Re: [PATCH] iio: potentiometer: ds1803: remove VLA usage

From: Gustavo A. R. Silva
Date: Tue Mar 13 2018 - 13:07:15 EST




On 03/13/2018 11:59 AM, Himanshu Jha wrote:
On Tue, Mar 13, 2018 at 11:31:19AM -0500, Gustavo A. R. Silva wrote:


On 03/13/2018 11:24 AM, Himanshu Jha wrote:
Hi Gustavo,

On Tue, Mar 13, 2018 at 10:23:43AM -0500, Gustavo A. R. Silva wrote:
In preparation to enabling -Wvla, remove VLA. In this particular
case use macro ARRAY_SIZE so the length of array _result_ can be
computed at preprocessing time.

The use of stack Variable Length Arrays needs to be avoided, as they
can be a vector for stack exhaustion, which can be both a runtime bug
or a security flaw. Also, in general, as code evolves it is easy to
lose track of how big a VLA can get. Thus, we can end up having runtime
failures that are hard to debug.

Also, fixed as part of the directive to remove all VLAs from
the kernel: https://lkml.org/lkml/2018/3/7/621

Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
---

It is already applied as I had sent the patch few days ago.
https://lkml.org/lkml/2018/3/10/164

I specifically CC'ed you and Kees to avoid the patch collisions.


I see. Can you please update this spreadsheet:

https://docs.google.com/spreadsheets/d/1OcfyKK8pJ24esYhSEsW4Q2boZE7UTGbYsSEEtFXf7U0/edit

Updated!

Also,

drivers/iio/humidity/hts221_i2c.c:43:2: warning: ISO C90
forbids variable length array âsendâ [-Wvla]

This was already removed in recent commit when regmap API was used.

"6217792 iio: humidity: hts221: add regmap API support"

For this I added a short note in the *Notes* column.


Awesome.

Thank you
--
Gustavo