Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B897FC433EF for ; Thu, 2 Dec 2021 14:36:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358602AbhLBOjp (ORCPT ); Thu, 2 Dec 2021 09:39:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358563AbhLBOjl (ORCPT ); Thu, 2 Dec 2021 09:39:41 -0500 Received: from mail-oi1-x22d.google.com (mail-oi1-x22d.google.com [IPv6:2607:f8b0:4864:20::22d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B229C06174A for ; Thu, 2 Dec 2021 06:36:19 -0800 (PST) Received: by mail-oi1-x22d.google.com with SMTP id t19so55881539oij.1 for ; Thu, 02 Dec 2021 06:36:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=lc5f8V7U1qeIZMO/3oPn6uEImdj6hfKGGM9TNkHj2Xk=; b=HWplDAiYE/bfYKcxYxJZTdeU94qjLg13BvzdPO4g7ih9KOKMe2SrJtUcEHelW3SHAz VSEr4hgGVpQo1cAzH09mGF+9fj7Pj3WIgnBZKBiN2ajivkM7MK1nUlk3JoteFCYz67sR ZR3weVDCtWuSRSF6kWiFOjhhMOpfSXaH0KDswyKfc3TnEHp+R0l54oSNFc2f+VCpdohL ISlicDg1KT1zM2R5rdykFeujqPuROa0/oWFs0/BlVPvx5/q4MMknOQA0xANVQKtZ2ujw xJ4Fi7+odqxOibQZvzunJcLbADcdyxTBkDgp1CcrRwF/+FNExhlbYJM9fCTH2KuezQTZ Xrng== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=lc5f8V7U1qeIZMO/3oPn6uEImdj6hfKGGM9TNkHj2Xk=; b=iXet+6OKQPbxRLxqTBkBdM4OT4MIIpw2Fd2VbxhngIOV4g98uwS37q2wW3SugcVfmQ SVmlKCxzLOhrlnBia3fzRzdCJ39QrlFMhgLsu7OGtNe7NnX52F+JHiFe2z3YgqqofJbG hnmLDKH3W/z95rfScTh3jzTGuN+CH4rFDn0qEnauTjXOm1oTukmeF6gNkTo95+SIssXp 9jUdiV4QP3SvctPLXlDhHzrDMi2sH+X1AIlDgicS05NzSf6uxG0UA29iw6Sg7aZ9IlYs oUtC9liqQ0yg1bj1YLPyOGdYiBXglfSZxi6CNJHSPMlGouJiMECbdt+EygBih3buog4N 5WXw== X-Gm-Message-State: AOAM530rqD8N9eZOa7tzIsmY7FRa6rzVfg/lhXyKKJXx0u3XV5ZUxB8J TwOkQe+0w6jysiATguxvEf4Ss5ON1tPLPRFKdCGko7w+o0sUGg== X-Google-Smtp-Source: ABdhPJww3T7wVoEMLLphTGCtsexdTb9S+iBjJpV6IYKDAw3axBzsEcnpum0KKk+vtDsuZTG452EOwcToO/wTPIdP54c= X-Received: by 2002:a05:6808:1903:: with SMTP id bf3mr4698798oib.7.1638455778073; Thu, 02 Dec 2021 06:36:18 -0800 (PST) MIME-Version: 1.0 References: <20211202143331.15259-1-wangkefeng.wang@huawei.com> In-Reply-To: <20211202143331.15259-1-wangkefeng.wang@huawei.com> From: Marco Elver Date: Thu, 2 Dec 2021 15:36:06 +0100 Message-ID: Subject: Re: [PATCH v3] arm64: Enable KCSAN To: Kefeng Wang Cc: Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, mark.rutland@arm.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2 Dec 2021 at 15:23, Kefeng Wang wrote: > > This patch enables KCSAN for arm64, with updates to build rules > to not use KCSAN for several incompatible compilation units. > > Resent GCC version(at least GCC10) made outline-atomics as the s/Resent/Recent/ > default option(unlike Clang), which will cause linker errors > for kernel/kcsan/core.o. Disables the out-of-line atomics by > no-outline-atomics to fix the linker errors. > > Meanwhile, as Mark said[1], there is a specific issue on arm64 > about ARM64_BTI with Clang 11 if KCSAN enabled, which is fixed > by Clang 12, add CLANG_VERSION check. And also some latent issues > are need to be fixed which isn't just a KCSAN problem, we make > the KCSAN depends on EXPERT for now. > > Tested selftest and kcsan_test(built with GCC11 and Clang 13), > and all passed. > > [1] https://lkml.org/lkml/2021/12/1/354 Please use lore/kernel.org permalinks. For this one it'd be: https://lkml.kernel.org/r/YadiUPpJ0gADbiHQ@FVFF77S0Q05N (But I think if this is the final version of the patch, hopefully a maintainer can amend the commit message.) > Signed-off-by: Kefeng Wang Acked-by: Marco Elver # kernel/kcsan is still valid, given nothing changed there. I leave the rest to Mark. Thanks, -- Marco > --- > Tested on Qemu with clang 13 / gcc 11, based on 5.16-rc3. > > [ 0.221518] kcsan: enabled early > [ 0.222422] kcsan: strict mode configured > ... > [ 5.839223] kcsan: selftest: 3/3 tests passed > ... > [ 517.895102] # kcsan: pass:24 fail:0 skip:0 total:24 > [ 517.896393] # Totals: pass:168 fail:0 skip:0 total:168 > [ 517.897502] ok 1 - kcsan > > v3: > - add EXPERT and CLANG_VERSION depends suggested by Mark Rutland > v2: > - tested on GCC11 and disable outline-atomics for kernel/kcsan/core.c > suggested by Marco Elver > > arch/arm64/Kconfig | 1 + > arch/arm64/kernel/vdso/Makefile | 1 + > arch/arm64/kvm/hyp/nvhe/Makefile | 1 + > kernel/kcsan/Makefile | 1 + > 4 files changed, 4 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 4ff73299f8a9..3a7b17742cde 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -150,6 +150,7 @@ config ARM64 > select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN > select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN > select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE) > + select HAVE_ARCH_KCSAN if EXPERT && (CC_IS_GCC || CLANG_VERSION >= 120000) > select HAVE_ARCH_KFENCE > select HAVE_ARCH_KGDB > select HAVE_ARCH_MMAP_RND_BITS > diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile > index 700767dfd221..60813497a381 100644 > --- a/arch/arm64/kernel/vdso/Makefile > +++ b/arch/arm64/kernel/vdso/Makefile > @@ -32,6 +32,7 @@ ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO > CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) $(GCC_PLUGINS_CFLAGS) \ > $(CC_FLAGS_LTO) > KASAN_SANITIZE := n > +KCSAN_SANITIZE := n > UBSAN_SANITIZE := n > OBJECT_FILES_NON_STANDARD := y > KCOV_INSTRUMENT := n > diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile > index c3c11974fa3b..24b2c2425b38 100644 > --- a/arch/arm64/kvm/hyp/nvhe/Makefile > +++ b/arch/arm64/kvm/hyp/nvhe/Makefile > @@ -89,6 +89,7 @@ KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS) $(CC_FLAGS_CFI) > # cause crashes. Just disable it. > GCOV_PROFILE := n > KASAN_SANITIZE := n > +KCSAN_SANITIZE := n > UBSAN_SANITIZE := n > KCOV_INSTRUMENT := n > > diff --git a/kernel/kcsan/Makefile b/kernel/kcsan/Makefile > index c2bb07f5bcc7..e893b0e1d62a 100644 > --- a/kernel/kcsan/Makefile > +++ b/kernel/kcsan/Makefile > @@ -8,6 +8,7 @@ CFLAGS_REMOVE_debugfs.o = $(CC_FLAGS_FTRACE) > CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE) > > CFLAGS_core.o := $(call cc-option,-fno-conserve-stack) \ > + $(call cc-option,-mno-outline-atomics) \ > -fno-stack-protector -DDISABLE_BRANCH_PROFILING > > obj-y := core.o debugfs.o report.o > -- > 2.26.2 >