From e9e4b6d302b5e7e4a04a3c7f78cb561a2c156a37 Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Mon, 7 Apr 2025 09:22:07 +0200
Subject: [PATCH] Initialize unused value when specializing to cdata metatable.

Reported by jakitliang. #1354
---
 src/lj_record.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/lj_record.c b/src/lj_record.c
index 20a7ea36..d336f642 100644
--- a/src/lj_record.c
+++ b/src/lj_record.c
@@ -854,7 +854,10 @@ int lj_record_mm_lookup(jit_State *J, RecordIndex *ix, MMS mm)
       return 0;  /* No metamethod. */
     }
     /* The cdata metatable is treated as immutable. */
-    if (LJ_HASFFI && tref_iscdata(ix->tab)) goto immutable_mt;
+    if (LJ_HASFFI && tref_iscdata(ix->tab)) {
+      mix.tab = TREF_NIL;
+      goto immutable_mt;
+    }
     ix->mt = mix.tab = lj_ir_ktab(J, mt);
     goto nocheck;
   }