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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,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 D09EEC55185 for ; Sat, 25 Apr 2020 22:48:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A387B2072B for ; Sat, 25 Apr 2020 22:48:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="a19cRORN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726355AbgDYWse (ORCPT ); Sat, 25 Apr 2020 18:48:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726232AbgDYWse (ORCPT ); Sat, 25 Apr 2020 18:48:34 -0400 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E70DBC09B04F for ; Sat, 25 Apr 2020 15:48:33 -0700 (PDT) Received: by mail-pl1-x643.google.com with SMTP id z6so5278365plk.10 for ; Sat, 25 Apr 2020 15:48:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=INjGMVxgX7lD+RGHEgxoq3gDShE5KD3g4HVfvBFmby0=; b=a19cRORNjk+/VdnJXmNiPknF3uo2PtEDXd+Wn4E4Yw2n5jXzONbHkfcL7Io7V4/h1A hqComD/2KShYjSZxHRAydagOWbxq3YizLF44RZb5NMD2WtxFknT5vLn3qoKXRKx43h5E obdJgZwA4bH5Uox8RuOWkBB9t/5HwOcUSuKEg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=INjGMVxgX7lD+RGHEgxoq3gDShE5KD3g4HVfvBFmby0=; b=sccpy0/5ZeEOWYcRgHpu5Jhzm/CC0Mk4HWGQCAyT8ifyD0gJZekhn4JPOf+uGhSh5F S/7SrBRIzXCahf0lSDsF/4ILwFTLT0K5t/MlCAZ+fyq0bdmzqtD1t5SLONRFd0Y60Rrm NwD5B5GBBWpRTEFEE66cjliRdC2aVYbot9zEv00LUfaayaKXp6JKcEyzfKu0iC13GA6f +sOj5IwMzqTaITzRISLnInDD6fRbqeo+sg33uXfVhkXSejU6k+/nvRM85qZD+EZgvDeB r5MH2p7QQowRcfa+IeGVfvoQ5GgDaBL6Gb+c3T/W7rAKwOPIz/lmUm/DgIYlZ1zdTUfs a4zw== X-Gm-Message-State: AGi0PuYO37muwYYTMpWtYIDcgr5+lggvsRlMgoMaet2RSBnbEHPaTrK0 ejmnkokKpop9CJlgitilerXnoQ== X-Google-Smtp-Source: APiQypLs6/BOi+uxr/spumGtn9iNGxndENmo4EqWuANXYqfmygIWEh2qromOmlkooNFsGiUVu4nPqA== X-Received: by 2002:a17:902:598f:: with SMTP id p15mr15950225pli.264.1587854913322; Sat, 25 Apr 2020 15:48:33 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id b15sm8864879pfd.139.2020.04.25.15.48.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 25 Apr 2020 15:48:32 -0700 (PDT) Date: Sat, 25 Apr 2020 15:48:31 -0700 From: Kees Cook To: Changbin Du Cc: Andrew Morton , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/slub: do not place freelist pointer to middle of object if redzone is on Message-ID: <202004251547.0F8E6856B@keescook> References: <20200425091338.24283-1-changbin.du@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200425091338.24283-1-changbin.du@gmail.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Apr 25, 2020 at 05:13:38PM +0800, Changbin Du wrote: > The recent kernel fails to boot when slub redzone is turned on. This is > caused by commit 3202fa62fb ("slub: relocate freelist pointer to middle of > object") which relocates freelist pointer to middle of object. In this > case, get_track() gets a wrong address and then the redzone is overwritten. Hi! A fix for this is already in -next: https://www.ozlabs.org/~akpm/mmotm/broken-out/slub-avoid-redzone-when-choosing-freepointer-location.patch the above doesn't disable the mitigation when using redzones, so I prefer that to this suggested solution. -- Kees Cook