drm/sun4i: tcon: prevent tcon->panel dereference if NULL

giuliobenetti · mripard · commit a8939766c75c · 2018-11-06T16:55:29.000+01:00
If tcon->panel pointer is NULL, trying to dereference from it (i.e. tcon->panel->connector) will cause a null pointer dereference. Add tcon->panel null pointer check before calling sun4i_tcon0_mode_set_dithering(). Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com> Fixes: f11adce ("drm/sun4i: tcon: Add dithering support for RGB565/RGB666 LCD panels") Reviewed-by: Chen-Yu Tsai <wens@csie.org> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181005215951.99003-2-giulio.benetti@micronovasrl.com
diff --git 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);
