From 7c570bff749eaf72be6f982c89facab3b16c42ae Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Wed, 3 Oct 2018 11:28:01 +0100 Subject: [PATCH] Fix exception in background metrics collection We attempted to iterate through a list on a separate thread without doing the necessary copying. --- synapse/metrics/background_process_metrics.py | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/synapse/metrics/background_process_metrics.py b/synapse/metrics/background_process_metrics.py index 173908299c..037f1c490e 100644 --- a/synapse/metrics/background_process_metrics.py +++ b/synapse/metrics/background_process_metrics.py @@ -101,9 +101,13 @@ class _Collector(object): labels=["name"], ) - # We copy the dict so that it doesn't change from underneath us + # We copy the dict so that it doesn't change from underneath us. + # We also copy the process lists as that can also change with _bg_metrics_lock: - _background_processes_copy = dict(_background_processes) + _background_processes_copy = { + k: list(v) + for k, v in six.iteritems(_background_processes) + } for desc, processes in six.iteritems(_background_processes_copy): background_process_in_flight_count.add_metric(