Etnaviv isn't CMA based, so this is certainly not a valid fix. It probably doesn't crash anymore, as it isn't properly freeing the pages backing the GEM object.
I've seen this crash in the early days of etnaviv a few times, but it hasn't happened to me in a long time.
I don't recognize this either, I haven't seen a kernel memory managment error while running glmark2 (or anything w/ etnaviv) for a long time. Strange.
Regards, Wladimir