On 09/22, Peter Xu wrote: > > On Tue, Sep 22, 2020 at 08:23:18PM +0200, Oleg Nesterov wrote: > > > > But I still think that !pte_none() -> pte_none() transition is not possible > > under mmap_write_lock()... > > > > OK, let me repeat I don't understans these code paths enough, let me reword: > > I don't see how this transition is possible. > > Though I guess I'll keep my wording, because I still think it's accurate to > me. :) > > Can we e.g. punch a page hole without changing vmas? punch a hole? I don't know what does it mean... However, I think you are right anyway. I forgot that (at least) truncate can clear this pte without mmap_sem after pte_unmap_unlock(). So I think you are right, the current code is wrong too. Thanks! Oleg.
