VAAPI XCB: properly lock on releasing libva connection.

vlc_va_Terminate() forgot to lock when releasing the libva connection. This
openned a window for a race condition.

modules/codec/avcodec/va.c

@@ -171,24 +171,27 @@ error:
 
 void vlc_va_Terminate( vlc_va_conn_t *conn )
 {
+    vlc_mutex_lock( &vlc_va_conn_lock );
     assert( conn );
+    assert( conn->i_ref_count > 0 );
 
     conn->i_ref_count--;
-    if( conn->i_ref_count > 0 )
-        return;
-
-    assert( conn->i_ref_count == 0 );
-    assert( conn->i_surface_count == 0 );
-    assert( conn->p_surface_ids == NULL );
+    if( conn->i_ref_count == 0 )
+    {
+        assert( conn->i_surface_count == 0 );
+        assert( conn->p_surface_ids == NULL );
 
-    if( conn->p_display )
+        assert( conn->p_display );
         vaTerminate( conn->p_display );
 
-    /* Reset values */
-    conn->p_display = 0;
-    conn->i_version_major = conn->i_version_minor = 0;
-    conn->i_ref_count = 0;
-    conn = NULL;
+        /* Reset values */
+        conn->p_display = 0;
+        conn->i_version_major = conn->i_version_minor = 0;
+        conn->i_ref_count = 0;
+        conn = NULL;
+    }
+
+    vlc_mutex_unlock( &vlc_va_conn_lock );
 }
 
 #endif

modules/codec/avcodec/vaapi_x11.c

@@ -361,7 +361,9 @@ void CloseVaapiX11(vlc_object_t *obj)
 
     if (sys->vaconn)
     {
+        sys->vaconn->lock();
         sys->vaconn->destroy_surfaces(sys->vaconn);
+        sys->vaconn->unlock();
         vlc_va_Terminate(sys->vaconn);
     }