Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932657Ab0FKUm6 (ORCPT ); Fri, 11 Jun 2010 16:42:58 -0400 Received: from terminus.zytor.com ([198.137.202.10]:55613 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756917Ab0FKUm5 (ORCPT ); Fri, 11 Jun 2010 16:42:57 -0400 Message-ID: <4C129FC7.8070308@zytor.com> Date: Fri, 11 Jun 2010 13:42:47 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-3.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: Krzysztof Halasa CC: Alan , Michal Marek , =?UTF-8?B?QW3DqXJpY28gV2FuZw==?= , linux-kernel@vger.kernel.org Subject: Re: Additional info on modpost segfault References: <20100604045118.GC5167@cr0.nay.redhat.com> <4C08A9D0.8000505@suse.cz> <1275929979.2923.0.camel@zowie.clueserver.org> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1737 Lines: 50 Michal, are you sending this to Linus? -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/