Re: [PATCH] ref_tracker: use %ld format specifier for PTR_ERR() during directory creation failure

[Qasim Ijaz <qasdev00@gmail.com>]

On Sat, Apr 12, 2025 at 08:32:45PM -0500, Nathan Chancellor wrote:
> Hi Qasim,
> 
> On Sat, Apr 12, 2025 at 11:27:44PM +0100, Qasim Ijaz wrote:
> > PTR_ERR yields type long, so use %ld format specifier in pr_warn.
> > 
> > Fixes: ada5a12aae58 ("ref_tracker: add a top level debugfs directory for ref_tracker")
> > Reported-by: kernel test robot <lkp@intel.com>
> > Closes: https://lore.kernel.org/oe-kbuild-all/202504130520.rX5EVbVq-lkp@intel.com/ 
> > Signed-off-by: Qasim Ijaz <qasdev00@gmail.com> 
> > ---
> >  lib/ref_tracker.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/lib/ref_tracker.c b/lib/ref_tracker.c
> > index 4064154252a6..02e9f0c3dd82 100644
> > --- a/lib/ref_tracker.c
> > +++ b/lib/ref_tracker.c
> > @@ -283,7 +283,7 @@ static int __init ref_tracker_debug_init(void)
> >  {
> >  	ref_tracker_debug_dir = debugfs_create_dir("ref_tracker", NULL);
> >  	if (IS_ERR(ref_tracker_debug_dir)) {
> > -		pr_warn("ref_tracker: unable to create ref_tracker debugfs directory: %d\n",
> > +		pr_warn("ref_tracker: unable to create ref_tracker debugfs directory: %ld\n",
> 
> While there is nothing wrong with doing this to resolve the warning, I
> think this would be a good opportunity to use the '%pe' format specifier
> [1] instead of '%ld', as that will print the symbolic error name (such
> as -EINVAL instead of just -22) and make it easier for people to
> decipher what has gone wrong.
> 
Hi Nathan,

Thanks for the suggestion, I think this would be an improvement over
using %ld.

Would you like me to include you in a suggested-by tag in patch v2?

Regards,
Qasim
>   pr_warn("ref_tracker: unable to create ref_tracker debugfs directory: %pe\n",
>           ref_tracker_debug_dir);
> 
> [1]: From the "error pointers" section in Documentation/core-api/printk-formats.rst
> 
> Cheers,
> Nathan
> 
> >  			PTR_ERR(ref_tracker_debug_dir));
> >  		ref_tracker_debug_dir = NULL;
> >  	}
> > -- 
> > 2.39.5
> > 
> >