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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 B28EEC07E9B for ; Mon, 12 Jul 2021 09:05:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8E840610A6 for ; Mon, 12 Jul 2021 09:05:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354440AbhGLJIc (ORCPT ); Mon, 12 Jul 2021 05:08:32 -0400 Received: from foss.arm.com ([217.140.110.172]:50646 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1378130AbhGLIkR (ORCPT ); Mon, 12 Jul 2021 04:40:17 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B82071FB; Mon, 12 Jul 2021 01:37:28 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.2.95]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D21A03F694; Mon, 12 Jul 2021 01:37:25 -0700 (PDT) Date: Mon, 12 Jul 2021 09:37:17 +0100 From: Mark Rutland To: Andrey Konovalov Cc: Sam Tebbs , Robin Murphy , Andrew Morton , Linux ARM , LKML , Catalin Marinas , Dmitry Vyukov , Alexander Potapenko , Andrey Ryabinin , Will Deacon , Marco Elver Subject: Re: [PATCH] kasan: fix build for CONFIG_KASAN_HW_TAGS Message-ID: <20210712083455.GA85732@C02TD0UTHF1T.local> References: <20210708144411.25467-1-mark.rutland@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 10, 2021 at 09:16:14PM +0200, Andrey Konovalov wrote: > On Thu, Jul 8, 2021 at 4:44 PM Mark Rutland wrote: > > > > When CONFIG_KASAN_HW_TAGS is selected, uses _RET_IP_, > > but doesn't explicitly include where this is defined. > > > > We used to get this via a transitive include, but since commit: > > > > f39650de687e3576 ("kernel.h: split out panic and oops helpers") > > > > ... this is no longer the case, and so we get a build failure: > > > > | CC arch/arm64/mm/kasan_init.o > > | In file included from arch/arm64/mm/kasan_init.c:10: > > | ./include/linux/kasan.h: In function 'kasan_slab_free': > > | ./include/linux/kasan.h:211:39: error: '_RET_IP_' undeclared (first use in this function) > > | 211 | return __kasan_slab_free(s, object, _RET_IP_, init); > > | | ^~~~~~~~ > > | ./include/linux/kasan.h:211:39: note: each undeclared identifier is reported only once for each function it appears in > > | ./include/linux/kasan.h: In function 'kasan_kfree_large': > > | ./include/linux/kasan.h:219:28: error: '_RET_IP_' undeclared (first use in this function) > > | 219 | __kasan_kfree_large(ptr, _RET_IP_); > > | | ^~~~~~~~ > > | ./include/linux/kasan.h: In function 'kasan_slab_free_mempool': > > | ./include/linux/kasan.h:226:34: error: '_RET_IP_' undeclared (first use in this function) > > | 226 | __kasan_slab_free_mempool(ptr, _RET_IP_); > > | | ^~~~~~~~ > > | ./include/linux/kasan.h: In function 'kasan_check_byte': > > | ./include/linux/kasan.h:277:35: error: '_RET_IP_' undeclared (first use in this function) > > | 277 | return __kasan_check_byte(addr, _RET_IP_); > > | | ^~~~~~~~ > > > > Fix this by including explicitly. > > Hi Mark, > > Marco already sent a fix for this. It should be in the mm tree. > (Although the link to it in the Andrew's notification email doesn't > work. But they rarely do :) > > > As a heads-up, there are some unrelated runtime issues with > > CONFIG_KASAN_HW_TAGS and the recent arm64 string routines rework, which > > I'm looking into now. If you boot-test with this applied, you should > > expect to see those. > > +Sam, +Robin > > Looks like the new strlen routine is making accesses past the allocated buffer. > > The guilty commit is 325a1de81287 ("arm64: Import updated version of > Cortex Strings' strlen"). FWIW, I already have a fix for this, I'm just cleaning it up and will post shortly. The issue is that the new strlen() will make unaligned 16-byte accesses within a naturally-aligned 4096-byte window and over-read by up to 15 bytes; we can fiddle with its alignment fixup to always align to 16 bytes when MTE is in use so any over-read is within the same MTE granule as the final byte of the string. I've checked the other routines, and AFAICT they never make accesses which staddle a 16-byte boundary. Thanks, Mark.