From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: Mon, 9 Oct 2017 10:43:53 +0200
Subject: drm/exynos: Fix potential NULL pointer dereference in suspend/resume
paths
Git-commit: 0a51897bfac9886d36e986d009df0317582b19a2
Patch-mainline: v4.14-rc6
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166
The patch 6e8edf8a7d8d: "drm/exynos: Fix suspend/resume support" introduced
a new code in suspend/resume paths. However it unconditionally dereference
drm_dev pointer, which might be NULL if suspend/resume happens before
Exynos DRM driver components bind. This patch fixes this issue.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: 6e8edf8a7d8d "drm/exynos: Fix suspend/resume support"
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/gpu/drm/exynos/exynos_drm_drv.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/exynos/exynos_drm_drv.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c
@@ -168,11 +168,13 @@ static struct drm_driver exynos_drm_driv
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 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);