mark QuotaMonitor as not running and invalidate monitors list

to prevent close of closed channel panic

pkg/controller/resourcequota/resource_quota_monitor.go

@@ -78,8 +78,9 @@ type QuotaMonitor struct {
 	// This channel is also protected by monitorLock.
 	stopCh <-chan struct{}
 
-	// running tracks whether Run() has been called.
-	// it is protected by monitorLock.
+	// running is set to true when the Run() function has been called.
+	// It will revert to false when the Run() function receives a cancellation.
+	// It is protected by monitorLock.
 	running bool
 
 	// monitors are the producer of the resourceChanges queue
@@ -331,6 +332,10 @@ func (qm *QuotaMonitor) Run(ctx context.Context) {
 	// Stop any running monitors.
 	qm.monitorLock.Lock()
 	defer qm.monitorLock.Unlock()
+	// Mark as not running so that no new monitors can be started.
+	// Not doing this here could cause goroutine leaks and deadlocks since it would make it possible for startMonitors
+	// to proceed and start new monitors after stopMonitors has been called.
+	qm.running = false
 	monitors := qm.monitors
 	stopped := 0
 	for _, monitor := range monitors {
@@ -339,6 +344,7 @@ func (qm *QuotaMonitor) Run(ctx context.Context) {
 			close(monitor.stopCh)
 		}
 	}
+	qm.monitors = nil
 	logger.Info("QuotaMonitor stopped monitors", "stopped", stopped, "total", len(monitors))
 }