Guard access to c.Queue explicitly.

Author: godwinpang

pkg/internal/controller/controller.go

@@ -332,11 +332,15 @@ func (c *Controller[request]) startEventSourcesLocked(ctx context.Context) error
 				sourceStartCtx, cancel := context.WithTimeout(ctx, c.CacheSyncTimeout)
 				defer cancel()
 
-				sourceStartErrChan := make(chan error, 1) // Buffer chan to not leak goroutine if we time out
+				sourceStartErrChan := make(chan error, 1)   // Buffer chan to not leak goroutine if we time out
+				hasAccessedQueueChan := make(chan struct{}) //
 				go func() {
 					defer close(sourceStartErrChan)
 					log.Info("Starting EventSource")
-					if err := watch.Start(ctx, c.Queue); err != nil {
+
+					q := c.Queue
+					close(hasAccessedQueueChan)
+					if err := watch.Start(ctx, q); err != nil {
 						sourceStartErrChan <- err
 						return
 					}
@@ -356,8 +360,8 @@ func (c *Controller[request]) startEventSourcesLocked(ctx context.Context) error
 				case err := <-sourceStartErrChan:
 					return err
 				case <-sourceStartCtx.Done():
-					defer func() { <-sourceStartErrChan }() // Ensure that watch.Start has been called to avoid prematurely releasing lock before accessing c.Queue
-					if didStartSyncingSource.Load() {       // We are racing with WaitForSync, wait for it to let it tell us what happened
+					defer func() { <-hasAccessedQueueChan }() // Ensure that watch.Start has been called to avoid prematurely releasing lock before accessing c.Queue
+					if didStartSyncingSource.Load() {         // We are racing with WaitForSync, wait for it to let it tell us what happened
 						return <-sourceStartErrChan
 					}
 					if ctx.Err() != nil { // Don't return an error if the root context got cancelled