Corrected bug in 'luaD_tryfuncTM'

The pointer to the metamethod can be invalidated by a finalizer that
can run during a GC in 'checkstackGCp'. (This commit also fixes a
detail in the manual.) Bug introduced in commit 91673a8ec.

1 files changed, 2 insertions, 1 deletions

diff --git a/ldo.c b/ldo.c
index 66f89036..f282a773 100644
--- a/ldo.c
+++ b/ldo.c
@@ -388,9 +388,10 @@ static void rethook (lua_State *L, CallInfo *ci, int nres) {
 ** an error if there is no '__call' metafield.
 */
 StkId luaD_tryfuncTM (lua_State *L, StkId func) {
-  const TValue *tm = luaT_gettmbyobj(L, s2v(func), TM_CALL);
+  const TValue *tm;
   StkId p;
   checkstackGCp(L, 1, func);  /* space for metamethod */
+  tm = luaT_gettmbyobj(L, s2v(func), TM_CALL);  /* (after previous GC) */
   if (l_unlikely(ttisnil(tm)))
     luaG_callerror(L, s2v(func));  /* nothing to call */
   for (p = L->top; p > func; p--)  /* open space for metamethod */