Re: [PATCH 01/23] gpiolib: Correct wrong kfree() usage for `kobj->name`

[Tzung-Bi Shih <tzungbi@kernel.org>]

On Fri, Jan 16, 2026 at 01:15:17PM +0000, Bartosz Golaszewski wrote:
> On Fri, 16 Jan 2026 09:10:14 +0100, Tzung-Bi Shih <tzungbi@kernel.org> said:
> > `kobj->name` should be freed by kfree_const()[1][2].  Correct it.
> >
> > [1] https://elixir.bootlin.com/linux/v6.18/source/lib/kasprintf.c#L41
> > [2] https://elixir.bootlin.com/linux/v6.18/source/lib/kobject.c#L695
> >
> 
> Please don't add links third-party groks to git commit messages.
> 
> > Cc: stable@vger.kernel.org
> > Fixes: c351bb64cbe6 ("gpiolib: free device name on error path to fix kmemleak")
> > Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
> > ---
> >  drivers/gpio/gpiolib.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> > index 5eb918da7ea2..ba9323432e3a 100644
> > --- a/drivers/gpio/gpiolib.c
> > +++ b/drivers/gpio/gpiolib.c
> > @@ -1263,7 +1263,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
> >  err_free_descs:
> >  	kfree(gdev->descs);
> >  err_free_dev_name:
> > -	kfree(dev_name(&gdev->dev));
> > +	kfree_const(dev_name(&gdev->dev));
> >  err_free_ida:
> >  	ida_free(&gpio_ida, gdev->id);
> >  err_free_gdev:
> > --
> > 2.52.0.457.g6b5491de43-goog
> >
> >
> 
> I've never paid attention to this bit but it really looks broken. I understand
> that this string won't get freed until we initialize refcounting on the
> underlying kobject but reaching two abstraction layers below to get the string
> for freeing out of the kobject looks incorrect to me.
> 
> It's also one of only two instances of doing kfree(dev_name(dev)), the other
> one being in drivers/scsi/hosts.c.
> 
> It looks to me that the device name is not really used in

The device name is indeed used in gpiochip_add_data_with_key().  E.g.,
gpiochip_get_ngpios() -> dev_err().

> gpiochip_add_data_with_key(). Can we move dev_set_name() after
> device_initialize()?

Sounds a good idea.  I'll try to approach it in accompany with the
aggressive patch 03/23.