Hi Hans, On Mon, Oct 07, 2024 at 09:46:47AM +0200, Hans Verkuil wrote: > Hi Laurent, > > Just a reminder: I have extensively reviewed this patch here: > > https://lore.kernel.org/linux-media/f4c49ccf-9dc9-475a-8fc9-4ef4c85a729a@xxxxxxxxx/ > > and here (specifically checking for mmap() races): > > https://lore.kernel.org/linux-media/1a10530f-b4bb-4244-84ff-1f2365ae9b23@xxxxxxxxx/ > > To the best of my ability I believe this patch is correct. > > Unless you have any additional concerns I plan to take this patch as a fix for > v6.12 on Monday next week. I thought we had an agreement that I could submit an alternative fix for v6.12. Can you therefore delay merging this patch until v6.12-rc6 ? > Alternatively, you can make a PR for 6.12 with this patch that I can pull from. > > Regards, > > Hans > > On 26/09/2024 07:59, Ricardo Ribalda wrote: > > uvc_unregister_video() can be called asynchronously from > > uvc_disconnect(). If the device is still streaming when that happens, a > > plethora of race conditions can occur. > > > > Make sure that the device has stopped streaming before exiting this > > function. > > > > If the user still holds handles to the driver's file descriptors, any > > ioctl will return -ENODEV from the v4l2 core. > > > > This change makes uvc more consistent with the rest of the v4l2 drivers > > using the vb2_fop_* and vb2_ioctl_* helpers. > > > > Reviewed-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx> > > Suggested-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx> > > Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx> > > --- > > This patch was part of the series: > > https://patchwork.linuxtv.org/project/linux-media/list/?series=13064 > > > > Moved out from it to ease the review. > > --- > > drivers/media/usb/uvc/uvc_driver.c | 32 +++++++++++++++++++++++++++++++- > > 1 file changed, 31 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > > index f0febdc08c2d..bee150b852e4 100644 > > --- a/drivers/media/usb/uvc/uvc_driver.c > > +++ b/drivers/media/usb/uvc/uvc_driver.c > > @@ -1919,11 +1919,41 @@ static void uvc_unregister_video(struct uvc_device *dev) > > struct uvc_streaming *stream; > > > > list_for_each_entry(stream, &dev->streams, list) { > > + /* Nothing to do here, continue. */ > > if (!video_is_registered(&stream->vdev)) > > continue; > > > > + /* > > + * For stream->vdev we follow the same logic as: > > + * vb2_video_unregister_device(). > > + */ > > + > > + /* 1. Take a reference to vdev */ > > + get_device(&stream->vdev.dev); > > + > > + /* 2. Ensure that no new ioctls can be called. */ > > video_unregister_device(&stream->vdev); > > - video_unregister_device(&stream->meta.vdev); > > + > > + /* 3. Wait for old ioctls to finish. */ > > + mutex_lock(&stream->mutex); > > + > > + /* 4. Stop streaming. */ > > + uvc_queue_release(&stream->queue); > > + > > + mutex_unlock(&stream->mutex); > > + > > + put_device(&stream->vdev.dev); > > + > > + /* > > + * For stream->meta.vdev we can directly call: > > + * vb2_video_unregister_device(). > > + */ > > + vb2_video_unregister_device(&stream->meta.vdev); > > + > > + /* > > + * Now both vdevs are not streaming and all the ioctls will > > + * return -ENODEV. > > + */ > > > > uvc_debugfs_cleanup_stream(stream); > > } > > > > --- > > base-commit: 81ee62e8d09ee3c7107d11c8bbfd64073ab601ad > > change-id: 20240926-uvc_stop_streaming-6e9fd20e97bc > > > > Best regards, > -- Regards, Laurent Pinchart
