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[34.150.221.228]) by smtp.gmail.com with ESMTPSA id ct2-20020a056214178200b0065b0d9b4ee7sm4199409qvb.20.2023.11.21.11.53.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Nov 2023 11:53:50 -0800 (PST) From: Ricardo Ribalda Subject: [PATCH v3 0/3] uvcvideo: Attempt N to land UVC race conditions fixes Date: Tue, 21 Nov 2023 19:53:47 +0000 Message-Id: <20231121-guenter-mini-v3-0-d8a5eae2312b@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIAMsKXWUC/33NQQrDIBAF0KsE17WMmtrYVe9Rukh0EgcSBU2EE nL3SpeFdjX8D+/PzjImwsxuzc4SFsoUQw3q1DDr+zAhJ1czkyAVKDB82jCsmPhCgXhnOi0G6Fo cBatk6DPyIfXB+orCNs+19JTXmF6fF0XU8/ixVgQHruXVCbCjRqPv1qe40LacY5rYs24V+c/L6 lG3AtzFgGvVlz+O4w2dFeAM8AAAAA== To: Mauro Carvalho Chehab Cc: Guenter Roeck , Tomasz Figa , Laurent Pinchart , Alan Stern , Hans Verkuil , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Sean Paul , Ricardo Ribalda , Sakari Ailus X-Mailer: b4 0.12.3 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 lot of (all?) of the video_is_registered() checks on Guenter's 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! Signed-off-by: Ricardo Ribalda --- Changes in v3: - Introduce media: uvcvideo: Do not halt the device after disconnect - Introduce media: uvcvideo: Always use uvc_status_stop() - Link to v2: https://lore.kernel.org/r/20230309-guenter-mini-v2-0-e6410d590d43@chromium.org 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 (1): media: uvcvideo: Lock video streams and queues while unregistering Ricardo Ribalda (2): media: uvcvideo: Always use uvc_status_stop() media: uvcvideo: Do not halt the device after disconnect drivers/media/usb/uvc/uvc_ctrl.c | 4 ---- drivers/media/usb/uvc/uvc_driver.c | 11 ++++++++++ drivers/media/usb/uvc/uvc_status.c | 2 +- drivers/media/usb/uvc/uvc_video.c | 45 ++++++++++++++++++++++++-------------- drivers/media/usb/uvc/uvcvideo.h | 2 ++ 5 files changed, 42 insertions(+), 22 deletions(-) --- base-commit: 98b1cc82c4affc16f5598d4fa14b1858671b2263 change-id: 20230309-guenter-mini-89861b084ef1 Best regards, -- Ricardo Ribalda