[PATCH AUTOSEL 4.9 04/19] gpu: drm: radeon: Fix a possible null-pointer dereference in radeon_connector_set_property()

Sasha Levin
2019-09-24T16:52:08Z

From: Jia-Ju Bai <baijiaju1990@gmail.com>

[ Upstream commit f3eb9b8f67bc28783eddc142ad805ebdc53d6339 ]

In radeon_connector_set_property(), there is an if statement on line 743
to check whether connector->encoder is NULL:
if (connector->encoder)

When connector->encoder is NULL, it is used on line 755:
if (connector->encoder->crtc)

Thus, a possible null-pointer dereference may occur.

To fix this bug, connector->encoder is checked before being used.

This bug is found by a static analysis tool STCheck written by us.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/radeon/radeon_connectors.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index c5e1aa5f1d8ea..efa875120071a 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -764,7 +764,7 @@ static int radeon_connector_set_property(struct drm_connector *connector, struct

radeon_encoder->output_csc = val;

- if (connector->encoder->crtc) {
+ if (connector->encoder && connector->encoder->crtc) {
struct drm_crtc *crtc = connector->encoder->crtc;
const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
--
2.20.1