Our webwork server is running on Ubuntu 20.04 lts. All of a sudden (or maybe related to the last Ubuntu update)
www-data spawns out pdflatex processes that eat a lot of cpu time to the point that it crashed the server.
After rebooting it, things look fine for a while, but the pdflatex processes got spawned out again (perhaps students are trying to make hardcopies)
Here is a typical line of what htop shows:
www-data 20 0 118M 43148 4604 R 100. 0.5 3h23:05 /usr/bin/pdflatex --no-shell-escape hardcopy
here 100 is the cpu%. Looks like the process (pdflatex) is hung up and not existing.
How can we fix this, any help is greatly appreciated.