Does the problem eventually end? How long has it stayed at 100% CPU? If the problem persists then please log into a VT (Ctrl+Alt+F4) and collect a backtrace (or backtraces) of the offending Xorg process using these steps:
https://wiki.ubuntu.com/Backtrace#Already_running_programs -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1800101 Title: gnome-shell uses 100% CPU To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1800101/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs