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=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 0D086C433DB for ; Mon, 8 Feb 2021 11:16:08 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8BA2C64E37 for ; Mon, 8 Feb 2021 11:16:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8BA2C64E37 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:References: To:From:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=+8OG23xzHeZugWKg8t8Rbq7Xcq0OQjGLAjPKp1t6VRM=; b=X6PIsw6NeTwm/j4vnm9BoHVni CNmwBCw0p44u/Hk27ttxKquArm6F4Hm1+H/U8fJOTBqeau/4eyV2HpCWExvSYfPl526kUdAGq1ZB5 GppMPd1c0TtZSgUOmQLvIrrUNb5Aw3utKo0Gyne4UW2qKa5L8/yUH7saqh+MXtD9D/aRIC95gQdiv teGKToERM7sBwWKKyZYQFlbYAuQDWhpJL2/v50mw+mNygUHsooHIYygCTzh6gBhuq5RP/e8/IKlcC I+79K54DagCh8KQFPNBDTO8gzLcYtz0tj5iQRhgJjMMa2otDV27+X2tc/kyt9uODbiCtHKcQt+XDO tX8oD2csQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l94VR-0005PY-Ns; Mon, 08 Feb 2021 11:15:01 +0000 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l94VN-0005Nj-Jr for linux-arm-kernel@lists.infradead.org; Mon, 08 Feb 2021 11:14:58 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612782897; 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=iMMAZUkyH+ZKGo/5ngkXcKGY7DpWIxntZe8dxLbr64A=; b=eoLYIMD8SorQivSRX48jD8x51UI710nCugbiHoa2jkXONC/vEMmbKxE6WviH1GCsRQ4CWt ijNcCPoYXA2KGz55cwPEkLzalTj+xcqidnOus0sy2JsTJ3L0c2utkmKVBZoko1hiSzoLUC yKUbyHmJLTRR0NM1Ytb8QtC2S15mMks= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-94-GXyOZsouM8ig9OB-3XPXHQ-1; Mon, 08 Feb 2021 06:14:53 -0500 X-MC-Unique: GXyOZsouM8ig9OB-3XPXHQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 15D6B80196E; Mon, 8 Feb 2021 11:14:49 +0000 (UTC) Received: from [10.36.113.240] (ovpn-113-240.ams2.redhat.com [10.36.113.240]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9DCA95C1D0; Mon, 8 Feb 2021 11:14:41 +0000 (UTC) Subject: Re: [PATCH v17 08/10] PM: hibernate: disable when there are active secretmem users From: David Hildenbrand To: Michal Hocko References: <20210208084920.2884-1-rppt@kernel.org> <20210208084920.2884-9-rppt@kernel.org> <38c0cad4-ac55-28e4-81c6-4e0414f0620a@redhat.com> <770690dc-634a-78dd-0772-3aba1a3beba8@redhat.com> Organization: Red Hat GmbH Message-ID: <21f4e742-1aab-f8ba-f0e7-40faa6d6c0bb@redhat.com> Date: Mon, 8 Feb 2021 12:14:40 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <770690dc-634a-78dd-0772-3aba1a3beba8@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210208_061457_741100_C58BBFCD X-CRM114-Status: GOOD ( 20.39 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Peter Zijlstra , Catalin Marinas , Dave Hansen , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, "H. Peter Anvin" , Christopher Lameter , Shuah Khan , Thomas Gleixner , Elena Reshetova , linux-arch@vger.kernel.org, Tycho Andersen , linux-nvdimm@lists.01.org, Will Deacon , x86@kernel.org, Matthew Wilcox , Mike Rapoport , Ingo Molnar , Michael Kerrisk , Palmer Dabbelt , Arnd Bergmann , James Bottomley , Hagen Paul Pfeifer , Borislav Petkov , Alexander Viro , Andy Lutomirski , Paul Walmsley , "Kirill A. Shutemov" , Dan Williams , linux-arm-kernel@lists.infradead.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Palmer Dabbelt , linux-fsdevel@vger.kernel.org, Shakeel Butt , Andrew Morton , Rick Edgecombe , Roman Gushchin , Mike Rapoport Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 08.02.21 12:13, David Hildenbrand wrote: > On 08.02.21 11:57, Michal Hocko wrote: >> On Mon 08-02-21 11:53:58, David Hildenbrand wrote: >>> On 08.02.21 11:51, Michal Hocko wrote: >>>> On Mon 08-02-21 11:32:11, David Hildenbrand wrote: >>>>> On 08.02.21 11:18, Michal Hocko wrote: >>>>>> On Mon 08-02-21 10:49:18, Mike Rapoport wrote: >>>>>>> From: Mike Rapoport >>>>>>> >>>>>>> It is unsafe to allow saving of secretmem areas to the hibernation >>>>>>> snapshot as they would be visible after the resume and this essentially >>>>>>> will defeat the purpose of secret memory mappings. >>>>>>> >>>>>>> Prevent hibernation whenever there are active secret memory users. >>>>>> >>>>>> Does this feature need any special handling? As it is effectivelly >>>>>> unevictable memory then it should behave the same as other mlock, ramfs >>>>>> which should already disable hibernation as those cannot be swapped out, >>>>>> no? >>>>>> >>>>> >>>>> Why should unevictable memory not go to swap when hibernating? We're merely >>>>> dumping all of our system RAM (including any unmovable allocations) to swap >>>>> storage and the system is essentially completely halted. >>>>> >>>> My understanding is that mlock is never really made visible via swap >>>> storage. >>> >>> "Using swap storage for hibernation" and "swapping at runtime" are two >>> different things. I might be wrong, though. >> >> Well, mlock is certainly used to keep sensitive information, not only to >> protect from major/minor faults. >> > > I think you're right in theory, the man page mentions "Cryptographic > security software often handles critical bytes like passwords or secret > keys as data structures" ... > > however, I am not aware of any such swap handling and wasn't able to > spot it quickly. Let me take a closer look. s/swap/hibernate/ -- Thanks, David / dhildenb _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel