initrd not loaded with > 4 GB and PAE kernel

Diego Santa Cruz Diego.SantaCruz at spinetix.com
Thu Dec 14 17:26:17 UTC 2006


> -----Original Message-----
> From: fedora-list-bounces at redhat.com [mailto:fedora-list-
> bounces at redhat.com] On Behalf Of Mikkel L. Ellertson
> Sent: Wednesday, December 06, 2006 5:43 PM
> To: For users of Fedora
> Subject: Re: initrd not loaded with > 4 GB and PAE kernel
> 
> Diego Santa Cruz wrote:
> > Hello,
> >
> > I have installed the FC6 kernel 2.6.18-1.2849.fc6PAE on a machine
with 4
> > GB of memory (of which the upper 2 GB are mapped by the BIOS above
the 4
> > GB barrier).
> >
> > The kernel is not booting since it does not find the initrd and thus
> > panics (cannot find init).
> >
> > Passing the mem=4096M option to the kernel solves the problem, but
> > limits the actual memory to 2 GB only.
> >
> > The BIOS-provided physical RAM map is:
> >  BIOS-e820: 0000000000000000 - 000000000009ec00 (usable)
> >  BIOS-e820: 000000000009ec00 - 00000000000a0000 (reserved)
> >  BIOS-e820: 00000000000e4000 - 0000000000100000 (reserved)
> >  BIOS-e820: 0000000000100000 - 000000007ffa0000 (usable)
> >  BIOS-e820: 000000007ffa0000 - 000000007ffae000 (ACPI data)
> >  BIOS-e820: 000000007ffae000 - 000000007ffe0000 (ACPI NVS)
> >  BIOS-e820: 000000007ffe0000 - 0000000080000000 (reserved)
> >  BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
> >  BIOS-e820: 00000000ffb00000 - 0000000100000000 (reserved)
> >  BIOS-e820: 0000000100000000 - 0000000180000000 (usable)
> >
[snip.]
> >
> It sounds like your BIOS is not passing the correct memory map to
> the kernel. You may need to look at the memmap boot options. This
> will let you pass the correct memory map to the kernel.
> 
> You can also try the noapic and/or the nolapic options, and see if
> they help.
> 

Thanks for the tips, but no success yet. The apic related options did
not improve the situation. About the memmap option I do not know how
should I build one. Any tips? The BIOS actually has a remapping option:
without remapping only 3 GB are made available, but everything is below
4 GB, with remapping the 2 to 4 GB zone is reserved and the upper 2 GB
are made available between 4 and 6. At least that is what the doc says.

Anyhow, I got a serial console set up and now I can see that the initrd
is loaded as an initramfs without complaints.

The /dev/console and /init files are found on the initramfs, but the
detected binary handler for init is binfmt-0000 (for which it attempts
to load a module). I guess it should be the script handler, so I suspect
that the contents of the /init file are somehow corrupted somewhere
(zeroes are read as the magic number instead of #!). Any ideas on what
might be going wrong?

I even tried to execute /bin/nash directly (using rdinit=/bin/nash) just
to see if nash started, but that failed too.

Many thanks,

Diego





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