Merge tag 'drm-misc-fixes-2018-11-07' of git://anongit.freedesktop.org/drm/drm-misc into drm-fixes

- sun4i: tcon->panel NULL deref protections (Giulio)

Cc: Giulio Benetti <giulio.benetti@micronovasrl.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Sean Paul <sean@poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20181107205051.GA27823@art_vandelay

3 files changed, 7 insertions, 6 deletions

diff --git a/drivers/gpu/drm/sun4i/sun4i_lvds.c b/drivers/gpu/drm/sun4i/sun4i_lvds.c
index af7dcb6da351..e7eb0d1e17be 100644
--- a/drivers/gpu/drm/sun4i/sun4i_lvds.c
+++ b/drivers/gpu/drm/sun4i/sun4i_lvds.c
@@ -75,7 +75,7 @@ static void sun4i_lvds_encoder_enable(struct drm_encoder *encoder)
 
         DRM_DEBUG_DRIVER("Enabling LVDS output\n");
 
-        if (!IS_ERR(tcon->panel)) {
+        if (tcon->panel) {
                 drm_panel_prepare(tcon->panel);
                 drm_panel_enable(tcon->panel);
         }
@@ -88,7 +88,7 @@ static void sun4i_lvds_encoder_disable(struct drm_encoder *encoder)
 
         DRM_DEBUG_DRIVER("Disabling LVDS output\n");
 
-        if (!IS_ERR(tcon->panel)) {
+        if (tcon->panel) {
                 drm_panel_disable(tcon->panel);
                 drm_panel_unprepare(tcon->panel);
         }
diff --git a/drivers/gpu/drm/sun4i/sun4i_rgb.c b/drivers/gpu/drm/sun4i/sun4i_rgb.c
index bf068da6b12e..f4a22689eb54 100644
--- a/drivers/gpu/drm/sun4i/sun4i_rgb.c
+++ b/drivers/gpu/drm/sun4i/sun4i_rgb.c
@@ -135,7 +135,7 @@ static void sun4i_rgb_encoder_enable(struct drm_encoder *encoder)
 
         DRM_DEBUG_DRIVER("Enabling RGB output\n");
 
-        if (!IS_ERR(tcon->panel)) {
+        if (tcon->panel) {
                 drm_panel_prepare(tcon->panel);
                 drm_panel_enable(tcon->panel);
         }
@@ -148,7 +148,7 @@ static void sun4i_rgb_encoder_disable(struct drm_encoder *encoder)
 
         DRM_DEBUG_DRIVER("Disabling RGB output\n");
 
-        if (!IS_ERR(tcon->panel)) {
+        if (tcon->panel) {
                 drm_panel_disable(tcon->panel);
                 drm_panel_unprepare(tcon->panel);
         }
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index c78cd35a1294..f949287d926c 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -491,7 +491,8 @@ static void sun4i_tcon0_mode_set_rgb(struct sun4i_tcon *tcon,
         sun4i_tcon0_mode_set_common(tcon, mode);
 
         /* Set dithering if needed */
-        sun4i_tcon0_mode_set_dithering(tcon, tcon->panel->connector);
+        if (tcon->panel)
+                sun4i_tcon0_mode_set_dithering(tcon, tcon->panel->connector);
 
         /* Adjust clock delay */
         clk_delay = sun4i_tcon_get_clk_delay(mode, 0);
@@ -555,7 +556,7 @@ static void sun4i_tcon0_mode_set_rgb(struct sun4i_tcon *tcon,
          * Following code is a way to avoid quirks all around TCON
          * and DOTCLOCK drivers.
          */
-        if (!IS_ERR(tcon->panel)) {
+        if (tcon->panel) {
                 struct drm_panel *panel = tcon->panel;
                 struct drm_connector *connector = panel->connector;
                 struct drm_display_info display_info = connector->display_info;