Re: [BUG] msr-trace.h:42 suspicious rcu_dereference_check() usage!

From: Andi Kleen
Date: Thu Feb 23 2017 - 12:11:27 EST


> > diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
> > index 0888a879120f..d6c6aa80675f 100644
> > --- a/arch/x86/kernel/process.c
> > +++ b/arch/x86/kernel/process.c
> > @@ -357,7 +357,7 @@ static void amd_e400_idle(void)
> > if (!amd_e400_c1e_detected) {
> > u32 lo, hi;
> >
> > - rdmsr(MSR_K8_INT_PENDING_MSG, lo, hi);
> > + RCU_NONIDLE(rdmsr(MSR_K8_INT_PENDING_MSG, lo, hi));
> >
> > if (lo & K8_INTP_C1E_ACTIVE_MASK) {
> > amd_e400_c1e_detected = true;
>
> hum, I might have missed some other solution in discussion,
> and can't see this one being pulled in.. should I resend this?

I suppose you could also use the new notrace msr variant.

BTW this check is quite annoying.

-Andi