Received-SPF: pass (google.com: domain of linux-kernel+bounces-73080-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) client-ip=147.75.199.223;
Precedence: bulk
MIME-Version: 1.0
References: <20240217150228.5788-2-johan+linaro@kernel.org>
 <c95f5ff3-8dad-4302-9384-92a9b83f7bdc@web.de> <ZdRTx2lmHBVlcLub@hovoldconsulting.com>
 <1afc87c-2c1f-df10-a0c8-2a267d44122@inria.fr> <CAA8EJppH9ey97yKFUccNLHhMKs3eUS55+rY0tXm_a6KGp9jtug@mail.gmail.com>
 <4938592e-3f7c-c1ae-dce3-fd1ca363296@inria.fr>
In-Reply-To: <4938592e-3f7c-c1ae-dce3-fd1ca363296@inria.fr>
From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date: Tue, 20 Feb 2024 15:35:35 +0200
Message-ID: <CAA8EJpq88ZKLFBuAvDuDSMD_DkPpMmBDZG_kQyUrSs-Noqm2SQ@mail.gmail.com>
Subject: Re: [PATCH 1/6] drm/bridge: aux-hpd: fix OF node leaks
To: Julia Lawall <julia.lawall@inria.fr>
Cc: Johan Hovold <johan@kernel.org>, Markus Elfring <Markus.Elfring@web.de>, 
	Johan Hovold <johan+linaro@kernel.org>, freedreno@lists.freedesktop.org, 
	dri-devel@lists.freedesktop.org, linux-phy@lists.infradead.org, 
	linux-arm-msm@vger.kernel.org, kernel-janitors@vger.kernel.org, 
	Andrzej Hajda <andrzej.hajda@intel.com>, Bjorn Andersson <andersson@kernel.org>, 
	Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@gmail.com>, 
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>, Maxime Ripard <mripard@kernel.org>, 
	Neil Armstrong <neil.armstrong@linaro.org>, Robert Foss <rfoss@kernel.org>, 
	Thomas Zimmermann <tzimmermann@suse.de>, Vinod Koul <vkoul@kernel.org>, 
	LKML <linux-kernel@vger.kernel.org>, Abhinav Kumar <quic_abhinavk@quicinc.com>, 
	Jernej Skrabec <jernej.skrabec@gmail.com>, Jonas Karlman <jonas@kwiboo.se>, 
	Kishon Vijay Abraham I <kishon@kernel.org>, Konrad Dybcio <konrad.dybcio@linaro.org>, 
	Kuogee Hsieh <quic_khsieh@quicinc.com>, 
	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>, Rob Clark <robdclark@gmail.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Tue, 20 Feb 2024 at 14:56, Julia Lawall <julia.lawall@inria.fr> wrote:
>
>
>
> On Tue, 20 Feb 2024, Dmitry Baryshkov wrote:
>
> > On Tue, 20 Feb 2024 at 13:52, Julia Lawall <julia.lawall@inria.fr> wrot=
e:
> > >
> > >
> > >
> > > On Tue, 20 Feb 2024, Johan Hovold wrote:
> > >
> > > > On Mon, Feb 19, 2024 at 06:48:30PM +0100, Markus Elfring wrote:
> > > > > > The two device node references taken during allocation need to =
be
> > > > > > dropped when the auxiliary device is freed.
> > > > > =E2=80=A6
> > > > > > +++ b/drivers/gpu/drm/bridge/aux-hpd-bridge.c
> > > > > =E2=80=A6
> > > > > > @@ -74,6 +75,8 @@ struct device *drm_dp_hpd_bridge_register(str=
uct device *parent,
> > > > > >
> > > > > >   ret =3D auxiliary_device_init(adev);
> > > > > >   if (ret) {
> > > > > > +         of_node_put(adev->dev.platform_data);
> > > > > > +         of_node_put(adev->dev.of_node);
> > > > > >           ida_free(&drm_aux_hpd_bridge_ida, adev->id);
> > > > > >           kfree(adev);
> > > > > >           return ERR_PTR(ret);
> > > > >
> > > > > The last two statements are also used in a previous if branch.
> > > > > https://elixir.bootlin.com/linux/v6.8-rc5/source/drivers/gpu/drm/=
bridge/aux-hpd-bridge.c#L63
> > > > >
> > > > > How do you think about to avoid such a bit of duplicate source co=
de
> > > > > by adding a label here?
> > > >
> > > > No, the current code is fine and what you are suggesting is in any =
case
> > > > unrelated to this fix.
> > > >
> > > > If this function ever grows a third error path like that, I too wou=
ld
> > > > consider it however.
> > >
> > > I guess these of_node_puts can all go away shortly with cleanup anywa=
y?
> >
> > I'm not sure about it. Those are long-living variables, so they are
> > not a subject of cleanup.h, are they?
>
> OK, I didn't look at this code in detail, but cleanup would just call
> of_node_put, not actually free the data.

Yes. The nodes should be put either in case of the failure or (if
everything goes fine) at the device unregistration.

--=20
With best wishes
Dmitry