On Wed, Nov 28, 2018 at 10:22:21AM -0500, Sasha Levin wrote:
> On Tue, Nov 27, 2018 at 07:16:56AM -0800, Johan Hovold wrote:
> >On Sun, Nov 11, 2018 at 08:17:40AM -0800, Greg Kroah-Hartman wrote:
> >>
> >> The patch below does not apply to the 4.9-stable tree.
> >> If someone wants it applied there, or to any other stable or longterm
> >> tree, then please email the backport, including the original git commit
> >> id to <stable@xxxxxxxxxxxxxxx>.
> >
> >This one also depends on
> >
> > 36156f9241cb ("of: add helper to lookup compatible child node")
>
> It seems to have more dependencies for 4.9.
Apparently just a trivial context change due to 4bf99144d2b4 ("drm:
Convert to using %pOF instead of full_name").
Compile-tested backport below.
Johan
>From 25904658b8a0975376a9118cfc07f5f3ebb1ea34 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@xxxxxxxxxx>
Date: Mon, 27 Aug 2018 10:21:46 +0200
Subject: [PATCH] drm/mediatek: fix OF sibling-node lookup
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@xxxxxxxxxxxxxxx> # 4.8
Cc: Junzhi Zhao <junzhi.zhao@xxxxxxxxxxxx>
Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Cc: CK Hu <ck.hu@xxxxxxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
[ johan: backport to 4.9 ]
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/gpu/drm/mediatek/mtk_hdmi.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi.c b/drivers/gpu/drm/mediatek/mtk_hdmi.c
index e097780752f6..863d030786e5 100644
--- 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(struct mtk_hdmi *hdmi,
}
/* 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(struct mtk_hdmi *hdmi,
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;
/*
--
2.19.2
