Automatic exit of webots on ubuntu

[HimGautam]

Hi, I was trying to use webots simulator to train and simulate quadruped robot by EPFL. While training, I activated optional render of polygon support. In the next run when I tried to accelerate the simulation, webots simulator crashed automatically with the following line on the console. /usr/local/bin/webots: line 90: 5289 Segmentation fault (core dumped) "$webots_home/bin/webots-bin" "$@"

Upon close examination of the recent changes, I disable the rendering of support polygon and now webots runs smoothly. I can share my work if needed.

[ad-daniel]

If you can provide a minimal example that shows the crash it would definitely help. I've tried a few worlds and I'm unable to reproduce the issue. Something related to your specific robot might be the cause

[HimGautam]

Hi, It can also be local to my system. I am currently using Lenovo Legion Y540 with 8GB RAM and Nvidia GeForce GTX 1650 with 4GB. However, I am attaching the link my work here.

[ygoumaz]

Hi,

I was able to reproduce your issue using your project in both develop and master branches. I identified the code line which throws the segmentation fault. It is located in src/nodes/WbSolid.cpp in prePhysicsStep(double ms):

for (i = 0; i < mJointChildren.size(); ++i)

The mJointChildren seems to be NULL at some point and calling the size() methods causes the crash. I suspect that the QVector object is getting deleted somewhere but I could not find where exactly.

Other observations: It seems to occur 99% of the time when the support polygon is containing 10 or more vertices. Also, I could only reproduce the issue when running in fast mode.

[stefaniapedrazzi]

@HimGautam this issue should now be fixed in #4569 and the patch should be available in the nightly build of R2022a-rev1 starting from tomorrow and as well in the next release of Webots. Please let us now if you should experience it again with the newest version of Webots.