From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56287C433E0 for ; Fri, 3 Jul 2020 22:39:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2CB4220747 for ; Fri, 3 Jul 2020 22:39:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726455AbgGCWjK (ORCPT ); Fri, 3 Jul 2020 18:39:10 -0400 Received: from jabberwock.ucw.cz ([46.255.230.98]:38894 "EHLO jabberwock.ucw.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726415AbgGCWjK (ORCPT ); Fri, 3 Jul 2020 18:39:10 -0400 Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id ECCA91C0C0F; Sat, 4 Jul 2020 00:39:05 +0200 (CEST) Date: Sat, 4 Jul 2020 00:39:05 +0200 From: Pavel Machek To: "Rafael J. Wysocki" Cc: Michal Hocko , "Catangiu, Adrian Costin" , "linux-mm@kvack.org" , "linux-pm@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "linux-api@vger.kernel.org" , "akpm@linux-foundation.org" , "rjw@rjwysocki.net" , "len.brown@intel.com" , "fweimer@redhat.com" , "keescook@chromium.org" , "luto@amacapital.net" , "wad@chromium.org" , "mingo@kernel.org" , "bonzini@gnu.org" , "Graf (AWS), Alexander" , "MacCarthaigh, Colm" , "Singh, Balbir" , "Sandu, Andrei" , "Brooker, Marc" , "Weiss, Radu" , "Manwaring, Derek" Subject: Re: [RFC]: mm,power: introduce MADV_WIPEONSUSPEND Message-ID: <20200703223905.GB25072@amd> References: <20200703113026.GT18446@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="oC1+HKm2/end4ao3" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-api-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org --oC1+HKm2/end4ao3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri 2020-07-03 14:17:50, Rafael J. Wysocki wrote: > On Fri, Jul 3, 2020 at 1:30 PM Michal Hocko wrote: > > > > On Fri 03-07-20 10:34:09, Catangiu, Adrian Costin wrote: > > > This patch adds logic to the kernel power code to zero out contents of > > > all MADV_WIPEONSUSPEND VMAs present in the system during its transiti= on > > > to any suspend state equal or greater/deeper than Suspend-to-memory, > > > known as S3. > > > > How does the application learn that its memory got wiped? S2disk is an > > async operation and it can happen at any time during the task execution. > > So how does the application work to prevent from corrupted state - e.g. > > when suspended between two memory loads? >=20 > This doesn't affect hibernation AFAICS, but system suspend > (suspend-to-RAM or suspend-to-idle, or standby) is async too. >=20 > I guess this calls for an interface to notify user space (that opted > in to receive such notifications) on system-wide suspend start and > finish. We could simply provide a file that would produce single byte 'e' when entering the suspend and different byte 'x' when exiting... Not sure how useful that would be for the crypto stuff... Best regards, Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --oC1+HKm2/end4ao3 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAl7/s4kACgkQMOfwapXb+vIUJQCfZyt+lUVQmqy5smyeJI74Hz2s FDAAoJdmlYDuJFsp9s0LjrrhyUvYHQG+ =XPvj -----END PGP SIGNATURE----- --oC1+HKm2/end4ao3--