From: Jessica Yu <jeyu@kernel.org>
To: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Cc: Guenter Roeck <linux@roeck-us.net>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Matthias Maennich <maennich@google.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"Cc: Android Kernel" <kernel-team@android.com>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Joel Fernandes (Google)" <joel@joelfernandes.org>,
Lucas De Marchi <lucas.de.marchi@gmail.com>,
maco@android.com, sspatil@google.com,
Will Deacon <will@kernel.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
linux-modules@vger.kernel.org,
linux-usb <linux-usb@vger.kernel.org>,
USB Mass Storage on Linux <usb-storage@lists.one-eyed-alien.net>,
linux-watchdog@vger.kernel.org
Subject: Re: [usb-storage] Re: [PATCH v4 12/12] RFC: watchdog: export core symbols in WATCHDOG_CORE namespace
Date: Thu, 5 Sep 2019 12:41:47 +0200 [thread overview]
Message-ID: <20190905104147.GA27788@linux-8ccs> (raw)
In-Reply-To: <CAA6KcBBeP9xYbVws4=RMFNA4kyrodE-R3mifhbkee-Q+jFRcoQ@mail.gmail.com>
+++ Matthew Dharm [04/09/19 09:16 -0700]:
>On Wed, Sep 4, 2019 at 5:12 AM Guenter Roeck <linux@roeck-us.net> wrote:
>>
>> Note that I don't object to the patch set in general. There may be symbols
>> which only need be exported in the context of a single subsystem or even
>> driver (if a driver consists of more than one module). For example, a mfd
>> driver may export symbols which should only be called by its client drivers.
>> In such a situation, it may well be beneficial to limit the use of exported
>> symbols.
>
>I can appreciate this benefit.
>
>> I am not sure what good that does in practice (if I understand correctly,
>> a driver only has to declare that it wants to use a restricted use symbol
>> if it wants to use it), but that is a different question.
>
>I think this question implies that you are coming from the perspective
>of "security" or wanting to restrict access to the underlying
>functions, rather than wanting to clean-up the way symbols are handled
>for manageability / maintainability purposes (which is the goal, as I
>understand it).
>
>HOWEVER, I have one question: If these patches are included, and
>someone wants to introduce a bit of code which needs to use two
>symbols from different namespaces but with the same name, can that be
>done? That is, if driver A has symbol 'foo' and driver B has symbol
>'foo' (both in their respective namespaces), and driver C wants to use
>A.foo and B.foo, can that be supported?
As of now, we currently don't support this - modpost will warn if a
symbol is exported more than once (across modules + vmlinux), and the
module loader currently assumes exported symbol names are unique. Do
you have a concrete use case? If there is a strong need for this, I
don't think it'd be too hard to implement.
Thanks,
Jessica
next prev parent reply other threads:[~2019-09-05 10:41 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
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 [this message]
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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