| Message ID | 1548629863510.35899@ece.ufl.edu (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | : media : hackrf : memory leak | expand |
Hi Tuba, On 1/27/19 11:57 PM, Yavuz, Tuba wrote: > > > Due to a missing v4l2_device_get function in the hackrf_probe function, > the reference count of the v4l2_device object reaches zero inside the > wrong API function (video_unregister_device) instead of v4l2_device_put. > This causes a memory leak as the release callback would not get called. The refcount is 1 after calling v4l2_device_register(). Each video_register_device call will increment the refcount by 1. When a video node is released (v4l2_device_release) the refcount is decremented, and when the device is disconnected (hackrf_disconnect) the refcount is decremented again. So I don't see where there is a memory leak, and neither do I understand how incrementing the refcount would prevent a memory leak. I would expect that it causes a memory leak! Is there something else going on here? Regards, Hans > > > Reported-by: Tuba Yavuz <tuba@ece.ufl.edu> > Signed-off-by: Tuba Yavuz <tuba@ece.ufl.edu> > --- > > > --- drivers/media/usb/hackrf/hackrf.c.orig 2019-01-26 11:37:18.912210823 -0500 > +++ drivers/media/usb/hackrf/hackrf.c 2019-01-27 17:50:41.660736688 -0500 > @@ -1524,6 +1524,7 @@ static int hackrf_probe(struct usb_inter > "Failed to register as video device (%d)\n", ret); > goto err_video_unregister_device_rx; > } > + v4l2_device_get(&dev->v4l2_dev); > dev_info(dev->dev, "Registered as %s\n", > video_device_node_name(&dev->tx_vdev)); > >
Hi Hans, You are right.. This was a false positive due to a bug in my environment model. Obviously, v4l2_device_disconnect does not affect the v4l2_device reference count. Best, Tuba
--- drivers/media/usb/hackrf/hackrf.c.orig 2019-01-26 11:37:18.912210823 -0500 +++ drivers/media/usb/hackrf/hackrf.c 2019-01-27 17:50:41.660736688 -0500 @@ -1524,6 +1524,7 @@ static int hackrf_probe(struct usb_inter "Failed to register as video device (%d)\n", ret); goto err_video_unregister_device_rx; } + v4l2_device_get(&dev->v4l2_dev); dev_info(dev->dev, "Registered as %s\n", video_device_node_name(&dev->tx_vdev));
Due to a missing v4l2_device_get function in the hackrf_probe function, the reference count of the v4l2_device object reaches zero inside the wrong API function (video_unregister_device) instead of v4l2_device_put. This causes a memory leak as the release callback would not get called. Reported-by: Tuba Yavuz <tuba@ece.ufl.edu> Signed-off-by: Tuba Yavuz <tuba@ece.ufl.edu> ---