From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755887AbZBJOUr (ORCPT ); Tue, 10 Feb 2009 09:20:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754240AbZBJOUj (ORCPT ); Tue, 10 Feb 2009 09:20:39 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:34412 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754053AbZBJOUj (ORCPT ); Tue, 10 Feb 2009 09:20:39 -0500 Date: Tue, 10 Feb 2009 15:20:26 +0100 From: Ingo Molnar To: Tejun Heo Cc: hpa@zytor.com, jeremy@goop.org, tglx@linutronix.de, linux-kernel@vger.kernel.org, x86@kernel.org, rusty@rustcorp.com.au Subject: Re: [PATCHSET x86/master] add stack protector support for x86_32 Message-ID: <20090210142026.GD16147@elte.hu> References: <1234186798-16820-1-git-send-email-tj@kernel.org> <20090209135557.GB14785@elte.hu> <20090209141209.GA24323@elte.hu> <499186FB.4070506@kernel.org> <49918C3C.8030208@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49918C3C.8030208@kernel.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Tejun Heo wrote: > Tejun Heo wrote: > > Ingo Molnar wrote: > >> * Ingo Molnar wrote: > >> > >>> [...] I might not get around testing it today and pushing it out into tip:master, > >>> but i pushed out the core/percpu bits, should you queue up further changes. > >> ok, activated it for -tip testing, and there's a 64-bit build failure caused by > >> it: > >> > >> arch/x86/kernel/head64.o: In function `x86_64_start_reservations': > >> head64.c:(.init.text+0x26): undefined reference to `__stack_chk_guard' > >> head64.c:(.init.text+0xc2): undefined reference to `__stack_chk_guard' > >> arch/x86/kernel/head64.o: In function `x86_64_start_kernel': > >> head64.c:(.init.text+0x104): undefined reference to `__stack_chk_guard' > >> head64.c:(.init.text+0x1cd): undefined reference to `__stack_chk_guard' > >> arch/x86/kernel/head.o: In function `reserve_ebda_region': > >> head.c:(.init.text+0xb): undefined reference to `__stack_chk_guard' > >> arch/x86/kernel/head.o:head.c:(.init.text+0x87): more undefined references to > >> `__stack_chk_guard' follow > > > > Call to __stack_chk_guard is probably generated automatically. > > Strangely, my gcc only generates calls to __stack_chk_fail. > > > > > gcc --version > > gcc (SUSE Linux) 4.3.2 [gcc-4_3-branch revision 141291] > > Copyright (C) 2008 Free Software Foundation, Inc. > > This is free software; see the source for copying conditions. There is NO > > warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. > > > nm build/vmlinux|grep __stack_chk_ > > 00000000f0fdf6cb A __crc___stack_chk_fail > > ffffffff80d53e50 r __kcrctab___stack_chk_fail > > ffffffff80d5ff81 r __kstrtab___stack_chk_fail > > ffffffff80d3d140 r __ksymtab___stack_chk_fail > > ffffffff80248619 T __stack_chk_fail > > > > I'll try other compilers but which version are you using? The > > difference is that before the patchset, -fno-stack-protector was > > always added whether stackprotector was enabled or not so this problem > > wasn't visible (at the cost of bogus stackprotector of course). We'll > > probably need to add __stack_chk_guard or disable if gcc generates > > such symbol. I'll play with different gccs. > > Can't reproduce with gcc-4.1 or 4.2. Any chance you're using distcc > w/ a build machine w/ glibc < 2.4? __stack_chk_guard is the symbol > gcc fetches stack canary from if TLS is not supported, so somehow gcc > thought that TLS wasn't available while building head64. yeah - i also used distcc. Maybe the nostackp makefile magic gets confused about that? Ingo