Re: exported symbols

[Greg KH <greg@kroah.com>]

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