linux-kernel - Re: [PATCH] leds: fix a missing check of return value of lp55xx

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Message-ID: <333a5518-ad9d-868c-a5b6-731e10c053ea@gmail.com>
Date:   Fri, 28 Dec 2018 17:52:27 +0100
From:   Jacek Anaszewski <jacek.anaszewski@...il.com>
To:     Kangjie Lu <kjlu@....edu>
Cc:     pakki001@....edu, Pavel Machek <pavel@....cz>,
        linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] leds: fix a missing check of return value of lp55xx_read

Hi Kangjie,

Thank you for the patch.

On 12/26/18 5:18 AM, Kangjie Lu wrote:
> When lp55xx_read() fails, "status" is an uninitialized variable and thus
> may contain random value; using it leads to undefined behaviors.
> 
> The fix inserts a check for the return value of lp55xx_read: if it
> fails, returns with its error code.
> 
> Signed-off-by: Kangjie Lu <kjlu@....edu>
> ---
>   drivers/leds/leds-lp5523.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/leds/leds-lp5523.c b/drivers/leds/leds-lp5523.c
> index a2e74feee2b2..fd64df5a57a5 100644
> --- a/drivers/leds/leds-lp5523.c
> +++ b/drivers/leds/leds-lp5523.c
> @@ -318,7 +318,9 @@ static int lp5523_init_program_engine(struct lp55xx_chip *chip)
>   
>   	/* Let the programs run for couple of ms and check the engine status */
>   	usleep_range(3000, 6000);
> -	lp55xx_read(chip, LP5523_REG_STATUS, &status);
> +	ret = lp55xx_read(chip, LP5523_REG_STATUS, &status);
> +	if (ret)
> +		return ret;
>   	status &= LP5523_ENG_STATUS_MASK;
>   
>   	if (status != LP5523_ENG_STATUS_MASK) {
> 

Applied to fixes-for-4.21 branch of linux-leds.git.

-- 
Best regards,
Jacek Anaszewski