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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A009CC3A5A6 for ; Thu, 19 Sep 2019 18:26:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7F4A1207FC for ; Thu, 19 Sep 2019 18:26:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391989AbfISS0y (ORCPT ); Thu, 19 Sep 2019 14:26:54 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:57466 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389805AbfISS0y (ORCPT ); Thu, 19 Sep 2019 14:26:54 -0400 Received: from [167.98.27.226] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iB18i-000664-79; Thu, 19 Sep 2019 19:26:48 +0100 Received: from ben by deadeye with local (Exim 4.92.1) (envelope-from ) id 1iB18h-0001a6-C8; Thu, 19 Sep 2019 19:26:47 +0100 Message-ID: Subject: Re: [PATCH STABLE 4.9] x86, mm, gup: prevent get_page() race with munmap in paravirt guest From: Ben Hutchings To: Vlastimil Babka , stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, Jann Horn , Ben Hutchings , xen-devel@lists.xenproject.org, Oscar Salvador , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Juergen Gross , "Kirill A . Shutemov" , Vitaly Kuznetsov , Linus Torvalds , Borislav Petkov , Dave Hansen , Andy Lutomirski Date: Thu, 19 Sep 2019 19:26:41 +0100 In-Reply-To: <20190802160614.8089-1-vbabka@suse.cz> References: <20190802160614.8089-1-vbabka@suse.cz> Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-FBmeXmh5MpmOJLyUNuxi" User-Agent: Evolution 3.30.5-1.1 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 167.98.27.226 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-FBmeXmh5MpmOJLyUNuxi Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2019-08-19 at 18:58 +0100, Vlastimil Babka wrote: [...] > Hi, I'm sending this stable-only patch for consideration because it's pro= bably > unrealistic to backport the 4.13 switch to generic GUP. I can look at 4.4= and > 3.16 if accepted. The RCU page table freeing could be also considered. I would be interested in backports for 3.16 and 4.4. > Note the patch also includes page refcount protection. I found out that > 8fde12ca79af ("mm: prevent get_user_pages() from overflowing page refcoun= t") > backport to 4.9 missed the arch-specific gup implementations: > https://lore.kernel.org/lkml/6650323f-dbc9-f069-000b-f6b0f941a065@suse.cz= / [...] I suppose that still needs to be addressed for 4.9, right? Ben. --=20 Ben Hutchings Quantity is no substitute for quality, but it's the only one we've got. --=-FBmeXmh5MpmOJLyUNuxi Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEErCspvTSmr92z9o8157/I7JWGEQkFAl2DyGIACgkQ57/I7JWG EQmtMBAAi586lgxSJosug6EchWJu1bRh3VBWNNPgJ4J6ffWIDUl3ADDOA94ewtHd yv3AmUmnMZf6HzM2pxfWzVtzEUf2MnaUtttFjJ3ChyY1PYTd+sKB9xL63Frdfv4K rhLq/Gh/buYvFzvPAgLFIF9OedV4winWz1OM66ZFPKs56UzTMGWS6FxEDgsuSeVL UJbi/nU7eEV9BWu7hcnYWedHXemtvzJdVApsDSypcHloXHBDmMl1wkVyYhpKp5UZ M6s56CvPZXWrIpVo8/YJYIuPLB1ExeaqvddJHGQ8sZAjkcFDSXwTonASK5YdiVYa +7NtLgVp1sKLls2FDVrhKP70XVwB9HkeThnShdifTO4Q3YIfRF8DjaWwl2EtaC2b OGOGCdBZZY7kMFdGPiySxQarEAFGK4N6aNeAdl7Dst2XH88olWmSwy4m6Auw/hBD V5npJtk92/M/QILGzyjrmABefbktwY2xo+byqoAHY/CBGZv/p/WfNikBQpCb7s4g 1LKslHq9CzQzTSoD7EYkjrNHtNFZHhYrJCM8INcM3aK589/3t+ktz13QxKVrCGIp jZjWn2QA5uINC26dkeszYhzyInFsKO4QeR7riuxKH13rH+D+bVel5HpL8q7gvefd toAfqG2c3MrjekRhyA8GyTRoHz7LAPbvH+J2tJhA++9AcFW+5l8= =jVXl -----END PGP SIGNATURE----- --=-FBmeXmh5MpmOJLyUNuxi--