Commit 36d421e6 authored by Zack Rusin's avatar Zack Rusin
Browse files

drm/vmwgfx: Stop accessing buffer objects which failed init 



ttm_bo_init_reserved on failure puts the buffer object back which
causes it to be deleted, but kfree was still being called on the same
buffer in vmw_bo_create leading to a double free.

After the double free the vmw_gem_object_create_with_handle was
setting the gem function objects before checking the return status
of vmw_bo_create leading to null pointer access.

Fix the entire path by relaying on ttm_bo_init_reserved to delete the
buffer objects on failure and making sure the return status is checked
before setting the gem function objects on the buffer object.

Signed-off-by: default avatarZack Rusin <zackr@vmware.com>
Fixes: 8afa13a0 ("drm/vmwgfx: Implement DRIVER_GEM")
Reviewed-by: default avatarMaaz Mombasawala <mombasawalam@vmware.com>
Reviewed-by: default avatarMartin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230208180050.2093426-1-zack@kde.org
parent a44df74c

drivers/gpu/drm/vmwgfx/vmwgfx_bo.c

+3 −1
Original line number Diff line number Diff line
@@ -416,13 +416,15 @@ int vmw_bo_create(struct vmw_private *vmw, 
		return -ENOMEM;

	}



	/*

	 * vmw_bo_init will delete the *p_bo object if it fails

	 */

	ret = vmw_bo_init(vmw, *p_bo, params, vmw_bo_free);

	if (unlikely(ret != 0))

		goto out_error;



	return ret;

out_error:

	kfree(*p_bo);

	*p_bo = NULL;

	return ret;

}

drivers/gpu/drm/vmwgfx/vmwgfx_gem.c

+2 −2
Original line number Diff line number Diff line
@@ -127,11 +127,11 @@ int vmw_gem_object_create_with_handle(struct vmw_private *dev_priv, 
	};



	ret = vmw_bo_create(dev_priv, &params, p_vbo);



	(*p_vbo)->tbo.base.funcs = &vmw_gem_object_funcs;

	if (ret != 0)

		goto out_no_bo;



	(*p_vbo)->tbo.base.funcs = &vmw_gem_object_funcs;



	ret = drm_gem_handle_create(filp, &(*p_vbo)->tbo.base, handle);

	/* drop reference from allocate - handle holds it now */

	drm_gem_object_put(&(*p_vbo)->tbo.base);