static int snd_seq_ioctl_running_mode(struct snd_seq_client *client, void  *arg)
{
	struct snd_seq_running_info *info = arg;
	struct snd_seq_client *cptr;
	int err = 0;

	/* requested client number */
	cptr = snd_seq_client_use_ptr(info->client);
	if (cptr == NULL)
		return -ENOENT;		/* don't change !!! */

#ifdef SNDRV_BIG_ENDIAN
	if (!info->big_endian) {
		err = -EINVAL;
		goto __err;
	}
#else
	if (info->big_endian) {
		err = -EINVAL;
		goto __err;
	}

#endif
	if (info->cpu_mode > sizeof(long)) {
		err = -EINVAL;
		goto __err;
	}
	cptr->convert32 = (info->cpu_mode < sizeof(long));
 __err:
	snd_seq_client_unlock(cptr);
	return err;
}

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.