Re: Potential NULL pointer reference in platform_device_register()

[Greg KH <gregkh@suse.de>]

On Thu, Dec 10, 2009 at 04:20:02PM +0800, Wu Zhangjin wrote:
> Hi, Greg KH,
> 
> Should we filter the potential NULL pointer in
> platform_device_register() like this?
> 
> drivers/base/platform.c:
> 
> int platform_device_register(struct platform_device *pdev)
> {
> +	 if (!pdev)
> +                return -EINVAL;

Why, who is calling this function with a NULL pointer?

> 
>         device_initialize(&pdev->dev);
>         return platform_device_add(pdev);
> }
> EXPORT_SYMBOL_GPL(platform_device_register);
> 
> Of course, the developers need to ensure they not register a NULL
> platform device, but sometimes they will not know that.

Why would you never know that?

> Perhaps the above method will hide the real bug, so, what about BUG_ON(!
> pdev).

That is what happens today anyway if you pass a NULL pointer in :)

thanks,

greg k-h