diff --git a/reactos/drivers/ksfilter/ks/swenum.c b/reactos/drivers/ksfilter/ks/swenum.c
index 08d5286bd58..8430b64a1f4 100644
--- a/reactos/drivers/ksfilter/ks/swenum.c
+++ b/reactos/drivers/ksfilter/ks/swenum.c
@@ -1156,12 +1156,12 @@ KspBusWorkerRoutine(
     BOOLEAN DoInvalidate = FALSE;
     KIRQL OldLevel;
 
-    /* acquire lock */
-    KeAcquireSpinLock(&BusDeviceExtension->Lock, &OldLevel);
-
     /* get device extension */
     BusDeviceExtension = (PBUS_ENUM_DEVICE_EXTENSION)Parameter;
 
+    /* acquire lock */
+    KeAcquireSpinLock(&BusDeviceExtension->Lock, &OldLevel);
+
     /* get current time */
     KeQuerySystemTime(&Time);