Re: [PATCH] userfaultfd: mcopy_atomic: update cases returning -ENOENT

[Andrea Arcangeli]

On Tue, Feb 07, 2017 at 05:02:50PM +0200, Mike Rapoport wrote:
> Hello Andrew,
> 
> The patch below is an incremental fixup for concerns Andrea raised at [1].
> Please let me know if you prefer me to update the original patch and
> resend.
> 
> [1] http://www.spinics.net/lists/linux-mm/msg121267.html
> 
> --
> Sincerely yours,
> Mike.
> 
> From 8acff65ecee8ca4cc892d35b45125c34568d1c93 Mon Sep 17 00:00:00 2001
> From: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
> Date: Tue, 7 Feb 2017 11:50:17 +0200
> Subject: [PATCH] userfaultfd: mcopy_atomic: update cases returning -ENOENT
> 
> As Andrea commented in [1], if the VMA covering the address was unmapped,
> we may end up with a VMA a way above the faulting address. In this case we
> would like to return -ENOENT to allow uffd monitor detection of VMA
> removal.
> 
> [1] http://www.spinics.net/lists/linux-mm/msg121267.html
> 
> Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>

Reviewed-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>