linux-kernel - [PATCH v2] drm/of: free the iterator object on failure

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Message-Id: <20210714143300.20632-1-steven.price@arm.com>
Date:   Wed, 14 Jul 2021 15:33:00 +0100
From:   Steven Price <steven.price@....com>
To:     Daniel Vetter <daniel@...ll.ch>, David Airlie <airlied@...ux.ie>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>
Cc:     Steven Price <steven.price@....com>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Biju Das <biju.das.jz@...renesas.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Pavel Machek <pavel@...x.de>
Subject: [PATCH v2] drm/of: free the iterator object on failure

When bailing out due to the sanity check the iterator value needs to be
freed because the early return prevents for_each_child_of_node() from
doing the dereference itself.

Fixes: 6529007522de ("drm: of: Add drm_of_lvds_get_dual_link_pixel_order")
Signed-off-by: Steven Price <steven.price@....com>
---
 drivers/gpu/drm/drm_of.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

v2: Fixes now refers to the original commit as suggested by Laurent, rather
than 4ee48cc5586b ("drm: of: Fix double-free bug") which only fixed part of
the problem. Note that 4ee48cc5586b is a dependency for this patch to
cleanly apply.

diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c
index 197c57477344..997b8827fed2 100644
--- a/drivers/gpu/drm/drm_of.c
+++ b/drivers/gpu/drm/drm_of.c
@@ -331,8 +331,10 @@ static int drm_of_lvds_get_remote_pixels_type(
 		 * configurations by passing the endpoints explicitly to
 		 * drm_of_lvds_get_dual_link_pixel_order().
 		 */
-		if (!current_pt || pixels_type != current_pt)
+		if (!current_pt || pixels_type != current_pt) {
+			of_node_put(endpoint);
 			return -EINVAL;
+		}
 	}
 
 	return pixels_type;
-- 
2.20.1