From: Nicholas Piggin <npiggin@gmail.com>
To: Ian Campbell <ijc@hellion.org.uk>
Cc: Michal Marek <mmarek@suse.com>,
Ben Hutchings <ben@decadent.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>,
Adam Borowski <kilobyte@angband.pl>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
Debian kernel maintainers <debian-kernel@lists.debian.org>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>, Ingo Molnar <mingo@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Dodji Seketeli <dodji@seketeli.org>
Subject: Re: [PATCH] x86/kbuild: enable modversions for symbols exported from asm
Date: Sat, 10 Dec 2016 02:15:29 +1000 [thread overview]
Message-ID: <20161210021529.4a6e684f@roar.ozlabs.ibm.com> (raw)
In-Reply-To: <1481296893.4509.135.camel@hellion.org.uk>
On Fri, 09 Dec 2016 15:21:33 +0000
Ian Campbell <ijc@hellion.org.uk> wrote:
> On Fri, 2016-12-09 at 13:33 +1000, Nicholas Piggin wrote:
> >
> > Well I simply tested the outcome. If you have:
> >
> > struct blah {
> > int x;
> > };
> > int foo(struct blah *blah)
> > {
> > return blah->x;
> > }
> > EXPORT(foo);
> >
> > $ nm vmlinux | grep __crc_foo
> > 00000000a0cf13a0 A __crc_foo
> >
> > Now change to
> >
> > struct blah {
> > int y;
> > int x;
> > };
> >
> > $ nm vmlinux | grep __crc_foo
> > 00000000a0cf13a0 A __crc_foo
> >
> > It just doesn't catch these things.
>
> I found the same when I just added your snippet to init/main.c.
>
> _But_ when I moved the struct into include/types.h (which happened to
> be included by init/main.c) then, with just x in the struct:
>
> $ make -s init/main.{o,symtypes} && grep -E foo\|blah init/main.symtypes && nm init/main.o | grep __crc_foo
> s#blah struct blah { int x ; }
> foo int foo ( s#blah * )
> 000000000cd0312e A __crc_foo
>
> but adding y:
>
> $ make -s init/main.{o,symtypes} && grep -E foo\|blah init/main.symtypes && nm init/main.o | grep __crc_foo
> s#blah struct blah { int x ; int y ; }
> foo int foo ( s#blah * )
> 00000000eda220c6 A __crc_foo
>
> So it does catch things in that case.
>
> With struct blah inline in main.c it was:
>
> $ make -s init/main.{o,symtypes} && grep -E foo\|blah init/main.symtypes && nm init/main.o | grep __crc_foo
> s#blah struct blah { UNKNOWN }
> foo int foo ( s#blah * )
> 00000000a0cf13a0 A __crc_foo
>
> So I suppose it only cares about structs which are in headers, which I
> guess makes sense. I think it is working in at least one of the
> important cases.
Aha thanks, well that's my mistake. Clever little bugger, isn't it? Okay
it's not so useless as I first thought!
That said, a dwarf based checker tool should be able to do as good a job
(maybe a bit better because report is very informative and it may pick up
compiler alignments or padding options). So I still think it's worth
looking at those if we can remove modversions.
Thanks,
Nick
next prev parent reply other threads:[~2016-12-09 16:15 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
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20161210021529.4a6e684f@roar.ozlabs.ibm.com \
--to=npiggin@gmail.com \
--cc=arnd@arndb.de \
--cc=ben@decadent.org.uk \
--cc=debian-kernel@lists.debian.org \
--cc=dodji@seketeli.org \
--cc=gregkh@linuxfoundation.org \
--cc=ijc@hellion.org.uk \
--cc=kilobyte@angband.pl \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=mmarek@suse.com \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).