[PATCH 1/1] radeon: fix a possible null pointer dereference

[Yuanjun Gong]

From: Gong Yuanjun <ruc_gongyuanjun at 163.com>

In radeon_fp_native_mode(), the return value of drm_mode_duplicate()
is assigned to mode, which will lead to a NULL pointer dereference
on failure of drm_mode_duplicate(). Add a check to avoid npd.

The failure status of drm_cvt_mode() on the other path is checked too.

Signed-off-by: Gong Yuanjun <ruc_gongyuanjun at 163.com>
---
 drivers/gpu/drm/radeon/radeon_connectors.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index 0cb1345c6ba4..fabe4f4ca124 100644
--- a/drivers/gpu/drm/radeon/radeon_connectors.c
+++ b/drivers/gpu/drm/radeon/radeon_connectors.c
@@ -473,6 +473,8 @@ static struct drm_display_mode *radeon_fp_native_mode(struct drm_encoder *encode
 	    native_mode->vdisplay != 0 &&
 	    native_mode->clock != 0) {
 		mode = drm_mode_duplicate(dev, native_mode);
+		if (!mode)
+			return NULL;
 		mode->type = DRM_MODE_TYPE_PREFERRED | DRM_MODE_TYPE_DRIVER;
 		drm_mode_set_name(mode);
 
@@ -487,6 +489,8 @@ static struct drm_display_mode *radeon_fp_native_mode(struct drm_encoder *encode
 		 * simpler.
 		 */
 		mode = drm_cvt_mode(dev, native_mode->hdisplay, native_mode->vdisplay, 60, true, false, false);
+		if (!mode)
+			return NULL;
 		mode->type = DRM_MODE_TYPE_PREFERRED | DRM_MODE_TYPE_DRIVER;
 		DRM_DEBUG_KMS("Adding cvt approximation of native panel mode %s\n", mode->name);
 	}
-- 
2.17.1