[alsa-devel] memory leak in mix/pcm_upmix.c mix/pcm_downmix.c!!!

[Takashi Iwai]

On Wed, 30 Aug 2017 07:51:59 +0200,
boozer asm wrote:
> 
> eg.
> in function:SND_PCM_PLUGIN_DEFINE_FUNC(upmix)
> 487     mix = calloc(1, sizeof(*mix));
> 488     if (mix == NULL)
> 489         return -ENOMEM;
> 
> mix is allocated here. but at close function, it is not freed, and no
> __destructor function available to free it.
> 
> and in alsa-lib/src/pcm/pcm_extplug.c
> static int snd_pcm_extplug_close(snd_pcm_t *pcm)
> {
>     extplug_priv_t *ext = pcm->private_data;
> 
>     snd_pcm_close(ext->plug.gen.slave);
>     clear_ext_params(ext);
>     if (ext->data->callback->close)
>     {
>         ext->data->callback->close(ext->data);
>     }
>     free(ext);
>     return 0;
> }
> this function does NOT free ext->data.
> and
> 366 static int upmix_close(snd_pcm_extplug_t *ext)
> 367 {
> 368     snd_pcm_upmix_t *mix = (snd_pcm_upmix_t *)ext;
> 369     free(mix->delayline[0]);
> 370     free(mix->delayline[1]);
> 371     return 0;
> 372 }
> 
> and this function does NOT free mix itself.
> 
> so I think there is memory leak.

It's freed in snd_pcm_extplug_close().
mix is identical with ext in the case of upmix.


Takashi