From 1d42cee941c13ac3a0e85ce6cc139824060d7e3c Mon Sep 17 00:00:00 2001
From: tonyyuyiding <tonyyuyiding@gmail.com>
Date: Mon, 21 Sep 2026 15:27:32 +0800
Subject: [PATCH 1/2] gh-157875: Fix reference leak when a JIT trace is rewound

---
 Lib/test/test_capi/test_opt.py                | 20 +++++++++++++++++++
 ...-09-21-15-11-11.gh-issue-157875.KLAOhf.rst |  1 +
 Python/optimizer.c                            |  3 +++
 3 files changed, 24 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Core_and_Builtins/2026-09-21-15-11-11.gh-issue-157875.KLAOhf.rst

diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
index 36efab518781410..db9fa994feb5d12 100644
--- a/Lib/test/test_capi/test_opt.py
+++ b/Lib/test/test_capi/test_opt.py
@@ -7,6 +7,7 @@
 import gc
 import os
 import types
+import weakref
 
 import _opcode
 
@@ -624,6 +625,25 @@ def testfunc(n, m):
         self.assertIn("_FOR_ITER_TIER_TWO", uops)
         self.assertNotIn("_ITER_NEXT_INLINE", uops)
 
+    def test_trace_rewind_decref(self):
+        # gh-157875: trace rewind should not leak reference
+        def run():
+            class C:
+                def __iter__(self):
+                    return self
+                def __next__(self):
+                    raise StopIteration
+
+            obj = C()
+            for _ in range(TIER2_THRESHOLD):
+                for _ in obj:
+                    pass
+            return weakref.ref(C)
+
+        ref = run()
+        gc.collect()
+        self.assertIsNone(ref())
+
 
 @requires_specialization
 @unittest.skipIf(Py_GIL_DISABLED, "optimizer not yet supported in free-threaded builds")
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-09-21-15-11-11.gh-issue-157875.KLAOhf.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-09-21-15-11-11.gh-issue-157875.KLAOhf.rst
new file mode 100644
index 000000000000000..0918d53b5d369c4
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-09-21-15-11-11.gh-issue-157875.KLAOhf.rst
@@ -0,0 +1 @@
+Fix a reference leak when a JIT trace is rewound.
diff --git a/Python/optimizer.c b/Python/optimizer.c
index e05adb344c8d06d..4ae72304c162068 100644
--- a/Python/optimizer.c
+++ b/Python/optimizer.c
@@ -789,6 +789,9 @@ _PyJit_translate_single_bytecode_to_trace(
         {
             _PyUOpInstruction *curr = uop_buffer_last(trace);
             while (curr->opcode != _SET_IP && uop_buffer_length(trace) > 2) {
+                if (_PyUop_Flags[curr->opcode] & HAS_RECORDS_VALUE_FLAG) {
+                    Py_XDECREF((PyObject *)(uintptr_t)curr->operand0);
+                }
                 trace->next--;
                 curr = uop_buffer_last(trace);
             }

From 22598ed3fe4ba32228ba0aaa4a21d68c0f2990aa Mon Sep 17 00:00:00 2001
From: tonyyuyiding <tonyyuyiding@gmail.com>
Date: Mon, 21 Sep 2026 15:43:33 +0800
Subject: [PATCH 2/2] update test name

---
 Lib/test/test_capi/test_opt.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
index db9fa994feb5d12..c078944a96184d6 100644
--- a/Lib/test/test_capi/test_opt.py
+++ b/Lib/test/test_capi/test_opt.py
@@ -625,8 +625,7 @@ def testfunc(n, m):
         self.assertIn("_FOR_ITER_TIER_TWO", uops)
         self.assertNotIn("_ITER_NEXT_INLINE", uops)
 
-    def test_trace_rewind_decref(self):
-        # gh-157875: trace rewind should not leak reference
+    def test_157875_trace_rewind_ref_leak(self):
         def run():
             class C:
                 def __iter__(self):