Data race condition

The value of the shared data will be determined by the interleaving of thread execution. Thread shared data is accessed without holding an appropriate lock, possibly causing a race condition
/src/mongo/util/alarm_runner_background_thread.cpp:51: MISSING_LOCK 175021 Accessing "this->_thread" without holding lock "mongo::AlarmRunnerBackgroundThread._mutex". Elsewhere, "mongo::AlarmRunnerBackgroundThread._thread" is written to with "AlarmRunnerBackgroundThread._mutex" held 1 out of 1 times.