linux-kernel - Re: [PATCH] gpio: fix memory leak in gpiod_request

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Message-ID: <CAMRc=MffACd5XyGVv4DQO9AhbeYiVhougS8_SJ23xHd-jpfF2g@mail.gmail.com>
Date: Mon, 19 Feb 2024 08:44:04 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Xiaolei Wang <xiaolei.wang@...driver.com>, Linus Walleij <linus.walleij@...aro.org>
Cc: linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH] gpio: fix memory leak in gpiod_request_commit()

On Sun, Feb 18, 2024 at 6:49 PM Bartosz Golaszewski <brgl@...ev.pl> wrote:
>
> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
>
> We now copy the label string directly in desc_set_label() so it must not
> be done a second time in gpiod_request_commit().
>
> Fixes: 1f2bcb8c8ccd ("gpio: protect the descriptor label with SRCU")
> Reported-by: Xiaolei Wang <xiaolei.wang@...driver.com>
> Closes: https://lore.kernel.org/all/20240217135255.1128716-1-xiaolei.wang@windriver.com/T/
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> ---
>  drivers/gpio/gpiolib.c | 6 ------
>  1 file changed, 6 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index e4dd13d81b4d..3c22920bd201 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -2250,12 +2250,6 @@ static int gpiod_request_commit(struct gpio_desc *desc, const char *label)
>         if (test_and_set_bit(FLAG_REQUESTED, &desc->flags))
>                 return -EBUSY;
>
> -       if (label) {
> -               label = kstrdup_const(label, GFP_KERNEL);
> -               if (!label)
> -                       return -ENOMEM;
> -       }
> -
>         /* NOTE:  gpio_request() can be called in early boot,
>          * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
>          */
> --
> 2.40.1
>

I should probably stop coding while sleep-deprived and in the evening,
I realized now I sent the exact same fix as you. I thought this was
removing the allocation from desc_set_label() and not
gpiod_request_commit().

I'll go ahead and apply your patch and you can disregard this thread.

Thanks!
Bartosz