diff --git a/util/async.c b/util/async.c
index 38c53c2..a8094aa 100644
--- a/util/async.c
+++ b/util/async.c
@@ -60,6 +60,8 @@ HRESULT async_submit(struct async *async, struct irp *irp, async_task_t task)
         return task(async->ctx, irp);
     }
 
+    EnterCriticalSection(&async->lock);
+
     if (async->thread == NULL) {
         /* Ensure our worker thread is running */
         async->thread = (HANDLE) _beginthreadex(
@@ -75,8 +77,6 @@ HRESULT async_submit(struct async *async, struct irp *irp, async_task_t task)
         }
     }
 
-    EnterCriticalSection(&async->lock);
-
     while (async->task != NULL) {
         ok = SleepConditionVariableCS(&async->avail, &async->lock, INFINITE);