Re: [PATCH 1/6] drm/bridge: aux-hpd: fix OF node leaks

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
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>
Subject: Re: [PATCH 1/6] drm/bridge: aux-hpd: fix OF node leaks
Date: Tue, 20 Feb 2024 13:55:40 +0200	[thread overview]
Message-ID: <CAA8EJppH9ey97yKFUccNLHhMKs3eUS55+rY0tXm_a6KGp9jtug@mail.gmail.com> (raw)
In-Reply-To: <1afc87c-2c1f-df10-a0c8-2a267d44122@inria.fr>

On Tue, 20 Feb 2024 at 13:52, Julia Lawall <julia.lawall@inria.fr> wrote:
>
>
>
> 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.
> > > …
> > > > +++ b/drivers/gpu/drm/bridge/aux-hpd-bridge.c
> > > …
> > > > @@ -74,6 +75,8 @@ struct device *drm_dp_hpd_bridge_register(struct device *parent,
> > > >
> > > >   ret = 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 code
> > > 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 would
> > consider it however.
>
> I guess these of_node_puts can all go away shortly with cleanup anyway?

I'm not sure about it. Those are long-living variables, so they are
not a subject of cleanup.h, are they?

-- 
With best wishes
Dmitry