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[209.132.180.67]) by mx.google.com with ESMTP id m67si8395796oib.117.2020.02.18.11.28.12; Tue, 18 Feb 2020 11:28:24 -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=@nifty.com header.s=dec2015msa header.b=cdbBFOXF; 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=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726384AbgBRT2G (ORCPT + 99 others); Tue, 18 Feb 2020 14:28:06 -0500 Received: from conssluserg-05.nifty.com ([210.131.2.90]:27158 "EHLO conssluserg-05.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726296AbgBRT2F (ORCPT ); Tue, 18 Feb 2020 14:28:05 -0500 Received: from mail-vs1-f44.google.com (mail-vs1-f44.google.com [209.85.217.44]) (authenticated) by conssluserg-05.nifty.com with ESMTP id 01IJRjGi005013 for ; Wed, 19 Feb 2020 04:27:46 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conssluserg-05.nifty.com 01IJRjGi005013 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1582054066; bh=0LaSGEGizcBcrlCJXQ7v7CjwfgybxWS3s9NbZtBPJ5k=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=cdbBFOXFZ23x11aP2VoefVJIUawvYaxkVvVaNmaQ7ksASvnS8r3oXIBBdPafGx/3e 5q1IkX/NeM/uWc43eT+Ny9Vv1fiEF5EVjLCeJ3oaX7dKCPbryL7Q/5zBg9hxZdot66 HGusDwaPEiHgISwr3KDYxdU4jQApQG/klhNVH6p9w1dMklkcOdiD+b1+Npbtbf4XUZ ZrWoZtljCj0fTYg/WeNyn5rHWnt1yJU3GtZ+PIZuJ5zCRqo8OZzviWS11lggCiCUrw /w3LUDVLJdYMVH16pnpYJvknQPvvCFq/5cR0fvfYleE6TWV0aVAEebDX2aoQ/9DXpF zNF5/jJNIOOVg== X-Nifty-SrcIP: [209.85.217.44] Received: by mail-vs1-f44.google.com with SMTP id r18so13801276vso.5 for ; Tue, 18 Feb 2020 11:27:46 -0800 (PST) X-Gm-Message-State: APjAAAUwP0Ap455/vYaIAQ2eiruJxoPib6tmBanNCGGU5j+c/apbA4fd wwusx/l0mTKgSXVho7uUHjyxTeFcS49O3YyJXzY= X-Received: by 2002:a05:6102:48b:: with SMTP id n11mr11885261vsa.181.1582054064789; Tue, 18 Feb 2020 11:27:44 -0800 (PST) MIME-Version: 1.0 References: <20200214143709.6490-1-jeyu@kernel.org> <20200217145644.GA221719@google.com> <20200218160553.GA18056@linux-8ccs> In-Reply-To: <20200218160553.GA18056@linux-8ccs> From: Masahiro Yamada Date: Wed, 19 Feb 2020 04:27:09 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] modpost: return error if module is missing ns imports and MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n To: Jessica Yu Cc: Matthias Maennich , Linux Kernel Mailing List , Martijn Coenen Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 19, 2020 at 1:06 AM Jessica Yu wrote: > > +++ 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? I would not say this is a horrible duplication, but if you avoid repeating the same string, maybe you could do like this: PRINTF log(enum loglevel loglevel, const char *fmt, ...) BTW, you accidentally changed the indentation of add_namespace(&mod->missing_namespaces, exp->namespace); > >>+ 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 you follow Matthias' suggestion "follow the naming of the config option: allow_missing_ns_imports (with default = 1)." the option is inverted, and you can write it more simply: $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-n) \ -- Best Regards Masahiro Yamada