[PATCH 0/6] PowerPc 8xx TLB/MMU fixes

[Joakim Tjernlund]

Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote on 06/10/2009 00:37:28:
>
> On Tue, 2009-10-06 at 00:31 +0200, Joakim Tjernlund wrote:
> >
> > regs or regs->nip is NULL? Either one does not make sense
> > In any case it might be a secondary problem as DAR is NULL already
> > when you
> > enter the page fault.
> > >
> > >                 insn = *((unsigned long *)regs->nip);
> > > c000e110:       80 a9 00 00     lwz     r5,0(r9)
> > >
> > > fails.
> >
> > hmm, I wonder if you managed to invalidate the a kernel TLB?
> > Are you using pinned kernel TLBs?
>
> You should not dereference a user address like that. Use get_user !

Ah, forgot about that. Will change

>
> Obviously you got 0 in SRR0 for some reason (somebody tried to jump
> to 0, either intentionally or as a result of some other problem) and
> the above will crash the kernel when it happens.
>
> Cheers,
> Ben.
>
>
>