From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422861AbdD0UWW (ORCPT ); Thu, 27 Apr 2017 16:22:22 -0400 Received: from mail-io0-f171.google.com ([209.85.223.171]:32928 "EHLO mail-io0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422844AbdD0UWH (ORCPT ); Thu, 27 Apr 2017 16:22:07 -0400 MIME-Version: 1.0 In-Reply-To: <201704270938.I52YmjxT%fengguang.wu@intel.com> References: <1493160997-126108-3-git-send-email-keescook@chromium.org> <201704270938.I52YmjxT%fengguang.wu@intel.com> From: Kees Cook Date: Thu, 27 Apr 2017 13:22:05 -0700 X-Google-Sender-Auth: LL7zh-4e-DEZ8y4vTOKL1eGFtnk Message-ID: Subject: Re: [PATCH v2 2/2] x86, refcount: Implement fast refcount overflow protection To: Josh Poimboeuf Cc: LKML , Peter Zijlstra , PaX Team , Jann Horn , Eric Biggers , Christoph Hellwig , "axboe@kernel.dk" , James Bottomley , Elena Reshetova , Hans Liljestrand , David Windsor , "x86@kernel.org" , Ingo Molnar , Arnd Bergmann , Greg Kroah-Hartman , "David S. Miller" , Rik van Riel , linux-arch , "kernel-hardening@lists.openwall.com" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 26, 2017 at 6:31 PM, kbuild test robot wrote: > Hi Kees, > > [auto build test WARNING on next-20170424] > [cannot apply to tip/x86/core linus/master linux/master v4.9-rc8 v4.9-rc7 v4.9-rc6 v4.11-rc8] > [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] > > url: https://github.com/0day-ci/linux/commits/Kees-Cook/x86-refcount-Implement-fast-refcount-overflow/20170426-210530 > config: x86_64-allmodconfig (attached as .config) > compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901 > reproduce: > # save the attached .config to linux build tree > make ARCH=x86_64 > > All warnings (new ones prefixed by >>): > >>> drivers//scsi/scsi_scan.o: warning: objtool: .text.refcount_overflow+0x5: special: can't find orig instruction Hi Josh, I'm seeing this error being generated on areas that are using a cross-section exception handler. I can't quite see why the .o checker is unhappy, so I figured I'd ask you first. :) The code is generated with calls to __REFCOUNT_CHECK() which is defined like this: +#define __REFCOUNT_EXCEPTION(size) \ + ".if "__stringify(size)" == 4\n\t" \ + ".pushsection .text.refcount_overflow\n" \ + ".elseif "__stringify(size)" == -4\n\t" \ + ".pushsection .text.refcount_underflow\n" \ + ".else\n" \ + ".error \"invalid size\"\n" \ + ".endif\n" \ + "111:\tlea %[counter],%%"_ASM_CX"\n\t" \ + "int $"__stringify(X86_REFCOUNT_VECTOR)"\n" \ + "222:\n\t" \ + ".popsection\n" \ + "333:\n" \ + _ASM_EXTABLE(222b, 333b) + +#define __REFCOUNT_CHECK(size) \ + "js 111f\n" \ + __REFCOUNT_EXCEPTION(size) + +#define __REFCOUNT_ERROR(size) \ + "jmp 111f\n" \ + __REFCOUNT_EXCEPTION(size) I assume it doesn't like seeing an exception split across .text and .text.refcount_overflow, but I haven't been able to figure out how that distinction would be made by the checker. :P Thanks! -Kees > -- > /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute >>> drivers/scsi/qla2xxx/qla_target.o: warning: objtool: .text.refcount_overflow+0x23: special: can't find orig instruction > -- > /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute >>> drivers/nvme/target/core.o: warning: objtool: .text.refcount_overflow+0x19: special: can't find orig instruction > -- > /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute >>> drivers/nvme/target/rdma.o: warning: objtool: .text.refcount_overflow+0x5: special: can't find orig instruction > -- > /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute >>> drivers/nvme/target/fcloop.o: warning: objtool: .text.refcount_overflow+0x6: special: can't find orig instruction > -- > /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute >>> net/batman-adv/bat_v.o: warning: objtool: .text.refcount_underflow+0xc: special: can't find orig instruction > -- > /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute >>> net/batman-adv/bat_v_elp.o: warning: objtool: .text.refcount_overflow+0xa: special: can't find orig instruction > -- > /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute >>> net/batman-adv/fragmentation.o: warning: objtool: .text.refcount_overflow+0xa: special: can't find orig instruction > -- > /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute >>> net/batman-adv/icmp_socket.o: warning: objtool: .text.refcount_overflow+0xb: special: can't find orig instruction > -- > /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute >>> net/batman-adv/main.o: warning: objtool: .text.refcount_overflow+0xb: special: can't find orig instruction > -- > /kbuild/src/consumer/include/linux/compiler.h:264:8: sparse: attribute 'no_sanitize_address': unknown attribute >>> net/batman-adv/multicast.o: warning: objtool: .text.refcount_overflow+0xf: special: can't find orig instruction > .. > > --- > 0-DAY kernel test infrastructure Open Source Technology Center > https://lists.01.org/pipermail/kbuild-all Intel Corporation -- Kees Cook Pixel Security