FFI: Fix dangling reference to CType in carith_checkarg().

Reported by Sergey Kaplun. #1108

1 files changed, 4 insertions, 0 deletions

diff --git a/src/lj_carith.c b/src/lj_carith.c
index 96384e87..bad5fe66 100644
--- a/src/lj_carith.c
+++ b/src/lj_carith.c
@@ -42,9 +42,13 @@ static int carith_checkarg(lua_State *L, CTState *cts, CDArith *ca)
         p = (uint8_t *)cdata_getptr(p, ct->size);
         if (ctype_isref(ct->info)) ct = ctype_rawchild(cts, ct);
       } else if (ctype_isfunc(ct->info)) {
+        CTypeID id0 = i ? ctype_typeid(cts, ca->ct[0]) : 0;
         p = (uint8_t *)*(void **)p;
         ct = ctype_get(cts,
           lj_ctype_intern(cts, CTINFO(CT_PTR, CTALIGN_PTR|id), CTSIZE_PTR));
+        if (i) {  /* cts->tab may have been reallocated. */
+          ca->ct[0] = ctype_get(cts, id0);
+        }
       }
       if (ctype_isenum(ct->info)) ct = ctype_child(cts, ct);
       ca->ct[i] = ct;