Re: Fix suspicious RCU usage in msr tracing.

From: Andi Kleen
Date: Tue Mar 15 2016 - 12:40:00 EST


> Back in January, Andi suggested swapping the order in which
> we ack the APIC irq, so it too is protected by rcu.
> There was no follow-up, and it seems to work for me.
>
> Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

-Andi

> Signed-off-by: Dave Jones <davej@xxxxxxxxxxxxxxxxx>
>
> diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
> index c80f6b6f3da2..e8c4fba52d3d 100644
> --- a/arch/x86/include/asm/apic.h
> +++ b/arch/x86/include/asm/apic.h
> @@ -644,8 +644,8 @@ static inline void entering_irq(void)
>
> static inline void entering_ack_irq(void)
> {
> - ack_APIC_irq();
> entering_irq();
> + ack_APIC_irq();
> }
>
> static inline void ipi_entering_ack_irq(void)

--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only