Re: [PATCH] net/mlx5: fix possible stack overflows

Zhu Yanjun
2024-02-19T12:19:35Z

在 2024/2/19 17:05, Hamdan Agbariya 写道:
>> 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
>>
>
> No need to zero the buffers, as it does not have any necessity and it will only affect performance.
> Thanks,

Sorry. I can not get your point. Can you explain why no need to zero the
buffers? Thanks in advance.

> Hamdan
>
>
>
>
>> 2). Add the zero functionality to your patch

If a buffer is used for many times, is it necessary to zero it before it
is used again?

Thanks,
Zhu Yanjun

>>
>> From my perspective, it is good to the whole commit.
>>
>> Please Jason and Leon comment on this.
>>
>> Thanks,
>>
>> Zhu Yanjun
>>
>>>
>>> Arnd