Re: [PATCH v2] iio: adc: ade9000: fix NULL pointer dereference in clkout registration

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 21 Sep 2026 10:51:46 +0000
"Miclaus, Antoniu" <Antoniu.Miclaus@analog.com> wrote:

> --
> Antoniu Miclăuş
> 
> > -----Original Message-----
> > From: Jonathan Cameron <jic23@kernel.org>
> > Sent: Monday, September 21, 2026 6:12 AM
> > To: Linmao Li <lilinmao@kylinos.cn>; Miclaus, Antoniu
> > <Antoniu.Miclaus@analog.com>
> > Cc: Sa, Nuno <Nuno.Sa@analog.com>; Hennerich, Michael
> > <Michael.Hennerich@analog.com>; David Lechner <dlechner@baylibre.com>;
> > Andy Shevchenko <andy@kernel.org>; linux <linux@analog.com>; linux-
> > iio@vger.kernel.org; linux-kernel@vger.kernel.org; stable@vger.kernel.org
> > Subject: Re: [PATCH v2] iio: adc: ade9000: fix NULL pointer dereference in
> > clkout registration
> > 
> > On Mon, 31 Aug 2026 00:57:28 +0100
> > Jonathan Cameron <jic23@kernel.org> wrote:
> >   
> > > On Wed, 26 Aug 2026 16:31:56 +0800
> > > Linmao Li <lilinmao@kylinos.cn> wrote:
> > >  
> > > > ade9000_setup_clkout() passes NULL as the register address when
> > > > registering a divider clock. During clock registration, the common
> > > > clock framework calls clk_divider_recalc_rate(), which dereferences
> > > > the address through readl(). As a result, probing an ADE9000 configured
> > > > as a clock provider with an external input clock crashes.
> > > >
> > > > CLKOUT passes CLKIN through without changing its rate. Register it as
> > > > a 1:1 fixed-factor clock, which does not require register access.
> > > >
> > > > This change does not affect the configuration using the internal clock,
> > > > for which the driver does not register a clock provider.
> > > >
> > > > Fixes: 81de7b4619fc ("iio: adc: add ade9000 support")
> > > > Cc: stable@vger.kernel.org
> > > > Signed-off-by: Linmao Li <lilinmao@kylinos.cn>  
> > >
> > > Looking for a tag from Antoniu for this one.  
> > Antoniu
> > 
> > Please take a look at this.  
> 
> Sorry for the late response, thanks for the ping!
> 
> > 
> > Jonathan
> >   
> > >  
> > > > ---
> > > > Changes in v2:
> > > > - Clarify that the configuration using the internal clock is unaffected.
> > > >
> > > >  drivers/iio/adc/ade9000.c | 5 +++--
> > > >  1 file changed, 3 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/drivers/iio/adc/ade9000.c b/drivers/iio/adc/ade9000.c
> > > > index e57e24b6acdf7..4e96cc37fbedf 100644
> > > > --- a/drivers/iio/adc/ade9000.c
> > > > +++ b/drivers/iio/adc/ade9000.c
> > > > @@ -1647,8 +1647,9 @@ static int ade9000_setup_clkout(struct device  
> > *dev, struct ade9000_state *st)  
> > > >  		return 0;
> > > >
> > > >  	/* CLKOUT passes through CLKIN with divider of 1 */
> > > > -	clkout_hw = devm_clk_hw_register_divider(dev, "clkout",  
> > __clk_get_name(st->clkin),  
> > > > -						 CLK_SET_RATE_PARENT,  
> > NULL, 0, 1, 0, NULL);  
> > > > +	clkout_hw = devm_clk_hw_register_fixed_factor(dev, "clkout",
> > > > +						      __clk_get_name(st->clkin),
> > > > +						      CLK_SET_RATE_PARENT, 1,  
> > 1);  
> 
> Reviewed-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> 
Applied to the fixes-togreg branch of iio.git
Not that will probably not go upstream until the next merge window.

Thanks,

Jonathan

> > > >  	if (IS_ERR(clkout_hw))
> > > >  		return dev_err_probe(dev, PTR_ERR(clkout_hw), "Failed to  
> > register clkout");  
> > > >
> > > >
> > > > base-commit: 6b9f23b5460818aaf199dda90210d5fc08d66c8f  
> > >
> > >  
>