From mboxrd@z Thu Jan  1 00:00:00 1970
From: Greg KH <greg@kroah.com>
Date: Sat, 19 Sep 2009 22:40:04 +0000
Subject: Re: exported symbols
Message-Id: <20090919224004.GA9567@kroah.com>
List-Id: <kernel-janitors.vger.kernel.org>
References: <Pine.LNX.4.64.0909182336590.4238@ask.diku.dk>
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To: kernel-janitors@vger.kernel.org

On Fri, Sep 18, 2009 at 11:39:34PM +0200, Julia Lawall wrote:
> Functions that are exported using EXPORT_SYMBOL, and thus are presumably 
> freely available for use in dynamically loaded modules, do not seem to 
> very often check the validity of their inputs.  For a simple example, 
> the following code from arch/arm/mach-realview/clock.c does not even check 
> that clk is not NULL:
> 
>  unsigned long clk_get_rate(struct clk *clk)
>  {
>         return clk->rate;
>  }
>  EXPORT_SYMBOL(clk_get_rate);
> 
> Is this a problem?

No, as long as all callers are not passing NULL :)

Seriously, it's not an issue, putting error checking for everything
causes a lot of extra code for no reason, as we can easily audit all
callers of these symbols, it is not always necessary to check the
paramters.

thanks,

greg k-h