ue_stack_lte: make sure to execute stack commands on Stack thread

some commands were executed from the calling thread which may lead
to concurrent access to members. Detected by TSAN. The patch
moves all remaining calls (the majority was alread moved) to the
Stack task queue.

srsue/src/stack/ue_stack_lte.cc

@@ -271,35 +271,46 @@ bool ue_stack_lte::switch_on()
 
 bool ue_stack_lte::switch_off()
 {
-  // generate detach request with switch-off flag
-  nas.switch_off();
-
-  // wait for max. 5s for it to be sent (according to TS 24.301 Sec 25.5.2.2)
-  int cnt = 0, timeout_ms = 5000;
-  while (not rrc.srbs_flushed() && ++cnt <= timeout_ms) {
-    std::this_thread::sleep_for(std::chrono::milliseconds(1));
-  }
-  bool detach_sent = true;
-  if (not rrc.srbs_flushed()) {
-    srslog::fetch_basic_logger("NAS").warning("Detach couldn't be sent after %dms.", timeout_ms);
-    detach_sent = false;
+  if (running) {
+    ue_task_queue.try_push([this]() {
+      // generate detach request with switch-off flag
+      nas.switch_off();
+
+      // wait for max. 5s for it to be sent (according to TS 24.301 Sec 25.5.2.2)
+      int cnt = 0, timeout_ms = 5000;
+      while (not rrc.srbs_flushed() && ++cnt <= timeout_ms) {
+        std::this_thread::sleep_for(std::chrono::milliseconds(1));
+      }
+      if (not rrc.srbs_flushed()) {
+        srslog::fetch_basic_logger("NAS").warning("Detach couldn't be sent after %dms.", timeout_ms);
+      }
+    });
   }
-
-  return detach_sent;
+  return true;
 }
 
 bool ue_stack_lte::enable_data()
 {
-  // perform attach request
-  srsran::console("Turning off airplane mode.\n");
-  return nas.enable_data();
+  if (running) {
+    ue_task_queue.try_push([this]() {
+      // perform attach request
+      srsran::console("Turning off airplane mode.\n");
+      nas.enable_data();
+    });
+  }
+  return true;
 }
 
 bool ue_stack_lte::disable_data()
 {
-  // generate detach request
-  srsran::console("Turning on airplane mode.\n");
-  return nas.disable_data();
+  if (running) {
+    ue_task_queue.try_push([this]() {
+      // generate detach request
+      srsran::console("Turning on airplane mode.\n");
+      nas.disable_data();
+    });
+  }
+  return true;
 }
 
 bool ue_stack_lte::start_service_request()