linux-kernel - Re: [Patch v8 2/6] leds: ledtrig-tty: free allocated ttyname buffer on deactivate

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Message-ID: <2023112356-amount-undertook-cdb2@gregkh>
Date:   Thu, 23 Nov 2023 14:06:28 +0000
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Florian Eckert <fe@....tdt.de>
Cc:     Eckert.Florian@...glemail.com, jirislaby@...nel.org, pavel@....cz,
        lee@...nel.org, kabel@...nel.org, u.kleine-koenig@...gutronix.de,
        m.brock@...mierlo.com, linux-kernel@...r.kernel.org,
        linux-serial@...r.kernel.org, linux-leds@...r.kernel.org
Subject: Re: [Patch v8 2/6] leds: ledtrig-tty: free allocated ttyname buffer
 on deactivate

On Thu, Nov 09, 2023 at 09:50:34AM +0100, Florian Eckert wrote:
> The ttyname buffer for the ledtrig_tty_data struct is allocated in the
> sysfs ttyname_store() function. This buffer must be released on trigger
> deactivation. This was missing and is thus a memory leak.
> 
> While we are at it, the tty handler in the ledtrig_tty_data struct should
> also be returned in case of the trigger deactivation call.
> 
> Fixes: fd4a641ac88f ("leds: trigger: implement a tty trigger")
> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
> Signed-off-by: Florian Eckert <fe@....tdt.de>
> ---
>  drivers/leds/trigger/ledtrig-tty.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/leds/trigger/ledtrig-tty.c b/drivers/leds/trigger/ledtrig-tty.c
> index 8ae0d2d284af..3e69a7bde928 100644
> --- a/drivers/leds/trigger/ledtrig-tty.c
> +++ b/drivers/leds/trigger/ledtrig-tty.c
> @@ -168,6 +168,10 @@ static void ledtrig_tty_deactivate(struct led_classdev *led_cdev)
>  
>  	cancel_delayed_work_sync(&trigger_data->dwork);
>  
> +	kfree(trigger_data->ttyname);
> +	tty_kref_put(trigger_data->tty);
> +	trigger_data->tty = NULL;
> +

This should be a stand-alone patch with a proper cc: stable tag added as
well so that it can be accepted now, as it is independent of this new
feature you are adding.

thanks,

greg k-h