linux-kernel - Re: [PATCH 7/7] modpost: handle relocations mismatch in __ex

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Message-ID: <20150414123516.GB2925@chrystal.uk.oracle.com>
Date:	Tue, 14 Apr 2015 14:35:17 +0200
From:	Quentin Casasnovas <quentin.casasnovas@...cle.com>
To:	Thierry Reding <thierry.reding@...il.com>
Cc:	Quentin Casasnovas <quentin.casasnovas@...cle.com>,
	lkml <linux-kernel@...r.kernel.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Rusty Russell <rusty@...tcorp.com.au>
Subject: Re: [PATCH 7/7] modpost: handle relocations mismatch in __ex_table.

On Tue, Apr 14, 2015 at 02:14:14PM +0200, Thierry Reding wrote:
> On Tue, Mar 17, 2015 at 01:40:02PM +0100, Quentin Casasnovas wrote:
> > If one of these addresses point to a non-executable section, something is
> > seriously wrong since it either means the kernel will never fault from
> > there or it will not be able to jump to there.  As both cases are serious
> > enough, we simply error out in these cases so the build fails and the
> > developper has to fix the issue.
> > 
> > Signed-off-by: Quentin Casasnovas <quentin.casasnovas@...cle.com>
> > ---
> >  scripts/mod/modpost.c | 141 ++++++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 141 insertions(+)
> 
> This causes a bunch of mismatch warnings on 32-bit and 64-bit ARM
> because there are two additional sections, .text.fixup and
> .exception.text that store executable code. I've attached a patch
> to fix those, but feel free to squash that into the original commit
> if that's still possible.
>

Thanks Thierry!

Your patch looks good to me, though I was wondering if we should just add
.text.* in the TEXT_SECTIONS macro.  Some architectures define
-ffunction-sections (parisc, score, metag and frv) so there are tons of
useless warnings on these..  It also means the current modpost sanity
checks don't run for those so it might even uncover some real mismatch ;)

Quentin
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