[PATCH 5.4 1/2] media: vim2m: Register video device after setting up internals

[Mark-PK Tsai <mark-pk.tsai@mediatek.com>]

commit 	cf7f34777a5b4100a3a44ff95f3d949c62892bdd upstream.

Prevent NULL (or close to NULL) pointer dereference in various places by
registering the video device only when the V4L2 m2m framework has been set
up.

Fixes: commit 96d8eab5d0a1 ("V4L/DVB: [v5,2/2] v4l: Add a mem-to-mem videobuf framework test device")
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
[ backport to 5.4 LTS ]
CC: stable@vger.kernel.org
Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
---
 drivers/media/platform/vim2m.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/media/platform/vim2m.c b/drivers/media/platform/vim2m.c
index 8d6b09623d88..02f5bc82ba46 100644
--- a/drivers/media/platform/vim2m.c
+++ b/drivers/media/platform/vim2m.c
@@ -1333,12 +1333,6 @@ static int vim2m_probe(struct platform_device *pdev)
 	vfd->lock = &dev->dev_mutex;
 	vfd->v4l2_dev = &dev->v4l2_dev;
 
-	ret = video_register_device(vfd, VFL_TYPE_GRABBER, 0);
-	if (ret) {
-		v4l2_err(&dev->v4l2_dev, "Failed to register video device\n");
-		goto error_v4l2;
-	}
-
 	video_set_drvdata(vfd, dev);
 	v4l2_info(&dev->v4l2_dev,
 		  "Device registered as /dev/video%d\n", vfd->num);
@@ -1353,6 +1347,12 @@ static int vim2m_probe(struct platform_device *pdev)
 		goto error_dev;
 	}
 
+	ret = video_register_device(vfd, VFL_TYPE_GRABBER, 0);
+	if (ret) {
+		v4l2_err(&dev->v4l2_dev, "Failed to register video device\n");
+		goto error_m2m;
+	}
+
 #ifdef CONFIG_MEDIA_CONTROLLER
 	dev->mdev.dev = &pdev->dev;
 	strscpy(dev->mdev.model, "vim2m", sizeof(dev->mdev.model));
@@ -1366,7 +1366,7 @@ static int vim2m_probe(struct platform_device *pdev)
 						 MEDIA_ENT_F_PROC_VIDEO_SCALER);
 	if (ret) {
 		v4l2_err(&dev->v4l2_dev, "Failed to init mem2mem media controller\n");
-		goto error_dev;
+		goto error_v4l2;
 	}
 
 	ret = media_device_register(&dev->mdev);
@@ -1381,11 +1381,13 @@ static int vim2m_probe(struct platform_device *pdev)
 error_m2m_mc:
 	v4l2_m2m_unregister_media_controller(dev->m2m_dev);
 #endif
-error_dev:
+error_v4l2:
 	video_unregister_device(&dev->vfd);
 	/* vim2m_device_release called by video_unregister_device to release various objects */
 	return ret;
-error_v4l2:
+error_m2m:
+	v4l2_m2m_release(dev->m2m_dev);
+error_dev:
 	v4l2_device_unregister(&dev->v4l2_dev);
 error_free:
 	kfree(dev);
-- 
2.18.0