Re: [PATCH] ALSA: usb-audio: Fix a potential memory leak in scarlett2_init_notify()

[Takashi Iwai <tiwai@suse.de>]

On Sun, 03 Sep 2023 15:06:00 +0200,
Christophe JAILLET wrote:
> 
> If usb_alloc_coherent() or usb_urb_ep_type_check() fail, we should release
> the resources previously allocated.

Those are freed in the caller side, start_input_streams() instead.


thanks,

Takashi

> 
> Fixes: ff49d1df79ae ("ALSA: usb-audio: USB MIDI 2.0 UMP support")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
>  sound/usb/midi2.c | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/sound/usb/midi2.c b/sound/usb/midi2.c
> index a27e244650c8..4109c82adff6 100644
> --- a/sound/usb/midi2.c
> +++ b/sound/usb/midi2.c
> @@ -302,7 +302,8 @@ static int alloc_midi_urbs(struct snd_usb_midi2_endpoint *ep)
>  		ctx->urb = usb_alloc_urb(0, GFP_KERNEL);
>  		if (!ctx->urb) {
>  			dev_err(&ep->dev->dev, "URB alloc failed\n");
> -			return -ENOMEM;
> +			err = -ENOMEM;
> +			goto err_free_all;
>  		}
>  		ctx->ep = ep;
>  		buffer = usb_alloc_coherent(ep->dev, len, GFP_KERNEL,
> @@ -310,7 +311,8 @@ static int alloc_midi_urbs(struct snd_usb_midi2_endpoint *ep)
>  		if (!buffer) {
>  			dev_err(&ep->dev->dev,
>  				"URB buffer alloc failed (size %d)\n", len);
> -			return -ENOMEM;
> +			err = -ENOMEM;
> +			goto err_free_cur_urb;
>  		}
>  		if (ep->interval)
>  			usb_fill_int_urb(ctx->urb, ep->dev, ep->pipe,
> @@ -322,13 +324,22 @@ static int alloc_midi_urbs(struct snd_usb_midi2_endpoint *ep)
>  		if (err < 0) {
>  			dev_err(&ep->dev->dev, "invalid MIDI EP %x\n",
>  				endpoint);
> -			return err;
> +			goto err_free_cur_dma;
>  		}
>  		ctx->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
>  		ep->num_urbs++;
>  	}
>  	ep->urb_free = ep->urb_free_mask = GENMASK(ep->num_urbs - 1, 0);
>  	return 0;
> +
> +err_free_cur_dma:
> +	usb_free_coherent(ep->dev, len, buffer, ctx->urb->transfer_dma);
> +err_free_cur_urb:
> +	usb_free_urb(ctx->urb);
> +	ctx->urb = NULL;
> +err_free_all:
> +	free_midi_urbs(ep);
> +	return err;
>  }
>  
>  static struct snd_usb_midi2_endpoint *
> -- 
> 2.34.1
>