From mboxrd@z Thu Jan  1 00:00:00 1970
From: Archit Taneja <archit@ti.com>
Subject: Re: [PATCH] drm/omap: Don't dereference list head when the connectors
	list is empty
Date: Tue, 24 Dec 2013 12:05:24 +0530
Message-ID: <52B92B2C.1090806@ti.com>
References: <1387812473-31696-1-git-send-email-laurent.pinchart@ideasonboard.com>
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To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>, dri-devel@lists.freedesktop.org
List-Id: dri-devel@lists.freedesktop.org

Hi,

On Monday 23 December 2013 08:57 PM, Laurent Pinchart wrote:
> The connectors list iterator returns the list head when the list is
> empty. Fix it by returning NULL in that case.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>   drivers/gpu/drm/omapdrm/omap_fb.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/omapdrm/omap_fb.c b/drivers/gpu/drm/omapdrm/omap_fb.c
> index f2b8f06..1b48cf2 100644
> --- a/drivers/gpu/drm/omapdrm/omap_fb.c
> +++ b/drivers/gpu/drm/omapdrm/omap_fb.c
> @@ -301,8 +301,11 @@ struct drm_connector *omap_framebuffer_get_next_connector(
>   	struct list_head *connector_list = &dev->mode_config.connector_list;
>   	struct drm_connector *connector = from;
>
> -	if (!from)
> +	if (!from) {
> +		if (list_empty(connector_list))
> +			return NULL;
>   		return list_first_entry(connector_list, typeof(*from), head);

looks like there is a list function which does that too:

list_first_entry_or_null()

We could probably replace it with this.

Archit

> +	}
>
>   	list_for_each_entry_from(connector, connector_list, head) {
>   		if (connector != from) {
>