Re: [PATCH 1/2] iio: accel: kxsd9: fix use-after-free on remove

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 03 Jul 2026 22:53:22 +0530
Biren Pandya <birenpandya@gmail.com> wrote:

> The kxsd9 driver currently calls iio_triggered_buffer_cleanup() before
> iio_device_unregister() in the remove() function. This order creates a
> race condition where userspace can still access sysfs or ioctl interfaces
> while the triggered buffers are being torn down, potentially leading to
> a use-after-free.
> 
> Fix this by swapping the cleanup order. Unregister the IIO device first
> to guarantee that all userspace interfaces are destroyed and no new
> accesses can occur before cleaning up the triggered buffers.
> 
> This vulnerability was flagged by the Sashiko automated review system.
> 
> Link: https://sashiko.dev/#/patchset/20260621193036.78549-2-birenpandya@gmail.com
> Fixes: 9a9a369d6178 ("iio: accel: kxsd9: Deploy system and runtime PM")
That tag touches the pm runtime stuff just below, but nothing to do with the
bug reported here.

Should be:
Fixes: 0427a106a98a ("iio: accel: kxsd9: Add triggered buffer handling")

> Cc: stable@vger.kernel.org
> Signed-off-by: Biren Pandya <birenpandya@gmail.com>
> ---
>  drivers/iio/accel/kxsd9.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/accel/kxsd9.c b/drivers/iio/accel/kxsd9.c
> index 7ac885d94d7f4..27adcdd312014 100644
> --- a/drivers/iio/accel/kxsd9.c
> +++ b/drivers/iio/accel/kxsd9.c
> @@ -478,8 +478,8 @@ void kxsd9_common_remove(struct device *dev)
>  	struct iio_dev *indio_dev = dev_get_drvdata(dev);
>  	struct kxsd9_state *st = iio_priv(indio_dev);
>  
> -	iio_triggered_buffer_cleanup(indio_dev);
>  	iio_device_unregister(indio_dev);
> +	iio_triggered_buffer_cleanup(indio_dev);
>  	pm_runtime_get_sync(dev);
>  	pm_runtime_put_noidle(dev);
>  	pm_runtime_disable(dev);
>