Re: [PATCH v5 00/25] userfaultfd: write protection support

[Bobby Powers]

On Wed, Jun 19, 2019 at 7:20 PM Peter Xu <peterx@xxxxxxxxxx> wrote:
> This series implements initial write protection support for
> userfaultfd.  Currently both shmem and hugetlbfs are not supported
> yet, but only anonymous memory.  This is the 4nd version of it.
>
> The latest code can also be found at:
>
>   https://github.com/xzpeter/linux/tree/uffd-wp-merged

Hi Peter - I ported the branch you had above on top of v5.4.20 (what I
happened to be running locally), and fixed one issue that was causing
crashes for me:
https://github.com/bpowers/linux/commit/61086b5a0fa4aeb494e86d999926551a4323b84f

I wrote a small test program here:
https://github.com/plasma-umass/Mesh/blob/master/src/test/userfaultfd-kernel-copy.cc
and write protection support for userfaultfd (with eventual shmem
support) would be _hugely_ helpful for a userspace memory allocator
I'm working on.

Is there anything I can do to help get this considered for mainline?
We have some time before the 5.7 merge window opens up.

Tested-by: Bobby Powers <bobbypowers@xxxxxxxxx>