Re: [PATCH v2 8/9] drm/rockchip: gem: Don't alloc/free gem buf before drm dev registered

[jeffy]

Hi Daniel,

On 04/03/2017 03:41 PM, Daniel Vetter wrote:
> On Sat, Apr 01, 2017 at 07:35:28PM +0800, Jeffy Chen wrote:
> > Signed-off-by: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
> > ---
> >
> > Changes in v2: None
>
> Wut? How is this even possible? If you haven't registered the driver yet,
> there's no way for userspace to call allocation functions. Anything else
> is a driver bug that should be handled by fixing the driver load sequence.
> The only thing I can imagine is that you init the fbdev stuff too early,
> in that case pls fix that. Not apply this duct-tape here.
after unbind drm drivers, userspace may still have the chance to call 
gem ioctls before we call drm_dev_register again. and we can add a 
sanity check here to avoid invalid access.

i'll try to make a better commit message in next version soon, thanx for 
reply.
> Thanks, Daniel
>
> >   drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 8 ++++++++
> >   1 file changed, 8 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> > index df9e570..2bf8024 100644
> > --- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> > +++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
> > @@ -184,6 +184,9 @@ static int rockchip_gem_alloc_buf(struct rockchip_gem_object *rk_obj,
> >   	struct drm_device *drm = obj->dev;
> >   	struct rockchip_drm_private *private = drm->dev_private;
> >
> > +	if (!drm->registered)
> > +		return -ENODEV;
> > +
> >   	if (private->domain)
> >   		return rockchip_gem_alloc_iommu(rk_obj, alloc_kmap);
> >   	else
> > @@ -208,6 +211,11 @@ static void rockchip_gem_free_dma(struct rockchip_gem_object *rk_obj)
> >
> >   static void rockchip_gem_free_buf(struct rockchip_gem_object *rk_obj)
> >   {
> > +	struct drm_device *drm = rk_obj->base.dev;
> > +
> > +	if (!drm->registered)
> > +		return;
> > +
> >   	if (rk_obj->pages)
> >   		rockchip_gem_free_iommu(rk_obj);
> >   	else
> > --
> > 2.1.4
> >
> >
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