Re: [PATCH] x86/umwait: Fix error handling in umwait_init()

From: Thomas Gleixner
Date: Sat Aug 10 2019 - 01:25:27 EST


On Fri, 9 Aug 2019, Fenghua Yu wrote:
> +/*
> + * The CPU hotplug callback sets the control MSR to the original control
> + * value.
> + */
> +static int umwait_cpu_offline(unsigned int cpu)
> +{
> + /*
> + * This code is protected by the CPU hotplug already and
> + * orig_umwait_control_cached is never changed after it caches
> + * the original control MSR value in umwait_init(). So there
> + * is no race condition here.
> + */
> + wrmsr(MSR_IA32_UMWAIT_CONTROL, orig_umwait_control_cached, 0);

Even my brain compiler emits an error here.

Thanks,

tglx