drm/radeon: fix a possible null pointer dereference

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@163.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c
index a16892c..58db799 100644 (file)
--- 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);
        }