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Message-ID: <11f40993-ec02-48b7-aec5-13ff7cddf665@linux.dev>
Date: Fri, 16 Feb 2024 08:43:18 +0800
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Subject: Re: [PATCH] net/mlx5: fix possible stack overflows
To: Arnd Bergmann <arnd@arndb.de>, Arnd Bergmann <arnd@kernel.org>,
 Saeed Mahameed <saeedm@nvidia.com>, Leon Romanovsky <leon@kernel.org>
Cc: "David S . Miller" <davem@davemloft.net>,
 Eric Dumazet <edumazet@google.com>, Jakub Kicinski <kuba@kernel.org>,
 Paolo Abeni <pabeni@redhat.com>, Yevgeny Kliteynik <kliteyn@nvidia.com>,
 Alex Vesker <valex@nvidia.com>, Hamdan Igbaria <hamdani@nvidia.com>,
 Netdev <netdev@vger.kernel.org>, linux-rdma@vger.kernel.org,
 linux-kernel@vger.kernel.org
References: <20240213100848.458819-1-arnd@kernel.org>
 <84874528-daea-424d-af63-b9b86835fae6@linux.dev>
 <2ebe5a36-ce81-4d26-a12b-7affbd65c5e3@app.fastmail.com>
From: Zhu Yanjun <yanjun.zhu@linux.dev>
In-Reply-To: <2ebe5a36-ce81-4d26-a12b-7affbd65c5e3@app.fastmail.com>
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在 2024/2/15 16:03, Arnd Bergmann 写道:
> On Thu, Feb 15, 2024, at 01:18, Zhu Yanjun wrote:
>> 在 2024/2/13 18:08, Arnd Bergmann 写道:
>>>    static int
>>> -dr_dump_rule_rx_tx(struct seq_file *file, struct mlx5dr_rule_rx_tx *rule_rx_tx,
>>> +dr_dump_rule_rx_tx(struct seq_file *file, char *buff,
>>> +		   struct mlx5dr_rule_rx_tx *rule_rx_tx,
>>>    		   bool is_rx, const u64 rule_id, u8 format_ver)
>>>    {
>>>    	struct mlx5dr_ste *ste_arr[DR_RULE_MAX_STES + DR_ACTION_MAX_STES];
>>> @@ -533,7 +532,7 @@ dr_dump_rule_rx_tx(struct seq_file *file, struct mlx5dr_rule_rx_tx *rule_rx_tx,
>>>    		return 0;
>>>    
>>>    	while (i--) {
>>> -		ret = dr_dump_rule_mem(file, ste_arr[i], is_rx, rule_id,
>> Before buff is reused, I am not sure whether buff should be firstly
>> zeroed or not.
> I don't see why it would, but if you want to zero it, that would be
> a separate patch that is already needed on the existing code,
> which never zeroes its buffers.

Sure. I agree with you. In the existing code, the buffers are not zeroed.

But to a buffer which is used for several times, it is good to zero it 
before it is used again.

Can you add a new commit with the following?

1). Zero the buffers in the existing code

2). Add the zero functionality to your patch

 From my perspective, it is good to the whole commit.

Please Jason and Leon comment on this.

Thanks,

Zhu Yanjun

>
>      Arnd