static inline void lazy_mmu_mode_pause(void)
  {
+	struct lazy_mmu_state *state = &current->lazy_mmu_state;
+
+	VM_WARN_ON(state->nesting_level == 0 || !state->active);
+
+	state->active = false;
  	arch_leave_lazy_mmu_mode();

Just one question:

Don't we want to allow for pause/resume when not enabled? Would seem 
valid to me, because pause/resume code should actually not worry about 
that, right?

if (!state->nesting_level) {
	VM_WARN_ON(state->active);
	return;
}
VM_WARN_ON(!state->active);
state->active = false;
arch_leave_lazy_mmu_mode();

-- 
Cheers

David / dhildenb