Pixmap pointer is used but may be null in resource.c
size->refCnt = pixmap->refcnt;
if (pixmap && pixmap->refcnt)
https://gitlab.freedesktop.org/xorg/xserver/-/blob/master/dix/resource.c#L274-276
size->refCnt = pixmap->refcnt;
if (pixmap && pixmap->refcnt)
https://gitlab.freedesktop.org/xorg/xserver/-/blob/master/dix/resource.c#L274-276