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SubjectRe: [PATCH V5 1/1] bpf: control events stored in PERF_EVENT_ARRAY maps trace data output when perf sampling
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发自我的 iPhone

> 在 2015年10月21日,下午9:49,Peter Zijlstra <peterz@infradead.org> 写道:
>
>> On Wed, Oct 21, 2015 at 09:42:12PM +0800, Wangnan (F) wrote:
>> How can an eBPF program access a !local event:
>>
>> when creating perf event array we don't care which perf event
>> is for which CPU, so perf program can access any perf event in
>> that array.
>
> So what is stopping the eBPF thing from calling perf_event_read_local()
> on a !local event and triggering a kernel splat?

I can understand the perf_event_read_local() case, but I really can't understand
what is stopping us to write to an atomic field belong to a !local perf event.
Could you please give a further explanation?

Thank you.
>



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