From: Steve Wise <swise@opengridcomputing.com>
To: Dave Jones <davej@redhat.com>, linux-kernel@vger.kernel.org
Subject: Re: Oops mystery
Date: Fri, 12 Jul 2013 11:53:30 -0500 [thread overview]
Message-ID: <51E0348A.2030208@opengridcomputing.com> (raw)
In-Reply-To: <20130712164816.GE1020@redhat.com>
On 7/12/2013 11:48 AM, Dave Jones wrote:
> On Fri, Jul 12, 2013 at 10:48:21AM -0500, Steve Wise wrote:
>
> > So 'movb $0x0,0xe(%rax,%rdx,1)' should be storing 0 into the byte
> > location:
> >
> > %rax + 0xe + (%rdx * 1) ==
> > 0x40fc+ 0xe + 0xffff8808b5500000 ==
> > 0xffff8808b5540fce.
> >
> > That address is readable in the crash dump:
> >
> > crash> x/8b 0x0000000000040fc0+0xe+0xffff8808b5500000
> > 0xffff8808b5540fce: 0x00 0x00 0x00 0x00 0x00 0x00
> > 0x00 0x00
> >
> > And why does the page fault show 0x40fc0 as the faulting address? It
> > should be 0xffff8808b5540fce and it shouldn't have caused a page fault.
> >
> > What am I missing?
>
> Random guess: Is that page marked read-only perhaps ?
It shouldn't be. :) How can I get this info via the crash dump? The
memory was allocated with dma_alloc_coherent(). Why would the page
fault occur on 0x40fc0 though? That makes me think my analysis so far
is incorrect.
Steve.
next prev parent reply other threads:[~2013-07-12 16:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-12 15:48 Oops mystery Steve Wise
2013-07-12 16:48 ` Dave Jones
2013-07-12 16:53 ` Steve Wise [this message]
2013-07-12 17:00 ` Dave Jones
2013-07-12 17:08 ` Steve Wise
2013-07-12 17:14 ` Dave Jones
2013-07-12 19:24 ` Steve Wise
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