4.9-stable review patch. If anyone has any objections, please let me know.
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From: Johan Hovold johan@kernel.org
commit ceff2f4dcd44abf35864d9a99f85ac619e89a01d upstream.
Use the new of_get_compatible_child() helper to lookup the sibling instead of using of_find_compatible_node(), which searches the entire tree from a given start node and thus can return an unrelated (i.e. non-sibling) node.
This also addresses a potential use-after-free (e.g. after probe deferral) as the tree-wide helper drops a reference to its first argument (i.e. the parent device node).
While at it, also fix the related cec-node reference leak.
Fixes: 8f83f26891e1 ("drm/mediatek: Add HDMI support") Cc: stable stable@vger.kernel.org # 4.8 Cc: Junzhi Zhao junzhi.zhao@mediatek.com Cc: Philipp Zabel p.zabel@pengutronix.de Cc: CK Hu ck.hu@mediatek.com Cc: David Airlie airlied@linux.ie Signed-off-by: Johan Hovold johan@kernel.org Signed-off-by: Rob Herring robh@kernel.org [ johan: backport to 4.9 ] Signed-off-by: Johan Hovold johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/mediatek/mtk_hdmi.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/mediatek/mtk_hdmi.c +++ b/drivers/gpu/drm/mediatek/mtk_hdmi.c @@ -1446,8 +1446,7 @@ static int mtk_hdmi_dt_parse_pdata(struc }
/* The CEC module handles HDMI hotplug detection */ - cec_np = of_find_compatible_node(np->parent, NULL, - "mediatek,mt8173-cec"); + cec_np = of_get_compatible_child(np->parent, "mediatek,mt8173-cec"); if (!cec_np) { dev_err(dev, "Failed to find CEC node\n"); return -EINVAL; @@ -1457,8 +1456,10 @@ static int mtk_hdmi_dt_parse_pdata(struc if (!cec_pdev) { dev_err(hdmi->dev, "Waiting for CEC device %s\n", cec_np->full_name); + of_node_put(cec_np); return -EPROBE_DEFER; } + of_node_put(cec_np); hdmi->cec_dev = &cec_pdev->dev;
/*