Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751974AbdC0SvY (ORCPT ); Mon, 27 Mar 2017 14:51:24 -0400 Received: from mail-it0-f41.google.com ([209.85.214.41]:37063 "EHLO mail-it0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751294AbdC0SvP (ORCPT ); Mon, 27 Mar 2017 14:51:15 -0400 MIME-Version: 1.0 In-Reply-To: <201703271633.xbYHmB37%fengguang.wu@intel.com> References: <20170326210825.23255-3-ewk@edkovsky.org> <201703271633.xbYHmB37%fengguang.wu@intel.com> From: Kees Cook Date: Mon, 27 Mar 2017 11:42:57 -0700 X-Google-Sender-Auth: Lx1slzJgfmbrJ1Bx498zoGwsF-k Message-ID: Subject: Re: [PATCH v4 2/2] extable: verify address is read-only To: Jakub Kicinski , Catalin Marinas , Heiko Carstens , Eddie Kovsky Cc: kbuild-all@01.org, kbuild test robot , Jessica Yu , Rusty Russell , LKML , "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 Content-Length: 3486 Lines: 87 On Mon, Mar 27, 2017 at 1:43 AM, kbuild test robot wrote: > Hi Eddie, > > [auto build test ERROR on next-20170323] > [cannot apply to linus/master linux/master jeyu/modules-next v4.9-rc8 v4.9-rc7 v4.9-rc6 v4.11-rc4] > [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/Eddie-Kovsky/module-verify-address-is-read-only/20170327-142922 > config: blackfin-BF561-EZKIT-SMP_defconfig (attached as .config) > compiler: bfin-uclinux-gcc (GCC) 6.2.0 > reproduce: > wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > # save the attached .config to linux build tree > make.cross ARCH=blackfin > > All errors (new ones prefixed by >>): > > kernel/built-in.o: In function `core_kernel_rodata': >>> kernel/extable.c:169: undefined reference to `__start_data_ro_after_init' >>> kernel/extable.c:169: undefined reference to `__start_data_ro_after_init' >>> kernel/extable.c:169: undefined reference to `__end_data_ro_after_init' >>> kernel/extable.c:169: undefined reference to `__end_data_ro_after_init' >>> kernel/extable.c:169: undefined reference to `__start_data_ro_after_init' >>> kernel/extable.c:169: undefined reference to `__start_data_ro_after_init' >>> kernel/extable.c:169: undefined reference to `__end_data_ro_after_init' >>> kernel/extable.c:169: undefined reference to `__end_data_ro_after_init' Hm, I'm confused about this. blackfin includes include/asm-generic-vmlinux.lds.h and uses the RO_DATA macro (which resolves to RO_DATA_SECTION to RO_AFTER_INIT_DATA which defines __[start|end]_data_ro_after_init. Also, it seems that commit d7c19b066dcf4bd19c4385e8065558d4e74f9e73 ("mm: kmemleak: scan .data.ro_after_init") added a potentially redundant section name (s390 already calls this __[start|end]_ro_after_init). I'd like to get this cleaned up, since having multiple names for the same thing is confusing: diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S index 000e6e91f6a0..3667d20e997f 100644 --- a/arch/s390/kernel/vmlinux.lds.S +++ b/arch/s390/kernel/vmlinux.lds.S @@ -62,9 +62,11 @@ SECTIONS . = ALIGN(PAGE_SIZE); __start_ro_after_init = .; + __start_data_ro_after_init = .; .data..ro_after_init : { *(.data..ro_after_init) } + __end_data_ro_after_init = .; EXCEPTION_TABLE(16) . = ALIGN(PAGE_SIZE); __end_ro_after_init = .; And it seems that this hunk is wrong (__end_ro_after_init includes s390's exception table, etc). I think we should remove the ..._data_... name and use s390's name. I'll send an adjustment patch, but we'll still need to deal with blackfin. -Kees > > vim +169 kernel/extable.c > > 163 int core_kernel_rodata(unsigned long addr) > 164 { > 165 if (addr >= (unsigned long)__start_rodata && > 166 addr < (unsigned long)__end_rodata) > 167 return 1; > 168 > > 169 if (addr >= (unsigned long)__start_data_ro_after_init && > 170 addr < (unsigned long)__end_data_ro_after_init) > 171 return 1; > 172 > > --- > 0-DAY kernel test infrastructure Open Source Technology Center > https://lists.01.org/pipermail/kbuild-all Intel Corporation -- Kees Cook Pixel Security