From 05f1984e1a862e4b3d3c3b370c773492e2edf84a Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Fri, 8 Oct 2021 16:50:35 +0200
Subject: [PATCH] Fix interaction of profiler and ITERN recording.

Reported and analyzed by vfprintf. #754
---
 src/lj_record.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/lj_record.c b/src/lj_record.c
index 4fe1a056..30722814 100644
--- a/src/lj_record.c
+++ b/src/lj_record.c
@@ -663,7 +663,9 @@ static LoopEvent rec_itern(jit_State *J, BCReg ra, BCReg rb)
 #else
   RecordIndex ix;
   /* Since ITERN is recorded at the start, we need our own loop detection. */
-  if (J->pc == J->startpc && J->cur.nins > REF_FIRST &&
+  if (J->pc == J->startpc &&
+      (J->cur.nins > REF_FIRST+1 ||
+       (J->cur.nins == REF_FIRST+1 && J->cur.ir[REF_FIRST].o != IR_PROF)) &&
       J->framedepth + J->retdepth == 0 && J->parent == 0 && J->exitno == 0) {
     lj_record_stop(J, LJ_TRLINK_LOOP, J->cur.traceno);  /* Looping trace. */
     return LOOPEV_ENTER;