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Date:   Wed, 27 Jul 2022 16:39:56 +0800
From:   Peter Chen <peter.chen@kernel.org>
To:     Andrey Strachuk <strochuk@ispras.ru>
Cc:     Pawel Laszczak <pawell@cadence.com>,
        Roger Quadros <rogerq@kernel.org>,
        Aswath Govindraju <a-govindraju@ti.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        ldv-project@linuxtesting.org
Subject: Re: [PATCH v2] usb: cdns3: change place of 'priv_ep' assignment in
 cdns3_gadget_ep_dequeue(), cdns3_gadget_ep_enable()
Message-ID: <20220727083956.GA269370@nchen-desktop>
References: <20220718160052.4188-1-strochuk@ispras.ru>
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In-Reply-To: <20220718160052.4188-1-strochuk@ispras.ru>
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On 22-07-18 19:00:52, Andrey Strachuk wrote:
> If 'ep' is NULL, result of ep_to_cdns3_ep(ep) is invalid pointer
> and its dereference with priv_ep->cdns3_dev may cause panic.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Signed-off-by: Andrey Strachuk <strochuk@ispras.ru>
> Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
> ---
>  drivers/usb/cdns3/cdns3-gadget.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
> index 5c15c48952a6..aea5db0ec72d 100644
> --- a/drivers/usb/cdns3/cdns3-gadget.c
> +++ b/drivers/usb/cdns3/cdns3-gadget.c
> @@ -2285,13 +2285,14 @@ static int cdns3_gadget_ep_enable(struct usb_ep *ep,
>  	int val;
> 
>  	priv_ep = ep_to_cdns3_ep(ep);
> -	priv_dev = priv_ep->cdns3_dev;
> -	comp_desc = priv_ep->endpoint.comp_desc;
>  
>  	if (!ep || !desc || desc->bDescriptorType != USB_DT_ENDPOINT) {
>  		dev_dbg(priv_dev->dev, "usbss: invalid parameters\n");
>  		return -EINVAL;
>  	}
> +
> +	comp_desc = priv_ep->endpoint.comp_desc;
> +	priv_dev = priv_ep->cdns3_dev;
> 
>  	if (!desc->wMaxPacketSize) {
>  		dev_err(priv_dev->dev, "usbss: missing wMaxPacketSize\n");
> @@ -2600,7 +2601,7 @@ int cdns3_gadget_ep_dequeue(struct usb_ep *ep,
>  			    struct usb_request *request)
>  {
>  	struct cdns3_endpoint *priv_ep = ep_to_cdns3_ep(ep);
> -	struct cdns3_device *priv_dev = priv_ep->cdns3_dev;
> +	struct cdns3_device *priv_dev;
>  	struct usb_request *req, *req_temp;
>  	struct cdns3_request *priv_req;
>  	struct cdns3_trb *link_trb;
> @@ -2610,6 +2611,8 @@ int cdns3_gadget_ep_dequeue(struct usb_ep *ep,
>  
>  	if (!ep || !request || !ep->desc)
>  		return -EINVAL;
> +
> +	priv_dev = priv_ep->cdns3_dev;
> 
>  	spin_lock_irqsave(&priv_dev->lock, flags);
> 
> -- 

Acked-by: Peter Chen <peter.chen@kernel.org>

-- 

Thanks,
Peter Chen