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From: Andrew Morton <akpm@osdl.org>
To: Johannes Weiner <hnazfoo@googlemail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: BUG() on apm resume in 2.6.18-rc2
Date: Thu, 27 Jul 2006 00:08:56 -0700	[thread overview]
Message-ID: <20060727000856.f75d2603.akpm@osdl.org> (raw)
In-Reply-To: <20060727062932.GA32598@leiferikson.gentoo>

On Thu, 27 Jul 2006 08:29:32 +0200
Johannes Weiner <hnazfoo@googlemail.com> wrote:

> Hi,
> 
> On Wed, Jul 26, 2006 at 11:10:49PM -0700, Andrew Morton wrote:
> > This?
> > 
> > --- a/./arch/i386/kernel/cpu/mcheck/mce.h~mce-section-fix
> > +++ a/./arch/i386/kernel/cpu/mcheck/mce.h
> > @@ -9,6 +9,6 @@ void winchip_mcheck_init(struct cpuinfo_
> >  /* Call the installed machine check handler for this CPU setup. */
> >  extern fastcall void (*machine_check_vector)(struct pt_regs *, long error_code);
> >  
> > -extern int mce_disabled __initdata;
> > +extern int mce_disabled;
> >  extern int nr_mce_banks;
> 
> What hinted you to that? I didn't read much oopses, so...
> 

(please always do reply-to-all)

That was an easy one - it crashed at

EIP is at mcheck_init+0x4/0x80

right at the start of mcheck_init(), so it had to be the access of
mce_disabled.

It accessed the address c0729c38:

BUG: unable to handle kernel paging request at virtual address c0729c38

and the code dump shows an access to that address.

And the only way in which an access to a global variable of this nature can
oops is if that variable has been unmapped from the kenrel address space. 
We unmap (and reuse) the __init memory, so it had to be a sectioning bug.

  reply	other threads:[~2006-07-27  7:09 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-07-27  3:38 BUG() on apm resume in 2.6.18-rc2 J. Bruce Fields
2006-07-27  6:10 ` Andrew Morton
2006-07-27  6:29   ` Johannes Weiner
2006-07-27  7:08     ` Andrew Morton [this message]
2006-07-27  7:38       ` Johannes Weiner
2006-07-28  4:34   ` J. Bruce Fields

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