Fix potential crash at application shutdown when deep userdata were created before Lanes is required

2 files changed, 12 insertions, 2 deletions

diff --git a/src/lanes.c b/src/lanes.c
index 7b1a707..d4b4c73 100644
--- a/src/lanes.c
+++ b/src/lanes.c
@@ -1756,7 +1756,10 @@ static int selfdestruct_gc( lua_State* L)
         // Locks for 'tools.c' inc/dec counters
         MUTEX_FREE( &U->deep_lock);
         MUTEX_FREE( &U->mtid_lock);
-
+        // universe is no longer available (nor necessary)
+        // we need to do this in case some deep userdata objects were created before Lanes was initialized,
+        // as potentially they will be garbage collected after Lanes at application shutdown
+        universe_store( L, NULL);
         return 0;
 }
 
diff --git a/src/universe.c b/src/universe.c
index 00de1f3..4689a09 100644
--- a/src/universe.c
+++ b/src/universe.c
@@ -56,7 +56,14 @@ void universe_store( lua_State* L, Universe* U)
 {
         STACK_CHECK( L);
         push_unique_key( L, UNIVERSE_REGKEY);
-        lua_pushlightuserdata( L, U);
+        if( NULL != U)
+        {
+                lua_pushlightuserdata( L, U);
+        }
+        else
+        {
+                lua_pushnil( L);
+        }
         lua_rawset( L, LUA_REGISTRYINDEX);
         STACK_END( L, 0);
 }