[PATCH] usbtv: Fix refcounting mixup

[PATCH] usbtv: Fix refcounting mixup

[Oliver Neukum]

The premature free in the error path is blocked by V4L
refcounting, not USB refcounting. Thanks to
Ben Hutchings for review.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Fixes: 50e704453553 ("media: usbtv: prevent double free in error case")
---
 drivers/media/usb/usbtv/usbtv-core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/usbtv/usbtv-core.c b/drivers/media/usb/usbtv/usbtv-core.c
index 5095c380b2c1..4a03c4d66314 100644
--- a/drivers/media/usb/usbtv/usbtv-core.c
+++ b/drivers/media/usb/usbtv/usbtv-core.c
@@ -113,7 +113,8 @@ static int usbtv_probe(struct usb_interface *intf,
 
 usbtv_audio_fail:
 	/* we must not free at this point */
-	usb_get_dev(usbtv->udev);
+	v4l2_device_get(&usbtv->v4l2_dev);
+	/* this will undo the v4l2_device_get() */
 	usbtv_video_free(usbtv);
 
 usbtv_video_fail:
-- 
2.13.6

Re: [PATCH] usbtv: Fix refcounting mixup

[Greg KH]

On Tue, May 15, 2018 at 01:51:37PM +0200, Oliver Neukum wrote:
> The premature free in the error path is blocked by V4L
> refcounting, not USB refcounting. Thanks to
> Ben Hutchings for review.
> 
> Signed-off-by: Oliver Neukum <oneukum@suse.com>
> Fixes: 50e704453553 ("media: usbtv: prevent double free in error case")

Please add:
Cc: stable <stable@vger.kernel.org>

to this patch as well so I pick up the fix in the stable trees.

And a "Reported-by:" line would be nice as well to give credit to Ben :)

thanks,

greg k-h