so", at 0x7ffff7eed171, in ros::CallbackQueue::callOneCB(ros::CallbackQueue::TLS*)
#13 Object "/opt/ros/noetic/lib/libroscpp.so", at 0x7ffff7f3f138, in ros::SubscriptionQueue::call()
#12 Source "/opt/ros/noetic/include/ros/subscription_callback_helper.h", line 144, in call [0x5555556fe2ca]
141: virtual void call(SubscriptionCallbackHelperCallParams& params)
142: {
143: Event event(params.event, create);
> 144: callback(ParameterAdapter

::getParameter(event));
145: }
146:
147: virtual const std::type_info& getTypeInfo()
#11 Source "/usr/include/boost/function/function_template.hpp", line 763, in operator() [0x555555702548]
760: if (this->empty())
761: boost::throw_exception(bad_function_call());
762:
> 763: return get_vtable()->invoker
764: (this->functor BOOST_FUNCTION_COMMA BOOST_FUNCTION_ARGS);
765: }
#10 Source "/usr/include/boost/function/function_template.hpp", line 158, in invoke [0x5555556b57eb]
155: f = reinterpret_cast<FunctionObj*>(function_obj_ptr.data);
156: else
157: f = reinterpret_cast<FunctionObj*>(function_obj_ptr.members.obj_ptr);
> 158: BOOST_FUNCTION_RETURN((f)(BOOST_FUNCTION_ARGS));
159: }
160: };
#9 Source "/usr/include/boost/function/function_template.hpp", line 763, in operator() [0x5555556c1db5]
760: if (this->empty())
761: boost::throw_exception(bad_function_call());
762:
> 763: return get_vtable()->invoker
764: (this->functor BOOST_FUNCTION_COMMA BOOST_FUNCTION_ARGS);
765: }
#8 Source "/usr/include/boost/function/function_template.hpp", line 158, in invoke [0x555555696649]
155: f = reinterpret_cast<FunctionObj>(function_obj_ptr.data);
156: else
157: f = reinterpret_cast<FunctionObj*>(function_obj_ptr.members.obj_ptr);
> 158: BOOST_FUNCTION_RETURN((*f)(BOOST_FUNCTION_ARGS));
159: }
160: };
#7 Source "/usr/include/boost/bind/bind.hpp", line 1306, in operator()<const boost::shared_ptr<const sensor_msgs::PointCloud2<std::allocator > >&> [0x5555556a70ac]
1303: template result_type operator()( A1 && a1 )
1304: {
1305: rrlist1< A1 > a( a1 );
>1306: return l_( type<result_type>(), f_, a, 0 );
1307: }
1308:
1309: template result_type operator()( A1 && a1 ) const
#6 Source "/usr/include/boost/bind/bind.hpp", line 319, in operator()<boost::mfi::mf1<void, SubMapFusion, const boost::shared_ptr<const sensor_msgs::PointCloud2<std::allocator > >&>, boost::bi::rrlist1<const boost::shared_ptr<const sensor_msgs::PointCloud2<std::allocator > >&> > [0x5555556b5515]
317: template<class F, class A> void operator()(type, F & f, A & a, int)
318: {
> 319: unwrapper::unwrap(f, 0)(a[base_type::a1_], a[base_type::a2_]);
320: }
321:
322: template<class F, class A> void operator()(type, F const & f, A & a, int) const
#5 Source "/usr/include/boost/bind/mem_fn_template.hpp", line 165, in operator() [0x5555556c1a47]
163: R operator()(T * p, A1 a1) const
164: {
> 165: BOOST_MEM_FN_RETURN (p->f_)(a1);
166: }
167:
168: template R operator()(U & u, A1 a1) const
#4 Source "/home/jcwang/code/ws_di-lui-sam/src/di_lui_sam/src/subMapFusion.cpp", line 681, in laserCloudInfoHandler [0x55555561e8f4]
679: isKeyframe(context_info);
680: buildFrameList(context_info);
> 681: buildSubmap(context_info);
682: }
683: // std::cout << "laser: finished! " << std::endl;
684: }
#3 Source "/home/jcwang/code/ws_di-lui-sam/src/di_lui_sam/src/subMapFusion.cpp", line 1109, in buildSubmap [0x555555623a08]
1106: _downsize_filtermap.setInputCloud(cloud_in_ego_odom);
1107: _downsize_filtermap.filter(_cloud_temp);
1108:
>1109: buildiKDTree(_cloud_temp);//////TODO：这里有问题，会重复释放内存
1110: mtx_map.lock();
1111: *_lidarmap_current += *_cloud_temp;
1112: _cloud_temp->clear();
#2 Source "/home/jcwang/code/ws_di-lui-sam/src/di_lui_sam/src/subMapFusion.cpp", line 1164, in buildiKDTree [0x555555624060]
1161: }
1162:
1163: double st_time = omp_get_wtime();
>1164: ikdtree.Add_Points(PointToAdd, true);
1165: double kdtree_incremental_time = omp_get_wtime() - st_time;
1166: }
#1 Source "/home/jcwang/code/ws_di-lui-sam/src/di_lui_sam/third_parties/ikd-Tree/ikd_Tree.cpp", line 501, in Add_Points [0x7ffff72eff4d]
498: mid_point.y = Box_of_Point.vertex_min[1] + (Box_of_Point.vertex_max[1] - Box_of_Point.vertex_min[1]) / 2.0;
499: mid_point.z = Box_of_Point.vertex_min[2] + (Box_of_Point.vertex_max[2] - Box_of_Point.vertex_min[2]) / 2.0;
500: PointVector().swap(Downsample_Storage);
> 501: Search_by_range(Root_Node, Box_of_Point, Downsample_Storage);
502: min_dist = calc_dist(PointToAdd[i], mid_point);
503: downsample_result = PointToAdd[i];
504: for (int index = 0; index < Downsample_Storage.size(); index++)
#0 Source "/home/jcwang/code/ws_di-lui-sam/src/di_lui_sam/third_parties/ikd-Tree/ikd_Tree.cpp", line 1268, in Search_by_range [0x7ffff72ecce4]
1265: if (!root->point_deleted)
1266: Storage.push_back(root->point);
1267: }
>1268: if ((Rebuild_Ptr == nullptr) || root->left_son_ptr != *Rebuild_Ptr)
1269: {
1270: Search_by_range(root->left_son_ptr, boxpoint, Storage);
1271: }
Segmentation fault (Address not mapped to object [(nil)])

[FPSE12]

I have the same issue, I got a "segment fault" when I use the "Add_Points" function.

[ludovicoruga]

I am also experiencing the same issue:

Any support would be greatly appreciated!

[ludovicoruga]

I noticed that if I set the value if 'Minimal_Unbalanced_Tree_Size' to INIFINITY in ikd_tree.h, the segmentation fault error stops happening. I think this could indicate an issue with the re-building process in the second thread.
This is not a viable solution since when the tree size increases, the computation time increases exponentially, but could give an idea on where to look for to fix the issue.

I hope this can be useful!

[ning-zelin]

rebuild thread: write Rebuild_Ptr:

add points thread: read Rebuild_Ptr:

This variable was read and written without mutex, leading to a segmentation fault. This is merely my initial hypothesis and has yet to be confirmed.

[XYudong]

Experiencing the same issue here. Having the same hypothesis as what @ning-zelin mentioned.
A temporary workaround could be:

1. comment out the code creating the rebuild_thread to disable multi-threading for rebuild;
2. adjust Rebuild() method to always use the plain rebuild pipeline;

which seems work for me currently.

[supersupercoconut]

Experiencing the same issue here. Having the same hypothesis as what @ning-zelin mentioned. A temporary workaround could be:

1. comment out the code creating the rebuild_thread to disable multi-threading for rebuild;
2. adjust Rebuild() method to always use the plain rebuild pipeline;

which seems work for me currently.
Thanks!! I commeted out the pthread_create( &rebuild_thread, NULL, multi_thread_ptr, ( void * ) this ); Its works now !!