lkml.org 
[lkml]   [2018]   [Jul]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC v3 PATCH 4/5] mm: mmap: zap pages with read mmap_sem for large mapping
On Mon, Jul 02, 2018 at 02:49:28PM +0200, Michal Hocko wrote:
> On Mon 02-07-18 15:33:50, Kirill A. Shutemov wrote:
> [...]
> > I probably miss the explanation somewhere, but what's wrong with allowing
> > other thread to re-populate the VMA?
>
> We have discussed that earlier and it boils down to how is racy access
> to munmap supposed to behave. Right now we have either the original
> content or SEGV. If we allow to simply madvise_dontneed before real
> unmap we could get a new page as well. There might be (quite broken I
> would say) user space code that would simply corrupt data silently that
> way.

Okay, so we add a lot of complexity to accommodate broken userspace that
may or may not exist. Is it right? :)

--
Kirill A. Shutemov

\
 
 \ /
  Last update: 2018-07-03 10:13    [W:0.640 / U:0.196 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site