static int ffs_func_eps_enable(struct ffs_function *func)
{
	struct ffs_data *ffs      = func->ffs;
	struct ffs_ep *ep         = func->eps;
	struct ffs_epfile *epfile = ffs->epfiles;
	unsigned count            = ffs->eps_count;
	unsigned long flags;
	int ret = 0;

	spin_lock_irqsave(&func->ffs->eps_lock, flags);
	do {
		struct usb_endpoint_descriptor *ds;
		int desc_idx;

		if (ffs->gadget->speed == USB_SPEED_SUPER)
			desc_idx = 2;
		else if (ffs->gadget->speed == USB_SPEED_HIGH)
			desc_idx = 1;
		else
			desc_idx = 0;

		/* fall-back to lower speed if desc missing for current speed */
		do {
			ds = ep->descs[desc_idx];
		} while (!ds && --desc_idx >= 0);

		if (!ds) {
			ret = -EINVAL;
			break;
		}

		ep->ep->driver_data = ep;
		ep->ep->desc = ds;
		ret = usb_ep_enable(ep->ep);
		if (likely(!ret)) {
			epfile->ep = ep;
			epfile->in = usb_endpoint_dir_in(ds);
			epfile->isoc = usb_endpoint_xfer_isoc(ds);
		} else {
			break;
		}

		wake_up(&epfile->wait);

		++ep;
		++epfile;
	} while (--count);
	spin_unlock_irqrestore(&func->ffs->eps_lock, flags);

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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.