[PATCH] drm/radeon: fix rare segfault

[Christian König]

On 02.07.2012 18:40, j.glisse at gmail.com wrote:
> From: Jerome Glisse <jglisse at redhat.com>
>
> In gem idle/busy ioctl the radeon object was derefenced after
> drm_gem_object_unreference_unlocked which in case the object
> have been destroyed lead to use of a possibly free pointer with
> possibly wrong data.
>
> Signed-off-by: Jerome Glisse <jglisse at redhat.com>

Reviewed-by: Christian König <christian.koenig at amd.com>

> ---
>   drivers/gpu/drm/radeon/radeon_gem.c |   10 ++++++----
>   1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_gem.c b/drivers/gpu/drm/radeon/radeon_gem.c
> index 74176c5..c8838fc 100644
> --- a/drivers/gpu/drm/radeon/radeon_gem.c
> +++ b/drivers/gpu/drm/radeon/radeon_gem.c
> @@ -325,6 +325,7 @@ int radeon_gem_mmap_ioctl(struct drm_device *dev, void *data,
>   int radeon_gem_busy_ioctl(struct drm_device *dev, void *data,
>   			  struct drm_file *filp)
>   {
> +	struct radeon_device *rdev = dev->dev_private;
>   	struct drm_radeon_gem_busy *args = data;
>   	struct drm_gem_object *gobj;
>   	struct radeon_bo *robj;
> @@ -350,13 +351,14 @@ int radeon_gem_busy_ioctl(struct drm_device *dev, void *data,
>   		break;
>   	}
>   	drm_gem_object_unreference_unlocked(gobj);
> -	r = radeon_gem_handle_lockup(robj->rdev, r);
> +	r = radeon_gem_handle_lockup(rdev, r);
>   	return r;
>   }
>   
>   int radeon_gem_wait_idle_ioctl(struct drm_device *dev, void *data,
>   			      struct drm_file *filp)
>   {
> +	struct radeon_device *rdev = dev->dev_private;
>   	struct drm_radeon_gem_wait_idle *args = data;
>   	struct drm_gem_object *gobj;
>   	struct radeon_bo *robj;
> @@ -369,10 +371,10 @@ int radeon_gem_wait_idle_ioctl(struct drm_device *dev, void *data,
>   	robj = gem_to_radeon_bo(gobj);
>   	r = radeon_bo_wait(robj, NULL, false);
>   	/* callback hw specific functions if any */
> -	if (robj->rdev->asic->ioctl_wait_idle)
> -		robj->rdev->asic->ioctl_wait_idle(robj->rdev, robj);
> +	if (rdev->asic->ioctl_wait_idle)
> +		robj->rdev->asic->ioctl_wait_idle(rdev, robj);
>   	drm_gem_object_unreference_unlocked(gobj);
> -	r = radeon_gem_handle_lockup(robj->rdev, r);
> +	r = radeon_gem_handle_lockup(rdev, r);
>   	return r;
>   }
>