linux-kernel - Re: [PATCH] leds: trigger: oneshot: One function call less in pattern

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Date: Thu, 11 Jan 2024 10:41:09 +0000
From: Lee Jones <lee@...nel.org>
To: Markus Elfring <Markus.Elfring@....de>
Cc: linux-leds@...r.kernel.org, kernel-janitors@...r.kernel.org,
	Pavel Machek <pavel@....cz>, LKML <linux-kernel@...r.kernel.org>,
	cocci@...ia.fr
Subject: Re: [PATCH] leds: trigger: oneshot: One function call less in
 pattern_init() after error detection

On Tue, 26 Dec 2023, Markus Elfring wrote:

> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Tue, 26 Dec 2023 22:02:08 +0100
> 
> The kfree() function was called in one case by
> the pattern_init() function during error handling
> even if the passed variable contained a null pointer.

It's totally valid to call kfree() on a NULL pointer:

  * If @object is NULL, no operation is performed.

Why do we care all that much?

> This issue was detected by using the Coccinelle software.
> 
> Thus use another label.
> 
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>  drivers/leds/trigger/ledtrig-oneshot.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/leds/trigger/ledtrig-oneshot.c b/drivers/leds/trigger/ledtrig-oneshot.c
> index bee3bd452abf..31061ec0afe6 100644
> --- a/drivers/leds/trigger/ledtrig-oneshot.c
> +++ b/drivers/leds/trigger/ledtrig-oneshot.c
> @@ -134,7 +134,7 @@ static void pattern_init(struct led_classdev *led_cdev)
> 
>  	pattern = led_get_default_pattern(led_cdev, &size);
>  	if (!pattern)
> -		goto out_default;
> +		goto out_settings;
> 
>  	if (size != 2) {
>  		dev_warn(led_cdev->dev,
> @@ -151,6 +151,7 @@ static void pattern_init(struct led_classdev *led_cdev)
> 
>  out_default:
>  	kfree(pattern);
> +out_settings:
>  	led_cdev->blink_delay_on = DEFAULT_DELAY;
>  	led_cdev->blink_delay_off = DEFAULT_DELAY;
>  }
> --
> 2.43.0
> 

-- 
Lee Jones [李琼斯]