2019-11-09 07:55:38

by Chuhong Yuan

Subject: [PATCH] drm/virtgpu: fix double unregistration

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 <[email protected]>
---
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

2019-11-12 09:41:59

by Daniel Vetter

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 <[email protected]>

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

2019-11-12 11:06:46

by Chuhong Yuan

Subject: Re: [PATCH] drm/virtgpu: fix double unregistration

On Tue, Nov 12, 2019 at 5:40 PM Daniel Vetter <[email protected]> wrote:
>
> 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 <[email protected]>
>
> 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
>

I am sorry that I have to focus on my current project in recent days.
But since this is a problem, I have written a Coccinelle script just now
to find drm_put_dev and open-code it.
I hope this helps.
The script is:

virtual patch

@ drm_put_dev depends on patch exists @
expression dev;
@@

- drm_put_dev(dev);
+ drm_dev_unregister(dev);
+ drm_dev_put(dev);

Regards,
Chuhong
> > ---
> > 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