[alsa-devel] [PATCH] ALSA: control: Fix breakage of user ctl element addition

[Takashi Sakamoto]

On Mar 13 2015 01:02, Takashi Iwai wrote:
> In the commit [2225e79b9b03: 'ALSA: core: reduce stack usage related
> to snd_ctl_new()'], the id field of the newly added kctl is untouched,
> thus all attribute like name string remain empty.  The fix is just to
> add the forgotten memcpy of the id field.
> 
> Fixes: 2225e79b9b03 ('ALSA: core: reduce stack usage related to snd_ctl_new()')
> Signed-off-by: Takashi Iwai <tiwai at suse.de>
> ---
>  sound/core/control.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/sound/core/control.c b/sound/core/control.c
> index 54a412af3224..d677c27746e9 100644
> --- a/sound/core/control.c
> +++ b/sound/core/control.c
> @@ -1267,6 +1267,7 @@ static int snd_ctl_elem_add(struct snd_ctl_file *file,
>  	err = snd_ctl_new(&kctl, count, access, file);
>  	if (err < 0)
>  		return err;
> +	memcpy(&kctl->id, &info->id, sizeof(kctl->id));
>  	kctl->private_data = kzalloc(sizeof(struct user_element) + private_size,
>  				     GFP_KERNEL);
>  	if (kctl->private_data == NULL) {

Oops, exactly... Thanks.

Reviewd-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>

I think the line can be simpler, like:

kctl->id = info->id;

But in both cases, assembler code may be the same due to compiler
optimization.


Takashi Sakamoto