Subject: Re: [PATCH 3/4] DRBG: Fix format string for debugging statements

From: Dan Carpenter <[email-masked]>
Date: Fri, 4 Jul 2014 14:21:16 +0300

On Sat, Jun 28, 2014 at 08:53:19PM -0700, Joe Perches wrote:
> On Sun, 2014-06-29 at 05:46 +0200, Stephan Mueller wrote:
> > Am Sonntag, 29. Juni 2014, 12:24:02 schrieb Stephen Rothwell:
> > 
> > Hi Stephen,
> > 
> > > Hi Stephan,
> > > 
> > > On Sat, 28 Jun 2014 22:01:46 +0200 Stephan Mueller <[email-masked]> 
> > wrote:
> > > > @@ -1987,8 +1987,9 @@ static int __init drbg_init(void)
> > > > 
> > > >  	if (ARRAY_SIZE(drbg_cores) * 2 > ARRAY_SIZE(drbg_algs)) {
> > > >  	
> > > >  		pr_info("DRBG: Cannot register all DRBG types"
> > > > 
> > > > -			"(slots needed: %lu, slots available: %lu)\n",
> > > > -			ARRAY_SIZE(drbg_cores) * 2, ARRAY_SIZE(drbg_algs));
> > > > +			"(slots needed: %u, slots available: %u)\n",
> > > > +			(unsigned int)ARRAY_SIZE(drbg_cores) * 2,
> > > > +			(unsigned int)ARRAY_SIZE(drbg_algs));
> > > 
> > > Doesn't ARRAY_SIZE() always return a size_t?  In which case surely we
> > > need no casts, but need to us %zu in the format string.
> > 
> > Unfortunately not at all. On my x86_64, I get the compiler warning that 
> > ARRAY_SIZE is a long unsigned int without the cast.
> 
> This should fix that.
> ---
>  include/linux/kernel.h | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 6e3d497..58bc57d 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -51,7 +51,8 @@
>  #define PTR_ALIGN(p, a)		((typeof(p))ALIGN((unsigned long)(p), (a)))
>  #define IS_ALIGNED(x, a)		(((x) & ((typeof(x))(a) - 1)) == 0)
>  
> -#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
> +#define ARRAY_SIZE(arr)						\
> +	(sizeof(arr) / sizeof((arr)[0]) + (size_t)__must_be_array(arr))

This change is a no-op isn't it?  I think Stephen Rothwell's suggestion
is correct.  In linux-next this was changed to %lu which also works...

Are there arches %zu and %lu are different?

regards,
dan carpenter