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

[Jonathan Cameron <jic23@kernel.org>]

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.

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