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[34.145.178.123]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6b09039c2b9sm1548886d6.28.2024.06.11.01.12.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Jun 2024 01:12:07 -0700 (PDT) From: Ricardo Ribalda Subject: [PATCH v5 0/4] uvcvideo: Attempt N to land UVC race conditions fixes Date: Tue, 11 Jun 2024 08:12:05 +0000 Message-Id: <20240611-guenter-mini-v5-0-047b6fe5d08b@chromium.org> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIANYGaGYC/33PTQrCMBAF4KtI1kYmvzauvIe4aJNpG7ApJLYg0 rs7CIKU6mp4A98b5skK5oiFnXZPlnGOJY6JgtnvmO/r1CGPgTKTIBUocLybMN0x8yGmyCtXWdF ApbEVjEhTF+RNrpPvCaXpdqNlH8t9zI/3iVnQuPxomwUHbuUxCPCtRWfPvs/jEKfhMOaOXalrl v+8JI9WCwjGQdBqw6uP16CkWXlF3uvGWxHoJdjy+tsfV16T184Z44WrsMaVX5blBWERQUlwAQA A 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 0.13.0 Back in 2020 Guenter published a set of patches to fix some race conditions in UVC: https://lore.kernel.org/all/20200917022547.198090-5-linux@roeck-us.net/ That kind of race conditions are not only seen in UVC, but are a common seen in 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 off (all?) of the video_is_registered() checks in Guenter's patches. Besides those checks, there were some other valid races fixed in his patches. This patchset tries to fix the races still present in our code. Thanks! Signed-off-by: Ricardo Ribalda --- Changes in v5: Thanks Hans! - Refactor unregister as vb2_video_unregister_device - I have tested the first patch independently from the others, so it could be merged in two steps if needed. - Link to v4: https://lore.kernel.org/r/20240327-guenter-mini-v4-0-49955c198eae@chromium.org Changes in v4: Thanks Sergey and Guenter - Fix typos - Move location of mutex_init - Split patch to make the suspend change explicit - Link to v3: https://lore.kernel.org/r/20240325-guenter-mini-v3-0-c4bc61d84e03@chromium.org Changes in v3: Thanks Hans! - Stop streaming during uvc_unregister() - Refactor the uvc_status code - 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 --- Ricardo Ribalda (4): media: uvcvideo: stop stream during unregister media: uvcvideo: Refactor the status irq API media: uvcvideo: Avoid race condition during unregister media: uvcvideo: Exit early if there is not int_urb drivers/media/usb/uvc/uvc_driver.c | 45 +++++++++++++++++++-------- drivers/media/usb/uvc/uvc_status.c | 62 +++++++++++++++++++++++++++++++++++--- drivers/media/usb/uvc/uvc_v4l2.c | 22 ++++---------- drivers/media/usb/uvc/uvcvideo.h | 10 +++--- 4 files changed, 103 insertions(+), 36 deletions(-) --- base-commit: b14257abe7057def6127f6fb2f14f9adc8acabdb change-id: 20230309-guenter-mini-89861b084ef1 Best regards,