diff --git a/cmd/vGPUmonitor/feedback.go b/cmd/vGPUmonitor/feedback.go
index 3d119e6c4c..cb86a6960b 100644
--- a/cmd/vGPUmonitor/feedback.go
+++ b/cmd/vGPUmonitor/feedback.go
@@ -71,7 +71,15 @@ func CheckPriority(utSwitchOn map[string]UtilizationPerDevice, p int, c *nvidia.
 	return false
 }
 
+var observeTestHook func()
+
 func Observe(lister *nvidia.ContainerLister) {
+	if observeTestHook != nil {
+		observeTestHook()
+	}
+	lister.Lock()
+	defer lister.UnLock()
+
 	utSwitchOn := map[string]UtilizationPerDevice{}
 	containers := lister.ListContainers()
 
diff --git a/cmd/vGPUmonitor/feedback_test.go b/cmd/vGPUmonitor/feedback_test.go
index 10c2177790..62074c8cbd 100644
--- a/cmd/vGPUmonitor/feedback_test.go
+++ b/cmd/vGPUmonitor/feedback_test.go
@@ -18,6 +18,7 @@ package main
 
 import (
 	"testing"
+	"time"
 
 	"github.com/Project-HAMi/HAMi/pkg/monitor/nvidia"
 )
@@ -160,3 +161,46 @@ func TestCheckBlocking_MultiDevice(t *testing.T) {
 		})
 	}
 }
+
+func TestObserve(t *testing.T) {
+	// Call Observe with an empty lister to cover the missing lines for codecov
+	// and to ensure no panics occur with locking/unlocking.
+	lister := &nvidia.ContainerLister{}
+
+	// Test that Observe actually acquires the lock deterministically.
+	lister.Lock()
+
+	reachedLock := make(chan struct{})
+	observeTestHook = func() {
+		close(reachedLock)
+	}
+	defer func() { observeTestHook = nil }()
+
+	done := make(chan struct{})
+	go func() {
+		Observe(lister)
+		close(done)
+	}()
+
+	// Wait until Observe reaches the lock boundary
+	<-reachedLock
+
+	// Ensure Observe is now blocked on the lock
+	select {
+	case <-done:
+		t.Fatal("Observe completed while lock was held by another goroutine, indicating it did not acquire the lock!")
+	default:
+		// Expected: Observe is blocked
+	}
+
+	// Release the lock
+	lister.UnLock()
+
+	// Now Observe should complete
+	select {
+	case <-done:
+		// Success
+	case <-time.After(1 * time.Second):
+		t.Fatal("Observe did not complete after lock was released")
+	}
+}