perf handle structure needs to be shared with the TRBE IRQ handler for capturing trace data and restarting the handle. There is a probability of an undefined reference based crash when etm event is being stopped while a TRBE IRQ also getting processed. This happens due the release of perf handle via perf_aux_output_end(). This stops the sinks via the link before releasing the handle, which will ensure that a simultaneous TRBE IRQ could not happen.
Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com --- This might cause problem with traditional sink devices which can be operated in both sysfs and perf mode. This needs to be addressed correctly. One option would be to move the update_buffer callback into the respective sink devices. e.g, disable().
drivers/hwtracing/coresight/coresight-etm-perf.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 534e205..1a37991 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -429,7 +429,9 @@ static void etm_event_stop(struct perf_event *event, int mode)
size = sink_ops(sink)->update_buffer(sink, handle, event_data->snk_config); + coresight_disable_path(path); perf_aux_output_end(handle, size); + return; }
/* Disabling the path make its elements available to other sessions */