Received: by 2002:a05:6358:d09b:b0:dc:cd0c:909e with SMTP id jc27csp15360145rwb; Mon, 28 Nov 2022 10:37:26 -0800 (PST) X-Google-Smtp-Source: AA0mqf7zszbteGAXnESScQ21cI1ubltVW2wVBjSzLChpk1/ozRo2FPq9i3lYSzBOSxKdOxcpmBKG X-Received: by 2002:a17:90a:fc92:b0:219:1545:bc57 with SMTP id ci18-20020a17090afc9200b002191545bc57mr16070149pjb.133.1669660646372; Mon, 28 Nov 2022 10:37:26 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1669660646; cv=none; d=google.com; s=arc-20160816; b=g6z5ZUitIrif0Q7m754ASl377GsIK6eUQxBU3Hnut5R/29YJooL9Q7y4DNzRMTj6/B H1D3IECxAGoSVisSKLkB5j8YattF2JXir5LL2u4Alnlvlg/qgkV5kyOzrtSjqmBv0+eA VofPsBh5foJRJjZPH722ZXsEjntTIL77JHJOWP4dfGm6dnkNVuzokaXwGgugn6DZE/MJ SqsaeFJ+3LiNfYyJOzXSQ91yYb+AuCTAXH0Dlpl7v3svDwN8hVvco8Dtbf4gLqXBHYgs UDR3W95FHhHeFEZo85O2prCWUHPD9Gn7sBPdsriFPPdtJG1zQssew/9wesJH25ZlzFsh +cOw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:in-reply-to :organization:from:references:cc:to:content-language:subject :user-agent:mime-version:date:message-id:dkim-signature; bh=yI2lsl64MrMPLmal/4OD6FwI+XLJK3nNMXWiQLT1Jqw=; b=XihVZKM5HAJjFiZQKQHj3daM07VYBg4wppFKQ47N+6VVbiTaHUN4XYfs4Uahcld31H qG8eXV1UvG9c3TdjOvhD4GFw0sqCL1z/G17d/a4evt7g82h5O077wnGdI1tQCK6vKUCp +Fg20vDKi9ZSqA4w31jZi7R1OOZ8zfSL7udNQXCo9lcaM+JKg/D7TdrPhrfnUv1CXTUb 4qlZHEJ/TqckJrSoRLSZXB55FXzPPTwu+zXiA1K2HzZjwAJZzPpZjICFIOnWH1+jQkKz uuSek/d5VDp1c+S0Tv8Bq/Y4ld94eobBsdhRJ+hc7LasgXGG0oDl2GxT+W0SacGU4OsH BtOg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=HMa9n6nZ; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id my13-20020a17090b4c8d00b00218a592ceacsi17536018pjb.107.2022.11.28.10.37.14; Mon, 28 Nov 2022 10:37:26 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=HMa9n6nZ; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232529AbiK1SW0 (ORCPT + 85 others); Mon, 28 Nov 2022 13:22:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234339AbiK1SWF (ORCPT ); Mon, 28 Nov 2022 13:22:05 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A81A42494A for ; Mon, 28 Nov 2022 10:08:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1669658888; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=yI2lsl64MrMPLmal/4OD6FwI+XLJK3nNMXWiQLT1Jqw=; b=HMa9n6nZw0qpNGTpZqZXnIgglYVt9zaIoLZJ491ueTXkCDBDwaCZ13l2XQUVJNXXcc5bue K4LljMt3ErgDq+xkosfhm4q+2dItajteadgzJ3mnaUUthBUUGHOLgeya20RdRkjNnBugmb xpI8vWEqgWLqkMCMzRKjK5Gu4M3Jt48= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-85-kqJduKCcNHqDGbOHcS1u9g-1; Mon, 28 Nov 2022 13:08:06 -0500 X-MC-Unique: kqJduKCcNHqDGbOHcS1u9g-1 Received: by mail-wr1-f71.google.com with SMTP id v2-20020adfa1c2000000b002420d780a32so1212746wrv.14 for ; Mon, 28 Nov 2022 10:08:06 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:organization:from:references :cc:to:content-language:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=yI2lsl64MrMPLmal/4OD6FwI+XLJK3nNMXWiQLT1Jqw=; b=sknINeqUm4sOlflvjZvh9jVeWEDtRtqvzrsSzFoRzd5RD/5dZVRtZQ+zZnRVoGJ94e hh+I03K1Lh2kxt2vB7jv9P/IixjbzhQhR2TeoA5Gu75EDp1QWeig0JmxTAjzxVqI50by xOWSWkH1A1XM/TjaSyYeZ8+0V8Neyn9jsy0mmC7CNC4B4Sm34oT46faGJEGeqZMEOuwX uC07/HCsSt3mU/uq7KaeEQLAW6xLnChfIq/GJPHqfe4GaEnC5mcc+JgrOYlo1a5Raeeg yaMrH1KHRF49e8bvm0iem7H4GcnBNAuUfjpjLAVO+WLNpop9KKmIGUoiYV8RSft8eueF EMlQ== X-Gm-Message-State: ANoB5plLy55AYccWS6M974r8cF3hpKUSuL9SsLg5bHHAx0b3fd8j8ZkU oNb4fY/H7zzmqB3zO3hdGqDhvV0/M+ekoLDsrzY2f/BXHWFUMf8NGdLhXSyw6h2C1cozop4l2Yd QiULNc/O0EGSKjuRSlsGI9npg X-Received: by 2002:a5d:4fc6:0:b0:236:84b5:b039 with SMTP id h6-20020a5d4fc6000000b0023684b5b039mr32459785wrw.411.1669658885495; Mon, 28 Nov 2022 10:08:05 -0800 (PST) X-Received: by 2002:a5d:4fc6:0:b0:236:84b5:b039 with SMTP id h6-20020a5d4fc6000000b0023684b5b039mr32459749wrw.411.1669658885174; Mon, 28 Nov 2022 10:08:05 -0800 (PST) Received: from ?IPV6:2003:cb:c702:9000:3d6:e434:f8b4:80cf? (p200300cbc702900003d6e434f8b480cf.dip0.t-ipconnect.de. [2003:cb:c702:9000:3d6:e434:f8b4:80cf]) by smtp.gmail.com with ESMTPSA id e5-20020a05600c4e4500b003b492753826sm15354156wmq.43.2022.11.28.10.08.04 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 28 Nov 2022 10:08:04 -0800 (PST) Message-ID: Date: Mon, 28 Nov 2022 19:08:03 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [PATCH v4 3/3] mm/khugepaged: Invoke MMU notifiers in shmem/file collapse paths Content-Language: en-US To: Jann Horn , security@kernel.org, Andrew Morton Cc: Yang Shi , Peter Xu , John Hubbard , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20221128180252.1684965-1-jannh@google.com> <20221128180252.1684965-3-jannh@google.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20221128180252.1684965-3-jannh@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-2.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A, RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28.11.22 19:02, Jann Horn wrote: > Any codepath that zaps page table entries must invoke MMU notifiers to > ensure that secondary MMUs (like KVM) don't keep accessing pages which > aren't mapped anymore. Secondary MMUs don't hold their own references to > pages that are mirrored over, so failing to notify them can lead to page > use-after-free. > > I'm marking this as addressing an issue introduced in commit f3f0e1d2150b > ("khugepaged: add support of collapse for tmpfs/shmem pages"), but most of > the security impact of this only came in commit 27e1f8273113 ("khugepaged: > enable collapse pmd for pte-mapped THP"), which actually omitted flushes > for the removal of present PTEs, not just for the removal of empty page > tables. > > Cc: stable@kernel.org > Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages") > Signed-off-by: Jann Horn Acked-by: David Hildenbrand -- Thanks, David / dhildenb