Return-path: Received: from mail-qk0-f169.google.com ([209.85.220.169]:36380 "EHLO mail-qk0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751333AbdCCN4J (ORCPT ); Fri, 3 Mar 2017 08:56:09 -0500 Received: by mail-qk0-f169.google.com with SMTP id 1so57147387qkl.3 for ; Fri, 03 Mar 2017 05:55:37 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <7e7a62de-3b79-6044-72fa-4ade418953d1@virtuozzo.com> References: <20170302163834.2273519-1-arnd@arndb.de> <20170302163834.2273519-2-arnd@arndb.de> <7e7a62de-3b79-6044-72fa-4ade418953d1@virtuozzo.com> From: Alexander Potapenko Date: Fri, 3 Mar 2017 14:55:35 +0100 Message-ID: (sfid-20170303_145840_920102_B53C2F5F) Subject: Re: [PATCH 01/26] compiler: introduce noinline_for_kasan annotation To: Andrey Ryabinin Cc: Arnd Bergmann , kasan-dev , Dmitry Vyukov , netdev@vger.kernel.org, LKML , linux-media@vger.kernel.org, linux-wireless@vger.kernel.org, kernel-build-reports@lists.linaro.org, "David S . Miller" Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Fri, Mar 3, 2017 at 2:50 PM, Andrey Ryabinin w= rote: > > > On 03/02/2017 07:38 PM, Arnd Bergmann wrote: >> When CONFIG_KASAN is set, we can run into some code that uses incredible >> amounts of kernel stack: >> >> drivers/staging/dgnc/dgnc_neo.c:1056:1: error: the frame size of 11112 b= ytes is larger than 2048 bytes [-Werror=3Dframe-larger-than=3D] >> drivers/media/i2c/cx25840/cx25840-core.c:4960:1: error: the frame size o= f 94000 bytes is larger than 2048 bytes [-Werror=3Dframe-larger-than=3D] >> drivers/media/dvb-frontends/stv090x.c:3430:1: error: the frame size of 5= 312 bytes is larger than 3072 bytes [-Werror=3Dframe-larger-than=3D] >> >> This happens when a sanitizer uses stack memory each time an inline func= tion >> gets called. This introduces a new annotation for those functions to mak= e >> them either 'inline' or 'noinline' dependning on the CONFIG_KASAN symbol= . >> >> Signed-off-by: Arnd Bergmann >> --- >> include/linux/compiler.h | 11 +++++++++++ >> 1 file changed, 11 insertions(+) >> >> diff --git a/include/linux/compiler.h b/include/linux/compiler.h >> index f8110051188f..56b90897a459 100644 >> --- a/include/linux/compiler.h >> +++ b/include/linux/compiler.h >> @@ -416,6 +416,17 @@ static __always_inline void __write_once_size(volat= ile void *p, void *res, int s >> */ >> #define noinline_for_stack noinline >> >> +/* >> + * CONFIG_KASAN can lead to extreme stack usage with certain patterns w= hen >> + * one function gets inlined many times and each instance requires a st= ack >> + * ckeck. >> + */ >> +#ifdef CONFIG_KASAN >> +#define noinline_for_kasan noinline __maybe_unused > > > noinline_iff_kasan might be a better name. noinline_for_kasan gives the = impression > that we always noinline function for the sake of kasan, while noinline_if= f_kasan > clearly indicates that function is noinline only if kasan is used. FWIW we may be facing the same problem with other compiler-based tools, e.g. KMSAN (which isn't there yet). So it might be better to choose a macro name that doesn't use the name "KAS= AN". E.g. noinline_iff_memtool (or noinline_iff_memory_tool if that's not too lo= ng). WDYT? >> +#else >> +#define noinline_for_kasan inline >> +#endif >> + >> #ifndef __always_inline >> #define __always_inline inline >> #endif >> > > -- > You received this message because you are subscribed to the Google Groups= "kasan-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an= email to kasan-dev+unsubscribe@googlegroups.com. > To post to this group, send email to kasan-dev@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgi= d/kasan-dev/7e7a62de-3b79-6044-72fa-4ade418953d1%40virtuozzo.com. > For more options, visit https://groups.google.com/d/optout. --=20 Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Stra=C3=9Fe, 33 80636 M=C3=BCnchen Gesch=C3=A4ftsf=C3=BChrer: Matthew Scott Sucherman, Paul Terence Manicle Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg