[Gllug] Debugging kernel loading initrd

John Edwards john at cornerstonelinux.co.uk
Sun Apr 27 22:48:50 UTC 2008


On Sun, Apr 27, 2008 at 10:54:59PM +0100, Richard Jones wrote:
> On Sun, Apr 27, 2008 at 02:46:31PM +0100, John Edwards wrote:
>> (gdb) r
>> Starting program: /home/john/temp/ipcop-1.9.1_trunk-r1332+busybox-static_instroot+hello/bin/sh
>> warning: shared library handler failed to enable breakpoint
>> Failed to read a valid object file image from memory.
> 
> Do you understand why you get this error??

I am not a C programmer, so don't have much of a clue. I'm guessing
that the shared library message is because that version of busybox
was statically compiled and so gdb can not add a dynamic library.


>> Program received signal SIGILL, Illegal instruction.
>> 0x080630f1 in ?? ()
>> (gdb) disass
>> No function contains program counter for selected frame.
> 
> It should be possible to disassemble the location (0x080630f1) even
> though it's not part of any function (at least according to gdb, but
> most likely it _is_ part of some function). 

Maybe possible for a C programmer to disassemble it. But I've not used
a disassembler for many many years.


> I'm still interested to
> know what instruction it is that exists on P-II and above but not on
> your basic Pentiums (Pentia?).

The glibc was being built on a i686 CPU with "-march=i486" and
"-mtune=generic" CFLAGS. I'm currently rebuilding the whole system
with "--host=i486-pc-linux-gnu" added to glibc configure options to
see if that helps.

If you have access to a Pentium CPU and are really interested I could
email you the compressed initramfs (7MB).


-- 
#---------------------------------------------------------#
|    John Edwards   Email: john at cornerstonelinux.co.uk    |
#---------------------------------------------------------#
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