Re: [PATCH V5 1/1] bpf: control events stored in PERF_EVENT_ARRAY maps trace data output when perf sampling

[pi3orama]

发自我的 iPhone

> 在 2015年10月21日，下午9:49，Peter Zijlstra <peterz@xxxxxxxxxxxxx> 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.
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/