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

[boozer asm]

Hi  Takashi,

i think mix is same as ext->data instead ext. ext is of extplug_priv_t *;
so it is definitely not mix which is of snd_pcm_upmix_t

 33 struct snd_pcm_upmix {
 34     snd_pcm_extplug_t ext;

typedef struct snd_pcm_extplug_priv {
    snd_pcm_plugin_t plug;
    snd_pcm_extplug_t *data;
between upmix and extplug_priv, there is a gap plug, which forbid ext to be
converted to mix directly.
so free(ext) in snd_pcm_extplug_close does NOT promise it will free mix too.

2017-08-30 15:02 GMT+08:00 Takashi Iwai <tiwai at suse.de>:

> 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
>