diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 19338d2..0c719c6 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -449,6 +449,8 @@
 	tsk->mm = tsk->active_mm = mm;
 	preempt_disable();
 	update_mm(mm, tsk);
+	atomic_inc(&mm->context.attach_count);
+	atomic_dec(&old_mm->context.attach_count);
 	cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
 	preempt_enable();
 	task_unlock(tsk);