A ”segmentation error“ occurred while the program was running.

[YuanyeMa]

A segmentation error occurred after the program ran for a while, and the stack was as follows.

Thread 14 "stageros" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffd67fc700 (LWP 15891)]
0x00007ffff693d979 in Stg::World::Raytrace(Stg::Ray const&) () from /opt/ros/melodic/lib/libstage.so.4.3.0
(gdb) bt
#0  0x00007ffff693d979 in Stg::World::Raytrace(Stg::Ray const&) () from /opt/ros/melodic/lib/libstage.so.4.3.0
#1  0x00007ffff6933c9a in Stg::ModelRanger::Sensor::Update(Stg::ModelRanger*) () from /opt/ros/melodic/lib/libstage.so.4.3.0
#2  0x00007ffff6934b1a in Stg::ModelRanger::Update() () from /opt/ros/melodic/lib/libstage.so.4.3.0
#3  0x00007ffff69232fd in Stg::Model::UpdateWrapper(Stg::Model*, void*) () from /opt/ros/melodic/lib/libstage.so.4.3.0
#4  0x00007ffff693effe in Stg::World::ConsumeQueue(unsigned int) () from /opt/ros/melodic/lib/libstage.so.4.3.0
#5  0x00007ffff693f08e in Stg::World::update_thread_entry(std::pair<Stg::World*, int>*) () from /opt/ros/melodic/lib/libstage.so.4.3.0
#6  0x00007ffff6b706db in start_thread (arg=0x7fffd67fc700) at pthread_create.c:463
#7  0x00007ffff59b988f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

[chesternimiz]

I also have this problem but it is not very often to occur.
I think after the crash, you can rename the newly saved model file to the loading file name and restart the program, which will start learning based on your newest model.

[Acmece]

Hi, @kevin-y-ma

You can find that there is rospy.sleep() function in the content of reset_pose and reset_world.

If you make the sleep last for a longer time, it could be better.

This problem come from the code of simulator Stage. Here are some related issues and discussion that may be helpful:

• stage_ros crashes

• Memory leak in stage(_ros) and resulting segfault

Further development of Stage_ROS package may be conducted.

Welcome to fix the bug and pull a request here!

[YuanyeMa]

It works. thanks for your replay.