From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F3D2C433E0 for ; Tue, 22 Dec 2020 08:05:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4B9D23110 for ; Tue, 22 Dec 2020 08:05:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726022AbgLVIFX (ORCPT ); Tue, 22 Dec 2020 03:05:23 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:42222 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725811AbgLVIFW (ORCPT ); Tue, 22 Dec 2020 03:05:22 -0500 Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 7A1C39E6; Tue, 22 Dec 2020 09:04:40 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1608624280; bh=u9ey3spq/ryytAsWdO8BpNmB77m31wxs7DKBWTLcGQ4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JdIQv2IWvf2m95HlOkHlJ/foyoJOE9gi/4EPlVO/WR/oQzBFvl8wW1pIMUgCfPBcb o27gwQ4KxLtb5uLFtLrPR9faCTPueGPKq1zxsWFy+lvwaCTlGDJCqOjXONDVTHSJrh +nOG5IyoCVT187jWQErVMoVVZwteOCeLpLshZQs8= Date: Tue, 22 Dec 2020 10:04:32 +0200 From: Laurent Pinchart To: Ricardo Ribalda Cc: Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 01/12] media: uvcvideo: Fix race condition handling events Message-ID: References: <20201221164819.792019-1-ribalda@chromium.org> <20201221164819.792019-2-ribalda@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20201221164819.792019-2-ribalda@chromium.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Ricardo, Thank you for the patch. On Mon, Dec 21, 2020 at 05:48:08PM +0100, Ricardo Ribalda wrote: > The control and its data needs to be copied to the workqueue at the same > time to avoid half-updates of the events. > This is, events reported to userspace were the control id does not match > its value. Actually, after discussing this with you on IRC, I'm not sure there's a problem. The URB is resubmitted by uvc_ctrl_status_event_work(), so the data shouldn't be overwritten before it is processed. > Signed-off-by: Ricardo Ribalda > --- > drivers/media/usb/uvc/uvc_ctrl.c | 2 +- > drivers/media/usb/uvc/uvcvideo.h | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c > index 011e69427b7c..aa18dcdf8165 100644 > --- a/drivers/media/usb/uvc/uvc_ctrl.c > +++ b/drivers/media/usb/uvc/uvc_ctrl.c > @@ -1332,7 +1332,7 @@ bool uvc_ctrl_status_event(struct urb *urb, struct uvc_video_chain *chain, > return false; > } > > - w->data = data; > + memcpy(w->data, data, ctrl->info.size); > w->urb = urb; > w->chain = chain; > w->ctrl = ctrl; > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h > index a3dfacf069c4..0db6c2e0bd98 100644 > --- a/drivers/media/usb/uvc/uvcvideo.h > +++ b/drivers/media/usb/uvc/uvcvideo.h > @@ -678,7 +678,7 @@ struct uvc_device { > struct urb *urb; > struct uvc_video_chain *chain; > struct uvc_control *ctrl; > - const void *data; > + u8 data[UVC_MAX_STATUS_SIZE]; > } async_ctrl; > }; > -- Regards, Laurent Pinchart