@@ 136,7 136,7 @@ int load_config(int data_dir_fd, struct 
 		return PTR_ERR(lua);
 	}
 
-	L = xlua_get_state(lua);
+	L = xlua_lock(lua);
 
 	switch (lua_type(L, -1)) {
 		case LUA_TTABLE:

          
@@ 159,7 159,7 @@ int load_config(int data_dir_fd, struct 
 	ret = 0;
 
 err_lua:
-	xlua_put_and_close(lua, L);
+	xlua_close_locked(lua, L);
 
 	if (ret)
 		fprintf(stderr, "Error: failed to load config: %s\n",

          

@@ 333,7 333,7 @@ struct xlua_state *script_load(struct xf
 		return lua;
 	}
 
-	L = xlua_get_state(lua);
+	L = xlua_lock(lua);
 
 	if (lua_type(L, -1) != LUA_TTABLE) {
 		fprintf(stderr, "Error: contest script init failed: "

          
@@ 385,12 385,12 @@ struct xlua_state *script_load(struct xf
 
 	ASSERT_LUA_STACK(L, 0);
 
-	xlua_put_state(lua, L);
+	xlua_unlock(lua, L);
 
 	return lua;
 
 err:
-	xlua_put_and_close(lua, L);
+	xlua_close_locked(lua, L);
 
 	return ERR_PTR(ret);
 }

          
@@ 456,13 456,13 @@ int script_event_export(struct xlua_stat
 	int type;
 	int ret;
 
-	L = xlua_get_state(lua);
+	L = xlua_lock(lua);
 
 	type = lua_getfield(L, LUA_REGISTRYINDEX, EVENT_EXPORT);
 	if (type == LUA_TNIL) {
 		lua_pop(L, 1);
 		ASSERT_LUA_STACK(L, 0);
-		xlua_put_state(lua, L);
+		xlua_unlock(lua, L);
 		snprintf(error, errlen, "Contest doesn't define an export "
 			 "function");
 		return -ENOTSUP;

          
@@ 474,7 474,7 @@ int script_event_export(struct xlua_stat
 
 	ASSERT_LUA_STACK(L, 0);
 
-	xlua_put_state(lua, L);
+	xlua_unlock(lua, L);
 
 	return ret;
 }

          
@@ 492,13 492,13 @@ int script_event_field_change(struct xlu
 	int type;
 	int ret;
 
-	L = xlua_get_state(lua);
+	L = xlua_lock(lua);
 
 	type = lua_getfield(L, LUA_REGISTRYINDEX, EVENT_FIELD_CHANGED);
 	if (type == LUA_TNIL) {
 		lua_pop(L, 1);
 		ASSERT_LUA_STACK(L, 0);
-		xlua_put_state(lua, L);
+		xlua_unlock(lua, L);
 		return 0;
 	}
 

          
@@ 545,7 545,7 @@ int script_event_field_change(struct xlu
 out:
 	ASSERT_LUA_STACK(L, 0);
 
-	xlua_put_state(lua, L);
+	xlua_unlock(lua, L);
 
 	return ret;
 }

          
@@ 557,13 557,13 @@ static int event_qso(struct xlua_state *
 	int type;
 	int ret;
 
-	L = xlua_get_state(lua);
+	L = xlua_lock(lua);
 
 	type = lua_getfield(L, LUA_REGISTRYINDEX, event);
 	if (type == LUA_TNIL) {
 		lua_pop(L, 1);
 		ASSERT_LUA_STACK(L, 0);
-		xlua_put_state(lua, L);
+		xlua_unlock(lua, L);
 		return 0;
 	}
 

          
@@ 571,7 571,7 @@ static int event_qso(struct xlua_state *
 
 	ASSERT_LUA_STACK(L, 0);
 
-	xlua_put_state(lua, L);
+	xlua_unlock(lua, L);
 
 	return ret;
 }

          

@@ 1993,7 1993,7 @@ static void print_stats(void)
 		return;
 	}
 
-	L = xlua_get_state(lua);
+	L = xlua_lock(lua);
 
 	/* iterate over all the QSOs */
 	for (qso = index_iter_history_start(&ctx, true), failed = false;

          
@@ 2015,7 2015,7 @@ static void print_stats(void)
 	if (ret)
 		printf("Error: %s\n", error);
 
-	xlua_put_and_close(lua, L);
+	xlua_close_locked(lua, L);
 }
 
 static void state_free(void)

          

@@ 48,13 48,13 @@ static void process(const char *scriptna
 		return;
 	}
 
-	L = xlua_get_state(lua);
+	L = xlua_lock(lua);
 
 	ret = xlua_call(L, "main", 0, 0, error, sizeof(error));
 	if (ret)
 		printf("Error: failed to execute lua: %s\n", error);
 
-	xlua_put_and_close(lua, L);
+	xlua_close_locked(lua, L);
 }
 
 static void usage(const char *prog)

          

@@ 59,8 59,8 @@ extern struct xlua_state *xlua_init_scri
 					   size_t errlen);
 extern void xlua_close(struct xlua_state *lua);
 
-extern lua_State *xlua_get_state(struct xlua_state *lua);
-extern void xlua_put_state(struct xlua_state *lua, lua_State *L);
+extern lua_State *xlua_lock(struct xlua_state *lua);
+extern void xlua_unlock(struct xlua_state *lua, lua_State *L);
 
 /* return raw script data */
 extern int xlua_script_find(const char *name, const uint8_t **data_r,

          
@@ 101,8 101,9 @@ static inline struct xlua_state *xlua_in
 	return xlua_init_at(AT_FDCWD, script_fname, nresults, error, errlen);
 }
 
-static inline void xlua_put_and_close(struct xlua_state *lua, lua_State *L)
+static inline void xlua_close_locked(struct xlua_state *lua, lua_State *L)
 {
+	xlua_unlock(lua, L);
 	xlua_close(lua);
 }
 

          

@@ 30,6 30,7 @@ 
 
 struct xlua_state {
 	lua_State *L;
+	struct lock lock;
 };
 
 extern int xlua_load_script_internal(lua_State *L, const char *scriptname,

          

@@ 26,6 26,8 @@ 
 #include "xlua-impl.h"
 #include "script.h"
 
+static LOCK_CLASS(xlua_state_lc);
+
 int lua2errno(int e)
 {
 	switch (e) {

          
@@ 240,6 242,8 @@ static struct xlua_state *__xlua_init(co
 		return ERR_PTR(-ENOMEM);
 	}
 
+	MXINIT(&lua->lock, &xlua_state_lc);
+
 	lua->L = luaL_newstate();
 	if (!lua->L) {
 		strcpy_safe(error, "failed to allocate lua state", errlen);

          
@@ 249,6 253,8 @@ static struct xlua_state *__xlua_init(co
 
 	L = lua->L;
 
+	MXLOCK(&lua->lock);
+
 	luaL_openlibs(L);
 
 	xlua_register(L);

          
@@ 263,6 269,7 @@ static struct xlua_state *__xlua_init(co
 
 	ASSERT_LUA_STACK(L, nresults);
 
+	MXUNLOCK(&lua->lock);
 
 	return lua;
 

          
@@ 271,7 278,11 @@ err_free:
 
 	lua_close(L);
 
+	MXUNLOCK(&lua->lock);
+
 err:
+	MXDESTROY(&lua->lock);
+
 	free(lua);
 
 	return ERR_PTR(lua2errno(ret));

          
@@ 326,19 337,25 @@ struct xlua_state *xlua_init_script(cons
 
 void xlua_close(struct xlua_state *lua)
 {
+	MXDESTROY(&lua->lock);
+
 	lua_close(lua->L);
 
 	free(lua);
 }
 
-lua_State *xlua_get_state(struct xlua_state *lua)
+lua_State *xlua_lock(struct xlua_state *lua)
 {
+	MXLOCK(&lua->lock);
+
 	return lua->L;
 }
 
-void xlua_put_state(struct xlua_state *lua, lua_State *L)
+void xlua_unlock(struct xlua_state *lua, lua_State *L)
 {
 	ASSERT3P(lua->L, ==, L);
+
+	MXUNLOCK(&lua->lock);
 }
 
 int xlua_call(lua_State *L, const char *funcname, int nargs, int nresults,