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[195.135.220.15]) by mx.google.com with ESMTPS id v27si3019564edb.444.2019.02.01.01.11.54 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 01 Feb 2019 01:11:54 -0800 (PST) Received-SPF: softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org 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 09D1EB047; Fri, 1 Feb 2019 09:11:54 +0000 (UTC) Date: Fri, 1 Feb 2019 10:11:52 +0100 From: Michal Hocko To: Vlastimil Babka Cc: Andrew Morton , Linus Torvalds , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, Peter Zijlstra , Greg KH , Jann Horn , Jiri Kosina , Dominique Martinet , Andy Lutomirski , Dave Chinner , Kevin Easton , Matthew Wilcox , Cyril Hrubis , Tejun Heo , "Kirill A . Shutemov" , Daniel Gruss , Jiri Kosina , Josh Snyder Subject: Re: [PATCH 3/3] mm/mincore: provide mapped status when cached status is not allowed Message-ID: <20190201091152.GG11599@dhcp22.suse.cz> References: <20190130124420.1834-1-vbabka@suse.cz> <20190130124420.1834-4-vbabka@suse.cz> <20190131100907.GS18811@dhcp22.suse.cz> <99ee4d3e-aeb2-0104-22be-b028938e7f88@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <99ee4d3e-aeb2-0104-22be-b028938e7f88@suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) 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 Fri 01-02-19 10:04:23, Vlastimil Babka wrote: > The side channel exists anyway as long as process can e.g. check if > its rss shrinked, and I doubt we are going to remove that possibility. Well, but rss update will not tell you that the page has been faulted in which is the most interesting part. You shouldn't be able to sniff on /proc/$vicimt/smaps as an attacker. -- Michal Hocko SUSE Labs