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From:   Robert Foss <robert.foss@linaro.org>
Date:   Mon, 8 Aug 2022 11:33:37 +0200
Message-ID: <CAG3jFyuMboP9OBJgYD01thVvhdb6wR5BeLN+za_ZUFM1QT4HDg@mail.gmail.com>
Subject: Re: [PATCH] gpu: lontium-lt9611: Fix NULL pointer dereference in lt9611_connector_init()
To:     Zeng Jingxiang <zengjx95@gmail.com>
Cc:     andrzej.hajda@intel.com, narmstrong@baylibre.com,
        Laurent.pinchart@ideasonboard.com, jonas@kwiboo.se,
        jernej.skrabec@gmail.com, airlied@linux.ie, daniel@ffwll.ch,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        Zeng Jingxiang <linuszeng@tencent.com>
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On Wed, 27 Jul 2022 at 09:31, Zeng Jingxiang <zengjx95@gmail.com> wrote:
>
> From: Zeng Jingxiang <linuszeng@tencent.com>
>
> A NULL check for bridge->encoder shows that it may be NULL, but it
> already been dereferenced on all paths leading to the check.
> 812     if (!bridge->encoder) {
>
> Dereference the pointer bridge->encoder.
> 810     drm_connector_attach_encoder(&lt9611->connector, bridge->encoder);
>
> Signed-off-by: Zeng Jingxiang <linuszeng@tencent.com>
> ---
>  drivers/gpu/drm/bridge/lontium-lt9611.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/lontium-lt9611.c b/drivers/gpu/drm/bridge/lontium-lt9611.c
> index 7ef8fe5abc12..81a4751573fa 100644
> --- a/drivers/gpu/drm/bridge/lontium-lt9611.c
> +++ b/drivers/gpu/drm/bridge/lontium-lt9611.c
> @@ -807,13 +807,14 @@ static int lt9611_connector_init(struct drm_bridge *bridge, struct lt9611 *lt961
>
>         drm_connector_helper_add(&lt9611->connector,
>                                  &lt9611_bridge_connector_helper_funcs);
> -       drm_connector_attach_encoder(&lt9611->connector, bridge->encoder);
>
>         if (!bridge->encoder) {
>                 DRM_ERROR("Parent encoder object not found");
>                 return -ENODEV;
>         }
>
> +       drm_connector_attach_encoder(&lt9611->connector, bridge->encoder);
> +
>         return 0;
>  }
>
> --
> 2.27.0
>

Applied to drm-misc-next.