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=-2.2 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 C2F34C3A5A6 for ; Mon, 23 Sep 2019 08:48:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8B5122087C for ; Mon, 23 Sep 2019 08:48:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8B5122087C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 26B956B0007; Mon, 23 Sep 2019 04:48:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 21B5F6B0008; Mon, 23 Sep 2019 04:48:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 132186B000A; Mon, 23 Sep 2019 04:48:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0076.hostedemail.com [216.40.44.76]) by kanga.kvack.org (Postfix) with ESMTP id E79566B0007 for ; Mon, 23 Sep 2019 04:48:08 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 868A2824CA1C for ; Mon, 23 Sep 2019 08:48:08 +0000 (UTC) X-FDA: 75965558256.07.grape04_470c1d683ff2f X-HE-Tag: grape04_470c1d683ff2f X-Filterd-Recvd-Size: 2594 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf48.hostedemail.com (Postfix) with ESMTP for ; Mon, 23 Sep 2019 08:48:08 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 1D2A4AAB2; Mon, 23 Sep 2019 08:48:06 +0000 (UTC) Subject: Re: [PATCH STABLE 4.9] x86, mm, gup: prevent get_page() race with munmap in paravirt guest To: Ben Hutchings , 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 References: <20190802160614.8089-1-vbabka@suse.cz> From: Vlastimil Babka Message-ID: <78bbba27-81ed-40db-eb6e-5add997b2027@suse.cz> Date: Mon, 23 Sep 2019 10:48:04 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 9/19/19 8:26 PM, Ben Hutchings wrote: > 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 probably >> 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 refcount") >> 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? Yeah, I'll take a look, thanks for reminding. > Ben. >