Re: [cip-dev] [PATCH 4.19.y-cip 11/17] drm: of: Add drm_of_lvds_get_dual_link_pixel_order

["Pavel Machek" <pavel@ucw.cz>]

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Hi!

> commit 6529007522ded00b8912c079250620fa7a732166 upstream.
> 
> An LVDS dual-link connection is made of two links, with even
> pixels transitting on one link, and odd pixels on the other
> link. The device tree can be used to fully describe dual-link
> LVDS connections between encoders and bridges/panels.
> The sink of an LVDS dual-link connection is made of two ports,
> the corresponding OF graph port nodes can be marked
> with either dual-lvds-even-pixels or dual-lvds-odd-pixels,
> and that fully describes an LVDS dual-link connection,
> including pixel order.

There is double-free bug here, AFAICT:

> +	for_each_child_of_node(port_node, endpoint) {
> +		struct device_node *remote_port;
> +		int current_pt;
> +
> +		if (!of_node_name_eq(endpoint, "endpoint"))
> +			continue;
> +
> +		remote_port = of_graph_get_remote_port(endpoint);
> +		if (!remote_port) {
> +			of_node_put(remote_port);
> +			return -EPIPE;
> +		}
> +
> +		current_pt = drm_of_lvds_get_port_pixels_type(remote_port);
> +		of_node_put(remote_port);

You have put remote_port here.

> +		if (pixels_type < 0)
> +			pixels_type = current_pt;
> +
> +		/*
> +		 * Sanity check, ensure that all remote endpoints have the same
> +		 * pixel type. We may lift this restriction later if we need to
> +		 * support multiple sinks with different dual-link
> +		 * configurations by passing the endpoints explicitly to
> +		 * drm_of_lvds_get_dual_link_pixel_order().
> +		 */
> +		if (!current_pt || pixels_type != current_pt) {
> +			of_node_put(remote_port);
> +			return -EINVAL;

And again here.

Now... it is only a problem in error path, so maybe easiest way is to
fix it in the mainline and then backport the fix here...

Best regards,

								Pavel
-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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