I did not expect to find another report on this. I've been str=
uggling with what
appears to be the exact same crash for over 6 months. The difference for me=
 is
that, this is not caused by Unreal Editor 4; It's triggered exclusively by =
the
KDE desktop, usually when alt-tab switching between windows. My machine is
rendered unresponsive approximately every 1 to 4 days.

I found this after googling parts of my own dmesg output, which seem to be
identical to what you've pasted in the first comment. I too have a RadeonSI
card, in my case a Radeon R7 370 from Gigabyte. My OS is openSUSE Tumbleweed
x64.

More information is available on my report, where I've posted my fair share=
 of
logs and observations on the problem. We should first of all determine if t=
his
is the same issue beyond doubt, then hopefully combining the information we=
've
both obtained can lead to a solution.

https://bugs.freedesktop.org/show_bug.=
cgi?id=3D100306