Comment # 58 on bug 1028575 from Mircea Kitsune

I have important new information. After yet more weeks of testing, I seem to
have found both of the common triggers for this issue. The crash happens a few
hours after either of the following actions is preformed:

1 - Desktop effects are toggled at runtime. Pressing Alt + Shift + F12 twice to
turn compositing off then back on will mine the system with this crash.

2 - I insert my USB stick or external drive into an USB port, mount it and
access it in Dolphin, then unmount and remove it. A few hours after I've
inserted / removed my drive, the freeze occurs. I suspect this has to do with
the device notifier popping up in the system tray, asking what action to
preform on the device or telling me the device is safe to unplug.

I'm not sure if the themes I'm using might have any relevancy. Considering this
is a graphics problem, I figured I'd share this info as well so others can test
them if they wish. I'm using the Plasma / KWin theme Freeze with the default
Breeze icons / cursor / widget style:

https://www.opendesktop.org/p/998653/
https://www.opendesktop.org/p/1002663/