From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754789Ab0F2Jnu (ORCPT ); Tue, 29 Jun 2010 05:43:50 -0400 Received: from cantor.suse.de ([195.135.220.2]:42632 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754658Ab0F2Jns (ORCPT ); Tue, 29 Jun 2010 05:43:48 -0400 Date: Tue, 29 Jun 2010 11:43:42 +0200 From: Michal Marek To: stable@kernel.org Cc: Krzysztof =?utf-8?Q?Ha=C5=82asa?= , Alan , linux-kernel@vger.kernel.org Subject: [PATCH for stable] kbuild: Fix modpost segfault Message-ID: <20100629094341.GA26045@sepie.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Greg, please add this to stable, it's a bug that started showing up with newer gcc. The upstream commit is 1c938663d58b5b2965976a6f54cc51b5d6f691aa. Thanks, Michal From: Krzysztof Halasa Alan writes: > program: /home/alan/GitTrees/linux-2.6-mid-ref/scripts/mod/modpost -o > Module.symvers -S vmlinux.o > > Program received signal SIGSEGV, Segmentation fault. It just hit me. It's the offset calculation in reloc_location() which overflows: return (void *)elf->hdr + sechdrs[section].sh_offset + (r->r_offset - sechdrs[section].sh_addr); E.g. for the first rodata r entry: r->r_offset < sechdrs[section].sh_addr and the expression in the parenthesis produces 0xFFFFFFE0 or something equally wise. Reported-by: Alan Signed-off-by: Krzysztof Hałasa Tested-by: Alan Signed-off-by: Michal Marek diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 3318692..f877900 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1342,7 +1342,7 @@ static unsigned int *reloc_location(struct elf_info *elf, int section = sechdr->sh_info; return (void *)elf->hdr + sechdrs[section].sh_offset + - (r->r_offset - sechdrs[section].sh_addr); + r->r_offset - sechdrs[section].sh_addr; } static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)