* anon_vma_fork(). The first three want an exact copy of src, while the last
* one, anon_vma_fork(), may try to reuse an existing anon_vma to prevent
* endless growth of anon_vma. Since dst->anon_vma is set to NULL before call,
* anon_vma_fork(). The first three want an exact copy of src, while the last
* one, anon_vma_fork(), may try to reuse an existing anon_vma to prevent
* endless growth of anon_vma. Since dst->anon_vma is set to NULL before call,