From: Martijn Coenen <maco@android.com>
To: Jessica Yu <jeyu@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Michal Marek <michal.lkml@markovi.net>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
"the arch/x86 maintainers" <x86@kernel.org>,
Alan Stern <stern@rowland.harvard.edu>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Oliver Neukum <oneukum@suse.com>, Arnd Bergmann <arnd@arndb.de>,
Stephen Boyd <sboyd@codeaurora.org>,
Philippe Ombredanne <pombredanne@nexb.com>,
Kate Stewart <kstewart@linuxfoundation.org>,
Sam Ravnborg <sam@ravnborg.org>,
linux-kbuild@vger.kernel.org,
linux-m68k <linux-m68k@lists.linux-m68k.org>,
USB list <linux-usb@vger.kernel.org>,
USB Storage list <usb-storage@lists.one-eyed-alien.net>,
linux-scsi@vger.kernel.org,
Linux-Arch <linux-arch@vger.kernel.org>,
Martijn Coenen <maco@google.com>,
Sandeep Patil <sspatil@google.com>,
Iliyan Malchev <malchev@google.com>,
Joel Fernandes <joelaf@google.com>
Subject: Re: [PATCH 2/6] module: add support for symbol namespaces.
Date: Fri, 20 Jul 2018 09:54:16 +0200 [thread overview]
Message-ID: <CAB0TPYFVSWtJ6RPRUZ1bpS-rBaV7YyPR-4B2Ogxs+FNAbiScNw@mail.gmail.com> (raw)
In-Reply-To: <20180719163208.5xvrafugpcbhh7kj@linux-8ccs>
Hi Jessica,
On Thu, Jul 19, 2018 at 6:32 PM, Jessica Yu <jeyu@kernel.org> wrote:
> First, thanks a lot for the patchset. This is definitely something that
> will help distros as well to declutter the exported symbol space and
> provide a more cleanly defined kernel interface.
Thanks, that's good to hear!
> Hm, I'm wondering if we could avoid all this extra module-ns-dependency
> checking work if we just put the import stuff as a modinfo tag, like
> have MODULE_IMPORT_NS() insert an "import:" tag like we already do for
> module parameters, author, license, aliases, etc. Then we'd have that
> information pretty much from the start of load_module() and we don't
> need to wait for relocations to be applied to __knsimport. Then you
> could do the namespace checking right at resolve_symbol() instead of
> going through the extra step of building a dependency list to be
> verified later.
I believe I did consider modinfo when I started with this a while
back, but don't recall right now why I didn't decide to use it;
perhaps it was the lack of support for multiple identical tags. Since
both modpost and the module loader have access to them, I don't see
why it wouldn't work, and indeed I suspect it would make the module
loader a bit simpler. I'll rework this and see what it looks like.
Thanks,
Martijn
>
> Also, this would get rid of the extra __knsimport section, the extra
> ns_dependencies field in struct module, and all those helper functions that
> manage it. In addition, having the modinfo tag may potentially help with
> debugging as we have the namespace imports clearly listed if we don't have
> the source code for a module. We'd probably need to modify get_modinfo() to
> handle multiple import: tags though. Luis [1] had written some code a while
> ago to handle multiple (of the same) modinfo tags.
>
> Thoughts on this?
>
> Thanks,
>
> Jessica
>
> [1] https://lkml.kernel.org/r/20171130023605.29568-3-mcgrof@kernel.org
>
>
>> getname:
>> /* We must make copy under the lock if we failed to get ref. */
>> strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
>> @@ -3061,6 +3118,11 @@ static int find_module_sections(struct module *mod,
>> struct load_info *info)
>> sizeof(*mod->gpl_syms),
>> &mod->num_gpl_syms);
>> mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
>> +
>> + mod->ns_imports = section_objs(info, "__knsimport",
>> + sizeof(*mod->ns_imports),
>> + &mod->num_ns_imports);
>> +
>> mod->gpl_future_syms = section_objs(info,
>> "__ksymtab_gpl_future",
>> sizeof(*mod->gpl_future_syms),
>> @@ -3381,6 +3443,19 @@ static int post_relocation(struct module *mod,
>> const struct load_info *info)
>> return module_finalize(info->hdr, info->sechdrs, mod);
>> }
>>
>> +static void verify_namespace_dependencies(struct module *mod)
>> +{
>> + struct module_ns_dep *ns_dep;
>> +
>> + list_for_each_entry(ns_dep, &mod->ns_dependencies, ns_dep) {
>> + if (!module_imports_ns(mod, ns_dep->namespace)) {
>> + pr_warn("%s: module uses symbols from namespace
>> %s,"
>> + " but does not import it.\n",
>> + mod->name, ns_dep->namespace);
>> + }
>> + }
>> +}
>> +
>> /* Is this module of this name done loading? No locks held. */
>> static bool finished_loading(const char *name)
>> {
>> @@ -3682,6 +3757,8 @@ static int load_module(struct load_info *info, const
>> char __user *uargs,
>> if (err)
>> goto free_module;
>>
>> + INIT_LIST_HEAD(&mod->ns_dependencies);
>> +
>> #ifdef CONFIG_MODULE_SIG
>> mod->sig_ok = info->sig_ok;
>> if (!mod->sig_ok) {
>> @@ -3730,6 +3807,8 @@ static int load_module(struct load_info *info, const
>> char __user *uargs,
>> if (err < 0)
>> goto free_modinfo;
>>
>> + verify_namespace_dependencies(mod);
>> +
>> flush_module_icache(mod);
>>
>> /* Now copy in args */
>> --
>> 2.18.0.203.gfac676dfb9-goog
>>
>
next prev parent reply other threads:[~2018-07-20 7:54 UTC|newest]
Thread overview: 134+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-16 12:21 [PATCH 0/6] Symbol namespaces Martijn Coenen
2018-07-16 12:21 ` [PATCH 1/6] export: explicitly align struct kernel_symbol Martijn Coenen
2018-07-16 12:21 ` [PATCH 2/6] module: add support for symbol namespaces Martijn Coenen
2018-07-19 16:32 ` Jessica Yu
2018-07-20 7:54 ` Martijn Coenen [this message]
2018-07-20 14:49 ` Jessica Yu
2018-07-20 15:42 ` Martijn Coenen
2018-07-23 11:12 ` Jessica Yu
2018-07-24 7:44 ` Martijn Coenen
2018-07-24 7:56 ` Martijn Coenen
2018-07-25 15:55 ` Jessica Yu
2018-07-25 16:48 ` Lucas De Marchi
2018-07-26 7:44 ` Martijn Coenen
2018-07-16 12:21 ` [PATCH 3/6] modpost: add support for checking " Martijn Coenen
2018-07-16 12:21 ` [PATCH 4/6] modpost: add support for generating namespace dependencies Martijn Coenen
2018-07-23 6:49 ` Jessica Yu
2018-07-16 12:21 ` [PATCH 5/6] scripts: Coccinelle script for " Martijn Coenen
2018-07-16 12:21 ` [PATCH 6/6] RFC: USB: storage: move symbols into USB_STORAGE namespace Martijn Coenen
2018-07-17 15:04 ` Alan Stern
2018-07-18 13:28 ` Martijn Coenen
2018-07-16 15:33 ` [PATCH 0/6] Symbol namespaces Greg Kroah-Hartman
2018-07-23 14:28 ` Arnd Bergmann
2018-07-24 8:09 ` Martijn Coenen
2018-07-24 9:08 ` Arnd Bergmann
2019-08-13 12:16 ` [PATCH v2 0/10] Symbol namespaces - RFC Matthias Maennich
2019-08-13 12:16 ` [PATCH v2 01/10] module: support reading multiple values per modinfo tag Matthias Maennich
2019-08-13 12:40 ` Greg KH
2019-08-13 12:16 ` [PATCH v2 02/10] export: explicitly align struct kernel_symbol Matthias Maennich
2019-08-13 12:41 ` Greg KH
2019-08-13 12:17 ` [PATCH v2 03/10] module: add support for symbol namespaces Matthias Maennich
2019-08-13 15:26 ` Greg KH
2019-08-13 12:17 ` [PATCH v2 04/10] modpost: " Matthias Maennich
2019-08-13 15:27 ` Greg KH
2019-08-13 12:17 ` [PATCH v2 05/10] module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS Matthias Maennich
2019-08-13 18:17 ` Greg KH
2019-08-13 20:15 ` Saravana Kannan
2019-08-14 12:54 ` Matthias Maennich
2019-08-14 17:34 ` Saravana Kannan
2019-08-13 12:17 ` [PATCH v2 06/10] export: allow definition default namespaces in Makefiles or sources Matthias Maennich
2019-08-13 18:16 ` Greg KH
2019-08-13 18:16 ` Greg KH
2019-08-13 12:17 ` [PATCH v2 07/10] modpost: add support for generating namespace dependencies Matthias Maennich
2019-08-13 18:21 ` Greg KH
2019-08-13 12:17 ` [PATCH v2 08/10] scripts: Coccinelle script for " Matthias Maennich
2019-08-13 12:31 ` Julia Lawall
2019-08-13 12:44 ` Greg KH
2019-08-14 6:36 ` [Cocci] " Himanshu Jha
2019-08-14 8:03 ` Matthias Maennich
2019-08-15 13:50 ` [v2 " Markus Elfring
2019-08-22 9:18 ` Matthias Maennich
2019-08-22 11:00 ` Markus Elfring
2019-08-13 12:17 ` [PATCH v2 09/10] usb-storage: remove single-use define for debugging Matthias Maennich
2019-08-13 12:42 ` Greg KH
2019-08-13 13:12 ` Greg KH
2019-08-13 12:17 ` [PATCH v2 10/10] RFC: usb-storage: export symbols in USB_STORAGE namespace Matthias Maennich
2019-08-13 12:45 ` Greg KH
2019-08-13 12:47 ` Greg KH
2019-08-13 15:02 ` Matthias Maennich
[not found] ` <20190821114955.12788-1-maennich@google.com>
2019-08-21 11:49 ` [PATCH v3 01/11] module: support reading multiple values per modinfo tag Matthias Maennich
2019-08-21 11:49 ` [PATCH v3 02/11] export: explicitly align struct kernel_symbol Matthias Maennich
2019-08-21 11:49 ` [PATCH v3 03/11] module: add support for symbol namespaces Matthias Maennich
2019-08-27 15:37 ` Jessica Yu
2019-08-27 16:04 ` Matthias Maennich
2019-08-21 11:49 ` [PATCH v3 04/11] modpost: " Matthias Maennich
2019-08-26 16:21 ` Jessica Yu
2019-08-27 14:41 ` Matthias Maennich
2019-08-28 9:43 ` Jessica Yu
2019-08-28 9:55 ` Matthias Maennich
2019-08-28 10:16 ` Jessica Yu
2019-08-21 11:49 ` [PATCH v3 05/11] module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS Matthias Maennich
2019-08-21 11:49 ` [PATCH v3 06/11] export: allow definition default namespaces in Makefiles or sources Matthias Maennich
2019-08-28 10:49 ` Jessica Yu
2019-08-28 10:56 ` Matthias Maennich
2019-08-21 11:49 ` [PATCH v3 07/11] modpost: add support for generating namespace dependencies Matthias Maennich
2019-08-21 11:49 ` [PATCH v3 08/11] scripts: Coccinelle script for " Matthias Maennich
2019-08-22 6:09 ` [v3 " Markus Elfring
2019-08-29 12:13 ` [PATCH v3 " Jessica Yu
2019-08-21 11:49 ` [PATCH v3 09/11] usb-storage: remove single-use define for debugging Matthias Maennich
2019-08-21 12:37 ` Greg KH
2019-08-21 13:21 ` Thomas Gleixner
2019-08-21 13:32 ` Greg KH
2019-08-21 11:49 ` [PATCH v3 10/11] RFC: usb-storage: export symbols in USB_STORAGE namespace Matthias Maennich
2019-08-21 12:38 ` Greg KH
2019-08-21 14:36 ` Jessica Yu
2019-08-21 23:13 ` Christoph Hellwig
2019-08-22 8:32 ` Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 00/12] Symbol Namespaces Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 01/12] module: support reading multiple values per modinfo tag Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 02/12] export: explicitly align struct kernel_symbol Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 03/12] module: add support for symbol namespaces Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 04/12] modpost: " Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 05/12] module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 06/12] export: allow definition default namespaces in Makefiles or sources Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 07/12] modpost: add support for generating namespace dependencies Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 08/12] scripts: Coccinelle script for " Matthias Maennich
2019-09-04 9:53 ` Masahiro Yamada
2019-09-05 14:46 ` Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 09/12] docs: Add documentation for Symbol Namespaces Matthias Maennich
2019-09-04 7:16 ` Greg KH
2019-09-03 15:06 ` [PATCH v4 10/12] usb-storage: remove single-use define for debugging Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 11/12] RFC: usb-storage: export symbols in USB_STORAGE namespace Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 12/12] RFC: watchdog: export core symbols in WATCHDOG_CORE namespace Matthias Maennich
2019-09-03 16:10 ` Guenter Roeck
2019-09-04 8:45 ` Masahiro Yamada
2019-09-04 12:12 ` Guenter Roeck
2019-09-04 16:16 ` [usb-storage] " Matthew Dharm
2019-09-05 10:41 ` Jessica Yu
2019-09-05 10:52 ` Arnd Bergmann
2019-09-05 11:16 ` Jessica Yu
2019-09-05 11:25 ` Masahiro Yamada
2019-09-05 12:00 ` Greg Kroah-Hartman
2019-09-05 11:25 ` Matthias Maennich
2019-09-04 9:37 ` [PATCH v4 00/12] Symbol Namespaces Masahiro Yamada
2019-09-06 10:32 ` [PATCH v5 00/11] " Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 01/11] module: support reading multiple values per modinfo tag Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 02/11] export: explicitly align struct kernel_symbol Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 03/11] module: add support for symbol namespaces Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 04/11] modpost: " Matthias Maennich
2019-09-26 22:24 ` [PATCH] modpost: Copy namespace string into 'struct symbol' Shaun Ruffell
2019-09-27 5:31 ` Greg Kroah-Hartman
2019-09-27 8:03 ` Matthias Maennich
2019-09-30 21:20 ` Shaun Ruffell
2019-10-01 16:19 ` Matthias Maennich
2019-10-01 19:37 ` Shaun Ruffell
2019-09-06 10:32 ` [PATCH v5 05/11] module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 06/11] export: allow definition default namespaces in Makefiles or sources Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 07/11] modpost: add support for generating namespace dependencies Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 08/11] scripts: Coccinelle script for " Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 09/11] docs: Add documentation for Symbol Namespaces Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 10/11] usb-storage: remove single-use define for debugging Matthias Maennich
2019-09-06 12:59 ` Jessica Yu
2019-09-06 13:22 ` Greg KH
2019-09-06 10:32 ` [PATCH v5 11/11] usb-storage: export symbols in USB_STORAGE namespace Matthias Maennich
2019-09-09 8:35 ` [PATCH v5 00/11] Symbol Namespaces Jessica Yu
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