Re: [PATCH] iio: accel: kxsd9: Fix runtime PM leak in kxsd9_write_raw()

[Jonathan Cameron]

On Wed, 16 Sep 2026 19:33:47 +0200
Linus Walleij <linusw@xxxxxxxxxx> wrote:

> On Wed, Sep 16, 2026 at 6:12 PM Wentao Liang <vulab@xxxxxxxxxxx> wrote:
> 
> > pm_runtime_get_sync() increments the usage counter even on failure, so
> > every successful call must be paired with a put. Rejecting an invalid
> > scale value returned early and skipped the paired
> > pm_runtime_put_autosuspend(), permanently preventing runtime suspend.
> >
> > Fixes: 9a9a369d6178 ("iio: accel: kxsd9: Deploy system and runtime PM")
> > Cc: stable@xxxxxxxxxxxxxxx  
> 
> It's NOT that important.
Also not the current code...
static int kxsd9_write_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int val,
			   int val2,
			   long mask)
{
	int ret = -EINVAL;
	struct kxsd9_state *st = iio_priv(indio_dev);

	pm_runtime_get_sync(st->dev);

	if (mask == IIO_CHAN_INFO_SCALE) {
		/* Check no integer component */
		if (val)
			ret = -EINVAL;
		else
			ret = kxsd9_write_scale(indio_dev, val2);
	}

	pm_runtime_put_autosuspend(st->dev);

	return ret;
}

Which could be improved via the ACQUIRE magic but none the less doesn't
have this bug. Was fixed back in June.

Jonathan



> 
> > Signed-off-by: Wentao Liang <vulab@xxxxxxxxxxx>  
> 
> Reviewed-by: Linus Walleij <linusw@xxxxxxxxxx>
> 
> Yours,
> Linus Walleij