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, 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 11BFFC433E7 for ; Mon, 12 Oct 2020 08:01:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 664E52080D for ; Mon, 12 Oct 2020 08:01:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 664E52080D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4E3AD940007; Mon, 12 Oct 2020 04:01:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 494EA900002; Mon, 12 Oct 2020 04:01:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3AB1E940007; Mon, 12 Oct 2020 04:01:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0155.hostedemail.com [216.40.44.155]) by kanga.kvack.org (Postfix) with ESMTP id 0BDDD900002 for ; Mon, 12 Oct 2020 04:01:05 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 8A8B61EF1 for ; Mon, 12 Oct 2020 08:01:05 +0000 (UTC) X-FDA: 77362527690.26.touch61_1a0b40f271f8 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin26.hostedemail.com (Postfix) with ESMTP id 69B331804B656 for ; Mon, 12 Oct 2020 08:01:05 +0000 (UTC) X-HE-Tag: touch61_1a0b40f271f8 X-Filterd-Recvd-Size: 1850 Received: from gentwo.org (gentwo.org [3.19.106.255]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Mon, 12 Oct 2020 08:01:04 +0000 (UTC) Received: by gentwo.org (Postfix, from userid 1002) id 249E63F19D; Mon, 12 Oct 2020 08:01:04 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id 226783EC24; Mon, 12 Oct 2020 08:01:04 +0000 (UTC) Date: Mon, 12 Oct 2020 08:01:04 +0000 (UTC) From: Christopher Lameter X-X-Sender: cl@www.lameter.com To: Kees Cook cc: Andrew Morton , stable@vger.kernel.org, Marco Elver , Jonathan Corbet , Pekka Enberg , David Rientjes , Joonsoo Kim , Vlastimil Babka , Roman Gushchin , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2 2/3] mm/slub: Fix redzoning for small allocations In-Reply-To: <20201009195411.4018141-3-keescook@chromium.org> Message-ID: References: <20201009195411.4018141-1-keescook@chromium.org> <20201009195411.4018141-3-keescook@chromium.org> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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, 9 Oct 2020, Kees Cook wrote: > Store the freelist pointer out of line when object_size is smaller than > sizeof(void *) and redzoning is enabled. > > (Note that no caches with such a size are known to exist in the kernel > currently.) Ummm... The smallest allowable cache size is sizeof(void *) as I recall. mm/slab_common.c::kmem_sanity_check() checks the sizes when caches are created. NAK.