[PATCH] usb: mtu3: Fix possible use-before-initialization bug

[Chunfeng Yun (云春峰)]

On Sun, 2023-07-09 at 17:48 -0700, Yu Hao wrote:
>  	 
> External email : Please do not click links or open attachments until
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>  Hi Hervé,
> 
> Thanks for the comments. How about this patch?
> ---
>  drivers/usb/mtu3/mtu3_gadget_ep0.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/mtu3/mtu3_gadget_ep0.c
> b/drivers/usb/mtu3/mtu3_gadget_ep0.c
> index e4fd1bb14a55..af2884943c2a 100644
> --- a/drivers/usb/mtu3/mtu3_gadget_ep0.c
> +++ b/drivers/usb/mtu3/mtu3_gadget_ep0.c
> @@ -600,7 +600,7 @@ static void ep0_tx_state(struct mtu3 *mtu)
>         mtu3_readl(mtu->mac_base, U3D_EP0CSR));
>  }
> 
> -static void ep0_read_setup(struct mtu3 *mtu, struct usb_ctrlrequest
> *setup)
> +static int ep0_read_setup(struct mtu3 *mtu, struct usb_ctrlrequest
> *setup)
>  {
>     struct mtu3_request *mreq;
>     u32 count;
> @@ -608,6 +608,8 @@ static void ep0_read_setup(struct mtu3 *mtu,
> struct usb_ctrlrequest *setup)
> 
>     csr = mtu3_readl(mtu->mac_base, U3D_EP0CSR) & EP0_W1C_BITS;
>     count = mtu3_readl(mtu->mac_base, U3D_RXCOUNT0);
> +   if (count == 0)
> +       return -EINVAL;
> 
Which SoC encounter this issue?

if there is no data in fifo, no interrupt will arise, so don't read
setup packet.


>     ep0_read_fifo(mtu->ep0, (u8 *)setup, count);
> 
> @@ -642,7 +644,8 @@ __acquires(mtu->lock)
>     struct mtu3_request *mreq;
>     int handled = 0;
> 
> -   ep0_read_setup(mtu, &setup);
> +   if (ep0_read_setup(mtu, &setup))
> +       return -EINVAL;
>     trace_mtu3_handle_setup(&setup);
> 
>     if ((setup.bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD)
> @@ -764,7 +767,9 @@ irqreturn_t mtu3_ep0_isr(struct mtu3 *mtu)
>             break;
>         }
> 
> -       ep0_handle_setup(mtu);
> +       if (ep0_handle_setup(mtu))
> +           break;
> +
>         ret = IRQ_HANDLED;
>         break;
>     default: