Probably also worth noting that as of 4.15, my laptop hangs with a black screen
on suspend/resume. Magic SysRq seems to be about the only thing the computer
responds to if I close and then open the lid. It seems somewhat likely this is
related, due to my aforementioned kernel oopsies on resumes and the fact they
had very similar stack traces to these warnings.

I'm not sure how to get any relevant logging output from these hangs though.
Any suggestions?