Re: [BUG] call hook again when lua yield in count hook

["G.k Ray" <gzlkylin@...>]

Not related to program count, the reason is that the CIST_HOOKYIELD status was not handled when calling the call hook. 

A potential solution is to ensure that the luaD_hookcall is not executed during VM yielding, thereby preventing it from being invoked repeatedly.

Fix:

diff --git a/lvm.c b/lvm.c
index 2b437bdf..fd52127c 100644
--- a/lvm.c
+++ b/lvm.c
@@ -1165,7 +1165,8 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
       if (cl->p->is_vararg)
         trap = 0;  /* hooks will start after VARARGPREP instruction */
       else  /* check 'call' hook */
-        luaD_hookcall(L, ci);
+        if (!(ci->callstatus & CIST_HOOKYIELD))
+          luaD_hookcall(L, ci);
     }
     ci->u.l.trap = 1;  /* assume trap is on, for now */
   }

Roberto Ierusalimschy <roberto@inf.puc-rio.br>于2023年7月22日 周六02:23写道：

> A correction

Thanks for the feedback.

The bug seems to be caused by the iteraction between both hooks. It
seems to go like that:

- The function starts: As the function is in its first instruction,
it calls the Call hook.

- Then, it checks the Count hook. As its counter goes to zero,
it calls the Count hook *and* does not move the program counter,
because it does not execute the current instruction yet.

- When the thread resumes, it is (yet) in the first instruction of
the current function, so it calls the Call hook again.

-- Roberto