Re: [tip:x86/kaslr] x86, relocs: Add more per-cpu gold special cases

From: Ingo Molnar
Date: Tue Oct 15 2013 - 02:04:33 EST



* Kees Cook <keescook@xxxxxxxxxxxx> wrote:

> On Mon, Oct 14, 2013 at 9:28 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> > On 10/14/2013 07:19 AM, H. Peter Anvin wrote:
> >> My guess is that the 95 addresses are randomized and the 82 address is an address which failed to relocate.
> >
> >> ffffffff82a04a58 is:
> >> ffffffff82a03000 t init_per_cpu__gdt_page
> >
> >
> > Specifically, it looks like the percpu stuff isn't getting set up correctly.
>
> It wouldn't surprise me if there are even more percpu things to fix.
> It's the main area we've continued to trip over while working on this
> with various linkers. Which linker and version are you seeing this
> with?

The failure I saw triggered with fairly modern userspace:

GNU ld version 2.23.52.0.1-9.fc19 20130226

gcc version 4.8.1 20130603 (Red Hat 4.8.1-1) (GCC)

Thanks,

Ingo
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