From mboxrd@z Thu Jan  1 00:00:00 1970
From: Alexei Starovoitov <ast@plumgrid.com>
Subject: Re: [PATCH net-next 2/3] bpf: introduce bpf_perf_event_output()
 helper
Date: Thu, 22 Oct 2015 08:38:02 -0700
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Cc: "David S. Miller" <davem@davemloft.net>,
	Ingo Molnar <mingo@kernel.org>, Wang Nan <wangnan0@huawei.com>,
	He Kuang <hekuang@huawei.com>,
	Arnaldo Carvalho de Melo <acme@infradead.org>,
	Daniel Borkmann <daniel@iogearbox.net>, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
To: Peter Zijlstra <peterz@infradead.org>
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On 10/22/15 6:59 AM, Peter Zijlstra wrote:
>> +	if (unlikely(event->oncpu != smp_processor_id()))
>> >+		return -EOPNOTSUPP;
>> >+
>> >+	perf_sample_data_init(&sample_data, 0, 0);
>> >+	sample_data.raw = &raw;
>> >+	perf_event_output(event, &sample_data, regs);
>> >+	return 0;
>> >+}
> Note that this function also very much requires event to be local.

correct. that's why there is a dynamic check above to prevent buggy
programs causing issues.