int snd_pcm_add_chmap_ctls(struct snd_pcm *pcm, int stream,
			   const struct snd_pcm_chmap_elem *chmap,
			   int max_channels,
			   unsigned long private_value,
			   struct snd_pcm_chmap **info_ret)
{
	struct snd_pcm_chmap *info;
	struct snd_kcontrol_new knew = {
		.iface = SNDRV_CTL_ELEM_IFACE_PCM,
		.access = SNDRV_CTL_ELEM_ACCESS_READ |
			SNDRV_CTL_ELEM_ACCESS_TLV_READ |
			SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK,
		.info = pcm_chmap_ctl_info,
		.get = pcm_chmap_ctl_get,
		.tlv.c = pcm_chmap_ctl_tlv,
	};
	int err;

	info = kzalloc(sizeof(*info), GFP_KERNEL);
	if (!info)
		return -ENOMEM;
	info->pcm = pcm;
	info->stream = stream;
	info->chmap = chmap;
	info->max_channels = max_channels;
	if (stream == SNDRV_PCM_STREAM_PLAYBACK)
		knew.name = "Playback Channel Map";
	else
		knew.name = "Capture Channel Map";
	knew.device = pcm->device;
	knew.count = pcm->streams[stream].substream_count;
	knew.private_value = private_value;
	info->kctl = snd_ctl_new1(&knew, info);
	if (!info->kctl) {
		kfree(info);
		return -ENOMEM;
	}
	info->kctl->private_free = pcm_chmap_ctl_private_free;
	err = snd_ctl_add(pcm->card, info->kctl);
	if (err < 0)
		return err;
	pcm->streams[stream].chmap_kctl = info->kctl;
	if (info_ret)
		*info_ret = info;
	return 0;
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.