diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index c85d75406c81..0f551a4a44cd 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -555,8 +555,10 @@ static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end,
 	}
 	rcu_read_unlock();
 
-	if (nr)
+	if (nr) {
+		BUG_ON(nr > atomic_read(&vmap_lazy_nr));
 		atomic_sub(nr, &vmap_lazy_nr);
+	}
 
 	if (nr || force_flush)
 		flush_tlb_kernel_range(*start, *end);