linux-kernel - Re: [PATCH] drm/gma500: fix potential NULL pointer dereference dereference

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Date:   Mon, 14 Aug 2017 16:12:14 +0200
From:   Daniel Vetter <daniel@...ll.ch>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Cc:     Patrik Jakobsson <patrik.r.jakobsson@...il.com>,
        David Airlie <airlied@...ux.ie>, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH] drm/gma500: fix potential NULL pointer dereference
 dereference

On Fri, Aug 11, 2017 at 08:55:15PM -0500, Gustavo A. R. Silva wrote:
> NULL check at line 528: if (!sender || !data_out || !len_out) {, implies
> that pointer _sender_ might be NULL.
> 
> Move pointer _sender_ dereference after NULL check in order to avoid a
> potential NULL pointer dereference.
> 
> This issue was detected with the help of Coccinelle.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@...eddedor.com>

Applied to drm-misc-next, thanks.
-Daniel

> ---
>  drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c b/drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c
> index 1616af2..c50534c 100644
> --- a/drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c
> +++ b/drivers/gpu/drm/gma500/mdfld_dsi_pkg_sender.c
> @@ -520,7 +520,7 @@ static int __read_panel_data(struct mdfld_dsi_pkg_sender *sender, u8 data_type,
>  			u8 *data, u16 len, u32 *data_out, u16 len_out, bool hs)
>  {
>  	unsigned long flags;
> -	struct drm_device *dev = sender->dev;
> +	struct drm_device *dev;
>  	int i;
>  	u32 gen_data_reg;
>  	int retry = MDFLD_DSI_READ_MAX_COUNT;
> @@ -530,6 +530,8 @@ static int __read_panel_data(struct mdfld_dsi_pkg_sender *sender, u8 data_type,
>  		return -EINVAL;
>  	}
>  
> +	dev = sender->dev;
> +
>  	/**
>  	 * do reading.
>  	 * 0) send out generic read request
> -- 
> 2.5.0
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

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