+ Pavel > -----Original Message----- > From: Steven Price <steven.price@xxxxxxx> > Sent: 12 July 2021 16:58 > To: Daniel Vetter <daniel@xxxxxxxx>; David Airlie <airlied@xxxxxxxx>; > Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>; Maxime Ripard > <mripard@xxxxxxxxxx>; Thomas Zimmermann <tzimmermann@xxxxxxx> > Cc: Steven Price <steven.price@xxxxxxx>; dri-devel@xxxxxxxxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; Biju Das <biju.das.jz@xxxxxxxxxxxxxx>; > Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > Subject: [PATCH] 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: 4ee48cc5586b ("drm: of: Fix double-free bug") > Signed-off-by: Steven Price <steven.price@xxxxxxx> > --- > 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://jpn01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.ker > nel.org%2Fr%2FYOxQ5TbkNrqCGBDJ%2540phenom.ffwll.local&data=04%7C01%7Cb > iju.das.jz%40bp.renesas.com%7Cb0570b66e03a43fb8fa008d9454dddaa%7C53d82571d > a1947e49cb4625a166a4a2a%7C0%7C0%7C637617023006562683%7CUnknown%7CTWFpbGZsb > 3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C10 > 00&sdata=cQICPYJzmgNkFsNw1wMH9Or73rohnCCGH1DrUg3hvhw%3D&reserved=0 > > 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