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Thu, 09 Mar 2023 06:44:19 -0800 (PST) Received: from alco.roam.corp.google.com ([2620:0:1059:10:1645:7aa4:a765:1966]) by smtp.gmail.com with ESMTPSA id l6-20020a50d6c6000000b004bdcc480c41sm9708931edj.96.2023.03.09.06.44.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Mar 2023 06:44:19 -0800 (PST) Subject: [PATCH v2 0/3] uvcvideo: Attempt N to land UVC race conditions fixes MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIALTwCWQC/3WNwQqDMBBEf0X23C1JLKn21P8oPZi4mgVNYKNCkf x7Q+89DW/gzZyQSZgyPJoThA7OnGIFc2nAhyHOhDxWBqNMq1rV47xT3Ehw5cjY9Z3VTnU3mjRUxQ 2Z0MkQfahS3JelloHzluTzuzh0jdeftUOjQmvuo1Z+stTbpw+SVt7Xa5IZ3qWUL2dRYMywAAAA From: Ricardo Ribalda Date: Thu, 09 Mar 2023 15:44:04 +0100 Message-Id: <20230309-guenter-mini-v2-0-e6410d590d43@chromium.org> To: Mauro Carvalho Chehab Cc: Ricardo Ribalda , Laurent Pinchart , Max Staudt , Alan Stern , Sakari Ailus , Guenter Roeck , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Sean Paul , Tomasz Figa , Hans Verkuil X-Mailer: b4 0.11.0-dev-696ae X-Developer-Signature: v=1; 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a=openpgp; fpr=9EC3BB66E2FC129A6F90B39556A0D81F9F782DA9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Back in 2020 Guenter published a set of patches to fix some race conditions on UVC. https://lore.kernel.org/all/20200917022547.198090-5-linux@roeck-us.net/ That kind of race conditions are not only seen on UVC, but are a common sin on almost all the kernel, so this is what it was decided back then that we should try to fix them at higher levels. After that. A lot of video_is_registered() were added to the core: ``` ribalda@alco:~/work/linux$ git grep is_registered drivers/media/v4l2-core/ drivers/media/v4l2-core/v4l2-compat-ioctl32.c: if (!video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (video_is_registered(vdev)) { drivers/media/v4l2-core/v4l2-dev.c: if (video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (!video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (vdev == NULL || !video_is_registered(vdev)) { drivers/media/v4l2-core/v4l2-dev.c: if (video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-dev.c: if (!vdev || !video_is_registered(vdev)) drivers/media/v4l2-core/v4l2-ioctl.c: if (!video_is_registered(vfd)) { drivers/media/v4l2-core/v4l2-subdev.c: if (video_is_registered(vdev)) { ``` And recently Sakari is trying to land: https://lore.kernel.org/linux-media/20230201214535.347075-1-sakari.ailus@linux.intel.com/ Which will make obsolete a lof (all?) of the video_is_registered() checks on Guenters patches. Besides those checks, there were some other valid races fixed on his patches. This series is just a rebase of what I think is missing on UVC even if we fixed v4l2/core with all the video_is_register() checks removed. Thanks! To: Mauro Carvalho Chehab Cc: Guenter Roeck Cc: Max Staudt Cc: Tomasz Figa Cc: Sakari Ailus Cc: Laurent Pinchart Cc: Alan Stern Cc: Hans Verkuil Cc: linux-media@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: Sean Paul Signed-off-by: Ricardo Ribalda --- Changes in v2: - Actually send the series to the ML an not only to individuals. - Link to v1: https://lore.kernel.org/r/20230309-guenter-mini-v1-0-627d10cf6e96@chromium.org --- Guenter Roeck (3): media: uvcvideo: Cancel async worker earlier media: uvcvideo: Lock video streams and queues while unregistering media: uvcvideo: Release stream queue when unregistering video device drivers/media/usb/uvc/uvc_ctrl.c | 11 +++++++---- drivers/media/usb/uvc/uvc_driver.c | 12 ++++++++++++ drivers/media/usb/uvc/uvcvideo.h | 1 + 3 files changed, 20 insertions(+), 4 deletions(-) --- base-commit: 63355b9884b3d1677de6bd1517cd2b8a9bf53978 change-id: 20230309-guenter-mini-89861b084ef1 Best regards, -- Ricardo Ribalda