Merge tag 'exynos-drm-fixes-for-v4.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos into drm-fixes

- Fix potential use-after-free issue in suspend/resume
  by cleanning up drvdata at unbind.
- Fix potential NULL pointer dereference issue in suspend/resume
  by setting drm_dev after checking if drm_dev is null or not.

* tag 'exynos-drm-fixes-for-v4.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos:
  drm/exynos: Clear drvdata after component unbind
  drm/exynos: Fix potential NULL pointer dereference in suspend/resume paths

drivers/gpu/drm/exynos/exynos_drm_drv.c

@@ -168,11 +168,13 @@ static struct drm_driver exynos_drm_driver = {
 static int exynos_drm_suspend(struct device *dev)
 {
 	struct drm_device *drm_dev = dev_get_drvdata(dev);
-	struct exynos_drm_private *private = drm_dev->dev_private;
+	struct exynos_drm_private *private;
 
 	if (pm_runtime_suspended(dev) || !drm_dev)
 		return 0;
 
+	private = drm_dev->dev_private;
+
 	drm_kms_helper_poll_disable(drm_dev);
 	exynos_drm_fbdev_suspend(drm_dev);
 	private->suspend_state = drm_atomic_helper_suspend(drm_dev);
@@ -188,11 +190,12 @@ static int exynos_drm_suspend(struct device *dev)
 static int exynos_drm_resume(struct device *dev)
 {
 	struct drm_device *drm_dev = dev_get_drvdata(dev);
-	struct exynos_drm_private *private = drm_dev->dev_private;
+	struct exynos_drm_private *private;
 
 	if (pm_runtime_suspended(dev) || !drm_dev)
 		return 0;
 
+	private = drm_dev->dev_private;
 	drm_atomic_helper_resume(drm_dev, private->suspend_state);
 	exynos_drm_fbdev_resume(drm_dev);
 	drm_kms_helper_poll_enable(drm_dev);
@@ -427,6 +430,7 @@ static void exynos_drm_unbind(struct device *dev)
 
 	kfree(drm->dev_private);
 	drm->dev_private = NULL;
+	dev_set_drvdata(dev, NULL);
 
 	drm_dev_unref(drm);
 }