On 06/15/2016 02:15 PM, Max Kellermann wrote:
> While removing all interfaces in media_device_unregister(), all
> media_interface pointers are freed. This is illegal and results in
> double kfree() if any media_interface is still linked at this point;
> maybe because a userspace process still has a file handle. Once the
> process closes the file handle, dvb_media_device_free() gets called,
> which frees the dvb_device.intf_devnode again.
>
> This patch removes the unnecessary kfree() call, and documents who's
> responsible for really freeing it.
>
> Signed-off-by: Max Kellermann <max@xxxxxxxxxxx>
> ---
> drivers/media/media-device.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
> index 33a9952..1db4707 100644
> --- a/drivers/media/media-device.c
> +++ b/drivers/media/media-device.c
> @@ -799,9 +799,11 @@ void media_device_unregister(struct media_device *mdev)
> /* Remove all interfaces from the media device */
> list_for_each_entry_safe(intf, tmp_intf, &mdev->interfaces,
> graph_obj.list) {
> + /* unlink the interface, but don't free it here; the
> + module which created it is responsible for freeing
> + it */
> __media_remove_intf_links(intf);
> media_gobj_destroy(&intf->graph_obj);
> - kfree(intf);
This change introduces memory leaks, since drivers are relying on
media_device_unregister() to free interfaces.
thanks,
-- Shuah
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