random panic and freezes on mpc8349 itx

[Nicolas Schichan <nschichan@freebox.fr>]

Hi,

I am currently working with an MPC8349ITX board and I have some trouble with 
the kernel as soon as it reaches userland.

If I boot the kernel with all the memory (256MB) available (no mem=... on the 
command line), I get random freezes or random kernel panics. Some times it 
won't even run init. Some times it will panic badly if I try to put some 
pressure to the system (stress --cpu 256). Some times it will hang 
immediately after logging in, ...

If I boot the kernel with mem=64M, these freeze and random panic disapear and 
I am able to run the stress program without any problems.

I have had this strange behaviour on both kernel 2.6.20 and 2.6.22 with 
mpc834x_itx_defconfig (both from kernel.org) (ARCH=powerpc).

I am inclined to say that it is not a broken RAM chip problem because if I use 
a 2.6.17 from kernel.org with all the RAM available (ARCH=ppc) configured 
with mpc834x_sys_defconfig (there was no defconfig for the itx board on this 
version) everything runs fine and I am able to run the stress program without 
any problems.

The panic does not happen very often, 90% of the time, the board hangs and 
stops responding to ping. When a panic do happen it is almost always in a 
different place.

Does any of you have met this problem before ? If you have any clues about 
what is hapenning I'd be glad to hear about it :)

Thank you for your attention,

Regards,

-- 
Nicolas Schichan