Re: perf: easily crash kernel with rapl event close

[Vince Weaver]

On Thu, 22 Jan 2015, Stephane Eranian wrote:

> Fix looks like this:
> 
> diff --git a/arch/x86/kernel/cpu/perf_event_intel_rapl.c
> b/arch/x86/kernel/cpu/perf_event_intel_rapl.c
> index 6e434f8..c4bb8b8 100644
> --- a/arch/x86/kernel/cpu/perf_event_intel_rapl.c
> +++ b/arch/x86/kernel/cpu/perf_event_intel_rapl.c
> @@ -142,7 +142,7 @@ static inline u64 rapl_scale(u64 v)
>          * or use ldexp(count, -32).
>          * Watts = Joules/Time delta
>          */
> -       return v << (32 - __this_cpu_read(rapl_pmu->hw_unit));
> +       return v << (32 - __this_cpu_read(rapl_pmu)->hw_unit);
>  }
> 
> 
> Will post the patch shortly.
> Thanks Vince for reporting this issue.

Well that's obviously a classic misplaced-parenthesis bug, but I patched 
and re-ran my tests anyway to make sure this really fixed things.
(It did).  So in case it is useful:

Tested-by: Vince Weaver <vincent.weaver@xxxxxxxxx>


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