On 24.09.2015 15:25, Frediano Ziglio wrote:
> qxl_bo_unref calls drm_gem_object_unreference_unlocked which
> locks dev->struct_mutex. However this lock could be already
> locked if the call came from qxl_gem_object_free.
> As we don't need to call qxl_bo_ref/qxl_bo_unref cause
> qxl_release_list_add will hold a reference by itself avoid
> to call them and the possible deadlock.
> 
> Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> ---
>  drivers/gpu/drm/qxl/qxl_release.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/qxl/qxl_release.c 
> b/drivers/gpu/drm/qxl/qxl_release.c
> index b66ec33..4efa8e2 100644
> --- a/drivers/gpu/drm/qxl/qxl_release.c
> +++ b/drivers/gpu/drm/qxl/qxl_release.c
> @@ -307,7 +307,7 @@ int qxl_alloc_surface_release_reserved(struct qxl_device 
> *qdev,
>               idr_ret = qxl_release_alloc(qdev, QXL_RELEASE_SURFACE_CMD, 
> release);
>               if (idr_ret < 0)
>                       return idr_ret;
> -             bo = qxl_bo_ref(to_qxl_bo(entry->tv.bo));
> +             bo = to_qxl_bo(entry->tv.bo);
>  
>               (*release)->release_offset = create_rel->release_offset + 64;
>  
> @@ -316,8 +316,6 @@ int qxl_alloc_surface_release_reserved(struct qxl_device 
> *qdev,
>               info = qxl_release_map(qdev, *release);
>               info->id = idr_ret;
>               qxl_release_unmap(qdev, *release, info);
> -
> -             qxl_bo_unref(&bo);
>               return 0;
>       }
>  
> 


Tested with:
 - Rawhide-Xfce-Live-1001.iso
  \ 4.3.0-0.rc3.git2.4.fc24.x86_64
   + v2-1-2-drm-qxl-avoid-buffer-reservation-in-qxl_crtc_page_flip.patch
   + v2-2-2-drm-qxl-avoid-dependency-lock.patch

Tested-by: poma <pomidorabelisima at gmail.com>


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