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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 80A52C433DB for ; Mon, 8 Feb 2021 10:57:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 014DD64E7D for ; Mon, 8 Feb 2021 10:57:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 014DD64E7D Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 644916B0070; Mon, 8 Feb 2021 05:57:08 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5F2826B0072; Mon, 8 Feb 2021 05:57:08 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4E4266B0073; Mon, 8 Feb 2021 05:57:08 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0051.hostedemail.com [216.40.44.51]) by kanga.kvack.org (Postfix) with ESMTP id 376256B0070 for ; Mon, 8 Feb 2021 05:57:08 -0500 (EST) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 04BC91EE6 for ; Mon, 8 Feb 2021 10:57:08 +0000 (UTC) X-FDA: 77794798536.03.key18_0b094d7275fe Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin03.hostedemail.com (Postfix) with ESMTP id D8EA928A4EB for ; Mon, 8 Feb 2021 10:57:07 +0000 (UTC) X-HE-Tag: key18_0b094d7275fe X-Filterd-Recvd-Size: 4579 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Mon, 8 Feb 2021 10:57:07 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1612781826; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ZIZtK7KGQOpq2x4SzJLMBFITOVmfiRO9HVwMLT9AWfk=; b=WpbjzGZc+3/YkHH1uGy0eGbUYo8oCacDxNQEQtRXANwZxHwtylTb3HKk6I403Q7833wHJ8 aLnM/cCkpwLJswRwURhqmjTvVUu01dIEr0vSyMIJGgoFeM+JOYdLAc7kCdZvfbthq/oS41 xyqZWWQ3VtQBnKDUYpZPwfTqaSytqRw= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id E729BAC6E; Mon, 8 Feb 2021 10:57:05 +0000 (UTC) Date: Mon, 8 Feb 2021 11:57:05 +0100 From: Michal Hocko To: David Hildenbrand 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 Subject: Re: [PATCH v17 08/10] PM: hibernate: disable when there are active secretmem users Message-ID: References: <20210208084920.2884-1-rppt@kernel.org> <20210208084920.2884-9-rppt@kernel.org> <38c0cad4-ac55-28e4-81c6-4e0414f0620a@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 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. -- Michal Hocko SUSE Labs