[PATCH 4.18 036/235] media: tw686x: Fix oops on buffer alloc failure

[Greg Kroah-Hartman]

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Krzysztof Ha?asa <khalasa@xxxxxxx>

[ Upstream commit 5a1a2f63d840dc2631505b607e11ff65ac1b7d3c ]

The error path currently calls tw686x_video_free() which requires
vc->dev to be initialized, causing a NULL dereference on uninitizalized
channels.

Fix this by setting the vc->dev fields for all the channels first.

Fixes: f8afaa8dbc0d ("[media] tw686x: Introduce an interface to support multiple DMA modes")

Signed-off-by: Krzysztof Ha?asa <khalasa@xxxxxxx>
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/media/pci/tw686x/tw686x-video.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

--- a/drivers/media/pci/tw686x/tw686x-video.c
+++ b/drivers/media/pci/tw686x/tw686x-video.c
@@ -1190,6 +1190,14 @@ int tw686x_video_init(struct tw686x_dev
 			return err;
 	}
 
+	/* Initialize vc->dev and vc->ch for the error path */
+	for (ch = 0; ch < max_channels(dev); ch++) {
+		struct tw686x_video_channel *vc = &dev->video_channels[ch];
+
+		vc->dev = dev;
+		vc->ch = ch;
+	}
+
 	for (ch = 0; ch < max_channels(dev); ch++) {
 		struct tw686x_video_channel *vc = &dev->video_channels[ch];
 		struct video_device *vdev;
@@ -1198,9 +1206,6 @@ int tw686x_video_init(struct tw686x_dev
 		spin_lock_init(&vc->qlock);
 		INIT_LIST_HEAD(&vc->vidq_queued);
 
-		vc->dev = dev;
-		vc->ch = ch;
-
 		/* default settings */
 		err = tw686x_set_standard(vc, V4L2_STD_NTSC);
 		if (err)