[PATCH] drm/radeon: avoid segfault on device open when accel is not working.

[Alex Deucher]

On Wed, May 7, 2014 at 4:35 PM,  <j.glisse at gmail.com> wrote:
> From: Jérôme Glisse <jglisse at redhat.com>
>
> When accel is not working on device with virtual address space radeon
> segfault because the ib buffer is NULL and trying to map it inside the
> virtual address space trigger segfault. This patch only map the ib
> buffer if accel is working.
>
> Cc: <stable at vger.kernel.org>
> Signed-off-by: Jérôme Glisse <jglisse at redhat.com>

Probably also fixes:
https://bugzilla.kernel.org/show_bug.cgi?id=73931

Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

> ---
>  drivers/gpu/drm/radeon/radeon_kms.c | 55 +++++++++++++++++++------------------
>  1 file changed, 29 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_kms.c b/drivers/gpu/drm/radeon/radeon_kms.c
> index 0cc47f1..eaaedba 100644
> --- a/drivers/gpu/drm/radeon/radeon_kms.c
> +++ b/drivers/gpu/drm/radeon/radeon_kms.c
> @@ -577,28 +577,29 @@ int radeon_driver_open_kms(struct drm_device *dev, struct drm_file *file_priv)
>                         return r;
>                 }
>
> -               r = radeon_bo_reserve(rdev->ring_tmp_bo.bo, false);
> -               if (r) {
> -                       radeon_vm_fini(rdev, &fpriv->vm);
> -                       kfree(fpriv);
> -                       return r;
> -               }
> +               if (rdev->accel_working) {
> +                       r = radeon_bo_reserve(rdev->ring_tmp_bo.bo, false);
> +                       if (r) {
> +                               radeon_vm_fini(rdev, &fpriv->vm);
> +                               kfree(fpriv);
> +                               return r;
> +                       }
>
> -               /* map the ib pool buffer read only into
> -                * virtual address space */
> -               bo_va = radeon_vm_bo_add(rdev, &fpriv->vm,
> -                                        rdev->ring_tmp_bo.bo);
> -               r = radeon_vm_bo_set_addr(rdev, bo_va, RADEON_VA_IB_OFFSET,
> -                                         RADEON_VM_PAGE_READABLE |
> -                                         RADEON_VM_PAGE_SNOOPED);
> +                       /* map the ib pool buffer read only into
> +                        * virtual address space */
> +                       bo_va = radeon_vm_bo_add(rdev, &fpriv->vm,
> +                                                rdev->ring_tmp_bo.bo);
> +                       r = radeon_vm_bo_set_addr(rdev, bo_va, RADEON_VA_IB_OFFSET,
> +                                                 RADEON_VM_PAGE_READABLE |
> +                                                 RADEON_VM_PAGE_SNOOPED);
>
> -               radeon_bo_unreserve(rdev->ring_tmp_bo.bo);
> -               if (r) {
> -                       radeon_vm_fini(rdev, &fpriv->vm);
> -                       kfree(fpriv);
> -                       return r;
> +                       radeon_bo_unreserve(rdev->ring_tmp_bo.bo);
> +                       if (r) {
> +                               radeon_vm_fini(rdev, &fpriv->vm);
> +                               kfree(fpriv);
> +                               return r;
> +                       }
>                 }
> -
>                 file_priv->driver_priv = fpriv;
>         }
>
> @@ -626,13 +627,15 @@ void radeon_driver_postclose_kms(struct drm_device *dev,
>                 struct radeon_bo_va *bo_va;
>                 int r;
>
> -               r = radeon_bo_reserve(rdev->ring_tmp_bo.bo, false);
> -               if (!r) {
> -                       bo_va = radeon_vm_bo_find(&fpriv->vm,
> -                                                 rdev->ring_tmp_bo.bo);
> -                       if (bo_va)
> -                               radeon_vm_bo_rmv(rdev, bo_va);
> -                       radeon_bo_unreserve(rdev->ring_tmp_bo.bo);
> +               if (rdev->accel_working) {
> +                       r = radeon_bo_reserve(rdev->ring_tmp_bo.bo, false);
> +                       if (!r) {
> +                               bo_va = radeon_vm_bo_find(&fpriv->vm,
> +                                                         rdev->ring_tmp_bo.bo);
> +                               if (bo_va)
> +                                       radeon_vm_bo_rmv(rdev, bo_va);
> +                               radeon_bo_unreserve(rdev->ring_tmp_bo.bo);
> +                       }
>                 }
>
>                 radeon_vm_fini(rdev, &fpriv->vm);
> --
> 1.9.0
>
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