linux-kernel - Re: [PATCH] gpio: sim: fix a memory leak

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Date:   Thu, 16 Feb 2023 16:42:20 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Bartosz Golaszewski <brgl@...ev.pl>
Cc:     Kent Gibson <warthog618@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Mirsad Goran Todorovac <mirsad.todorovac@....unizg.hr>
Subject: Re: [PATCH] gpio: sim: fix a memory leak

On Thu, Feb 16, 2023 at 03:15:55PM +0100, Bartosz Golaszewski wrote:
> Fix an inverted logic bug in gpio_sim_remove_hogs() that leads to GPIO
> hog structures never being freed.

Ha-ha, I stared to this code, and in the head I was "okay, this loop is until
chip_label is *not* NULL, so should be fine".

At the same time, "! is hard to process", see for example
2754435d4c82 ("ACPI / battery: get rid of negations in conditions")
which I had suggested.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

P.S. But my patch I mentioned looks also good to have, no?

> Fixes: cb8c474e79be ("gpio: sim: new testing module")
> Reported-by: Mirsad Goran Todorovac <mirsad.todorovac@....unizg.hr>
> Signed-off-by: Bartosz Golaszewski <brgl@...ev.pl>
> ---
>  drivers/gpio/gpio-sim.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
> index 60514bc5454f..9e3893b19e4f 100644
> --- a/drivers/gpio/gpio-sim.c
> +++ b/drivers/gpio/gpio-sim.c
> @@ -736,7 +736,7 @@ static void gpio_sim_remove_hogs(struct gpio_sim_device *dev)
>  
>  	gpiod_remove_hogs(dev->hogs);
>  
> -	for (hog = dev->hogs; !hog->chip_label; hog++) {
> +	for (hog = dev->hogs; hog->chip_label; hog++) {
>  		kfree(hog->chip_label);
>  		kfree(hog->line_name);
>  	}
> -- 
> 2.37.2
> 

-- 
With Best Regards,
Andy Shevchenko