Ok, thanks! However there was nothing in my /var/crash folder. Nonetheless I tried to file a new bug with ubuntu-bug xorg. It added lots of system information and logs.
here it is: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1754296 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1754177 Title: [bionic] xserver / startx crashes with Composite Disabled in xorg.conf To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1754177/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
