media: uvcvideo: Return queued buffers on start_streaming() failure

Return buffers if streaming fails to start due to uvc_pm_get() error.

This bug may be responsible for a warning I got running

    while :; do yavta -c3 /dev/video0; done

on an xHCI controller which failed under this workload.
I had no luck reproducing this warning again to confirm.

xhci_hcd 0000:09:00.0: HC died; cleaning up
usb 13-2: USB disconnect, device number 2
WARNING: CPU: 2 PID: 29386 at drivers/media/common/videobuf2/videobuf2-core.c:1803 vb2_start_streaming+0xac/0x120

Fixes: 7dd56c47784a ("media: uvcvideo: Remove stream->is_streaming field")
Cc: stable@vger.kernel.org
Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
Reviewed-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patch.msgid.link/20251015133642.3dede646.michal.pecio@gmail.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>

diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
index 681a74ed09fb1f109d2b21bf490e8b26eeec0a3e..8b8f44b4a0451ec1a5703ff96e039efcd29f57d0 100644 (file)
--- a/drivers/media/usb/uvc/uvc_queue.c
+++ b/drivers/media/usb/uvc/uvc_queue.c
@@ -177,18 +177,20 @@ static int uvc_start_streaming_video(struct vb2_queue *vq, unsigned int count)
 
        ret = uvc_pm_get(stream->dev);
        if (ret)
-               return ret;
+               goto err_buffers;
 
        queue->buf_used = 0;
 
        ret = uvc_video_start_streaming(stream);
-       if (ret == 0)
-               return 0;
+       if (ret)
+               goto err_pm;
 
-       uvc_pm_put(stream->dev);
+       return 0;
 
+err_pm:
+       uvc_pm_put(stream->dev);
+err_buffers:
        uvc_queue_return_buffers(queue, UVC_BUF_STATE_QUEUED);
-
        return ret;
 }