[PATCH 080/104] hdpvr: fix iteration over uninitialized lists in hdpvr_probe()

From: Luis Henriques
Date: Mon Sep 30 2013 - 06:19:58 EST -stable review patch. If anyone has any objections, please let me know.


From: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>

commit 2e923a0527ac439e135b9961e58d3acd876bba10 upstream.

free_buff_list and rec_buff_list are initialized in the middle of hdpvr_probe(),
but if something bad happens before that, error handling code calls hdpvr_delete(),
which contains iteration over the lists (via hdpvr_free_buffers()).
The patch moves the lists initialization to the beginning and by the way fixes
goto label in error handling of registering videodev.
Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@xxxxxxxxxxx>
[ luis: backported to 3.5:
- dropped hdpvr_register_videodev() error handling hunk ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
drivers/media/video/hdpvr/hdpvr-core.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/media/video/hdpvr/hdpvr-core.c b/drivers/media/video/hdpvr/hdpvr-core.c
index 304f43e..dcb7833 100644
--- a/drivers/media/video/hdpvr/hdpvr-core.c
+++ b/drivers/media/video/hdpvr/hdpvr-core.c
@@ -309,6 +309,11 @@ static int hdpvr_probe(struct usb_interface *interface,

dev->workqueue = 0;

+ /* init video transfer queues first of all */
+ /* to prevent oops in hdpvr_delete() on error paths */
+ INIT_LIST_HEAD(&dev->free_buff_list);
+ INIT_LIST_HEAD(&dev->rec_buff_list);
/* register v4l2_device early so it can be used for printks */
if (v4l2_device_register(&interface->dev, &dev->v4l2_dev)) {
dev_err(&interface->dev, "v4l2_device_register failed\n");
@@ -331,10 +336,6 @@ static int hdpvr_probe(struct usb_interface *interface,
if (!dev->workqueue)
goto error;

- /* init video transfer queues */
- INIT_LIST_HEAD(&dev->free_buff_list);
- INIT_LIST_HEAD(&dev->rec_buff_list);
dev->options = hdpvr_default_options;

if (default_video_input < HDPVR_VIDEO_INPUTS)

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