Re: [PATCH] usbip: vudc: check for NULL before use

From: Shuah Khan <shuah@kernel.org>
To: Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
	Valentina Manea <valentina.manea.m@gmail.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
	Shuah Khan <shuahkh@osg.samsung.com>,
	Shuah Khan <shuah@kernel.org>
Subject: Re: [PATCH] usbip: vudc: check for NULL before use
Date: Tue, 20 Dec 2016 07:31:44 -0700	[thread overview]
Message-ID: <f21975fa-1a59-29cc-843d-550866d55345@kernel.org> (raw)
In-Reply-To: <1482101091-3969-1-git-send-email-sudipm.mukherjee@gmail.com>

On 12/18/2016 03:44 PM, Sudip Mukherjee wrote:
> to_vep() is doing a container_of() on _ep. It is better to do the NULL
> check first and then use it.
> 
> Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
> ---
>  drivers/usb/usbip/vudc_dev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/usbip/vudc_dev.c b/drivers/usb/usbip/vudc_dev.c
> index 968471b..32ea604 100644
> --- a/drivers/usb/usbip/vudc_dev.c
> +++ b/drivers/usb/usbip/vudc_dev.c
> @@ -388,10 +388,10 @@ static int vep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
>  	unsigned long flags;
>  	int ret = 0;
>  
> -	ep = to_vep(_ep);
>  	if (!_ep)
>  		return -EINVAL;

Hmm. Linus's latest checks _ep and _req. Are you sure you are working
with the latest tree?

>  
> +	ep = to_vep(_ep);
>  	udc = ep_to_vudc(ep);
>  	if (!udc->driver)
>  		return -ESHUTDOWN;
>

thanks,
-- Shuah