Re: [PATCH v2 2/3 RESEND] mfd: max8907: Remove platform_data based probing

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] regulator: max8907: NULL pointer dereference if optional DT nodes are omitted
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commit 71b1062244be38a96a85d244d04303ea12b325fe
Author: Svyatoslav Ryhel <clamor95@gmail.com>

mfd: max8907: Remove platform_data based probing

This patch removes legacy platform_data based probing for the max8907
driver, converting it to be strictly device tree based.

> diff --git a/drivers/regulator/max8907-regulator.c b/drivers/regulator/max8907-regulator.c
> index e59aa7a3ee546..907ed3fca5e97 100644
> --- a/drivers/regulator/max8907-regulator.c
> +++ b/drivers/regulator/max8907-regulator.c
[ ... ]
> @@ -312,10 +311,9 @@ static int max8907_regulator_probe(struct platform_device *pdev)
>  		struct regulator_dev *rdev;
>  
>  		config.dev = pdev->dev.parent;
> -		if (pdata)
> -			idata = pdata->init_data[i];
> -		else
> -			idata = match_init_data(i);
> +
> +		idata = match_init_data(i);
> +

[Severity: High]
Will this cause a NULL pointer dereference if optional regulator nodes are
omitted from the device tree?

Since the patch removes the platform_data fallback, the driver now relies
entirely on match_init_data(i). If a system omits the nodes for
MAX8907_BBAT, MAX8907_SDBY, or MAX8907_VRTC, match_init_data() will return
NULL.

Looking at max8907_regulator_probe() just below this change, idata is
unconditionally dereferenced for these specific regulators:

drivers/regulator/max8907-regulator.c:max8907_regulator_probe() {
        ...
        switch (pmic->desc[i].id) {
        ...
        case MAX8907_BBAT:
        case MAX8907_SDBY:
        case MAX8907_VRTC:
                idata->supply_regulator = mbatt_rail_name;
                break;
        }
        ...
}

Could we add a NULL check for idata before dereferencing it here?

>  		config.init_data = idata;
>  		config.driver_data = pmic;
>  		config.regmap = max8907->regmap_gen;

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Sashiko AI review · https://sashiko.dev/#/patchset/20261014121544.138958-1-clamor95@gmail.com?part=2