From 1e64c1391f9a14115b5cc82066dbf545ae73ee27 Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Tue, 25 Oct 2022 16:44:06 -0300
Subject: [PATCH] Bug: stack overflow with nesting of coroutine.close

---
 lcorolib.c        |  4 ++--
 lstate.c          |  3 ++-
 ltests.c          |  2 +-
 lua.h             |  2 +-
 manual/manual.of  |  7 ++++++-
 testes/cstack.lua | 26 ++++++++++++++++++++++++++
 6 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/lcorolib.c b/lcorolib.c
index 785a1e81a..40b880b14 100644
--- a/src/lcorolib.c
+++ b/src/lcorolib.c
@@ -76,7 +76,7 @@ static int luaB_auxwrap (lua_State *L) {
   if (l_unlikely(r < 0)) {  /* error? */
     int stat = lua_status(co);
     if (stat != LUA_OK && stat != LUA_YIELD) {  /* error in the coroutine? */
-      stat = lua_resetthread(co);  /* close its tbc variables */
+      stat = lua_resetthread(co, L);  /* close its tbc variables */
       lua_assert(stat != LUA_OK);
       lua_xmove(co, L, 1);  /* move error message to the caller */
     }
@@ -172,7 +172,7 @@ static int luaB_close (lua_State *L) {
   int status = auxstatus(L, co);
   switch (status) {
     case COS_DEAD: case COS_YIELD: {
-      status = lua_resetthread(co);
+      status = lua_resetthread(co, L);
       if (status == LUA_OK) {
         lua_pushboolean(L, 1);
         return 1;
diff --git a/lstate.c b/lstate.c
index 1ffe1a0f7..4b5c10008 100644
--- a/src/lstate.c
+++ b/src/lstate.c
@@ -343,9 +343,10 @@ int luaE_resetthread (lua_State *L, int status) {
 }
 
 
-LUA_API int lua_resetthread (lua_State *L) {
+LUA_API int lua_resetthread (lua_State *L, lua_State *from) {
   int status;
   lua_lock(L);
+  L->nCcalls = (from) ? getCcalls(from) : 0;
   status = luaE_resetthread(L, L->status);
   lua_unlock(L);
   return status;
diff --git a/lua.h b/lua.h
index 219784cc0..bfba4d1e1 100644
--- a/src/lua.h
+++ b/src/lua.h
@@ -153,7 +153,7 @@ extern const char lua_ident[];
 LUA_API lua_State *(lua_newstate) (lua_Alloc f, void *ud);
 LUA_API void       (lua_close) (lua_State *L);
 LUA_API lua_State *(lua_newthread) (lua_State *L);
-LUA_API int        (lua_resetthread) (lua_State *L);
+LUA_API int        (lua_resetthread) (lua_State *L, lua_State *from);
 
 LUA_API lua_CFunction (lua_atpanic) (lua_State *L, lua_CFunction panicf);
 
diff --git a/testes/cstack.lua b/testes/cstack.lua
index ca76c8729..97afe9fd0 100644
--- a/testes/cstack.lua
+++ b/testes/cstack.lua
@@ -84,6 +84,32 @@ do   -- bug in 5.4.0
 end
 
 
+do    -- bug since 5.4.0
+  local count = 0
+  print("chain of 'coroutine.close'")
+  -- create N coroutines forming a list so that each one, when closed,
+  -- closes the previous one. (With a large enough N, previous Lua
+  -- versions crash in this test.)
+  local coro = false
+  for i = 1, 1000 do
+    local previous = coro
+    coro = coroutine.create(function()
+      local cc <close> = setmetatable({}, {__close=function()
+        count = count + 1
+        if previous then
+          assert(coroutine.close(previous))
+        end
+      end})
+      coroutine.yield()   -- leaves 'cc' pending to be closed
+    end)
+    assert(coroutine.resume(coro))  -- start it and run until it yields
+  end
+  local st, msg = coroutine.close(coro)
+  assert(not st and string.find(msg, "C stack overflow"))
+  print("final count: ", count)
+end
+
+
 do
   print("nesting of resuming yielded coroutines")
   local count = 0