linux-kernel - Re: [PATCH v6 2/3] leds: lp8860: Check return value of devm_mutex

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Message-ID: <1983260a-4362-44ca-af1a-0e20d2fee6db@ti.com>
Date: Mon, 9 Jun 2025 16:11:49 -0500
From: Andrew Davis <afd@...com>
To: Thomas Weißschuh <linux@...ssschuh.net>,
        Peter Zijlstra
	<peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
        Waiman Long
	<longman@...hat.com>, Boqun Feng <boqun.feng@...il.com>,
        Vicentiu Galanopulo
	<vicentiu.galanopulo@...ote-tech.co.uk>,
        Will Deacon <will@...nel.org>, Han
 Xu <han.xu@....com>,
        Haibo Chen <haibo.chen@....com>,
        Yogesh Gaur
	<yogeshgaur.83@...il.com>,
        Mark Brown <broonie@...nel.org>, Lee Jones
	<lee@...nel.org>,
        Pavel Machek <pavel@...nel.org>
CC: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        <linux-kernel@...r.kernel.org>, Bartosz Golaszewski <brgl@...ev.pl>,
        Bartosz
 Golaszewski <bartosz.golaszewski@...aro.org>,
        <linux-spi@...r.kernel.org>, <imx@...ts.linux.dev>,
        <linux-leds@...r.kernel.org>
Subject: Re: [PATCH v6 2/3] leds: lp8860: Check return value of
 devm_mutex_init()

On 6/9/25 3:38 PM, Thomas Weißschuh wrote:
> Even if it's not critical, the avoidance of checking the error code
> from devm_mutex_init() call today diminishes the point of using devm
> variant of it. Tomorrow it may even leak something.
> 
> Add the missed check.
> 
> Fixes: 87a59548af95 ("leds: lp8860: Use new mutex guards to cleanup function exits")
> Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
> ---
>   drivers/leds/leds-lp8860.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/leds/leds-lp8860.c b/drivers/leds/leds-lp8860.c
> index 52b97c9f2a03567aa12d4f63a951593a5e7017d5..0962c00c215a11f555a7878a3b65824b5219a1fa 100644
> --- a/drivers/leds/leds-lp8860.c
> +++ b/drivers/leds/leds-lp8860.c
> @@ -307,7 +307,9 @@ static int lp8860_probe(struct i2c_client *client)
>   	led->client = client;
>   	led->led_dev.brightness_set_blocking = lp8860_brightness_set;
>   
> -	devm_mutex_init(&client->dev, &led->lock);
> +	ret = devm_mutex_init(&client->dev, &led->lock);
> +	if (ret)
> +		return dev_err_probe(&client->dev, ret, "Failed to initialize lock\n");

I don't think the lock initialization can actually fail, if anything ever breaks
it will be the devm allocation, which is a ENOMEM situation, so probably not worth
printing anything. Either way is fine for __must_check sake so,

Acked-by: Andrew Davis <afd@...com>

>   
>   	led->regmap = devm_regmap_init_i2c(client, &lp8860_regmap_config);
>   	if (IS_ERR(led->regmap)) {
>