Re: [PATCH] net: stmmac: Avoid VLA usage

From: Jose Abreu
Date: Wed May 02 2018 - 10:08:10 EST




On 02-05-2018 13:36, Kees Cook wrote:
> On Wed, May 2, 2018 at 1:54 AM, Jose Abreu <Jose.Abreu@xxxxxxxxxxxx> wrote:
>> Hi Kees,
>>
>> On 01-05-2018 22:01, Kees Cook wrote:
>>> In the quest to remove all stack VLAs from the kernel[1], this switches
>>> the "status" stack buffer to use the existing small (8) upper bound on
>>> how many queues can be checked for DMA, and adds a sanity-check just to
>>> make sure it doesn't operate under pathological conditions.
>>>
>>> [1] https://urldefense.proofpoint.com/v2/url?u=http-3A__lkml.kernel.org_r_CA-2B55aFzCG-2DzNmZwX4A2FQpadafLfEzK6CC-3DqPXydAacU1RqZWA-40mail.gmail.com&d=DwIBAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=WHDsc6kcWAl4i96Vm5hJ_19IJiuxx_p_Rzo2g-uHDKw&m=TBD6a7UY2VbpPmV9LOW_eHAyg8uPq1ZPDhq93VROTVE&s=4fvOST1HhWmZ4lThQe-dHCJYEXNOwey00BCXOWm8tKo&e=
>>>
>>> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
>>>
>> I rather prefer the variables declaration in reverse-tree order,
>> but thats just a minor pick.
> I can explicitly reorder the other variables, if you want?

No need by me, unless Giuseppe or Alexandre prefer that. Thanks!

Best Regards,
Jose Miguel Abreu

>
>> Reviewed-by: Jose Abreu <joabreu@xxxxxxxxxxxx>
> Thanks!
>
>> PS: Is VLA warning switch in gcc already active? Because I didn't
>> see this warning in my builds.
> It is not. A bunch of people have been building with KCFLAGS=-Wvla to
> find the VLAs and sending patches. Once we get rid of them all, we can
> add the flag to the top-level Makefile.
>
> -Kees
>