From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from perceval.ideasonboard.com ([95.142.166.194]:42227 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753154Ab3AJKqo (ORCPT ); Thu, 10 Jan 2013 05:46:44 -0500 From: Laurent Pinchart To: Oliver Neukum Cc: linux-usb@vger.kernel.org, tom.leiming@gmail.com, linux-media@vger.kernel.org Subject: Re: [PATCH] uvc: fix race of open and suspend in error case Date: Thu, 10 Jan 2013 11:48:23 +0100 Message-ID: <1668668.TJ5Durkkcc@avalon> In-Reply-To: <1357812295-21174-1-git-send-email-oliver@neukum.org> References: <1357812295-21174-1-git-send-email-oliver@neukum.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-media-owner@vger.kernel.org List-ID: Hi Oliver, Thank you for the patch. On Thursday 10 January 2013 11:04:55 Oliver Neukum wrote: > Ming Lei reported: > IMO, there is a minor fault in the error handling path of > uvc_status_start() inside uvc_v4l2_open(), and the 'users' count > should have been decreased before usb_autopm_put_interface(). > In theory, the warning can be triggered when the device is > opened just between usb_autopm_put_interface() and > atomic_dec(&stream->dev->users). > The fix is trivial. > > Signed-off-by:Oliver Neukum I've slightly modified the commit message with more details about the warning: uvcvideo: Fix race of open and suspend in error case Ming Lei reported: IMO, there is a minor fault in the error handling path of uvc_status_start() inside uvc_v4l2_open(), and the 'users' count should have been decreased before usb_autopm_put_interface(). In theory, a [URB resubmission] warning can be triggered when the device is opened just between usb_autopm_put_interface() and atomic_dec(&stream->dev->users). The fix is trivial. Reported-by: Ming Lei Signed-off-by: Oliver Neukum Signed-off-by: Laurent Pinchart The patch is in my tree, I'll push it to v3.9. > --- > drivers/media/usb/uvc/uvc_v4l2.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/media/usb/uvc/uvc_v4l2.c > b/drivers/media/usb/uvc/uvc_v4l2.c index f2ee8c6..74937b7 100644 > --- a/drivers/media/usb/uvc/uvc_v4l2.c > +++ b/drivers/media/usb/uvc/uvc_v4l2.c > @@ -501,8 +501,8 @@ static int uvc_v4l2_open(struct file *file) > if (atomic_inc_return(&stream->dev->users) == 1) { > ret = uvc_status_start(stream->dev); > if (ret < 0) { > - usb_autopm_put_interface(stream->dev->intf); > atomic_dec(&stream->dev->users); > + usb_autopm_put_interface(stream->dev->intf); > kfree(handle); > return ret; > } -- Regards, Laurent Pinchart