This reverts commit aec8a40228acb385d60feec59b54573d307e60f3. The dma_buf field in struct drm_gem_object is not stable over the object instance's lifetime. The field becomes NULL when user space releases the final GEM handle on the buffer object. This resulted in a NULL-pointer deref.
Workarounds in commit 5307dce878d4 ("drm/gem: Acquire references on GEM handles for framebuffers") and commit f6bfc9afc751 ("drm/framebuffer: Acquire internal references on GEM handles") only solved the problem partially. They especially don't work for buffer objects without a DRM framebuffer associated. Hence, this revert to going back to using .import_attach->dmabuf. Signed-off-by: Thomas Zimmermann <tzimmerm...@suse.de> Reviewed-by: Simona Vetter <simona.vet...@ffwll.ch> --- drivers/gpu/drm/vmwgfx/vmwgfx_gem.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c b/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c index 7057d852951b..eedf1fe60be7 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_gem.c @@ -85,10 +85,10 @@ static int vmw_gem_vmap(struct drm_gem_object *obj, struct iosys_map *map) int ret; if (drm_gem_is_imported(obj)) { - ret = dma_buf_vmap(obj->dma_buf, map); + ret = dma_buf_vmap(obj->import_attach->dmabuf, map); if (!ret) { if (drm_WARN_ON(obj->dev, map->is_iomem)) { - dma_buf_vunmap(obj->dma_buf, map); + dma_buf_vunmap(obj->import_attach->dmabuf, map); return -EIO; } } @@ -102,7 +102,7 @@ static int vmw_gem_vmap(struct drm_gem_object *obj, struct iosys_map *map) static void vmw_gem_vunmap(struct drm_gem_object *obj, struct iosys_map *map) { if (drm_gem_is_imported(obj)) - dma_buf_vunmap(obj->dma_buf, map); + dma_buf_vunmap(obj->import_attach->dmabuf, map); else drm_gem_ttm_vunmap(obj, map); } -- 2.50.0