static int __ffs_data_got_descs(struct ffs_data *ffs,
				char *const _data, size_t len)
{
	char *data = _data, *raw_descs;
	unsigned os_descs_count = 0, counts[3], flags;
	int ret = -EINVAL, i;
	struct ffs_desc_helper helper;

	ENTER();

	if (get_unaligned_le32(data + 4) != len)
		goto error;

	switch (get_unaligned_le32(data)) {
	case FUNCTIONFS_DESCRIPTORS_MAGIC:
		flags = FUNCTIONFS_HAS_FS_DESC | FUNCTIONFS_HAS_HS_DESC;
		data += 8;
		len  -= 8;
		break;
	case FUNCTIONFS_DESCRIPTORS_MAGIC_V2:
		flags = get_unaligned_le32(data + 8);
		ffs->user_flags = flags;
		if (flags & ~(FUNCTIONFS_HAS_FS_DESC |
			      FUNCTIONFS_HAS_HS_DESC |
			      FUNCTIONFS_HAS_SS_DESC |
			      FUNCTIONFS_HAS_MS_OS_DESC |
			      FUNCTIONFS_VIRTUAL_ADDR |
			      FUNCTIONFS_EVENTFD)) {
			ret = -ENOSYS;
			goto error;
		}
		data += 12;
		len  -= 12;
		break;
	default:
		goto error;
	}

	if (flags & FUNCTIONFS_EVENTFD) {
		if (len < 4)
			goto error;
		ffs->ffs_eventfd =
			eventfd_ctx_fdget((int)get_unaligned_le32(data));
		if (IS_ERR(ffs->ffs_eventfd)) {
			ret = PTR_ERR(ffs->ffs_eventfd);
			ffs->ffs_eventfd = NULL;
			goto error;
		}
		data += 4;
		len  -= 4;
	}

	/* Read fs_count, hs_count and ss_count (if present) */
	for (i = 0; i < 3; ++i) {
		if (!(flags & (1 << i))) {
			counts[i] = 0;
		} else if (len < 4) {
			goto error;
		} else {
			counts[i] = get_unaligned_le32(data);
			data += 4;
			len  -= 4;
		}
	}
	if (flags & (1 << i)) {
		os_descs_count = get_unaligned_le32(data);
		data += 4;
		len -= 4;
	};

	/* Read descriptors */
	raw_descs = data;
	helper.ffs = ffs;
	for (i = 0; i < 3; ++i) {
		if (!counts[i])
			continue;
		helper.interfaces_count = 0;
		helper.eps_count = 0;
		ret = ffs_do_descs(counts[i], data, len,
				   __ffs_data_do_entity, &helper);
		if (ret < 0)
			goto error;
		if (!ffs->eps_count && !ffs->interfaces_count) {
			ffs->eps_count = helper.eps_count;
			ffs->interfaces_count = helper.interfaces_count;
		} else {
			if (ffs->eps_count != helper.eps_count) {
				ret = -EINVAL;
				goto error;
			}
			if (ffs->interfaces_count != helper.interfaces_count) {
				ret = -EINVAL;
				goto error;
			}
		}
		data += ret;
		len  -= ret;
	}
	if (os_descs_count) {
		ret = ffs_do_os_descs(os_descs_count, data, len,
				      __ffs_data_do_os_desc, ffs);
		if (ret < 0)
			goto error;
		data += ret;
		len -= ret;
	}

	if (raw_descs == data || len) {
		ret = -EINVAL;
		goto error;
	}

	ffs->raw_descs_data	= _data;
	ffs->raw_descs		= raw_descs;
	ffs->raw_descs_length	= data - raw_descs;
	ffs->fs_descs_count	= counts[0];
	ffs->hs_descs_count	= counts[1];
	ffs->ss_descs_count	= counts[2];
	ffs->ms_os_descs_count	= os_descs_count;

	return 0;

error:
	kfree(_data);
	return ret;
}

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.