Segmentation fault with generate_traffic.py

[Whisillus]

Hey, I encountered Segmentation fault when I tried to run the example "generate_traffic.py".

CARLA version: 0.9.12 Platform/OS: Ubuntu 20.04 Problem you have experienced: Got Segmentation fault (core dumped) with "python generate_traffic.py" What you expected to happen: emm...generate traffic successfully?

Steps to reproduce:

make launch (worked fine) click 'play' python dynamic_weather.py (this worked fine) ctrl+c (stop dynamic_weather.py) python generate_traffic.py (here i got Segmentation fault (core dumped) )

[jackbart94]

I've just tried it and everything works fine for me. Could you run it again, maybe using gdb to identify what is causing the Segmentation Fault? I can guide you through it.

[Whisillus]

@jackbart94 Thanks for your reply!

I ran it again, and tried to find which part caused the problem. When I ran "world.apply_settings(settings)"(Line 187), my UE crushed.

I have to force quit my UE. And the UE terminal show

[2021.09.02-14.59.55:405][637]LogTemp: Loaded OpenDrive file '/home/nielass/code/carla/Unreal/CarlaUE4/Content/Carla/Maps/OpenDrive/Town10HD_Opt.xodr'
[2021.09.02-14.59.55:736][640]LogTemp: Loaded OpenDrive file '/home/nielass/code/carla/Unreal/CarlaUE4/Content/Carla/Maps/OpenDrive/Town10HD_Opt.xodr'
/home/nielass/code/carla/Util/BuildTools/BuildCarlaUE4.sh: line 172: 29839 Killed                  ${GDB} ${UE4_ROOT}/Engine/Binaries/Linux/UE4Editor "${PWD}/CarlaUE4.uproject" ${RHI}
make: *** [Util/BuildTools/Linux.mk:7: launch] Error 137

Could you help me with that?

[jackbart94]

This doesn't say much. Please, do the following:

1. Before executing the generate_traffic.py, in your terminal type gdb python. This will launch gdb.
2. In the same terminal window, type run generate_traffic.py. This will seg fault, at least in your machine.
3. Once seg faults, type bt. This will print the backtrace of the error that caused the segmentation fault. If you can paste that backtrace here, it would help us quite a lot.

If anything is unclear, tell me!

[Whisillus]

@jackbart94

Thanks for detailed instructions.

''' Thread 1 "python" received signal SIGSEGV, Segmentation fault. _PyObject_GC_Alloc (use_calloc=0, basicsize=88) at /home/builder/ktietz/cos6/ci_cos6/python-split_1622827272909/work/Modules/gcmodule.c:2226 2226 /home/builder/ktietz/cos6/ci_cos6/python-split_1622827272909/work/Modules/gcmodule.c: No such file or directory. '''

[jackbart94]

Looks like a dependency error. Make sure you've installed everything you need to run CARLA by following this guide.

[ZhouY-JustLL]

@jackbart94

CARLA version: 0.9.13 Platform/OS: Ubuntu 18.04 python version: 3.9

I totally followed the building instruction in official carla documents, but met the same segmentation fault and same gdb information with generate_traffic.py. I tried some other scripts in PythonAPI/examples, and they all worked fine.

Then I find the segmentation fault was raise by world.get_random_location_from_navigation(). I hope this will give you more information about this problem.

If i couldn't solve the problem, is there any other way to randomly spawn a location for walkers?

[JoseZF]

Check issue #5325. It seems to be a compatibility issue with python 3.9