Fix race condition in Singleton and Application Manager failure to stop

When SDL is started, but the HMI is not, and we try to register a mobile
app (RegisterAppInterfaceRequest), then in this situation SDL can't be
stopped with ctrl+C - it enters in an endless cycle.
The reason for the problem is that we can't delete the AM, because the
RequestController thread of AM is still running (waiting in a cycle for
the HMI to respond). Also a second AM is created, because in the
Singleton we set to 0 the instance pointer before deleting it and
someone calls instance() before destroy() finishes, because there is no
common lock. The separate locks create a race condition.
The fix is to use a single mutex for the Singleton methods, introduce a
is_stopping_ flag in AM, set it to true in AM's Stop() method, and
also destroy RequestController's thread pool there.
Then check stop flag in RegisterAppInterfaceRequest::Run() and exit the
HMI waiting cycle there.

1 files changed, 11 insertions, 6 deletions

diff --git a/src/components/utils/include/utils/singleton.h b/src/components/utils/include/utils/singleton.h
index 41face4f2f..fff7294d1c 100644
--- a/src/components/utils/include/utils/singleton.h
+++ b/src/components/utils/include/utils/singleton.h
@@ -111,18 +111,24 @@ class Singleton {
 
   static T** instance_pointer();
   static Deleter* deleter();
+
+  static sync_primitives::Lock lock_;
 };
 
+
+template<typename T, class Deleter>
+sync_primitives::Lock Singleton<T, Deleter>::lock_;
+
+
 template<typename T, class Deleter>
 T* Singleton<T, Deleter>::instance() {
-  static sync_primitives::Lock lock;
 
   T* local_instance;
   atomic_pointer_assign(local_instance, *instance_pointer());
   memory_barrier();
 
   if (!local_instance) {
-    lock.Acquire();
+    lock_.Acquire();
     local_instance = *instance_pointer();
     if (!local_instance) {
       local_instance = new T();
@@ -130,7 +136,7 @@ T* Singleton<T, Deleter>::instance() {
       atomic_pointer_assign(*instance_pointer(), local_instance);
       deleter()->grab(local_instance);
     }
-    lock.Release();
+    lock_.Release();
   }
 
   return local_instance;
@@ -138,14 +144,13 @@ T* Singleton<T, Deleter>::instance() {
 
 template<typename T, class Deleter>
 void Singleton<T, Deleter>::destroy() {
-  static sync_primitives::Lock lock;
 
   T* local_instance;
   atomic_pointer_assign(local_instance, *instance_pointer());
   memory_barrier();
 
   if (local_instance) {
-    lock.Acquire();
+    lock_.Acquire();
     local_instance = *instance_pointer();
     if (local_instance) {
       atomic_pointer_assign(*instance_pointer(), 0);
@@ -153,7 +158,7 @@ void Singleton<T, Deleter>::destroy() {
       delete local_instance;
       deleter()->grab(0);
     }
-    lock.Release();
+    lock_.Release();
   }
 }