Re: [PATCH] ALSA: scarlett2: Prevent leaking urb

[Takashi Iwai <tiwai@xxxxxxx>]

On Tue, 21 May 2024 03:03:52 +0200,
Chen Ni wrote:
> 
> In scarlett2_init_notify() if kmalloc() fails the allocated urb should
> be released.

It's freed in the common USB mixer destructor (snd_usb_mixer_free()),
hence your patch will lead to a double-free.


thanks,

Takashi

> 
> Signed-off-by: Chen Ni <nichen@xxxxxxxxxxx>
> ---
>  sound/usb/mixer_scarlett2.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/usb/mixer_scarlett2.c b/sound/usb/mixer_scarlett2.c
> index 1150cf104985..4cad6b2a0292 100644
> --- a/sound/usb/mixer_scarlett2.c
> +++ b/sound/usb/mixer_scarlett2.c
> @@ -8637,9 +8637,10 @@ static int scarlett2_init_notify(struct usb_mixer_interface *mixer)
>  		return -ENOMEM;
>  
>  	transfer_buffer = kmalloc(private->wMaxPacketSize, GFP_KERNEL);
> -	if (!transfer_buffer)
> +	if (!transfer_buffer) {
> +		usb_free_urb(mixer->urb);
>  		return -ENOMEM;
> -
> +	}
>  	usb_fill_int_urb(mixer->urb, dev, pipe,
>  			 transfer_buffer, private->wMaxPacketSize,
>  			 scarlett2_notify, mixer, private->bInterval);
> -- 
> 2.25.1
> 
>