Re: PTI build regression with nvidia drivers

From: Thomas Gleixner
Date: Thu Jan 04 2018 - 13:25:52 EST


On Thu, 4 Jan 2018, Kees Cook wrote:
>
> This was pointed out in a few places, but not forwarded to lkml yet that I saw:
>
> https://devtalk.nvidia.com/default/topic/1028222/linux/lts-kernel-patch-for-intel-cpu-vulnerability-breaks-nvidia-driver/post/5230546
>
> Before and after PTI, cpu_tlbstate is a GPL export:
>
> $ git show v4.14:arch/x86/mm/init.c | grep cpu_tlbstate
> DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
> EXPORT_SYMBOL_GPL(cpu_tlbstate);
>
> But after PTI, inlining or something is dragging cpu_tlbstate into the
> open, causing build failures.
>
> Technically, to avoid regressions for that module, we'll need to drop
> the GPL marking on that symbol, or find some other solution...

Correct. It's indirect via the tlbflush inlines. We'll fix it as usual. Sigh....

Thanks,

tglx