LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Joel Fernandes <joel@joelfernandes.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, jreck@google.com,
	john.stultz@linaro.org, tkjos@google.com,
	gregkh@linuxfoundation.org, hch@infradead.org,
	"Al Viro" <viro@zeniv.linux.org.uk>,
	dancol@google.com, "J. Bruce Fields" <bfields@fieldses.org>,
	"Jeff Layton" <jlayton@kernel.org>,
	"Khalid Aziz" <khalid.aziz@oracle.com>,
	"Lei Yang" <Lei.Yang@windriver.com>,
	linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-mm@kvack.org,
	"Marc-André Lureau" <marcandre.lureau@redhat.com>,
	"Mike Kravetz" <mike.kravetz@oracle.com>,
	minchan@kernel.org, "Shuah Khan" <shuah@kernel.org>,
	valdis.kletnieks@vt.edu
Subject: Re: [PATCH v3 resend 1/2] mm: Add an F_SEAL_FUTURE_WRITE seal to memfd
Date: Fri, 9 Nov 2018 19:54:43 -0800
Message-ID: <20181110035443.GA26579@google.com> (raw)
In-Reply-To: <20181109123634.6fe7467bb9237851250c9c56@linux-foundation.org>

On Fri, Nov 09, 2018 at 12:36:34PM -0800, Andrew Morton wrote:
> On Wed,  7 Nov 2018 20:15:36 -0800 "Joel Fernandes (Google)" <joel@joelfernandes.org> wrote:
> 
> > Android uses ashmem for sharing memory regions. We are looking forward
> > to migrating all usecases of ashmem to memfd so that we can possibly
> > remove the ashmem driver in the future from staging while also
> > benefiting from using memfd and contributing to it. Note staging drivers
> > are also not ABI and generally can be removed at anytime.
> > 
> > One of the main usecases Android has is the ability to create a region
> > and mmap it as writeable, then add protection against making any
> > "future" writes while keeping the existing already mmap'ed
> > writeable-region active.  This allows us to implement a usecase where
> > receivers of the shared memory buffer can get a read-only view, while
> > the sender continues to write to the buffer.
> > See CursorWindow documentation in Android for more details:
> > https://developer.android.com/reference/android/database/CursorWindow
> 
> It appears that the memfd_create and fcntl manpages will require
> updating.  Please attend to this at the appropriate time?

Yes, I am planning to send those out shortly. I finished working on them.

Also just to let you know, I posted a fix for the security issue Jann Horn
reported and requested him to test it:
https://lore.kernel.org/lkml/20181109234636.GA136491@google.com/T/#m8d9d185e6480d095f0ab8f84bcb103892181f77d

This fix along with the 2 other patches I posted in v3 are all that's needed. thanks!

- Joel


  reply index

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-08  4:15 Joel Fernandes (Google)
2018-11-08  4:15 ` [PATCH v3 resend 2/2] selftests/memfd: Add tests for F_SEAL_FUTURE_WRITE seal Joel Fernandes (Google)
2018-11-09  8:49 ` [PATCH v3 resend 1/2] mm: Add an F_SEAL_FUTURE_WRITE seal to memfd Joel Fernandes
2018-11-09 20:36 ` Andrew Morton
2018-11-10  3:54   ` Joel Fernandes [this message]
2018-11-09 21:06 ` Jann Horn
2018-11-09 21:19   ` Jann Horn
2018-11-10  3:20     ` Joel Fernandes
2018-11-10  6:05       ` Andy Lutomirski
2018-11-10 18:24         ` Joel Fernandes
2018-11-10 18:45           ` Daniel Colascione
2018-11-10 19:11             ` Daniel Colascione
2018-11-10 19:55               ` Andy Lutomirski
2018-11-10 22:09               ` Joel Fernandes
2018-11-10 22:18                 ` Andy Lutomirski
2018-11-11  2:38                   ` Joel Fernandes
2018-11-11  3:40                     ` Andy Lutomirski
2018-11-11  4:01                       ` Joel Fernandes
2018-11-11  8:09                       ` Joel Fernandes
2018-11-11  8:30                         ` Daniel Colascione
2018-11-11 15:14                           ` Andy Lutomirski
2018-11-11 17:36                             ` Joel Fernandes
     [not found]       ` <CAKOZuethC7+YrRyyGciUCfhSSa9cCcAFJ8g_qEw9uh3TBbyOcg@mail.gmail.com>
2018-11-10 17:10         ` Joel Fernandes
2018-11-09 21:40   ` Andy Lutomirski
2018-11-09 20:02     ` Michael Tirado
2018-11-10  1:49       ` Joel Fernandes
2018-11-09 22:20   ` Daniel Colascione
2018-11-09 22:37     ` Andy Lutomirski
2018-11-09 22:42       ` Daniel Colascione
2018-11-09 23:14         ` Andy Lutomirski
2018-11-10  1:36           ` Joel Fernandes
2018-11-09 23:46   ` Joel Fernandes

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20181110035443.GA26579@google.com \
    --to=joel@joelfernandes.org \
    --cc=Lei.Yang@windriver.com \
    --cc=akpm@linux-foundation.org \
    --cc=bfields@fieldses.org \
    --cc=dancol@google.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=hch@infradead.org \
    --cc=jlayton@kernel.org \
    --cc=john.stultz@linaro.org \
    --cc=jreck@google.com \
    --cc=khalid.aziz@oracle.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=marcandre.lureau@redhat.com \
    --cc=mike.kravetz@oracle.com \
    --cc=minchan@kernel.org \
    --cc=shuah@kernel.org \
    --cc=tkjos@google.com \
    --cc=valdis.kletnieks@vt.edu \
    --cc=viro@zeniv.linux.org.uk \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git