[PATCH 4.4 017/114] perf/ring_buffer: Prevent concurent ring buffer access

4.4-stable review patch. If anyone has any objections, please let me know. -- [ Upstream commit cd6fb677ce7e460c25bdd66f689734102ec7d642 ] Some of the scheduling tracepoints allow the perf_tp_event code to write to ring buffer under different cpu than the code is running on.

[PATCH 4.4 017/114] perf/ring_buffer: Prevent concurent ring buffer access

4.4-stable review patch. If anyone has any objections, please let me know. -- [ Upstream commit cd6fb677ce7e460c25bdd66f689734102ec7d642 ] Some of the scheduling tracepoints allow the perf_tp_event code to write to ring buffer under different cpu than the code is running on.