From: Michal Marek <mmarek@suse.com>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ingo Molnar <mingo@kernel.org>, Al Viro <viro@zeniv.linux.org.uk>,
Adam Borowski <kilobyte@angband.pl>,
Philip Muller <philm@manjaro.org>,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
linux-arch <linux-arch@vger.kernel.org>,
linux-kbuild <linux-kbuild@vger.kernel.org>
Subject: Re: [PATCH] x86/kbuild: enable modversions for symbols exported from asm
Date: Thu, 24 Nov 2016 11:51:23 +0100 [thread overview]
Message-ID: <46e6def3-5724-90be-1844-d91b32bd2bcb@suse.com> (raw)
In-Reply-To: <20161124210355.4875c61a@roar.ozlabs.ibm.com>
Dne 24.11.2016 v 11:03 Nicholas Piggin napsal(a):
> On Thu, 24 Nov 2016 10:32:12 +0100
> Michal Marek <mmarek@suse.com> wrote:
>
>> On 2016-11-24 08:53, Nicholas Piggin wrote:
>>> On Thu, 24 Nov 2016 08:36:39 +0100
>>> Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
>>>
>>>> On Thu, Nov 24, 2016 at 06:20:26PM +1100, Nicholas Piggin wrote:
>>>>> But still, modversions is pretty complicated for what it gives us. It sends
>>>>> preprocessed C into a C parser that makes CRCs using type definitions of
>>>>> exported symbols, then turns those CRCs into a linker script which which is
>>>>> used to link the .o file with. What we get in return is a quite limited and
>>>>> symbol "versioning" system.
>>>>>
>>>>> What if we ripped all that out and just attached an explicit version to
>>>>> each export, and incompatible changes require an increment?
>>>>
>>>> How would that work for structures? Would that be required for every
>>>> EXPORT_SYMBOL* somehow?
>>>
>>> Yeah just have EXPORT_SYMBOL take another parameter which attaches a version
>>> number and use that as the value for the __crc_ symbol versions rather than
>>> a calculated CRC.
>>
>> The problem is that with every kernel release, the structures change in
>> a way that you would have to bump the version of virtually every export.
>>
>> At which point, there would be little difference between
>> CONFIG_MODVERSION on and off (without CONFIG_MODVERSION, we compare the
>> kernel version strings when loading modules).
>
>
> I'm not sure about that. If they are truly incompatible changes and
> MODVERSIONS does not pick up a different CRC, then it's even worse if
> incompatible modules are missed so often.
Now I'm confused: Are you suggesting to do this manual symbol versioning
for all exports, or only those defined in asm?
Thanks,
Michal
next prev parent reply other threads:[~2016-11-24 10:51 UTC|newest]
Thread overview: 113+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <a73aec83-ddad-2bdf-e612-178c9936a16f@manjaro.org>
[not found] ` <20161102004639.6870806d@roar.ozlabs.ibm.com>
2016-11-23 20:08 ` BUG: 4.9-rc6 Still "no symbol version" on boot Philip Müller
2016-11-23 20:14 ` Robert LeBlanc
2016-11-23 20:27 ` Philip Müller
2016-11-23 20:53 ` Adam Borowski
2016-11-23 21:01 ` Robert LeBlanc
2016-11-23 21:02 ` [PATCH] x86/kbuild: enable modversions for symbols exported from asm Adam Borowski
2016-11-23 23:10 ` Philip Müller
2016-11-24 4:40 ` Ingo Molnar
2016-11-24 5:20 ` Nicholas Piggin
2016-11-24 6:00 ` Ingo Molnar
2016-11-24 7:20 ` Nicholas Piggin
2016-11-24 7:36 ` Greg Kroah-Hartman
2016-11-24 7:53 ` Nicholas Piggin
2016-11-24 9:32 ` Michal Marek
2016-11-24 10:03 ` Nicholas Piggin
2016-11-24 10:51 ` Michal Marek [this message]
2016-11-24 9:38 ` Arnd Bergmann
2016-11-24 10:01 ` Nicholas Piggin
2016-11-24 9:56 ` Greg Kroah-Hartman
2016-11-24 10:31 ` Nicholas Piggin
2016-11-24 15:24 ` Greg Kroah-Hartman
2016-11-25 0:40 ` Nicholas Piggin
2016-11-25 18:00 ` Linus Torvalds
2016-11-26 0:37 ` Nicholas Piggin
2016-11-29 1:15 ` Ben Hutchings
2016-11-29 2:31 ` Nicholas Piggin
2016-11-29 9:14 ` Michal Marek
2016-11-29 4:08 ` Linus Torvalds
2016-11-29 13:19 ` Adam Borowski
2016-11-29 13:29 ` Ingo Molnar
2016-11-29 14:24 ` Adam Borowski
2016-11-29 13:51 ` Adam Borowski
[not found] ` <CA+55aFyZiB4YkwvqzrXO=HD8bcnc2xHkAYrek2QHVnhVvAi3Fw@mail.gmail.com>
2016-11-29 16:03 ` Michal Marek
2016-11-29 16:17 ` Linus Torvalds
2016-11-29 19:57 ` Ben Hutchings
2016-11-29 20:35 ` Linus Torvalds
2016-11-30 18:18 ` Nicholas Piggin
2016-11-30 18:40 ` Linus Torvalds
2016-11-30 21:33 ` Ben Hutchings
2016-12-01 1:55 ` Nicholas Piggin
2016-12-01 2:35 ` Ben Hutchings
2016-12-01 3:39 ` Nicholas Piggin
2016-12-01 16:12 ` Michal Marek
2016-12-02 14:36 ` Hannes Frederic Sowa
2016-12-09 3:33 ` Nicholas Piggin
2016-12-09 15:21 ` Ian Campbell
2016-12-09 16:15 ` Nicholas Piggin
2016-12-09 22:46 ` Dodji Seketeli
2016-12-10 12:41 ` Greg Kroah-Hartman
2016-12-12 3:50 ` Nicholas Piggin
2016-12-12 9:08 ` Ian Campbell
2016-12-14 17:59 ` Don Zickus
2016-12-13 1:07 ` Stanislav Kozina
2016-12-13 22:51 ` Michal Marek
2016-12-14 8:58 ` Dodji Seketeli
2016-12-14 9:15 ` Michal Marek
2016-12-14 9:36 ` Dodji Seketeli
2016-12-14 9:44 ` Michal Marek
2016-12-14 10:02 ` Dodji Seketeli
2016-12-14 10:15 ` Michal Marek
2016-12-14 9:56 ` Dodji Seketeli
2016-12-14 9:37 ` Michal Marek
2016-12-01 4:13 ` Don Zickus
2016-12-01 4:32 ` Nicholas Piggin
2016-12-01 15:20 ` Don Zickus
2016-12-01 15:26 ` Christoph Hellwig
2016-12-01 15:40 ` Don Zickus
2016-12-01 16:06 ` Greg Kroah-Hartman
2016-12-01 18:42 ` Don Zickus
2016-12-09 3:50 ` Nicholas Piggin
2016-12-09 7:55 ` Stanislav Kozina
2016-12-09 8:14 ` Nicholas Piggin
2016-12-09 14:36 ` Stanislav Kozina
2016-12-09 15:56 ` Nicholas Piggin
2016-12-09 16:03 ` Greg Kroah-Hartman
2016-12-12 9:48 ` Stanislav Kozina
2016-12-13 7:25 ` Nicholas Piggin
2016-12-14 14:04 ` Hannes Frederic Sowa
2016-12-15 2:06 ` Nicholas Piggin
2016-12-15 11:19 ` Hannes Frederic Sowa
2016-12-15 12:03 ` Nicholas Piggin
2016-12-15 13:15 ` Hannes Frederic Sowa
2016-12-15 14:15 ` Nicholas Piggin
2016-12-15 15:17 ` Hannes Frederic Sowa
2016-12-15 13:35 ` Stanislav Kozina
2016-12-09 16:16 ` Don Zickus
2016-12-01 10:48 ` Stanislav Kozina
2016-12-01 11:09 ` Nicholas Piggin
2016-12-01 11:33 ` Stanislav Kozina
2016-12-01 12:39 ` Nicholas Piggin
2016-12-01 15:19 ` Dodji Seketeli
2016-12-01 16:14 ` Michal Marek
2016-11-29 17:05 ` Adam Borowski
2016-11-29 17:10 ` Linus Torvalds
2016-11-29 17:14 ` Linus Torvalds
2016-12-01 13:58 ` Arnd Bergmann
2016-12-01 16:21 ` Michal Marek
2016-12-01 18:26 ` Linus Torvalds
2016-12-02 10:55 ` Arnd Bergmann
2016-12-02 12:40 ` [RFC, PATCH, v3.9] default exported asm symbols to zero Arnd Bergmann
2016-12-02 12:59 ` Geert Uytterhoeven
2016-12-02 14:51 ` Arnd Bergmann
2016-12-02 15:35 ` Adam Borowski
2016-12-03 4:36 ` Ben Hutchings
2016-12-03 10:43 ` Arnd Bergmann
2016-12-02 17:04 ` [PATCH] x86/kbuild: enable modversions for symbols exported from asm Linus Torvalds
2016-12-04 7:44 ` Alan Modra
2016-12-04 20:44 ` Linus Torvalds
2016-11-29 21:23 ` Michal Marek
2016-11-24 9:25 ` Michal Marek
2016-11-24 11:42 ` Regression: " Kalle Valo
2016-11-23 23:07 ` BUG: 4.9-rc6 Still "no symbol version" on boot Philip Müller
2016-11-28 17:10 ` Robert LeBlanc
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