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 !!

[seuganger]

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.

This will work for running, however the tree will not be rebuilded, the points number will be increasingly larger. It will bring much load to CPU, which leads to abnormally long time consumption of the algorithm. How do you solve the problem?

[Ecstasy-EC]

Hi all. It's been a long time since this issue was raised, but I'm sorry I didn't take this seriously.

Unfortunately, this problem cannot be solved very soon as it is my mistake in my code design. Simply adding a mutex for Rebuild_Ptr would avoid this problem but it will degrade the efficiency a lot.

As I recall that this problem never appeared in my previous extensive tests, I am guessing that it usually happens if the rebuilding process cannot catch up with the speed of the insertion (e.g., a large number of points for add_by_points). I would suggest either not inserting by a very high frequency or enabling the rebuilding thread only when the large-scale insertion is finished.

Thanks a lot for your attention to this problem. And sorry again for any inconvenience I might have caused from this issue.