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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 0DBC5C4361A for ; Thu, 3 Dec 2020 19:26:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 614E1221EC for ; Thu, 3 Dec 2020 19:26:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 614E1221EC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codesourcery.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BD1316B0068; Thu, 3 Dec 2020 14:26:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B5BDE6B006C; Thu, 3 Dec 2020 14:26:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A223A8D0001; Thu, 3 Dec 2020 14:26:35 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0143.hostedemail.com [216.40.44.143]) by kanga.kvack.org (Postfix) with ESMTP id 899066B0068 for ; Thu, 3 Dec 2020 14:26:35 -0500 (EST) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 4E195180AD80F for ; Thu, 3 Dec 2020 19:26:35 +0000 (UTC) X-FDA: 77552952750.04.tray55_5105f4b273be Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin04.hostedemail.com (Postfix) with ESMTP id 292708003FAF for ; Thu, 3 Dec 2020 19:26:35 +0000 (UTC) X-HE-Tag: tray55_5105f4b273be X-Filterd-Recvd-Size: 2875 Received: from esa3.mentor.iphmx.com (esa3.mentor.iphmx.com [68.232.137.180]) by imf49.hostedemail.com (Postfix) with ESMTP for ; Thu, 3 Dec 2020 19:26:34 +0000 (UTC) IronPort-SDR: roJUvTZl+FUf5a2H5jKIgGMMSCnUoMC9/CXlzVlTelnKlAStfvw3FdNfL+XEcyTgkoUEQyDbBc 46VENHzfNQlu2m4rWzYmzY2iw33ipUWrXPrIatTE3cKPfFCVKfZwOtfsW9UYb5fdVBPStYp21e vjONujJDcLMU8l9kR/9fsAMmk7quKeDH5ys8zZl4zOSZZNYahoJHGfQiVtxw0ndbsBCORymoEu DHwlPW/Ud/OrALQO554VE4QO1ZQrxIpe4MbxAwwjKUQJTfeuFbitpktDo3rmOKWiwDsJpysMqs jG4= X-IronPort-AV: E=Sophos;i="5.78,390,1599552000"; d="scan'208";a="55762307" Received: from orw-gwy-02-in.mentorg.com ([192.94.38.167]) by esa3.mentor.iphmx.com with ESMTP; 03 Dec 2020 11:26:32 -0800 IronPort-SDR: XP3ZEQho3UqMx3BhYt1pQPTeKTRf5W8xIRihDvtCBy7QtU3tUhB7Phh67eaOt39ZLijARoJO73 cBW5k8t56e6WIOt9w363v7E0h1PB4g96rULSv/vrukcnALazLbg9LMKxWVlqSItIB4K6zGmnTz u7XrTyVwuFlmYBhsHPoIow3V9+KfZOiXyj+S61ioyEUkHp2VYVyzHPEoMsmwD+WGYEjTfayuI0 GzEBbFfSClbc3UwEsqiOgNjJiNBnBtWa04/aokI9hKNeV4uCNJjw9HpC2rb7Qk5jK+xs3yWoiY lis= Date: Thu, 3 Dec 2020 19:26:25 +0000 From: Joseph Myers X-X-Sender: jsm28@digraph.polyomino.org.uk To: Florian Weimer CC: Andy Lutomirski , Topi Miettinen , , , , , Jann Horn , Kees Cook , Matthew Wilcox , Mike Rapoport , Linux API Subject: Re: [PATCH v5] mm: Optional full ASLR for mmap(), mremap(), vdso and stack In-Reply-To: <871rg6yf1i.fsf@oldenburg2.str.redhat.com> Message-ID: References: <05D72EA3-4862-4D80-82F5-9369834C3461@amacapital.net> <871rg6yf1i.fsf@oldenburg2.str.redhat.com> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-Originating-IP: [137.202.0.90] X-ClientProxiedBy: SVR-IES-MBX-04.mgc.mentorg.com (139.181.222.4) To svr-ies-mbx-01.mgc.mentorg.com (139.181.222.1) 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 Thu, 3 Dec 2020, Florian Weimer wrote: > My knowledge of probability theory is quite limited, so I have to rely > on simulations. But I think you would see a 40 GiB gap somewhere for a > 47-bit address space with 32K allocations, most of the time. Which is > not too bad. This is very close to a Poisson process (if the number of small allocations being distributed independently in the address space is large), so the probability that any given gap is at least x times the mean gap is about exp(-x). -- Joseph S. Myers joseph@codesourcery.com