linux-kernel - Re: [PATCH] drm/tegra: fix device leak on probe()

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Message-ID: <aSQtdG3MiSq9YJAP@hovoldconsulting.com>
Date: Mon, 24 Nov 2025 11:03:32 +0100
From: Johan Hovold <johan@...nel.org>
To: Thierry Reding <thierry.reding@...il.com>,
	Mikko Perttunen <mperttunen@...dia.com>
Cc: David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	dri-devel@...ts.freedesktop.org, linux-tegra@...r.kernel.org,
	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	Dmitry Osipenko <digetx@...il.com>
Subject: Re: [PATCH] drm/tegra: fix device leak on probe()

On Fri, Nov 21, 2025 at 12:24:32PM +0100, Johan Hovold wrote:
> Make sure to drop the reference taken when looking up the companion
> device during probe().
> 
> Note that holding a reference to a device does not prevent its driver
> data from going away so there is no point in keeping the reference.
> 
> Fixes: f68ba6912bd2 ("drm/tegra: dc: Link DC1 to DC0 on Tegra20")
> Cc: stable@...r.kernel.org	# 4.16
> Cc: Dmitry Osipenko <digetx@...il.com>
> Signed-off-by: Johan Hovold <johan@...nel.org>
> ---
>  drivers/gpu/drm/tegra/dc.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
> index 59d5c1ba145a..7a6b30df6a89 100644
> --- a/drivers/gpu/drm/tegra/dc.c
> +++ b/drivers/gpu/drm/tegra/dc.c
> @@ -3148,6 +3148,8 @@ static int tegra_dc_couple(struct tegra_dc *dc)
>  		dc->client.parent = &parent->client;
>  
>  		dev_dbg(dc->dev, "coupled to %s\n", dev_name(companion));
> +
> +		put_device(companion);

I noticed that this has been fixed in rc7 when rebasing so please
disregard this one.

Johan