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

[Linmao Li <lilinmao@kylinos.cn>]

在 2026/8/24 23:08, Andy Shevchenko 写道:
> On Mon, Aug 24, 2026 at 08:52:10PM +0800, Linmao Li 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.
> Do you have HW to test? What will be the result for the internal clock case?
No, unfortunately I do not have access to the hardware, so this is
based on code inspection only.

For the crystal oscillator case, the device tree does not provide a
clocks property. devm_clk_get_optional_enabled() therefore returns
NULL, and ade9000_setup_clkout() returns here:

         if (!device_property_present(dev, "#clock-cells") || !st->clkin)
                 return 0;

No clock provider is registered in that case. This behavior is
unchanged by the patch. The modified registration path is reached only
when an external input clock is present and the device is configured as
a clock provider.

Thanks,
Linmao
>