[PATCH] iio: add NULL pointer checks to iio device additional/removal

[PATCH] iio: add NULL pointer checks to iio device additional/removal

[Matt Ranostay]

Check if __iio_device_register and iio_device_unregister indio_dev
parameter isn't a NULL pointer.

Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
---
 drivers/iio/industrialio-core.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 0f4dbda3b9d3..6071e52903e5 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1896,13 +1896,14 @@ static const struct iio_buffer_setup_ops noop_ring_setup_ops;
 
 int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
 {
-	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	struct iio_dev_opaque *iio_dev_opaque;
 	struct fwnode_handle *fwnode;
 	int ret;
 
-	if (!indio_dev->info)
+	if (!indio_dev || !indio_dev->info)
 		return -EINVAL;
 
+	iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 	iio_dev_opaque->driver_module = this_mod;
 
 	/* If the calling driver did not initialize firmware node, do it here */
@@ -1987,7 +1988,12 @@ EXPORT_SYMBOL(__iio_device_register);
  **/
 void iio_device_unregister(struct iio_dev *indio_dev)
 {
-	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+	struct iio_dev_opaque *iio_dev_opaque;
+
+	if (!indio_dev)
+		return;
+
+	iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 
 	cdev_device_del(&iio_dev_opaque->chrdev, &indio_dev->dev);
 
-- 
2.36.1

Re: [PATCH] iio: add NULL pointer checks to iio device additional/removal

[Andy Shevchenko]

On Wed, Aug 3, 2022 at 2:04 PM Matt Ranostay <matt.ranostay@konsulko.com> wrote:
>
> Check if __iio_device_register and iio_device_unregister indio_dev
> parameter isn't a NULL pointer.

We refer to functions as func() in the text.

...

>  int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
>  {
> -       struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
> +       struct iio_dev_opaque *iio_dev_opaque;
>         struct fwnode_handle *fwnode;
>         int ret;
>
> -       if (!indio_dev->info)
> +       if (!indio_dev || !indio_dev->info)
>                 return -EINVAL;
>
> +       iio_dev_opaque = to_iio_dev_opaque(indio_dev);

Not sure we need this one. All callers check for indio_dev from the
allocator, otherwise I don't see a clean workflow when indio_dev is
NULL when calling register(). The other part is good.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] iio: add NULL pointer checks to iio device additional/removal

[Andy Shevchenko]

On Wed, Aug 3, 2022 at 7:57 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Wed, Aug 3, 2022 at 2:04 PM Matt Ranostay <matt.ranostay@konsulko.com> wrote:
> >
> > Check if __iio_device_register and iio_device_unregister indio_dev
> > parameter isn't a NULL pointer.

A couple more things:
- make sure you include all maintainers and reviewers (you may use my
"smart" script [1] for that)
- explain why you are doing this change

[1]: https://github.com/andy-shev/home-bin-tools/blob/master/ge2maintainer.sh

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH] iio: add NULL pointer checks to iio device additional/removal

[Jonathan Cameron]

On Wed, 3 Aug 2022 20:00:24 +0200
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:

> On Wed, Aug 3, 2022 at 7:57 PM Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
> > On Wed, Aug 3, 2022 at 2:04 PM Matt Ranostay <matt.ranostay@konsulko.com> wrote:  
> > >
> > > Check if __iio_device_register and iio_device_unregister indio_dev
> > > parameter isn't a NULL pointer.  
> 
> A couple more things:
> - make sure you include all maintainers and reviewers (you may use my
> "smart" script [1] for that)
> - explain why you are doing this change
> 

Agreed. I'm not sure of the reasoning for doing this.
I'd also expect to see it as part of a series where we might pass NULL to these
functions.

Thanks,

Jonathan


> [1]: https://github.com/andy-shev/home-bin-tools/blob/master/ge2maintainer.sh
>