[PATCH AUTOSEL 4.19 610/671] drm: panel-lvds: Potential Oops in probe error handling

Sasha Levin
2020-01-16T17:13:27Z

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit fb2ee9bf084bcaeff1e5be100decc0eacb4af2d5 ]

The "lvds->backlight" pointer could be NULL in situations where
of_parse_phandle() returns NULL. This code is cleaner if we use the
managed devm_of_find_backlight() so the clean up is automatic.

Fixes: 7c9dff5bd643 ("drm: panels: Add LVDS panel driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190911104928.GA15930@mwanda
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/panel/panel-lvds.c | 21 ++++-----------------
1 file changed, 4 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-lvds.c b/drivers/gpu/drm/panel/panel-lvds.c
index 8a1687887ae9..bd704a36c5d0 100644
--- a/drivers/gpu/drm/panel/panel-lvds.c
+++ b/drivers/gpu/drm/panel/panel-lvds.c
@@ -199,7 +199,6 @@ static int panel_lvds_parse_dt(struct panel_lvds *lvds)
static int panel_lvds_probe(struct platform_device *pdev)
{
struct panel_lvds *lvds;
- struct device_node *np;
int ret;

lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL);
@@ -245,14 +244,9 @@ static int panel_lvds_probe(struct platform_device *pdev)
return ret;
}

- np = of_parse_phandle(lvds->dev->of_node, "backlight", 0);
- if (np) {
- lvds->backlight = of_find_backlight_by_node(np);
- of_node_put(np);
-
- if (!lvds->backlight)
- return -EPROBE_DEFER;
- }
+ lvds->backlight = devm_of_find_backlight(lvds->dev);
+ if (IS_ERR(lvds->backlight))
+ return PTR_ERR(lvds->backlight);

/*
* TODO: Handle all power supplies specified in the DT node in a generic
@@ -268,14 +262,10 @@ static int panel_lvds_probe(struct platform_device *pdev)

ret = drm_panel_add(&lvds->panel);
if (ret < 0)
- goto error;
+ return ret;

dev_set_drvdata(lvds->dev, lvds);
return 0;
-
-error:
- put_device(&lvds->backlight->dev);
- return ret;
}

static int panel_lvds_remove(struct platform_device *pdev)
@@ -286,9 +276,6 @@ static int panel_lvds_remove(struct platform_device *pdev)

panel_lvds_disable(&lvds->panel);

- if (lvds->backlight)
- put_device(&lvds->backlight->dev);
-
return 0;
}

--
2.20.1