Re: [PATCH] Input: Fix a ref counting issue

[Christophe JAILLET]

Le 29/11/2020 à 20:49, Dmitry Torokhov a écrit :
> Hi Christophe,
>
> On Sun, Nov 29, 2020 at 09:45:16AM +0100, Christophe JAILLET wrote:
> > In case of a managed resource, 'devm_input_device_release()' already has a
> > 'input_put_device(dev)' call.
> >
> > Avoid a double reference decrement by explicitly calling
> > 'input_put_device()' only on non-managed input device.
> This patch is incorrect, as devres_destroy() that is used in
> input_free_device(), unlike devres_releasde(), does not actually call
> the "release" function. It simply destroys the devres object, but does
> not clear associated resources.

Crystal clear.
Thanks for the explanation and sorry for the noise.

CJ

> > Fixes: 2be975c6d920 ("Input: introduce managed input devices (add devres support)")
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > ---
> > This patch is completely speculative and compile tested only.
> > ---
> >   drivers/input/input.c | 3 ++-
> >   1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/input/input.c b/drivers/input/input.c
> > index 3cfd2c18eebd..c09c9f020667 100644
> > --- a/drivers/input/input.c
> > +++ b/drivers/input/input.c
> > @@ -1920,7 +1920,8 @@ void input_free_device(struct input_dev *dev)
> >   						devm_input_device_release,
> >   						devm_input_device_match,
> >   						dev));
> > -		input_put_device(dev);
> > +		else
> > +			input_put_device(dev);
> >   	}
> >   }
> >   EXPORT_SYMBOL(input_free_device);
> > --
> > 2.27.0
> Thanks.