Re: [patch 1/2] x86/tsc: Validate TSC_ADJUST after resume

From: Thomas Gleixner
Date: Tue Dec 13 2016 - 08:26:24 EST


On Tue, 13 Dec 2016, Peter Zijlstra wrote:

> On Tue, Dec 13, 2016 at 01:14:17PM -0000, Thomas Gleixner wrote:
> > --- a/arch/x86/power/cpu.c
> > +++ b/arch/x86/power/cpu.c
> > @@ -256,6 +256,7 @@ static void notrace __restore_processor_
> > mtrr_bp_restore();
> > perf_restore_debug_store();
> > msr_restore_context(ctxt);
> > + tsc_verify_tsc_adjust(true);
> > }
>
> Should we do that sooner, as in before calling
> restore_sched_clock_state() ? Otherwise we recompute the sched_clock
> deltas vs the wrecked TSC and then fix it up through the ADJUST,
> wrecking our sched clock again.

Ah. Indeed. Will fix. That needs some thought on the secondary CPUs as
well...

Thanks,

tglx