test(lifecycle): harden TOCTOU concurrent-Add race window (kernelevents+k8sevents)

components/receivers/k8sevents/lifecycle_test.go

@@ -283,6 +283,7 @@ func TestK8sevents_Lifecycle_ConcurrentAddDuringShutdown_NoPanic(t *testing.T) {
 	}
 
 	release := make(chan struct{})
+	shutdownGate := make(chan struct{})
 	var launched sync.WaitGroup
 	launched.Add(adders + 1)
 
@@ -305,13 +306,30 @@ func TestK8sevents_Lifecycle_ConcurrentAddDuringShutdown_NoPanic(t *testing.T) {
 	go func() {
 		launched.Done()
 		<-release
+		// Wait for shutdownGate to open before calling Shutdown. The
+		// gate fires AFTER the adders have been released for a brief
+		// scheduling window, which guarantees the race window straddles
+		// adders-in-flight + Shutdown rather than letting the
+		// shutdowner trivially win and force every Add into the
+		// closed-guard no-op branch. (Without this, on fast machines
+		// every adder consistently no-ops, defeating the test's
+		// TOCTOU-coverage purpose. Ported from containerstdout's
+		// hardened equivalent to deflake CI on fast schedulers.)
+		<-shutdownGate
 		runtime.Gosched()
 		shutdownErr = lc.Shutdown(context.Background())
 		close(shutdownDone)
 	}()
 
 	launched.Wait()
 	close(release)
+	// Give the adders a short scheduling window to land their Add()
+	// calls. The window is intentionally tiny — the race detector +
+	// the scheduler still interleave so SOME adders will no-op (which
+	// is also a tested outcome) — but it prevents the trivial
+	// shutdowner-wins-everything degenerate.
+	time.Sleep(50 * time.Microsecond)
+	close(shutdownGate)
 
 	select {
 	case <-shutdownDone:

components/receivers/kernelevents/lifecycle_test.go

@@ -293,6 +293,7 @@ func TestKernelevents_Lifecycle_ConcurrentAddDuringShutdown_NoPanic(t *testing.T
 	// Gate: all adders + the shutdowner block until release fires, so
 	// the race window opens at roughly the same wall-clock moment.
 	release := make(chan struct{})
+	shutdownGate := make(chan struct{})
 	var launched sync.WaitGroup
 	launched.Add(adders + 1)
 
@@ -315,13 +316,30 @@ func TestKernelevents_Lifecycle_ConcurrentAddDuringShutdown_NoPanic(t *testing.T
 	go func() {
 		launched.Done()
 		<-release
+		// Wait for shutdownGate to open before calling Shutdown. The
+		// gate fires AFTER the adders have been released for a brief
+		// scheduling window, which guarantees the race window straddles
+		// adders-in-flight + Shutdown rather than letting the
+		// shutdowner trivially win and force every Add into the
+		// closed-guard no-op branch. (Without this, on fast machines
+		// every adder consistently no-ops, defeating the test's
+		// TOCTOU-coverage purpose. Ported from containerstdout's
+		// hardened equivalent to deflake CI on fast schedulers.)
+		<-shutdownGate
 		runtime.Gosched()
 		shutdownErr = lc.Shutdown(context.Background())
 		close(shutdownDone)
 	}()
 
 	launched.Wait()
 	close(release)
+	// Give the adders a short scheduling window to land their Add()
+	// calls. The window is intentionally tiny — the race detector +
+	// the scheduler still interleave so SOME adders will no-op (which
+	// is also a tested outcome) — but it prevents the trivial
+	// shutdowner-wins-everything degenerate.
+	time.Sleep(50 * time.Microsecond)
+	close(shutdownGate)
 
 	select {
 	case <-shutdownDone: