Re: [PATCH] ALSA: scarlett2: Fix a potential memory leak in scarlett2_init_notify()

[Christophe JAILLET]

Le 03/09/2023 à 16:27, Takashi Iwai a écrit :
> On Sun, 03 Sep 2023 14:41:45 +0200,
> Christophe JAILLET wrote:
> > If kmalloc() fails, we should release 'mixer->urb'.
>
> This is released at the common error path in mixer.c,
> snd_usb_mixer_free(), hence it's not needed.

Agreed, sorry for the noise.

CJ

> And, even if freeing here, you must NULL-clear mixer->urb, too;
> otherwise it'll lead to double-free.
>
>
> thanks,
>
> Takashi
>
> > Fixes: 9e4d5c1be21f ("ALSA: usb-audio: Scarlett Gen 2 mixer interface")
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > ---
> >   sound/usb/mixer_scarlett_gen2.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/sound/usb/mixer_scarlett_gen2.c b/sound/usb/mixer_scarlett_gen2.c
> > index 9d11bb08667e..a439c7f64b2e 100644
> > --- a/sound/usb/mixer_scarlett_gen2.c
> > +++ b/sound/usb/mixer_scarlett_gen2.c
> > @@ -4060,8 +4060,10 @@ 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,
> > --
> > 2.34.1