From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753378AbcEINeO (ORCPT ); Mon, 9 May 2016 09:34:14 -0400 Received: from mail-am1on0140.outbound.protection.outlook.com ([157.56.112.140]:19843 "EHLO emea01-am1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751454AbcEINeM (ORCPT ); Mon, 9 May 2016 09:34:12 -0400 Authentication-Results: kvack.org; dkim=none (message not signed) header.d=none;kvack.org; dmarc=none action=none header.from=virtuozzo.com; Subject: Re: [PATCH v2 1/2] mm, kasan: improve double-free detection To: Dmitry Vyukov References: <20160506114727.GA2571@cherokee.in.rdlabs.hpecorp.net> <573065BD.2020708@virtuozzo.com> <20E775CA4D599049A25800DE5799F6DD1F627919@G4W3225.americas.hpqcorp.net> <57308A20.2050501@virtuozzo.com> CC: "Luruo, Kuthonuzo" , "glider@google.com" , "cl@linux.com" , "penberg@kernel.org" , "rientjes@google.com" , "iamjoonsoo.kim@lge.com" , "akpm@linux-foundation.org" , "kasan-dev@googlegroups.com" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" From: Andrey Ryabinin Message-ID: <573091CD.4080503@virtuozzo.com> Date: Mon, 9 May 2016 16:34:05 +0300 User-Agent: Mozilla/5.0 (X11; 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That will slightly increase size of objects <= (128 - 32) bytes. >> And if someone think otherwise, we can completely remove 'alloc_size' >> (we use it only to print size in report - not very useful). > > > Where did 128 come from? > We now should allocate only 32 bytes for 16-byte user object. If not, > there is something to fix. > I just said this wrong. I mean that the patch increases size of objects that have object_size <= (128 - 32). For bigger objects, the new 'struct kasan_[alloc,free]_meta' still fits into optimal redzone.