So I've been conducting lots of additional investigation with =
both the vanilla
kernel (4.18-rc7) and the kernel with your patch.

I took more time to try to recreate the scenarios that cause the crash
(monitoring system resources, etc.) and this is when I realized that my
swapfile was very small (only 2GB).

Short story - Upon further investigation I don't believe this is a bug with
DRM/amdgpu but rather the crash was caused because I simply ran out of memo=
ry
*and* swapspace combined.

I feel a little silly about this, I'm running Ubuntu 18.04 and I guess the
default swapfile size is 2GB.  I'm used to using swap partions which are the
same size as the system RAM, so I never considered that I could be running =
out
of *both*.

I think at this point it's safe to close the bug.  I'm going to increase my
swapfile size to 16GB and monitor my system more closely.  If I get the hard
system crash I'll first determine if I ran out of swap, and then if it appe=
ars
I had enough swap, I'll reopen this bug.

Thanks for your assistance!