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Message-ID: <f14b7f55-3e02-461d-94eb-a89980161ee7@bytedance.com>
Date: Tue, 30 Jan 2024 11:39:02 +0800
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Subject: Re: [External] [PATCH 04/20] mm: zswap: warn when referencing a dead
 entry
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To: Johannes Weiner <hannes@cmpxchg.org>,
 Andrew Morton <akpm@linux-foundation.org>
Cc: Nhat Pham <nphamcs@gmail.com>, Yosry Ahmed <yosryahmed@google.com>,
 linux-mm@kvack.org, linux-kernel@vger.kernel.org
References: <20240130014208.565554-1-hannes@cmpxchg.org>
 <20240130014208.565554-5-hannes@cmpxchg.org>
From: Chengming Zhou <zhouchengming@bytedance.com>
In-Reply-To: <20240130014208.565554-5-hannes@cmpxchg.org>
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On 2024/1/30 09:36, Johannes Weiner wrote:
> Put a standard sanity check on zswap_entry_get() for UAF scenario.
> 
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>

Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>

> ---
>  mm/zswap.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/mm/zswap.c b/mm/zswap.c
> index 9f05282efe3c..0c6adaf2fdb6 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -542,6 +542,7 @@ static void zswap_entry_free(struct zswap_entry *entry)
>  /* caller must hold the tree lock */
>  static void zswap_entry_get(struct zswap_entry *entry)
>  {
> +	WARN_ON_ONCE(!entry->refcount);
>  	entry->refcount++;
>  }
>