From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wr0-f193.google.com ([209.85.128.193]:39849 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750948AbeEUKZr (ORCPT ); Mon, 21 May 2018 06:25:47 -0400 Received: by mail-wr0-f193.google.com with SMTP id w18-v6so11703499wrn.6 for ; Mon, 21 May 2018 03:25:46 -0700 (PDT) From: Philipp Zabel To: Laurent Pinchart Cc: Guennadi Liakhovetski , linux-media@vger.kernel.org, Philipp Zabel Subject: [PATCH] media: uvcvideo: Fix driver reference counting Date: Mon, 21 May 2018 12:24:58 +0200 Message-Id: <20180521102458.3288-1-philipp.zabel@gmail.com> Sender: linux-media-owner@vger.kernel.org List-ID: kref_init initializes the reference count to 1, not 0. This additional reference is never released since the conversion to reference counters. As a result, uvc_delete is not called anymore when UVC cameras are disconnected. Fix this by adding an additional kref_put in uvc_disconnect and in the probe error path. This also allows to remove the temporary additional reference in uvc_unregister_video. Fixes: 9d15cd958c17 ("media: uvcvideo: Convert from using an atomic variable to a reference count") Signed-off-by: Philipp Zabel --- drivers/media/usb/uvc/uvc_driver.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index 2469b49b2b30..8e138201330f 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -1871,13 +1871,6 @@ static void uvc_unregister_video(struct uvc_device *dev) { struct uvc_streaming *stream; - /* Unregistering all video devices might result in uvc_delete() being - * called from inside the loop if there's no open file handle. To avoid - * that, increment the refcount before iterating over the streams and - * decrement it when done. - */ - kref_get(&dev->ref); - list_for_each_entry(stream, &dev->streams, list) { if (!video_is_registered(&stream->vdev)) continue; @@ -1887,8 +1880,6 @@ static void uvc_unregister_video(struct uvc_device *dev) uvc_debugfs_cleanup_stream(stream); } - - kref_put(&dev->ref, uvc_delete); } int uvc_register_video_device(struct uvc_device *dev, @@ -2184,6 +2175,7 @@ static int uvc_probe(struct usb_interface *intf, error: uvc_unregister_video(dev); + kref_put(&dev->ref, uvc_delete); return -ENODEV; } @@ -2201,6 +2193,7 @@ static void uvc_disconnect(struct usb_interface *intf) return; uvc_unregister_video(dev); + kref_put(&dev->ref, uvc_delete); } static int uvc_suspend(struct usb_interface *intf, pm_message_t message) -- 2.17.0