Re: [PATCH 20/22] pstore: %pF is only for function pointers

From: Anton Vorontsov
Date: Tue Jun 16 2015 - 18:37:17 EST


On Tue, Jun 16, 2015 at 03:02:50PM -0700, Kees Cook wrote:
> On Wed, Mar 11, 2015 at 8:13 PM, Scott Wood <scottwood@xxxxxxxxxxxxx> wrote:
> > Use %pS for actual addresses, otherwise you'll get bad output
> > on arches like ppc64 where %pF expects a function descriptor.
> >
> > Signed-off-by: Scott Wood <scottwood@xxxxxxxxxxxxx>
...
> > - seq_printf(s, "%d %08lx %08lx %pf <- %pF\n",
> > + seq_printf(s, "%d %08lx %08lx %ps <- %pS\n",
...
> Anton, does this look okay to you? (i.e. switching from function
> pointer to direct pointer?) vsprintf docs say:
> * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
> * function pointers are really function descriptors, which contain a
> * pointer to the real address.
>
> So this seems correct to me.
>
> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

Without questioning the confusing behaviour of "%pF", yes, sure... ack. :)

(However, intuitively I'd expect %pF to behave like %pS... but this surely not
going to change...)

Thanks!

Anton
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