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=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 8EE70C43461 for ; Thu, 17 Sep 2020 09:48:14 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2D66020770 for ; Thu, 17 Sep 2020 09:48:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="fGUjulhI" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2D66020770 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id ADB216B0055; Thu, 17 Sep 2020 05:48:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A63D36B005C; Thu, 17 Sep 2020 05:48:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8B6DB6B0062; Thu, 17 Sep 2020 05:48:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0195.hostedemail.com [216.40.44.195]) by kanga.kvack.org (Postfix) with ESMTP id 71DC76B0055 for ; Thu, 17 Sep 2020 05:48:13 -0400 (EDT) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 3213D8249980 for ; Thu, 17 Sep 2020 09:48:13 +0000 (UTC) X-FDA: 77272077666.18.rice84_410cd7927121 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin18.hostedemail.com (Postfix) with ESMTP id F39EC100EC676 for ; Thu, 17 Sep 2020 09:48:12 +0000 (UTC) X-HE-Tag: rice84_410cd7927121 X-Filterd-Recvd-Size: 5143 Received: from mail-wr1-f68.google.com (mail-wr1-f68.google.com [209.85.221.68]) by imf43.hostedemail.com (Postfix) with ESMTP for ; Thu, 17 Sep 2020 09:48:12 +0000 (UTC) Received: by mail-wr1-f68.google.com with SMTP id z1so1352703wrt.3 for ; Thu, 17 Sep 2020 02:48:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=EWVAkK9HAhFT14dUOAujUtY5YcpFnxpT4fxJHTF5BOY=; b=fGUjulhIB5feEidxD8CbRMQRZtBkcY74CpaCtIFwTz/c1lHbmgF+RxHQ5QcBrM2Qhd zp4X9v27+fX0syFcIXLODdzacwIEGhav/TGHLIuv5Qn0HI9t73IOD3WqeHw02rdkgOl9 TJXhDXq7erwEwkhNM3HQw/FM7wZpI4gQZGwsl6skPykaKrBpDYw4ixD7AO1mNaCGL46r txaIuynWbKRPbDWLpW0z4mLDszb2QOwKwXBlP5T05hVcaT1tOAQkVff8vgTwNIM1IN7H F9UCAGB/4LfqJk/b1VsVSHAGJkJPcGUYDf83zZKUw0VGNFpFBSRvSr3/VZ2xgg8qEfAx 7diA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=EWVAkK9HAhFT14dUOAujUtY5YcpFnxpT4fxJHTF5BOY=; b=iprgpdzCNr959KleLcnFxcu9X9FosszRRc6OSAIACJe0rr6q0BG4JnKxjMDl9mUmKT Q8XLeDANPcOrQnr1KlRFaHtORydeH24z4e6uIinRwd6qosxLbjdDMI7BYzwKi2QcVgIG 3Heu0yvNXZZdgtNHR0DpuEdswwHwHTYi+YxJsIBExJBGG51mUvDRf16Ogz/clp1xfYTg edtYNF5kGoavfyxYtBTvGdWtDjufEK2dCmHok8uINlO8qoxrp5nbqd5qxlB60sxfp6qK 5CfOqbOPkScDd2GEBUiLbgVhmNTBsk/rdkSG9Mi37DOyryrnVFVyMXKMyi64ZIUQpzBo QouA== X-Gm-Message-State: AOAM530Gr7XrRHyvemIQfhE2bEjjNPtNoh8QF9/Gi92l2tP9awk3Gtzw ApIxTwkTSQVCzvGKs5eMfjTraefjkFpT5cQ1ME0l2Q== X-Google-Smtp-Source: ABdhPJy/tul2S9Qpkkmj30T/q+nw4Nil13riChRbngdSqqrHzeA52FzPYShdWqFhYLJV4ql+y6skJ50UXxp5Lg/gpKA= X-Received: by 2002:a5d:60d0:: with SMTP id x16mr30836644wrt.196.1600336091166; Thu, 17 Sep 2020 02:48:11 -0700 (PDT) MIME-Version: 1.0 References: <20200915132046.3332537-1-elver@google.com> <20200915132046.3332537-5-elver@google.com> In-Reply-To: From: Alexander Potapenko Date: Thu, 17 Sep 2020 11:47:59 +0200 Message-ID: Subject: Re: [PATCH v2 04/10] mm, kfence: insert KFENCE hooks for SLAB To: Christopher Lameter Cc: Marco Elver , Andrew Morton , "H. Peter Anvin" , "Paul E. McKenney" , Andrey Konovalov , Andrey Ryabinin , Andy Lutomirski , Borislav Petkov , Catalin Marinas , Dave Hansen , David Rientjes , Dmitriy Vyukov , Eric Dumazet , Greg Kroah-Hartman , Ingo Molnar , Jann Horn , Jonathan.Cameron@huawei.com, Jonathan Corbet , Joonsoo Kim , Kees Cook , Mark Rutland , Pekka Enberg , Peter Zijlstra , Qian Cai , Thomas Gleixner , Vlastimil Babka , Will Deacon , "the arch/x86 maintainers" , "open list:DOCUMENTATION" , LKML , kasan-dev , Linux ARM , Linux Memory Management List Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: F39EC100EC676 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 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: > > static __always_inline void * > > -slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, > > +slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, si= ze_t orig_size, > > unsigned long caller) > > { > > The size of the object is available via a field in kmem_cache. And a > pointer to the current kmem_cache is already passed to the function. Why > is there a need to add an additional parameter? That's because we want to do our best detecting bugs on kmalloc-allocated objects. kmalloc is using size classes, so e.g. when allocating 272 bytes the object will be padded to 512. As a result, placing that object at the end of the page won't really help to detect out-of-bound accesses that are off by less than 270 bytes. We probably need to better clarify this in the patch description. --=20 Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Stra=C3=9Fe, 33 80636 M=C3=BCnchen Gesch=C3=A4ftsf=C3=BChrer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg