On Fri, Jul 21, 2023 at 06:00:15PM +0800, liulongfang wrote:
> On systems that use ECC memory. The ECC error of the memory will
> cause the USB controller to halt. It causes the usb_control_msg()
> operation to fail.
Why does ECC memory matter here?
> At this point, the returned buffer data is an abnormal value, and
> continuing to use it will lead to incorrect results.
>
> Therefore, it is necessary to judge the return value and exit.
>
> Signed-off-by: liulongfang <liulongfang@xxxxxxxxxx>
> ---
> drivers/usb/core/hub.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index a739403a9e45..6a43198be263 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -4891,6 +4891,16 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
> USB_DT_DEVICE << 8, 0,
> buf, GET_DESCRIPTOR_BUFSIZE,
> initial_descriptor_timeout);
> + /* On systems that use ECC memory, ECC errors can
> + * cause the USB controller to halt.
> + * It causes this operation to fail. At this time,
> + * the buf data is an abnormal value and needs to be exited.
> + */
> + if (r < 0) {
> + kfree(buf);
> + goto fail;
> + }
Are you sure this is correct? How was this tested? Seems to me that
this will still return "success" if this code path ever happens, what am
I missing?
thanks,
greg k-h
