Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932495Ab3DEFF5 (ORCPT ); Fri, 5 Apr 2013 01:05:57 -0400 Received: from ozlabs.org ([203.10.76.45]:57810 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751857Ab3DEFF4 (ORCPT ); Fri, 5 Apr 2013 01:05:56 -0400 From: Rusty Russell To: Sebastian Wankerl Cc: Sebastian Wankerl , linux-kernel@vger.kernel.org, Philip Kranz , i4passt@lists.informatik.uni-erlangen.de, linux-parisc@vger.kernel.org Subject: Re: [PATCH] Add non-zero module sections to sysfs In-Reply-To: <515D4A7F.5070102@cip.cs.fau.de> References: <1364994499-23708-1-git-send-email-sisewank@cip.cs.fau.de> <87mwtf3ya1.fsf@rustcorp.com.au> <515D4A7F.5070102@cip.cs.fau.de> User-Agent: Notmuch/0.14 (http://notmuchmail.org) Emacs/23.4.1 (i686-pc-linux-gnu) Date: Fri, 05 Apr 2013 14:30:50 +1030 Message-ID: <87vc81lj7x.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2209 Lines: 60 Sebastian Wankerl writes: > On 04/04/13 03:00, Rusty Russell wrote: >> Sebastian Wankerl writes: >>> Add non-zero module sections to sysfs on architectures unequal to PARISC. >>> KGDB needs all module sections for proper module debugging. Therefore, commit >>> 35dead4235e2b67da7275b4122fed37099c2f462 is revoked except for PARISC >>> architecture. >> #ifdef CONFIG_PARISC in the middle of kernel/module.c is super-ugly, and >> wrong. > > I don't see why this is wrong. It used to load all sections to sysfs > until the patch mentioned. Actually, it is the PARISC build chain which > is broken. Exactly. Don't workaround it here, revert it and put the duplicate-section-name fixup in parisc where it belongs. Assuming parisc still produces these dup sections: that patch is 4 years old now. Untested: diff --git a/arch/parisc/kernel/module.c b/arch/parisc/kernel/module.c index 2a625fb..28d32a2 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; >> My preference would be to fix kgdb. If the section is empty, what need >> does it have to examine it? > > GDB needs to know all sections of the binary and its addresses. Why? Does something refer to this empty section? Why has noone noticed this since 2009? > It is generally useful to be able to check up all sections of the binary > regardless if they are empty or not so one can see the binary's > structure. A zero-length section doesn't change the binary's structure. You don't see non-SHF_ALLOC sections either. Cheers, Rusty. -- 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/