cov: threadpool: lock during destruction

Author: lws-team

lib/misc/threadpool/threadpool.c

@@ -826,6 +826,7 @@ lws_threadpool_destroy(struct lws_threadpool *tp)
 #if defined(WIN32)
 	Sleep(1000);
 #endif
+	pthread_mutex_lock(&tp->lock); /* ======================== tpool lock */
 
 	task = tp->task_done_head;
 	while (task) {
@@ -835,6 +836,8 @@ lws_threadpool_destroy(struct lws_threadpool *tp)
 		task = next;
 	}
 
+	pthread_mutex_unlock(&tp->lock); /* -------------------- tpool unlock */
+
 	pthread_mutex_destroy(&tp->lock);
 
 	memset(tp, 0xdd, sizeof(*tp));