Re: [tip:perf/core] perf/x86: Fix USER/KERNEL tagging of samples

Peter Zijlstra
2012-07-10T08:53:02Z

On Tue, 2012-07-10 at 10:21 +0200, Ingo Molnar wrote:
> Another boundary condition would be when we intentionally
> twiddle the GDT: such as during suspend or during BIOS upcalls.
> Can we then get a PMU interrupt? If yes then this will probably
> result in garbage:
>
> > > > + desc = __this_cpu_ptr(&gdt_page.gdt[0]);
>
> it won't outright crash, we don't ever deallocate our GDT - but
> it will return a garbage RIP.

Nothing we can do about that though..

> Then there's also all the Xen craziness with segments ...

I don't think Xen Dom0 has PMU access, that would be their Hyper-visor
thingy's job, no?

Anyway, that seems a problem for Jeremy and Konrad..