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References: <20211212062407.138309-1-marcan@marcan.st> <20211212062407.138309-2-marcan@marcan.st>
In-Reply-To: <20211212062407.138309-2-marcan@marcan.st>
From:   Javier Martinez Canillas <javier@dowhile0.org>
Date:   Mon, 13 Dec 2021 09:44:19 +0100
Message-ID: <CABxcv=m4fu8h=FwY7R=thuvd13_ZbFqB9rNNN07QOAd__jdYSQ@mail.gmail.com>
Subject: Re: [PATCH v3 1/3] of: Move simple-framebuffer device handling from
 simplefb to of
To:     Hector Martin <marcan@marcan.st>
Cc:     Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Rob Herring <robh+dt@kernel.org>,
        Hans de Goede <hdegoede@redhat.com>,
        Alyssa Rosenzweig <alyssa@rosenzweig.io>,
        Pekka Paalanen <ppaalanen@gmail.com>,
        devicetree@vger.kernel.org,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Linux Kernel <linux-kernel@vger.kernel.org>
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Precedence: bulk

Hello Hector,

On Sun, Dec 12, 2021 at 7:24 AM Hector Martin <marcan@marcan.st> wrote:
>
> This code is required for both simplefb and simpledrm, so let's move it
> into the OF core instead of having it as an ad-hoc initcall in the
> drivers.
>
> Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
> Signed-off-by: Hector Martin <marcan@marcan.st>
> ---
>  drivers/of/platform.c          |  4 ++++
>  drivers/video/fbdev/simplefb.c | 21 +--------------------
>  2 files changed, 5 insertions(+), 20 deletions(-)
>

This is indeed a much better approach than what I suggested. I just
have one comment.

> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index b3faf89744aa..793350028906 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -540,6 +540,10 @@ static int __init of_platform_default_populate_init(void)
>                 of_node_put(node);
>         }
>
> +       node = of_get_compatible_child(of_chosen, "simple-framebuffer");

You have to check if the node variable is NULL here.

> +       of_platform_device_create(node, NULL, NULL);

Otherwise this could lead to a NULL pointer dereference if debug
output is enabled (the node->full_name is printed).

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

Best regards,
Javier