linux-kernel - Re: [PATCH][V2][next] regulator: axp20x: check rdev is null before dereferencing it

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Date:   Mon, 4 Feb 2019 19:13:30 +0000
From:   Colin Ian King <colin.king@...onical.com>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, Chen-Yu Tsai <wens@...e.org>
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH][V2][next] regulator: axp20x: check rdev is null before
 dereferencing it

ping?

On 22/12/2018 11:31, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> Currently rdev is dereferenced when assigning desc before rdev is null
> checked, hence there is a potential null pointer dereference on rdev.
> Fix this by null checking rdev first.
> 
> Detected by CoverityScan, CID#1476031 ("Dereference before null check")
> 
> Fixes: 77e3e3b165db ("regulator: axp20x: add software based soft_start for AXP209 LDO3")
> Signed-off-by: Colin Ian King <colin.king@...onical.com>
> ---
> 
> V2: Fix 2nd occurrance of this thinko
> 
> ---
>  drivers/regulator/axp20x-regulator.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/regulator/axp20x-regulator.c b/drivers/regulator/axp20x-regulator.c
> index 48af859fd053..0dfa4ea6bbdf 100644
> --- a/drivers/regulator/axp20x-regulator.c
> +++ b/drivers/regulator/axp20x-regulator.c
> @@ -367,7 +367,7 @@ static const int axp209_dcdc2_ldo3_slew_rates[] = {
>  static int axp20x_set_ramp_delay(struct regulator_dev *rdev, int ramp)
>  {
>  	struct axp20x_dev *axp20x = rdev_get_drvdata(rdev);
> -	const struct regulator_desc *desc = rdev->desc;
> +	const struct regulator_desc *desc;
>  	u8 reg, mask, enable, cfg = 0xff;
>  	const int *slew_rates;
>  	int rate_count = 0;
> @@ -375,6 +375,8 @@ static int axp20x_set_ramp_delay(struct regulator_dev *rdev, int ramp)
>  	if (!rdev)
>  		return -EINVAL;
>  
> +	desc = rdev->desc;
> +
>  	switch (axp20x->variant) {
>  	case AXP209_ID:
>  		if (desc->id == AXP20X_DCDC2) {
> @@ -436,11 +438,13 @@ static int axp20x_set_ramp_delay(struct regulator_dev *rdev, int ramp)
>  static int axp20x_regulator_enable_regmap(struct regulator_dev *rdev)
>  {
>  	struct axp20x_dev *axp20x = rdev_get_drvdata(rdev);
> -	const struct regulator_desc *desc = rdev->desc;
> +	const struct regulator_desc *desc;
>  
>  	if (!rdev)
>  		return -EINVAL;
>  
> +	desc = rdev->desc;
> +
>  	switch (axp20x->variant) {
>  	case AXP209_ID:
>  		if ((desc->id == AXP20X_LDO3) &&
>