linux-kernel - Re: [PATCH] drm/virtgpu: fix double unregistration

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Date:   Tue, 12 Nov 2019 10:40:31 +0100
From:   Daniel Vetter <daniel@...ll.ch>
To:     Chuhong Yuan <hslester96@...il.com>
Cc:     David Airlie <airlied@...ux.ie>, Gerd Hoffmann <kraxel@...hat.com>,
        Daniel Vetter <daniel@...ll.ch>,
        dri-devel@...ts.freedesktop.org,
        virtualization@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/virtgpu: fix double unregistration

On Sat, Nov 09, 2019 at 03:54:17PM +0800, Chuhong Yuan wrote:
> drm_put_dev also calls drm_dev_unregister, so dev will be unregistered
> twice.
> Replace it with drm_dev_put to fix it.
> 
> Signed-off-by: Chuhong Yuan <hslester96@...il.com>

Nice catch, I'll apply.

Since this is so confusing, we actually have a todo to remove drm_put_dev
completely from the codebase (and open-code it with explicit
unregister+put). Want to do that little patch series to update the
remaining few drivers and then remove drm_put_dev from core code?

Thanks, Daniel

> ---
>  drivers/gpu/drm/virtio/virtgpu_drv.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
> index 0fc32fa0b3c0..fccc24e21af8 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
> @@ -138,7 +138,7 @@ static void virtio_gpu_remove(struct virtio_device *vdev)
>  
>  	drm_dev_unregister(dev);
>  	virtio_gpu_deinit(dev);
> -	drm_put_dev(dev);
> +	drm_dev_put(dev);
>  }
>  
>  static void virtio_gpu_config_changed(struct virtio_device *vdev)
> -- 
> 2.23.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch