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 <ribalda@xxxxxxxxxxxx> --- 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); 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; -- 2.43.0.rc1.413.gea7ed67945-goog
