2022-05-31 22:04:34

by Miaoqian Lin

Subject: [PATCH 2/2] drm/meson: encoder_hdmi: Fix refcount leak in meson_encoder_hdmi_init

of_graph_get_remote_node() returns remote device nodepointer with
refcount incremented, we should use of_node_put() on it when done.
Add missing of_node_put() to avoid refcount leak.

Fixes: e67f6037ae1b ("drm/meson: split out encoder from meson_dw_hdmi")
Signed-off-by: Miaoqian Lin <[email protected]>
---
drivers/gpu/drm/meson/meson_encoder_hdmi.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/meson/meson_encoder_hdmi.c b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
index 5e306de6f485..f3341458f8b7 100644
--- a/drivers/gpu/drm/meson/meson_encoder_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
@@ -363,6 +363,7 @@ int meson_encoder_hdmi_init(struct meson_drm *priv)
}

meson_encoder_hdmi->next_bridge = of_drm_find_bridge(remote);
+ of_node_put(remote);
if (!meson_encoder_hdmi->next_bridge) {
dev_err(priv->dev, "Failed to find HDMI transceiver bridge\n");
return -EPROBE_DEFER;
--
2.25.1

2022-06-01 19:54:44

by Martin Blumenstingl

Subject: Re: [PATCH 2/2] drm/meson: encoder_hdmi: Fix refcount leak in meson_encoder_hdmi_init

Hello,

first of all: thank you for spotting this and sending a patch!

On Tue, May 31, 2022 at 4:49 PM Miaoqian Lin <[email protected]> wrote:
[...]
> diff --git a/drivers/gpu/drm/meson/meson_encoder_hdmi.c b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
> index 5e306de6f485..f3341458f8b7 100644
> --- a/drivers/gpu/drm/meson/meson_encoder_hdmi.c
> +++ b/drivers/gpu/drm/meson/meson_encoder_hdmi.c
> @@ -363,6 +363,7 @@ int meson_encoder_hdmi_init(struct meson_drm *priv)
> }
>
> meson_encoder_hdmi->next_bridge = of_drm_find_bridge(remote);
> + of_node_put(remote);
further down in the same function remote is used again:
pdev = of_find_device_by_node(remote);

My understanding is that we should only use of_node_put() once we
don't need to access the node (in this case the variable is "remote")
anymore.


Best regards,
Martin