Re: [PATCH 1/2] OPP: add index check to assert to avoid buffer overflow in _read_freq()

[Neil Armstrong <neil.armstrong@linaro.org>]

On 29/11/2024 10:04, Viresh Kumar wrote:
> On 29-11-24, 09:53, Neil Armstrong wrote:
>> Hi,
>>
>> On 29/11/2024 09:40, Viresh Kumar wrote:
>>> On 28-11-24, 11:07, Neil Armstrong wrote:
>>>> Pass the freq index to the assert function to make sure
>>>> we do not read a freq out of the opp->rates[] table.
>>>>
>>>> Without that the index value is never checked when called from
>>>> dev_pm_opp_find_freq_exact_indexed() or
>>>> dev_pm_opp_find_freq_ceil/floor_indexed().
>>>
>>> These APIs aren't supported for cases where we have more than one clks
>>> available and hence assert for single clk.
>>>
>>
>> I don't understand, the _indexed functions clearly have an index parameter
>> which is documented as "Clock index"
> 
> Ahh, I missed that there are few _indexed() helpers as well which you are
> correctly modifying.
> 
>> I agree we could leave the other ones with assert_single_clk, but we would
>> need to duplicate it to have one with the index parameter, so it felt simpler
>> to use assert_clk_index everywhere but indeed we do not exclude them for
>> when there's multiple clock...
> 
> What prevents a user to call dev_pm_opp_find_freq_exact() for a multi-clk setup
> after your patch ? As we use Index = 0 here in the code.
> 
> That's why I would prefer the earlier assert for all these, except the indexed
> ones.

Yes, let me send a v2 with this addressed

Thanks,
Neil