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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C361C61D97 for ; Wed, 22 Nov 2023 13:33:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344158AbjKVNda (ORCPT ); Wed, 22 Nov 2023 08:33:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47330 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343773AbjKVNd2 (ORCPT ); Wed, 22 Nov 2023 08:33:28 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4CEDE197; Wed, 22 Nov 2023 05:33:25 -0800 (PST) Received: from pendragon.ideasonboard.com (213-243-189-158.bb.dnainternet.fi [213.243.189.158]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 21726276; Wed, 22 Nov 2023 14:32:53 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1700659973; bh=ovNRFCOwfiedgo/BxjM6ABJ6tIltn5tkgyoVDp1O/vE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pKeOAKQZCqI9EPX5E6sIkR1baYbxjtlCecJ7izSg2dK9xA9w8qXyoaBdtUN3KP4UC il2klRfQnZOL0sNGdJorB2DLCGXAnhJcqtdTlyxOQWEi6y+o1dVT14fXuQ4VHzpn46 QwqPh4q3j5X1xrg3ImeanqvUsq1vaHgURP+PRUmw= Date: Wed, 22 Nov 2023 15:33:30 +0200 From: Laurent Pinchart To: Ricardo Ribalda Cc: Mauro Carvalho Chehab , Guenter Roeck , Tomasz Figa , Alan Stern , Hans Verkuil , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Sean Paul , Sakari Ailus Subject: Re: [PATCH v5 3/3] media: uvcvideo: Do not use usb_* functions after .disconnect Message-ID: <20231122133330.GE3909@pendragon.ideasonboard.com> References: <20231122-guenter-mini-v5-0-15d8cd8ed74f@chromium.org> <20231122-guenter-mini-v5-3-15d8cd8ed74f@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20231122-guenter-mini-v5-3-15d8cd8ed74f@chromium.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 22, 2023 at 11:45:49AM +0000, Ricardo Ribalda wrote: > usb drivers should not call to any I/O function after the > .disconnect() callback has been triggered. > https://www.kernel.org/doc/html/latest/driver-api/usb/callbacks.html#the-disconnect-callback > > If an application is receiving frames form a camera and the device is > disconnected: the device will call close() after the usb .disconnect() > callback has been called. The streamoff path will call usb_set_interface > or usb_clear_halt, which is not allowed. > > This patch only solves the calls to close() *after* .disconnect() is > being called. > > Trace: > [ 1065.389723] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter > [ 1065.390160] drivers/media/usb/uvc/uvc_driver.c:2264 uvc_disconnect exit > [ 1065.433956] drivers/media/usb/uvc/uvc_v4l2.c:659 uvc_v4l2_release enter > [ 1065.433973] drivers/media/usb/uvc/uvc_video.c:2274 uvc_video_stop_streaming enter > [ 1065.434560] drivers/media/usb/uvc/uvc_video.c:2285 uvc_video_stop_streaming exit > [ 1065.435154] drivers/media/usb/uvc/uvc_v4l2.c:680 uvc_v4l2_release exit > [ 1065.435188] drivers/media/usb/uvc/uvc_driver.c:2248 uvc_disconnect enter > > Signed-off-by: Ricardo Ribalda > --- > drivers/media/usb/uvc/uvc_driver.c | 2 ++ > drivers/media/usb/uvc/uvc_video.c | 45 ++++++++++++++++++++++++-------------- > drivers/media/usb/uvc/uvcvideo.h | 2 ++ > 3 files changed, 32 insertions(+), 17 deletions(-) > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > index d5dbf2644272..d78640d422f4 100644 > --- a/drivers/media/usb/uvc/uvc_driver.c > +++ b/drivers/media/usb/uvc/uvc_driver.c > @@ -2266,6 +2266,8 @@ static void uvc_disconnect(struct usb_interface *intf) > return; > > uvc_unregister_video(dev); > + /* Barrier needed to pair with uvc_video_stop_streaming(). */ > + smp_store_release(&dev->disconnected, true); I can't think this would be such a hot path that we really need barriers in the driver. > kref_put(&dev->ref, uvc_delete); > } > > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c > index 28dde08ec6c5..f5ef375088de 100644 > --- a/drivers/media/usb/uvc/uvc_video.c > +++ b/drivers/media/usb/uvc/uvc_video.c > @@ -2243,28 +2243,39 @@ int uvc_video_start_streaming(struct uvc_streaming *stream) > return ret; > } > > -void uvc_video_stop_streaming(struct uvc_streaming *stream) > +static void uvc_video_halt(struct uvc_streaming *stream) > { > - uvc_video_stop_transfer(stream, 1); > + unsigned int epnum; > + unsigned int pipe; > + unsigned int dir; > > if (stream->intf->num_altsetting > 1) { > usb_set_interface(stream->dev->udev, stream->intfnum, 0); > - } else { > - /* > - * UVC doesn't specify how to inform a bulk-based device > - * when the video stream is stopped. Windows sends a > - * CLEAR_FEATURE(HALT) request to the video streaming > - * bulk endpoint, mimic the same behaviour. > - */ > - unsigned int epnum = stream->header.bEndpointAddress > - & USB_ENDPOINT_NUMBER_MASK; > - unsigned int dir = stream->header.bEndpointAddress > - & USB_ENDPOINT_DIR_MASK; > - unsigned int pipe; > - > - pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir; > - usb_clear_halt(stream->dev->udev, pipe); > + return; > } > > + /* > + * UVC doesn't specify how to inform a bulk-based device > + * when the video stream is stopped. Windows sends a > + * CLEAR_FEATURE(HALT) request to the video streaming > + * bulk endpoint, mimic the same behaviour. > + */ > + epnum = stream->header.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK; > + dir = stream->header.bEndpointAddress & USB_ENDPOINT_DIR_MASK; > + pipe = usb_sndbulkpipe(stream->dev->udev, epnum) | dir; > + usb_clear_halt(stream->dev->udev, pipe); > +} > + > +void uvc_video_stop_streaming(struct uvc_streaming *stream) > +{ > + uvc_video_stop_transfer(stream, 1); > + > + /* > + * Barrier needed to pair with uvc_disconnect(). > + * We cannot call usb_* functions on a disconnected USB device. > + */ > + if (!smp_load_acquire(&stream->dev->disconnected)) > + uvc_video_halt(stream); > + > uvc_video_clock_cleanup(stream); > } > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h > index ba8f8c1f2c83..5b1a3643de05 100644 > --- a/drivers/media/usb/uvc/uvcvideo.h > +++ b/drivers/media/usb/uvc/uvcvideo.h > @@ -559,6 +559,8 @@ struct uvc_device { > unsigned int users; > atomic_t nmappings; > > + bool disconnected; > + > /* Video control interface */ > #ifdef CONFIG_MEDIA_CONTROLLER > struct media_device mdev; > -- Regards, Laurent Pinchart