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[209.132.180.67]) by mx.google.com with ESMTP id z199si7574007oia.192.2020.02.18.08.06.22; Tue, 18 Feb 2020 08:06:39 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=FB3XtSmY; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726486AbgBRQF7 (ORCPT + 99 others); Tue, 18 Feb 2020 11:05:59 -0500 Received: from mail.kernel.org ([198.145.29.99]:47314 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726360AbgBRQF6 (ORCPT ); Tue, 18 Feb 2020 11:05:58 -0500 Received: from linux-8ccs (p5B2812F9.dip0.t-ipconnect.de [91.40.18.249]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 17A90208C4; Tue, 18 Feb 2020 16:05:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582041958; bh=uxsydmaLYiWRBP1YEUE0J/D9SsS2i7BFVOmXJcknkls=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=FB3XtSmYfMVVrnf3YlMjGTIT5Fth77E08J3UneeouY/zVS9EvATh57yeL1uwQKVSQ hHfmHn0fvy0R4Q0hcrvZ1a/SC2ejVwc6L5aYXjI4AyfWQv1a320vAqesnHEeuxf2Om jLVTc6o9U/lkqvOZT4nsGt82MyaxDOI4PG+IH39s= Date: Tue, 18 Feb 2020 17:05:54 +0100 From: Jessica Yu To: Matthias Maennich Cc: Masahiro Yamada , linux-kernel@vger.kernel.org, Martijn Coenen Subject: Re: [PATCH] modpost: return error if module is missing ns imports and MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n Message-ID: <20200218160553.GA18056@linux-8ccs> References: <20200214143709.6490-1-jeyu@kernel.org> <20200217145644.GA221719@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20200217145644.GA221719@google.com> X-OS: Linux linux-8ccs 4.12.14-lp150.12.61-default x86_64 User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org +++ Matthias Maennich [17/02/20 14:56 +0000]: >Hi Jessica! > >On Fri, Feb 14, 2020 at 03:37:09PM +0100, Jessica Yu wrote: >>Currently when CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n, modpost only warns >>when a module is missing namespace imports. Under this configuration, such a module >>cannot be loaded into the kernel anyway, as the module loader would reject it. >>We might as well return a build error when a module is missing namespace imports >>under CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n, so that the build >>warning does not go ignored/unnoticed. > >I generally agree with the idea of the patch. Thanks for working on >this! I also can't remember any reason why I did not write it like this >initially. Probably just because I introduced this configuration option >quite late in the development process of the initial patches. > >> >>Signed-off-by: Jessica Yu >>--- >>scripts/Makefile.modpost | 1 + >>scripts/mod/modpost.c | 19 +++++++++++++++---- >>2 files changed, 16 insertions(+), 4 deletions(-) >> >>diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost >>index b4d3f2d122ac..a53660f910a9 100644 >>--- a/scripts/Makefile.modpost >>+++ b/scripts/Makefile.modpost >>@@ -53,6 +53,7 @@ MODPOST = scripts/mod/modpost \ >> $(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS))) \ >> $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \ >> $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \ >>+ $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS),,-N) \ >> $(if $(KBUILD_MODPOST_WARN),-w) >> >>ifdef MODPOST_VMLINUX >>diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c >>index 7edfdb2f4497..53e966f7d557 100644 >>--- a/scripts/mod/modpost.c >>+++ b/scripts/mod/modpost.c >>@@ -39,6 +39,8 @@ static int sec_mismatch_count = 0; >>static int sec_mismatch_fatal = 0; >>/* ignore missing files */ >>static int ignore_missing_files; >>+/* Return an error when there are missing namespace imports */ >>+static int missing_ns_import_error = 0; > >A more suitable name is maybe missing_ns_import_is_error or follow the >naming of the config option: allow_missing_ns_imports (with default = 1). > >> >>enum export { >> export_plain, export_unused, export_gpl, >>@@ -2216,9 +2218,15 @@ static int check_exports(struct module *mod) >> >> if (exp->namespace && >> !module_imports_namespace(mod, exp->namespace)) { >>- warn("module %s uses symbol %s from namespace %s, but does not import it.\n", >>- basename, exp->name, exp->namespace); >>- add_namespace(&mod->missing_namespaces, exp->namespace); >>+ if (missing_ns_import_error) { >>+ merror("module %s uses symbol %s from namespace %s, but does not import it.\n", >>+ basename, exp->name, exp->namespace); > >I would like to avoid the code duplication here. The string literal is >identical for both cases. Hm, but one is a call to merror() and the other to warn(). The previous if (warn_unresolved) block does the same thing. I am not sure how to simplify it to one call without introducing macro magic or overcomplicating things. Or were you thinking of something else? >>+ err = 1; > >Also, if we fail here, we might as well help the user to fix it by >suggesting to run `make nsdeps` (once per failed modpost run). Speaking >of which, `make nsdeps` is currently broken by this patch as it relies >on a successful (yet warning-full) build of the modules. So, in case of >`make nsdeps`, we probably have to omit the -N flag again when invoking >modpost. Good catch! Since KBUILD_NSDEPS is set when running `make nsdeps`, maybe we can do something like: diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index a53660f910a9..145703ef8d3a 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -53,7 +53,7 @@ MODPOST = scripts/mod/modpost \ $(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS))) \ $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \ $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \ - $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS),,-N) \ + $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS),,$(if $(KBUILD_NSDEPS),,-N)) \ $(if $(KBUILD_MODPOST_WARN),-w) ifdef MODPOST_VMLINUX Thanks for the review!