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* [PATCH] drm/of: free the iterator object on failure
@ 2021-07-12 15:57 Steven Price
  2021-07-12 16:03 ` Biju Das
                   ` (2 more replies)
  0 siblings, 3 replies; 10+ messages in thread
From: Steven Price @ 2021-07-12 15:57 UTC (permalink / raw)
  To: Daniel Vetter, David Airlie, Maarten Lankhorst, Maxime Ripard,
	Thomas Zimmermann
  Cc: Steven Price, dri-devel, linux-kernel, Biju Das, Laurent Pinchart

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: 4ee48cc5586b ("drm: of: Fix double-free bug")
Signed-off-by: Steven Price <steven.price@arm.com>
---
 drivers/gpu/drm/drm_of.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Daniel's email[1] made me take a look at this function and it appears
that for_each_child_of_node()'s interface had caused a bad bug fix due
to the hidden reference counting in the iterator.

[1] https://lore.kernel.org/r/YOxQ5TbkNrqCGBDJ%40phenom.ffwll.local

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


^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2021-07-15 10:32 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-07-12 15:57 [PATCH] drm/of: free the iterator object on failure Steven Price
2021-07-12 16:03 ` Biju Das
2021-07-12 16:50 ` Laurent Pinchart
2021-07-12 21:31   ` Steven Price
2021-07-12 21:55     ` Laurent Pinchart
2021-07-13 16:16       ` Steven Price
2021-07-14  8:35         ` Laurent Pinchart
2021-07-14 14:33 ` [PATCH v2] " Steven Price
2021-07-14 15:26   ` Laurent Pinchart
2021-07-15 10:32     ` Steven Price

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