On Fri, 07 Aug 2020 09:12:27 +0200, Dinghao Liu wrote:

When snd_usb_mixer_add_control() fails, elem needs to be freed just like when snd_ctl_new1() fails. However, current code is returning directly and ends up leaking memory.

No, this would lead to double-free. snd_ctl_add() shows a kind of special behavior, it already releases the object at its error path.

thanks,

Takashi

Fixes: 9e4d5c1be21f0 ("ALSA: usb-audio: Scarlett Gen 2 mixer interface") Signed-off-by: Dinghao Liu dinghao.liu@zju.edu.cn

---

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 74c00c905d24..4b2da0866cdc 100644 --- a/sound/usb/mixer_scarlett_gen2.c +++ b/sound/usb/mixer_scarlett_gen2.c @@ -964,8 +964,10 @@ static int scarlett2_add_new_ctl(struct usb_mixer_interface *mixer, strlcpy(kctl->id.name, name, sizeof(kctl->id.name));

err = snd_usb_mixer_add_control(&elem->head, kctl);

• if (err < 0)

• if (err < 0) {

• kfree(elem);
  

  return err;

• }

  if (kctl_return) *kctl_return = kctl;

-- 2.17.1