Re: OOPS: 2.6.24-rc5-mm1 -- EIP is at r_show+0x2a/0x70 -- (triggered by "cat /proc/iomem" AFTER suspend-to-disk/resume)

["Miles Lane" <miles.lane@gmail.com>]

On Dec 21, 2007 3:00 PM, Andrew Morton <akpm@linux-foundation.org> wrote:
> On Fri, 21 Dec 2007 11:06:49 -0500 "Miles Lane" <miles.lane@gmail.com> wrote:
>
> > > >
> > > > How do I determine what comes next?
> > > >
> > >
> > > By comparing it with the /proc/iomem from prior to suspending the machine.
> > >
> >
> > The offending information seems to be "90000000-90000fff : Intel Flush Page"
>
> ah-hah.  git-agpgart.patch
>
> > I hope this helps,
>
> It does, thanks.
>
> Dave, a `cat /proc/iomem' crashes after a suspend/resume cycle when it
> reaches the intel_private.ifp_resource record.
>
>
> intel_i915_configure() is called on each resume and it calls
> intel_i9xx_setup_flush() which zeroes out the already-registered `struct
> resource', causing core kernel to oops over a deref of
> parent/sibling/child.
>
> Probably this:
>
> --- a/drivers/char/agp/intel-agp.c~a
> +++ a/drivers/char/agp/intel-agp.c
> @@ -883,8 +883,6 @@ static void intel_i965_g33_setup_chipset
>  static void intel_i9xx_setup_flush(void)
>  {
>         /* setup a resource for this object */
> -       memset(&intel_private.ifp_resource, 0, sizeof(intel_private.ifp_resource));
> -
>         intel_private.ifp_resource.name = "Intel Flush Page";
>         intel_private.ifp_resource.flags = IORESOURCE_MEM;
>
> _
>
>
> will be enough to prevent the crash, but I suspect a bit more than that
> will be needed.
>

I tested with the patch applied, and the stackdump did not occur.
However, I notice that the values listed for Intel Page Flush is
changed from the pre-suspend values:

Before the suspend:
90000000-90000fff : Intel Flush Page

After the resume:
00000000-90001000 : Intel Flush Page

# patch -p1 < akpm.patch
patching file drivers/char/agp/intel-agp.c
Hunk #1 succeeded at 891 (offset 8 lines).

$ cat /proc/iomem
00000000-0009f7ff : System RAM
0009f800-0009ffff : reserved
000a0000-000bffff : Video RAM area
000c0000-000c7fff : Video ROM
000f0000-000fffff : System ROM
00100000-7f68ffff : System RAM
  00100000-0039e4a7 : Kernel code
0039e4a8-004f0983 : Kernel data
00553000-007ecdfb : Kernel bss
7f690000-7f698fff : ACPI Tables
7f699000-7f6fffff : ACPI Non-volatile Storage
7f700000-7fffffff : reserved
88000000-8bffffff : PCI CardBus #05
8c000000-8fffffff : PCI CardBus #05
00000000-90001000 : Intel Flush Page
c0000000-cfffffff : 0000:00:02.0
d0000000-d1ffffff : PCI Bus #02
d2000000-d3ffffff : PCI Bus #03
d4000000-d5ffffff : PCI Bus #02
d4000000-d4003fff : 0000:02:00.0
d4000000-d4003fff : sky2
d6000000-d7ffffff : PCI Bus #03
d6000000-d6000fff : 0000:03:00.0
d6000000-d6000fff : iwl3945
d8000000-d80fffff : PCI Bus #04
d8000000-d8003fff : 0000:04:09.1
d8004000-d8004fff : 0000:04:09.2
d8004000-d8004fff : tifm_7xx1
d8005000-d80057ff : 0000:04:09.1
d8005000-d80057ff : ohci1394
d8006000-d8006fff : 0000:04:09.0
d8006000-d8006fff : yenta_socket
d8100000-d817ffff : 0000:00:02.0
d8180000-d81fffff : 0000:00:02.1
d8200000-d823ffff : 0000:00:02.0
d8240000-d8243fff : 0000:00:1b.0
d8240000-d8243fff : ICH HD audio
d8444000-d84443ff : 0000:00:1d.7
d8444000-d84443ff : ehci_hcd
d8444400-d84447ff : 0000:00:1f.2
d8444400-d84447ff : ahci
e0000000-efffffff : PCI MMCONFIG 0
e0000000-efffffff : reserved
fec00000-fec0ffff : reserved
fed00000-fed003ff : HPET 0
fed00000-fed003ff : reserved
fed14000-fed19fff : reserved
fed1c000-fed8ffff : reserved
fee00000-fee00fff : reserved
ff000000-ffffffff : reserved