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=-5.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 91AFFC433E6 for ; Mon, 8 Feb 2021 11:26:52 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (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 162C364E8C for ; Mon, 8 Feb 2021 11:26:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 162C364E8C 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-nvdimm-bounces@lists.01.org Received: from ml01.vlan13.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id A1785100EB35C; Mon, 8 Feb 2021 03:26:51 -0800 (PST) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=63.128.21.124; helo=us-smtp-delivery-124.mimecast.com; envelope-from=david@redhat.com; receiver= Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 8EABA100EBBD8 for ; Mon, 8 Feb 2021 03:26:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612783607; 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=m3dJ61ykrqT6xZ75oELmWT0+ySTJ4cYepjC0Xzb/Htc=; b=FUdTrUQaO9NIQ6qfGUqdmhDpgZTil6ULiwXr8OFWRQfF5GZDPYxjbpnX9PdpiVMKEjLAxp TfKMxABTcZVWVF+cIwPIB6mhLcZL4nkBMX3gUuOEEbzZXrj77eHX5w/HatUyoLawO4cWK7 63+h4Q9e1Tzw/p06k2pWvrRQtPPUh50= 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-444-k4r9VghcN_OoP9Gu4wJEeA-1; Mon, 08 Feb 2021 06:26:45 -0500 X-MC-Unique: k4r9VghcN_OoP9Gu4wJEeA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 19E1D107ACED; Mon, 8 Feb 2021 11:26:41 +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 AA4511002388; Mon, 8 Feb 2021 11:26:32 +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> <21f4e742-1aab-f8ba-f0e7-40faa6d6c0bb@redhat.com> Organization: Red Hat GmbH Message-ID: <5db6ac46-d4e1-3c68-22a0-94f2ecde8801@redhat.com> Date: Mon, 8 Feb 2021 12:26:31 +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: <21f4e742-1aab-f8ba-f0e7-40faa6d6c0bb@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Message-ID-Hash: YQGJOD3ISALIA3VIY7BGAESH7HBK3FBO X-Message-ID-Hash: YQGJOD3ISALIA3VIY7BGAESH7HBK3FBO X-MailFrom: david@redhat.com X-Mailman-Rule-Hits: nonmember-moderation X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation CC: Mike Rapoport , Andrew Morton , Alexander Viro , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christopher Lameter , Dave Hansen , Elena Reshetova , "H. Peter Anvin" , Ingo Molnar , James Bottomley , "Kirill A. Shutemov" , Matthew Wilcox , Mark Rutland , Mike Rapoport , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Rick Edgecombe , Roman Gushchin , Shakeel Butt , Shuah Khan , Thomas Gleixner , Tycho Ander sen , Will Deacon , linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-nvdimm@lists.01.org, linux-riscv@lists.infradead.org, x86@kernel.org, Hagen Paul Pfeifer , Palmer Dabbelt X-Mailman-Version: 3.1.1 Precedence: list List-Id: "Linux-nvdimm developer list." Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: Content-Type: text/plain; charset="us-ascii"; format="flowed" Content-Transfer-Encoding: 7bit On 08.02.21 12:14, David Hildenbrand wrote: > 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/ My F33 system happily hibernates to disk, even with an application that succeeded in din doing an mlockall(). And it somewhat makes sense. Even my freshly-booted, idle F33 has $ cat /proc/meminfo | grep lock Mlocked: 4860 kB So, stopping to hibernate with mlocked memory would essentially prohibit any modern Linux distro to hibernate ever. -- Thanks, David / dhildenb _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org 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=-8.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 76909C433DB for ; Mon, 8 Feb 2021 11:49:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E18E64E92 for ; Mon, 8 Feb 2021 11:49:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233161AbhBHLtV (ORCPT ); Mon, 8 Feb 2021 06:49:21 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:38440 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233205AbhBHL2R (ORCPT ); Mon, 8 Feb 2021 06:28:17 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612783609; 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=m3dJ61ykrqT6xZ75oELmWT0+ySTJ4cYepjC0Xzb/Htc=; b=ZVS8fy6dU7jsaR0+XLT749YjYsZn6nu13l6fuMvEDi4P/bryvKOhVom9lLGZ7g9l3/x5l4 Wo+Cwa6/a3KbyralreX+SNhL9CMiOCZtaXBst00jZIiEMRDCoNDaAZrZmyiMre7Cwj+/IP z/Hgyf2E8dnLS8fyQAeF+/JeN+HuQ5M= 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-444-k4r9VghcN_OoP9Gu4wJEeA-1; Mon, 08 Feb 2021 06:26:45 -0500 X-MC-Unique: k4r9VghcN_OoP9Gu4wJEeA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 19E1D107ACED; Mon, 8 Feb 2021 11:26:41 +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 AA4511002388; Mon, 8 Feb 2021 11:26:32 +0000 (UTC) Subject: Re: [PATCH v17 08/10] PM: hibernate: disable when there are active secretmem users From: David Hildenbrand To: Michal Hocko Cc: Mike Rapoport , Andrew Morton , Alexander Viro , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christopher Lameter , Dan Williams , Dave Hansen , Elena Reshetova , "H. Peter Anvin" , Ingo Molnar , James Bottomley , "Kirill A. Shutemov" , Matthew Wilcox , Mark Rutland , Mike Rapoport , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Rick Edgecombe , Roman Gushchin , Shakeel Butt , Shuah Khan , Thomas Gleixner , Tycho Andersen , Will Deacon , linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-nvdimm@lists.01.org, linux-riscv@lists.infradead.org, x86@kernel.org, Hagen Paul Pfeifer , Palmer Dabbelt 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> <21f4e742-1aab-f8ba-f0e7-40faa6d6c0bb@redhat.com> Organization: Red Hat GmbH Message-ID: <5db6ac46-d4e1-3c68-22a0-94f2ecde8801@redhat.com> Date: Mon, 8 Feb 2021 12:26:31 +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: <21f4e742-1aab-f8ba-f0e7-40faa6d6c0bb@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08.02.21 12:14, David Hildenbrand wrote: > 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/ My F33 system happily hibernates to disk, even with an application that succeeded in din doing an mlockall(). And it somewhat makes sense. Even my freshly-booted, idle F33 has $ cat /proc/meminfo | grep lock Mlocked: 4860 kB So, stopping to hibernate with mlocked memory would essentially prohibit any modern Linux distro to hibernate ever. -- Thanks, David / dhildenb 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 0327DC433DB for ; Mon, 8 Feb 2021 11:27:06 +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 859EF64DD8 for ; Mon, 8 Feb 2021 11:27:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 859EF64DD8 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-riscv-bounces+linux-riscv=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=vU8WuUhMI6GX1AY9JnFxFD5+rvFaBW+YQ5ikSsXfp+c=; b=lE6PaErTE4+Yx/wunGfpowwFL KdMTBU9cxPcNRMI++qERcpubpc5vShhZcSmFY9s7SU4jffCtRQBGlD0bEOeR6xY24YWYStrXDTpV0 BGPNJLtZoZrX6w1aDKwud9KcQMyx9TBqcUg7Q/za2uOoKfWqLMCePp+M+YEpCiqy9+rfNN2t4VROD b3qJnBayhm0GjyLdBsIAKSzdbaQa5YaX1l5moHyFLwuscfKAZBGHbthJKWrB8dLjqnENrUhHQa8DW f7UqKKf552K4Sd6L3LVegQne+l2EBlTXw48uH19XKNdzGbGvKEOmgo8PM1fI7shf2vIatKVsZDYIi k/fPYiw8w==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l94gy-0007qv-IB; Mon, 08 Feb 2021 11:26:56 +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 1l94gr-0007nN-NN for linux-riscv@lists.infradead.org; Mon, 08 Feb 2021 11:26:51 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612783609; 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=m3dJ61ykrqT6xZ75oELmWT0+ySTJ4cYepjC0Xzb/Htc=; b=ZVS8fy6dU7jsaR0+XLT749YjYsZn6nu13l6fuMvEDi4P/bryvKOhVom9lLGZ7g9l3/x5l4 Wo+Cwa6/a3KbyralreX+SNhL9CMiOCZtaXBst00jZIiEMRDCoNDaAZrZmyiMre7Cwj+/IP z/Hgyf2E8dnLS8fyQAeF+/JeN+HuQ5M= 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-444-k4r9VghcN_OoP9Gu4wJEeA-1; Mon, 08 Feb 2021 06:26:45 -0500 X-MC-Unique: k4r9VghcN_OoP9Gu4wJEeA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 19E1D107ACED; Mon, 8 Feb 2021 11:26:41 +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 AA4511002388; Mon, 8 Feb 2021 11:26:32 +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> <21f4e742-1aab-f8ba-f0e7-40faa6d6c0bb@redhat.com> Organization: Red Hat GmbH Message-ID: <5db6ac46-d4e1-3c68-22a0-94f2ecde8801@redhat.com> Date: Mon, 8 Feb 2021 12:26:31 +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: <21f4e742-1aab-f8ba-f0e7-40faa6d6c0bb@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210208_062649_831508_2D292B17 X-CRM114-Status: GOOD ( 18.70 ) X-BeenThere: linux-riscv@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-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On 08.02.21 12:14, David Hildenbrand wrote: > 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/ My F33 system happily hibernates to disk, even with an application that succeeded in din doing an mlockall(). And it somewhat makes sense. Even my freshly-booted, idle F33 has $ cat /proc/meminfo | grep lock Mlocked: 4860 kB So, stopping to hibernate with mlocked memory would essentially prohibit any modern Linux distro to hibernate ever. -- Thanks, David / dhildenb _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv 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 D0086C433E0 for ; Mon, 8 Feb 2021 11:28:01 +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 583BA64DD8 for ; Mon, 8 Feb 2021 11:28:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 583BA64DD8 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=wILWHtuW/1g/eXH9eFieZdSAu1flRZxUkcDG9WhctZs=; b=FWOV+aq5yqaGkaFQLeB+7yNmq SI/7pdTNaPLB49OAJp1uevuIl2WCyDjZkpQkqljChwvUKKlZLnrVZqHqbqohV3uIwFm7DeD3ydB1x NmMZP8EvEm5mceiwbFgNyoxGLNQHpBs9932MXOZVt6LVxWzfp8EKDvq/EXC4QKv/7tied5gQaKcX4 yniUPFCnK/YBnA3NCErMQDHvvlNl7H/QQheZ9PkGrQG7rhDy+Q72CL04E1x5WupZWk/Eg1XgRVLZE 1La5hJ4yysIWGUXcLEPyLmUFaXiGBqt3M3yDnUQo+RXhEtynWOQdq39lLxYevzzhcIXNVCa0VUQRi YXWE9cIeQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l94gv-0007pW-GS; Mon, 08 Feb 2021 11:26:53 +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 1l94gr-0007nS-Pz for linux-arm-kernel@lists.infradead.org; Mon, 08 Feb 2021 11:26:51 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612783609; 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=m3dJ61ykrqT6xZ75oELmWT0+ySTJ4cYepjC0Xzb/Htc=; b=ZVS8fy6dU7jsaR0+XLT749YjYsZn6nu13l6fuMvEDi4P/bryvKOhVom9lLGZ7g9l3/x5l4 Wo+Cwa6/a3KbyralreX+SNhL9CMiOCZtaXBst00jZIiEMRDCoNDaAZrZmyiMre7Cwj+/IP z/Hgyf2E8dnLS8fyQAeF+/JeN+HuQ5M= 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-444-k4r9VghcN_OoP9Gu4wJEeA-1; Mon, 08 Feb 2021 06:26:45 -0500 X-MC-Unique: k4r9VghcN_OoP9Gu4wJEeA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 19E1D107ACED; Mon, 8 Feb 2021 11:26:41 +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 AA4511002388; Mon, 8 Feb 2021 11:26:32 +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>