Re: [tip:x86/urgent] x86: Add back _end symbol that is missing fromSymbol.map
From: Ingo Molnar
Date: Sun Nov 08 2009 - 07:42:56 EST
* Sam Ravnborg <sam@xxxxxxxxxxxx> wrote:
> On Sun, Nov 08, 2009 at 12:48:29PM +0100, Ingo Molnar wrote:
> >
> > * Sam Ravnborg <sam@xxxxxxxxxxxx> wrote:
> >
> > > On Sun, Nov 08, 2009 at 11:07:12AM +0000, tip-bot for Hannes Reinecke wrote:
> > > > Commit-ID: d1e4d37b79e944f6351ae38eb1ca7c9f7b506e76
> > > > Gitweb: http://git.kernel.org/tip/d1e4d37b79e944f6351ae38eb1ca7c9f7b506e76
> > > > Author: Hannes Reinecke <hare@xxxxxxx>
> > > > AuthorDate: Wed, 4 Nov 2009 07:19:32 -0800
> > > > Committer: Ingo Molnar <mingo@xxxxxxx>
> > > > CommitDate: Sun, 8 Nov 2009 12:05:03 +0100
> > > >
> > > > x86: Add back _end symbol that is missing from Symbol.map
> > > >
> > > > With 2.6.31 'crash' on x86_64 falls flat on its face as the
> > > > '_end' symbol is missing from the System.map file.
> > > >
> > > > The culprit is commit 091e52c3551d3031343df24b573b770b4c6c72b6,
> > > > which moved the '_end' symbol into it's own section. Apparently
> > > > this causes kallsyms to not reference it properly.
> > > >
> > > > So do not include _end in it's own section.
> > > >
> > > > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > > > Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
> > > > Cc: <stable@xxxxxxxxxx> # .31.x
> > > > LKML-Reference: <200911041519.nA4FJWEW030164@xxxxxxxxxxxxxxxxxxxxxxxxxx>
> > > > Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> > >
> > > I'm afraid this will break a RELOCTABLE i386 kernel.
> > >
> > > We fixed this up some time ago where we had to
> > > move the symbol definition inside a section
> > > to prevent the symbol being absolute.
> >
> > ah, indeed. So ... the question is then, why did _end disappear from
> > System.map?
>
> I think ld discards zero size sections. No need to keep them around if
> they are empty.
>
> Following patch should fix it up in a better way.
thanks Sam, that was fast!
> I reused most of Hannes changelog.
Hannes, if it works for you then please resend the patch with your
signoff so we can send it upstream-wards.
Thanks,
Ingo
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