The comment above from Jose Fonseca (and follow up from Feral's Edwin Smith)
imply that the problem here is with the game calling
glDrawRangeElementsBaseVertex with bad start/end values, resulting in the
indices being out-of-range which is illegal per the GL spec, and implying that
this is what causes the crash.

I have tried patching Mesa to effectively reduce glDrawRangeElementsBaseVertex
calls to glDrawElementsBaseVertex (i.e. same method but with no start/end
supplied). Patch follows below (inline because it is so short). However, I am
sorry to say that this did *not* prevent the crashes. I conclude that there may
still be a bug in Mesa and/or kernel space DRM (although it's possible my patch
isn't having the effect I intended - I'm not familiar enough with Mesa code
base to be sure).

diff --git a/src/mesa/vbo/vbo_exec_array.c b/src/mesa/vbo/vbo_exec_array.c
index f0245fd..d1f4ac6 100644
--- a/src/mesa/vbo/vbo_exec_array.c
+++ b/src/mesa/vbo/vbo_exec_array.c
@@ -935,7 +935,9 @@ vbo_exec_DrawRangeElementsBaseVertex(GLenum mode,
    (void) check_draw_elements_data;
 #endif

-   vbo_validated_drawrangeelements(ctx, mode, index_bounds_valid, start, end,
+   //vbo_validated_drawrangeelements(ctx, mode, index_bounds_valid, start,
end,
+   //               count, type, indices, basevertex, 1, 0);
+   vbo_validated_drawrangeelements(ctx, mode, GL_FALSE, ~0, ~0,
                    count, type, indices, basevertex, 1, 0);
 }