From: Brandt Bucher <brandtbucher@microsoft.com>
Date: Mon, 18 Jul 2022 16:00:41 +0000 (-0700)
Subject: GH-94893: Ignore caches when adding LOAD_FAST_CHECKs (GH-94894)
X-Git-Tag: v3.12.0a1~929
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b407312a24f12de76a928394099decd64f6049a6;p=thirdparty%2FPython%2Fcpython.git

GH-94893: Ignore caches when adding LOAD_FAST_CHECKs (GH-94894)
---

diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-07-15-22-47-44.gh-issue-94893.YiJYcW.rst b/Misc/NEWS.d/next/Core and Builtins/2022-07-15-22-47-44.gh-issue-94893.YiJYcW.rst
new file mode 100644
index 000000000000..6384ef92c654
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-07-15-22-47-44.gh-issue-94893.YiJYcW.rst	
@@ -0,0 +1,2 @@
+Fix an issue where frame object manipulations could corrupt inline bytecode
+caches.
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
index 3e97b75d4bf5..fe8eaa341fb3 100644
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -603,7 +603,8 @@ add_load_fast_null_checks(PyCodeObject *co)
     int changed = 0;
     _Py_CODEUNIT *instructions = _PyCode_CODE(co);
     for (Py_ssize_t i = 0; i < Py_SIZE(co); i++) {
-        switch (_Py_OPCODE(instructions[i])) {
+        int opcode = _Py_OPCODE(instructions[i]);
+        switch (opcode) {
             case LOAD_FAST:
             case LOAD_FAST__LOAD_FAST:
             case LOAD_FAST__LOAD_CONST:
@@ -619,6 +620,7 @@ add_load_fast_null_checks(PyCodeObject *co)
                 _Py_SET_OPCODE(instructions[i], STORE_FAST);
                 break;
         }
+        i += _PyOpcode_Caches[_PyOpcode_Deopt[opcode]];
     }
     if (changed) {
         // invalidate cached co_code object