Bug 1539919

Description of problem:

I am running Fedora 27 as a VM on a Mac using VirtualBox 5.2.6.  I have the guest additions for VirtualBox 5.2.7 installed on the VM (this is recommended by the VirtualBox website, apparently due to bugs in the guest additions for 5.2.6 that interact poorly with 3D rendering).  There is obviously still some instability, because I'm experiencing an issue where cinnamon randomly goes to 100% CPU and becomes unresponsive; so far, the only way to get things working again has been to go to a text TTY and kill cinnamon-session to restart the session—trying to do this by killing cinnamon itself results in an unresponsive blank screen.

Version-Release number of selected component (if applicable):

cinnamon-3.6.7-3.fc27.x86_64

How reproducible:

This is a random, intermittent issue; I've had cinnamon crash immediately after login, but I've also had it stay up for several hours.  Actively doing something vs. idling seems to have little effect; I actually noticed the symptoms of the failure mode on Saturday while my work laptop was idling and screen-saved.

Steps to Reproduce:
1. Run Fedora 27 with the cinnamon desktop on VirtualBox 5.2.6 on a MacOS host with the 5.2.7 guest additions installed
2. Login
3. Wait for a random period of time

Actual results:

cinnamon locks up with 100% CPU and becomes unresponsive

Expected results:

What I would prefer is if it actually just straight-up crashed and restarted, or crashed and prompted me to restart, rather than hanging so hard that even killing it has no effect.  Even if the actual underlying bug is in the VirtualBox additions, having a way for cinnamon to restart and return to usability would be better than me having to go manually kill the session.

Additional info:

I spotted no obvious pertinent information in /var/log/messages or /var/log/Xorg.0.log.old, though I did see a message indicating there's a key sequence (C-A-Esc) that's supposed to restart cinnamon, which I'll try next time it locks up (though I'm not exactly expecting it to work).  I'm happy to try other debugging steps if alerted to them.