static int __ffs_do_os_desc_header(enum ffs_os_desc_type *next_type,
				   struct usb_os_desc_header *desc)
{
	u16 bcd_version = le16_to_cpu(desc->bcdVersion);
	u16 w_index = le16_to_cpu(desc->wIndex);

	if (bcd_version != 1) {
		pr_vdebug("unsupported os descriptors version: %d",
			  bcd_version);
		return -EINVAL;
	}
	switch (w_index) {
	case 0x4:
		*next_type = FFS_OS_DESC_EXT_COMPAT;
		break;
	case 0x5:
		*next_type = FFS_OS_DESC_EXT_PROP;
		break;
	default:
		pr_vdebug("unsupported os descriptor type: %d", w_index);
		return -EINVAL;
	}

	return sizeof(*desc);
}

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.