From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.1 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BE1FAC47404 for ; Mon, 7 Oct 2019 06:46:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8146F20659 for ; Mon, 7 Oct 2019 06:46:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="FEpiYSxm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727032AbfJGGqg (ORCPT ); Mon, 7 Oct 2019 02:46:36 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:38658 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726202AbfJGGqf (ORCPT ); Mon, 7 Oct 2019 02:46:35 -0400 Received: by mail-wr1-f65.google.com with SMTP id w12so13747676wro.5 for ; Sun, 06 Oct 2019 23:46:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=GUI4psf4X65BdJQOo61gSGp6sUtBmnqbzSZ33CNSXV8=; b=FEpiYSxmONhoUt5laP56BsF0fWG4q4s21EuqxETZc3ZdfjqGbuupdtmD6npjyF59GU KxpgfXwe4GMDKQV3KIili9ek7WnqTg9w2nbr+snk0+BLD9uQUbi2kFPkL4LGrUYQP1NC MS9paPaiJSAlSJZftOarPjnn/HFBagRdj594dD8P8uWUyz1OiaiYK11/p/lncRWiIh62 IVsQ6sJZ17dRhCiyWBSk9+s6YbG7iP/6CBI7+k1H6kGqYJeUdZodKslqs3LpUMBA38G+ RE2M2f5uAzqKewgljtMxpW7MqJofQ5lYrjhXtqbrg4F6fYBoM/nzN4mmVVkfzxorwEHR 73Vg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=GUI4psf4X65BdJQOo61gSGp6sUtBmnqbzSZ33CNSXV8=; b=AulSokgGzqODwKVMgckPRqNMXwgp4DT1HainVLcpH96XopS6TD9SZ3WtOBcDJhUuUC 9c+gCthGukBMDOiSkETgC4nb/yOyB11hQAe3xzp8u7+p9rNKRNzuKBR/pHCics31CaGR KsQM5SjbMRrRpRcduLFnuQBNLoAnMwULHAbEw9DSkoHqmQdcp3QdEp5mU6VXJ+pRm5Wx iaha+/EHqcF/sUsHXOk31Dp7DuyLr/xjLo62SJfHT+FbzGL+e0D99IFWECNL5lc6CFva Rfus8D9SHjOMyWPfcXNdmO/0iFIqjGQGduzOwvoPpTp7rddsw4Kp2tYhxKf0MyKrw53M AK0Q== X-Gm-Message-State: APjAAAVKvQyhxCq3/hK6I/XVpC355s6lUo1HlfYYx6/up0TRMs1h9LJa 5NrzpkALgt9X3yqoBWwXYqotmw== X-Google-Smtp-Source: APXvYqyhWWW0aGEVKCb6oxvqfa/lZVGv/4trvdH+LsZPb816Q763laeVFhXIxGAomICdDu4Y5QRy2Q== X-Received: by 2002:a5d:62c6:: with SMTP id o6mr20341346wrv.243.1570430792299; Sun, 06 Oct 2019 23:46:32 -0700 (PDT) Received: from google.com ([2a00:79e0:d:210:e8f7:125b:61e9:733d]) by smtp.gmail.com with ESMTPSA id f143sm29345955wme.40.2019.10.06.23.46.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 06 Oct 2019 23:46:31 -0700 (PDT) Date: Mon, 7 Oct 2019 07:46:31 +0100 From: Matthias Maennich To: Masahiro Yamada Cc: Lucas De Marchi , lkml , "Cc: Android Kernel" , Stefan Wahren , Jessica Yu , Martijn Coenen , Greg Kroah-Hartman , linux-modules Subject: Re: [PATCH] depmod: create and use System.map.no_namespaces Message-ID: <20191007064631.GB142813@google.com> References: <20190917231031.81341-1-maennich@google.com> <20191004095748.223119-1-maennich@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: owner-linux-modules@vger.kernel.org Precedence: bulk List-ID: Hi! On Sat, Oct 05, 2019 at 04:53:56PM +0900, Masahiro Yamada wrote: >On Sat, Oct 5, 2019 at 3:25 AM Lucas De Marchi > wrote: >> >> On Fri, Oct 4, 2019 at 2:57 AM Matthias Maennich wrote: >> > >> > depmod in its current version is not aware of symbol namespace in >> > ksymtab entries introduced with 8651ec01daed ("module: add support for >> > symbol namespaces."). They have the form >> > >> > __ksymtab_NAMESPACE.symbol_name >> > >> > A fix for kmod's depmod has been proposed [1]. In order to support older >> > versions of depmod as well, create a System.map.no_namespaces during >> > scripts/depmod.sh that has the pre-namespaces format. That way users do >> > not immediately upgrade the userspace tool. >> > >> > [1] https://lore.kernel.org/linux-modules/20191004094136.166621-1-maennich@google.com/ >> > >> > Reported-by: Stefan Wahren >> > Fixes: 8651ec01daed ("module: add support for symbol namespaces.") >> > Cc: Masahiro Yamada >> > Cc: Lucas De Marchi >> > Cc: Jessica Yu >> > Cc: Martijn Coenen >> > Cc: Greg Kroah-Hartman >> > Cc: linux-modules@vger.kernel.org >> > Signed-off-by: Matthias Maennich >> > --- >> > >> > Please note this depends on the new ksymtab entry format proposed in >> > https://lore.kernel.org/lkml/20191003075826.7478-2-yamada.masahiro@socionext.com/ >> >> I don't really agree with that thought, more below. >> >> > >> > That is likely to be merged soon as well as it fixes problems in 5.4-rc*, hence >> > this patch depends on it. >> > >> > Cheers, >> > Matthias >> > >> > .gitignore | 1 + >> > scripts/depmod.sh | 8 +++++++- >> > 2 files changed, 8 insertions(+), 1 deletion(-) >> > >> > diff --git a/.gitignore b/.gitignore >> > index 70580bdd352c..5ed58a7cb433 100644 >> > --- a/.gitignore >> > +++ b/.gitignore >> > @@ -59,6 +59,7 @@ modules.order >> > /vmlinux-gdb.py >> > /vmlinuz >> > /System.map >> > +/System.map.no_namespaces >> > /Module.markers >> > /modules.builtin.modinfo >> > >> > diff --git a/scripts/depmod.sh b/scripts/depmod.sh >> > index e083bcae343f..602e1af072c7 100755 >> > --- a/scripts/depmod.sh >> > +++ b/scripts/depmod.sh >> > @@ -39,7 +39,13 @@ if $depmod_hack_needed; then >> > KERNELRELEASE=99.98.$KERNELRELEASE >> > fi >> > >> > -set -- -ae -F System.map >> > +# Older versions of depmod do not support symbol namespaces in ksymtab entries, >> > +# hence create an alternative System.map with namespace patched out to use for >> > +# depmod. I.e. transform entries as follows: >> > +# __ksymtab_NAMESPACE.symbol_name -> __ksymtab_symbol_name >> > +sed 's/__ksymtab_.*\./__ksymtab_/' System.map > System.map.no_namespaces >> >> So people with old kmod will have to know they need to pass >> System.map.no_namespaces rather than the usual >> System.map. Also, distros will need to be update to also copy the new >> file to the kernel package (or upgrade/patch kmod). >> >> I'd rather maintain the current format and fix the bug that patch is >> fixing. The namespace >> in the end IMO is just a small annoyance with a reason to exist. > >I agree, this fix is bad. >We should not bother kmod or any tools. >And System.map.no_namespaces is a cheesy workaround. Thanks for the feedback! Based on the discussion from last year about changing kmod/depmod for this change to the ksymtab entries, (https://lore.kernel.org/lkml/CAKi4VA+wvVxPxVSP6ruSR++TYvavKPNAQ5XhREF_9ZxeOKQirg@mail.gmail.com/), I assumed this approach would be acceptable. The workaround (yeah, it is a hack) is a way to mitigate the issue for people that can't update depmod so easily. System.map.no_namespaces was not intended to be part of any distribution, but rather used locally in depmod.sh. I could have made this more clear. > >BTW, I expressed my negative opinion in the review process >for the patch set. I am still not convinced with the >namespace feature, but anyway it was merged >(with poor review and test). > > > >Get back on track, probably the right fix would be to >stop using __ksymtab_.. > >It is not used for any purposes but passing > / pairs to modpost. > > >For example, __kstrtabns_##sym points to >the namespace string, so it would be possible >to parse it from modpost? > >Then, asm("__ksymtab_" #ns NS_SEPARATOR #sym) >will go away. I will give this a try. Cheers, Matthias > > >Masahiro > > > > >> Lucas De Marchi >> >> > + >> > +set -- -ae -F System.map.no_namespaces >> > if test -n "$INSTALL_MOD_PATH"; then >> > set -- "$@" -b "$INSTALL_MOD_PATH" >> > fi >> > -- >> > 2.23.0.581.g78d2f28ef7-goog >> > >> >> >> -- >> Lucas De Marchi > > > >-- >Best Regards >Masahiro Yamada