static int ucma_event_handler(struct rdma_cm_id *cm_id,
			      struct rdma_cm_event *event)
{
	struct ucma_event *uevent;
	struct ucma_context *ctx = cm_id->context;
	int ret = 0;

	uevent = kzalloc(sizeof(*uevent), GFP_KERNEL);
	if (!uevent)
		return event->event == RDMA_CM_EVENT_CONNECT_REQUEST;

	mutex_lock(&ctx->file->mut);
	uevent->cm_id = cm_id;
	ucma_set_event_context(ctx, event, uevent);
	uevent->resp.event = event->event;
	uevent->resp.status = event->status;
	if (cm_id->qp_type == IB_QPT_UD)
		ucma_copy_ud_event(cm_id->device, &uevent->resp.param.ud,
				   &event->param.ud);
	else
		ucma_copy_conn_event(&uevent->resp.param.conn,
				     &event->param.conn);

	if (event->event == RDMA_CM_EVENT_CONNECT_REQUEST) {
		if (!ctx->backlog) {
			ret = -ENOMEM;
			kfree(uevent);
			goto out;
		}
		ctx->backlog--;
	} else if (!ctx->uid || ctx->cm_id != cm_id) {
		/*
		 * We ignore events for new connections until userspace has set
		 * their context.  This can only happen if an error occurs on a
		 * new connection before the user accepts it.  This is okay,
		 * since the accept will just fail later. However, we do need
		 * to release the underlying HW resources in case of a device
		 * removal event.
		 */
		if (event->event == RDMA_CM_EVENT_DEVICE_REMOVAL)
			ucma_removal_event_handler(cm_id);

		kfree(uevent);
		goto out;
	}

	list_add_tail(&uevent->list, &ctx->file->event_list);
	wake_up_interruptible(&ctx->file->poll_wait);
	if (event->event == RDMA_CM_EVENT_DEVICE_REMOVAL)
		ucma_removal_event_handler(cm_id);
out:
	mutex_unlock(&ctx->file->mut);
	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 Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.