Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934590Ab3DKOJi (ORCPT ); Thu, 11 Apr 2013 10:09:38 -0400 Received: from mail-we0-f170.google.com ([74.125.82.170]:54798 "EHLO mail-we0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752513Ab3DKOJg (ORCPT ); Thu, 11 Apr 2013 10:09:36 -0400 Date: Thu, 11 Apr 2013 16:11:55 +0200 From: Philip Kranz To: Rusty Russell Cc: Philip Kranz , James Bottomley , Sebastian Wankerl , linux-kernel@vger.kernel.org, i4passt@lists.informatik.uni-erlangen.de, linux-parisc@vger.kernel.org Subject: Re: [PATCH] Add non-zero module sections to sysfs Message-ID: <20130411141155.GA21480@yoda.lan> References: <1364994499-23708-1-git-send-email-sisewank@cip.cs.fau.de> <87mwtf3ya1.fsf@rustcorp.com.au> <515D4A7F.5070102@cip.cs.fau.de> <87vc81lj7x.fsf@rustcorp.com.au> <1365156435.1970.31.camel@dabdike> <20130406104053.GA24710@yoda.lan> <878v4tbqve.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <878v4tbqve.fsf@rustcorp.com.au> User-Agent: Mutt/1.5.14 (2007-03-31) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2605 Lines: 67 On Mon, Apr 08, 2013 at 01:44:45PM +0930, Rusty Russell wrote: > Philip Kranz writes: > > Hello. > > > > On Fri, Apr 05, 2013 at 12:07:15PM +0200, James Bottomley wrote: > >> Just so you know: this isn't a parisc specific problem. Gcc produces > >> duplicate section names under various circumstances, but the one that > >> bites us is -ffunction-sections. Note that there are proposals to use > >> -ffunction-sections on all architectures (so we can garbage collect > >> unused functions) in which case you'll induce the bug identified in > >> 35dead4235e2b67da7275b4122fed37099c2f462 on every architecture > > > > I am not able to produce an object file with duplicate section names > > using gcc on x86. Even with -ffunction-sections, every section gets a > > unique name. Is this architecture-specific behaviour of gcc? > > Good point. ld -r will collapse them into the same section (since gcc > produces them they have to have the same section attributes). > > You can do it with --unique, but no arch uses that. PARISC has a > platform-specific toolchain hack which does that for .text sections. > (Thanks to Alan Modra for that clue...) Just for clarification, as we are currently preparing a patch set that depends on this: Would the patch below be an acceptable solution for this? Thanks, Philip diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c index 2a625fb..1fd4411 100644 --- a/arch/parisc/kernel/module.c +++ b/arch/parisc/kernel/module.c @@ -341,6 +341,11 @@ int module_frob_arch_sections(CONST Elf_Ehdr *hdr, ".PARISC.unwind", 14) == 0) me->arch.unwind_section = i; + /* we produce multiple, empty .text sections, and kallsyms + * gets upset. make non-alloc so it doesn't see them. */ + if (sechdrs[i].sh_size == 0) + sechdrs[i].sh_flags &= ~SHF_ALLOC; + if (sechdrs[i].sh_type != SHT_RELA) continue; diff --git a/kernel/module.c b/kernel/module.c index 3c2c72d..42e0d5a 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1316,7 +1316,7 @@ resolve_symbol_wait(struct module *mod, #ifdef CONFIG_KALLSYMS static inline bool sect_empty(const Elf_Shdr *sect) { - return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0; + return !(sect->sh_flags & SHF_ALLOC); } struct module_sect_attr -- 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/