Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760576Ab0FKWty (ORCPT ); Fri, 11 Jun 2010 18:49:54 -0400 Received: from cantor.suse.de ([195.135.220.2]:45631 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755801Ab0FKWtw (ORCPT ); Fri, 11 Jun 2010 18:49:52 -0400 Date: Sat, 12 Jun 2010 00:49:47 +0200 From: Michal Marek To: "H. Peter Anvin" Cc: Krzysztof Halasa , Alan , =?iso-8859-1?Q?Am=E9rico?= Wang , linux-kernel@vger.kernel.org Subject: Re: Additional info on modpost segfault Message-ID: <20100611224947.GA17453@sepie.suse.cz> References: <20100604045118.GC5167@cr0.nay.redhat.com> <4C08A9D0.8000505@suse.cz> <1275929979.2923.0.camel@zowie.clueserver.org> <4C129FC7.8070308@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4C129FC7.8070308@zytor.com> 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 Content-Length: 2262 Lines: 62 On Fri, Jun 11, 2010 at 01:42:47PM -0700, H. Peter Anvin wrote: > Michal, are you sending this to Linus? I'll, once Linus takes another pull request I sent a couple of hours ago. Thanks for the patch Krzysztof! Michal > > -hpa > > > On 06/10/2010 04:08 PM, Krzysztof Halasa wrote: > > 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. > > > > Does the attached patch fix it? > > > > Signed-off-by: Krzysztof Hałasa > > > > --- a/scripts/mod/modpost.c > > +++ b/scripts/mod/modpost.c > > @@ -1317,8 +1317,8 @@ static unsigned int *reloc_location(struct elf_info *elf, > > Elf_Shdr *sechdrs = elf->sechdrs; > > 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) > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/