From ce2dbe1f201ad9b2b97aea630045fe458d3c68b8 Mon Sep 17 00:00:00 2001
From: Lourival Vieira Neto <lourival.neto@ring-0.io>
Date: Wed, 22 Nov 2023 22:47:18 +0000
Subject: [PATCH] fix reentrant case of luantik_run

---
 lib/luanotifier.c | 13 +++++++++----
 lunatik.h         | 31 +++++++++++++++----------------
 2 files changed, 24 insertions(+), 20 deletions(-)

diff --git a/lib/luanotifier.c b/lib/luanotifier.c
index b0346b68..7ac545c8 100644
--- a/lib/luanotifier.c
+++ b/lib/luanotifier.c
@@ -93,9 +93,13 @@ static int luanotifier_call(struct notifier_block *nb, unsigned long event, void
 	luanotifier_t *notifier = container_of(nb, luanotifier_t, nb);
 	int ret;
 
-	notifier->running = true;
-	lunatik_run(notifier->runtime, luanotifier_handler, ret, notifier, event, data);
-	notifier->running = false;
+	if (notifier->running)
+		lunatik_handle(notifier->runtime, luanotifier_handler, ret, notifier, event, data);
+	else {
+		notifier->running = true;
+		lunatik_run(notifier->runtime, luanotifier_handler, ret, notifier, event, data);
+		notifier->running = false;
+	}
 	return ret;
 }
 
@@ -109,7 +113,6 @@ static int luanotifier_new(lua_State *L, luanotifier_register_t register_fn, lua
 	notifier = (luanotifier_t *)lua_newuserdatauv(L, sizeof(luanotifier_t), 1);
 	notifier->runtime = lunatik_toruntime(L);
 	notifier->nb.notifier_call = luanotifier_call;
-	notifier->running = false;
 	notifier->unregister = unregister_fn;
 	notifier->handler = handler_fn;
 
@@ -119,8 +122,10 @@ static int luanotifier_new(lua_State *L, luanotifier_register_t register_fn, lua
 	lua_pushvalue(L, -1);  /* push userdata */
 	notifier->ud = luaL_ref(L, LUA_REGISTRYINDEX); /* pops userdata */
 
+	notifier->running = true; /* notifier_call might be called directly (e.g., NETDEV_REGISTER) */
 	if (register_fn(&notifier->nb) != 0)
 		luaL_error(L, "couldn't create notifier");
+	notifier->running = false;
 
 	luaL_setmetatable(L, LUANOTIFIER_MT);
 	return 1; /* userdata */
diff --git a/lunatik.h b/lunatik.h
index e12e8969..a671fea7 100644
--- a/lunatik.h
+++ b/lunatik.h
@@ -82,23 +82,22 @@ static inline void lunatik_release(struct kref *kref)
 
 #define lunatik_cansleep(L)	(!lunatik_getready(L) || lunatik_getsleep(L))
 
-#define lunatik_run(runtime, handler, ret, ...)		\
+#define lunatik_handle(runtime, handler, ret, ...)	\
 do {							\
-	lua_State *L;					\
-	int unlocked = !lunatik_islocked(runtime);	\
-	if (likely(unlocked))				\
-		lunatik_lock(runtime);			\
-	L = runtime->L;					\
-	if (unlikely(!L))				\
-		ret = -ENXIO;				\
-	else {						\
-		int n;					\
-		n = lua_gettop(L);			\
-		ret = handler(L, ## __VA_ARGS__);	\
-		lua_settop(L, n);			\
-	}						\
-	if (likely(unlocked))				\
-		lunatik_unlock(runtime);		\
+	lua_State *L = runtime->L;			\
+	int n = lua_gettop(L);				\
+	ret = handler(L, ## __VA_ARGS__);		\
+	lua_settop(L, n);				\
+} while(0)
+
+#define lunatik_run(runtime, handler, ret, ...)				\
+do {									\
+	lunatik_lock(runtime);						\
+	if (unlikely(!runtime->L))					\
+		ret = -ENXIO;						\
+	else								\
+		lunatik_handle(runtime, handler, ret, ## __VA_ARGS__);	\
+	lunatik_unlock(runtime);					\
 } while(0)
 
 typedef struct lunatik_reg_s {