[PATCH AUTOSEL 5.3 17/87] drm/panel: check failure cases in the probe func

Sasha Levin
2019-09-24T16:42:55Z

From: Navid Emamdoost <navid.emamdoost@gmail.com>

[ Upstream commit afd6d4f5a52c16e1483328ac074abb1cde92c29f ]

The following function calls may fail and return NULL, so the null check
is added.
of_graph_get_next_endpoint
of_graph_get_remote_port_parent
of_graph_get_remote_port

Update: Thanks to Sam Ravnborg, for suggession on the use of goto to avoid
leaking endpoint.

Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190724195534.9303-1-navid.emamdoost@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../gpu/drm/panel/panel-raspberrypi-touchscreen.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
index 28c0620dfe0f9..b5b14aa059ea7 100644
--- a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
+++ b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
@@ -399,7 +399,13 @@ static int rpi_touchscreen_probe(struct i2c_client *i2c,

/* Look up the DSI host. It needs to probe before we do. */
endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
+ if (!endpoint)
+ return -ENODEV;
+
dsi_host_node = of_graph_get_remote_port_parent(endpoint);
+ if (!dsi_host_node)
+ goto error;
+
host = of_find_mipi_dsi_host_by_node(dsi_host_node);
of_node_put(dsi_host_node);
if (!host) {
@@ -408,6 +414,9 @@ static int rpi_touchscreen_probe(struct i2c_client *i2c,
}

info.node = of_graph_get_remote_port(endpoint);
+ if (!info.node)
+ goto error;
+
of_node_put(endpoint);

ts->dsi = mipi_dsi_device_register_full(host, &info);
@@ -428,6 +437,10 @@ static int rpi_touchscreen_probe(struct i2c_client *i2c,
return ret;

return 0;
+
+error:
+ of_node_put(endpoint);
+ return -ENODEV;
}

static int rpi_touchscreen_remove(struct i2c_client *i2c)
--
2.20.1