Port scheduler race condition fix from BTC upstream #133, 12519bf62b

src/scheduler.cpp

@@ -66,9 +66,10 @@ void CScheduler::serviceQueue()
 
             // Some boost versions have a conflicting overload of wait_until that returns void.
             // Explicitly use a template here to avoid hitting that overload.
-            while (!shouldStop() && !taskQueue.empty() &&
-                   newTaskScheduled.wait_until<>(lock, taskQueue.begin()->first) != boost::cv_status::timeout) {
-                // Keep waiting until timeout
+            while (!shouldStop() && !taskQueue.empty()) {
+                boost::chrono::system_clock::time_point timeToWaitFor = taskQueue.begin()->first;
+                if (newTaskScheduled.wait_until<>(lock, timeToWaitFor) == boost::cv_status::timeout)
+                    break; // Exit loop after timeout, it means we reached the time of the event
             }
 
             // If there are multiple threads, the queue can empty while we're waiting (another