media: hdpvr: fix iteration over uninitialized lists in hdpvr_probe()
Alexey Khoroshilov [Wed, 3 Jul 2013 19:17:34 +0000 (16:17 -0300)]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/media/usb/hdpvr/hdpvr-core.c

index 8247c19..77d7b7f 100644 (file)
@@ -311,6 +311,11 @@ 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");
@@ -333,10 +338,6 @@ 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)
@@ -413,7 +414,7 @@ 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 */