hdpvr: fix iteration over uninitialized lists in hdpvr_probe()

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@ispras.ru>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/media/video/hdpvr/hdpvr-core.c b/drivers/media/video/hdpvr/hdpvr-core.c
index 6eba006..060353e 100644 (file)
--- a/drivers/media/video/hdpvr/hdpvr-core.c
+++ b/drivers/media/video/hdpvr/hdpvr-core.c
@@ -297,6 +297,11 @@ 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)) {
                err("v4l2_device_register failed");
@@ -319,10 +324,6 @@ 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)
@@ -397,7 +398,7 @@ static int hdpvr_probe(struct usb_interface *interface,
                                    video_nr[atomic_inc_return(&dev_nr)]);
        if (retval < 0) {
                v4l2_err(&dev->v4l2_dev, "registering videodev failed\n");
-               goto error;
+               goto reg_fail;
        }
 
        /* let the user know what node this device is now attached to */