diff --git a/mm/memory.c b/mm/memory.c
index 5b7f2002e54b..bc9ba5a1f5b9 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -130,6 +130,7 @@ void __sync_task_rss_stat(struct task_struct *task, struct mm_struct *mm)
 
 	for (i = 0; i < NR_MM_COUNTERS; i++) {
 		if (task->rss_stat.count[i]) {
+			BUG_ON(!mm);
 			add_mm_counter(mm, i, task->rss_stat.count[i]);
 			task->rss_stat.count[i] = 0;
 		}
diff --git a/mm/mmu_context.c b/mm/mmu_context.c
index 0777654147c9..9e82e937000e 100644
--- a/mm/mmu_context.c
+++ b/mm/mmu_context.c
@@ -53,6 +53,7 @@ void unuse_mm(struct mm_struct *mm)
 	struct task_struct *tsk = current;
 
 	task_lock(tsk);
+	sync_mm_rss(tsk, mm);
 	tsk->mm = NULL;
 	/* active_mm is still 'mm' */
 	enter_lazy_tlb(mm, tsk);