mm/kasan: Detect double-free involving kfree_rcu_sheaf().

[mm/kasan: Detect double-free involving kfree_rcu_sheaf().] [patchwork series v1] submitter=Kuniyuki Iwashima patches (2): [1/2] mm/kasan: Detect double-free involving kfree_rcu_sheaf(). [2/2] mm/