From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759386AbcCDPFn (ORCPT ); Fri, 4 Mar 2016 10:05:43 -0500 Received: from mail-lb0-f178.google.com ([209.85.217.178]:34317 "EHLO mail-lb0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752387AbcCDPBN (ORCPT ); Fri, 4 Mar 2016 10:01:13 -0500 MIME-Version: 1.0 In-Reply-To: References: <00e9fa7d4adeac2d37a42cf613837e74850d929a.1456504662.git.glider@google.com> <56D471F5.3010202@gmail.com> <56D58398.2010708@gmail.com> Date: Fri, 4 Mar 2016 18:01:11 +0300 Message-ID: Subject: Re: [PATCH v4 5/7] mm, kasan: Stackdepot implementation. Enable stackdepot for SLAB From: Andrey Ryabinin To: Alexander Potapenko Cc: Dmitry Vyukov , Andrey Konovalov , Christoph Lameter , Andrew Morton , Steven Rostedt , Joonsoo Kim , JoonSoo Kim , Kostya Serebryany , kasan-dev , LKML , "linux-mm@kvack.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2016-03-04 17:52 GMT+03:00 Alexander Potapenko : > On Tue, Mar 1, 2016 at 12:57 PM, Andrey Ryabinin wrote: >> >> >> On 02/29/2016 08:12 PM, Dmitry Vyukov wrote: >> >>>>> diff --git a/lib/Makefile b/lib/Makefile >>>>> index a7c26a4..10a4ae3 100644 >>>>> --- a/lib/Makefile >>>>> +++ b/lib/Makefile >>>>> @@ -167,6 +167,13 @@ obj-$(CONFIG_SG_SPLIT) += sg_split.o >>>>> obj-$(CONFIG_STMP_DEVICE) += stmp_device.o >>>>> obj-$(CONFIG_IRQ_POLL) += irq_poll.o >>>>> >>>>> +ifeq ($(CONFIG_KASAN),y) >>>>> +ifeq ($(CONFIG_SLAB),y) >>>> >>>> Just try to imagine that another subsystem wants to use stackdepot. How this gonna look like? >>>> >>>> We have Kconfig to describe dependencies. So, this should be under CONFIG_STACKDEPOT. >>>> So any user of this feature can just do 'select STACKDEPOT' in Kconfig. >>>> >>>>> + obj-y += stackdepot.o >>>>> + KASAN_SANITIZE_slub.o := n >> _stackdepot.o >> >> >>>> >>>>> + >>>>> + stack->hash = hash; >>>>> + stack->size = size; >>>>> + stack->handle.slabindex = depot_index; >>>>> + stack->handle.offset = depot_offset >> STACK_ALLOC_ALIGN; >>>>> + __memcpy(stack->entries, entries, size * sizeof(unsigned long)); >>>> >>>> s/__memcpy/memcpy/ >>> >>> memcpy should be instrumented by asan/tsan, and we would like to avoid >>> that instrumentation here. >> >> KASAN_SANITIZE_* := n already takes care about this. >> __memcpy() is a special thing solely for kasan internals and some assembly code. >> And it's not available generally. > As far as I can see, KASAN_SANITIZE_*:=n does not guarantee it. > It just removes KASAN flags from GCC command line, it does not > necessarily replace memcpy() calls with some kind of a > non-instrumented memcpy(). > With removed kasan cflags '__SANITIZE_ADDRESS__' is not defined, hence enable the following defines from arch/x86/include/asm/string_64.h: #if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__) /* * For files that not instrumented (e.g. mm/slub.c) we * should use not instrumented version of mem* functions. */ #undef memcpy #define memcpy(dst, src, len) __memcpy(dst, src, len) #define memmove(dst, src, len) __memmove(dst, src, len) #define memset(s, c, n) __memset(s, c, n) #endif