media: uvcvideo: Avoid race condition during unregister

The control events are handled asynchronously by the driver. Once the
control event are handled, the urb is re-submitted.

If we simply kill the urb, there is a chance that a control event is
waiting to be processed, which will re-submit the urb after the device is
disconnected.

Fix this by calling uvc_status_suspend(), which flushes the async
controls and kills the URB in a race-free manner.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Link: https://lore.kernel.org/r/20240926-guenter-mini-v7-2-690441953d4a@chromium.org
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c
index 0bdba5383286408d2c158217d6a8eb6f97e95896..9c5e5e7b7bd7959ffc80f2a72c3adbca472e747e 100644 (file)
--- a/drivers/media/usb/uvc/uvc_status.c
+++ b/drivers/media/usb/uvc/uvc_status.c
@@ -294,7 +294,7 @@ int uvc_status_init(struct uvc_device *dev)
 
 void uvc_status_unregister(struct uvc_device *dev)
 {
-       usb_kill_urb(dev->int_urb);
+       uvc_status_suspend(dev);
        uvc_input_unregister(dev);
 }